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xen-ia64-devel

[Xen-ia64-devel] [PATCH 1/4] ia64/xen: paravirtualize ivt.S fault handle

Signed-off-by: Isaku Yamahata <yamahata@xxxxxxxxxxxxx>
---
 arch/ia64/xen/xenivt.S | 2204 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 2204 insertions(+), 0 deletions(-)
 create mode 100644 arch/ia64/xen/xenivt.S

diff --git a/arch/ia64/xen/xenivt.S b/arch/ia64/xen/xenivt.S
new file mode 100644
index 0000000..f2eaa1f
--- /dev/null
+++ b/arch/ia64/xen/xenivt.S
@@ -0,0 +1,2204 @@
+/*
+ * arch/ia64/xen/ivt.S
+ *
+ * Copyright (C) 2005 Hewlett-Packard Co
+ *     Dan Magenheimer <dan.magenheimer@xxxxxx>
+ */
+/*
+ * This file defines the interruption vector table used by the CPU.
+ * It does not include one entry per possible cause of interruption.
+ *
+ * The first 20 entries of the table contain 64 bundles each while the
+ * remaining 48 entries contain only 16 bundles each.
+ *
+ * The 64 bundles are used to allow inlining the whole handler for critical
+ * interruptions like TLB misses.
+ *
+ *  For each entry, the comment is as follows:
+ *
+ *             // 0x1c00 Entry 7 (size 64 bundles) Data Key Miss (12,51)
+ *  entry offset ----/     /         /                  /          /
+ *  entry number ---------/         /                  /          /
+ *  size of the entry -------------/                  /          /
+ *  vector name -------------------------------------/          /
+ *  interruptions triggering this vector ----------------------/
+ *
+ * The table is 32KB in size and must be aligned on 32KB boundary.
+ * (The CPU ignores the 15 lower bits of the address)
+ *
+ * Table is based upon EAS2.6 (Oct 1999)
+ */
+
+
+#include <asm/asmmacro.h>
+#include <asm/break.h>
+#include <asm/ia32.h>
+#include <asm/kregs.h>
+#include <asm/asm-offsets.h>
+#include <asm/pgtable.h>
+#include <asm/processor.h>
+#include <asm/ptrace.h>
+#include <asm/system.h>
+#include <asm/thread_info.h>
+#include <asm/unistd.h>
+#include <asm/errno.h>
+
+#ifdef CONFIG_XEN
+#define ia64_ivt xen_ivt
+#endif
+
+#if 1
+# define PSR_DEFAULT_BITS      psr.ac
+#else
+# define PSR_DEFAULT_BITS      0
+#endif
+
+#if 0
+  /*
+   * This lets you track the last eight faults that occurred on the CPU.  Make 
sure ar.k2 isn't
+   * needed for something else before enabling this...
+   */
+# define DBG_FAULT(i)  mov r16=ar.k2;; shl r16=r16,8;; add r16=(i),r16;;mov 
ar.k2=r16
+#else
+# define DBG_FAULT(i)
+#endif
+
+#ifdef CONFIG_XEN
+#include "xenminstate.h"
+#else
+#include "minstate.h"
+#endif
+
+#define FAULT(n)                                                               
        \
+       mov r31=pr;                                                             
        \
+       mov r19=n;;                     /* prepare to save predicates */        
        \
+       br.sptk.many dispatch_to_fault_handler
+
+       .section .text.ivt,"ax"
+
+       .align 32768    // align on 32KB boundary
+       .global ia64_ivt
+ia64_ivt:
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x0000 Entry 0 (size 64 bundles) VHPT Translation (8,20,47)
+ENTRY(vhpt_miss)
+       DBG_FAULT(0)
+       /*
+        * The VHPT vector is invoked when the TLB entry for the virtual page 
table
+        * is missing.  This happens only as a result of a previous
+        * (the "original") TLB miss, which may either be caused by an 
instruction
+        * fetch or a data access (or non-access).
+        *
+        * What we do here is normal TLB miss handing for the _original_ miss,
+        * followed by inserting the TLB entry for the virtual page table page
+        * that the VHPT walker was attempting to access.  The latter gets
+        * inserted as long as page table entry above pte level have valid
+        * mappings for the faulting address.  The TLB entry for the original
+        * miss gets inserted only if the pte entry indicates that the page is
+        * present.
+        *
+        * do_page_fault gets invoked in the following cases:
+        *      - the faulting virtual address uses unimplemented address bits
+        *      - the faulting virtual address has no valid page table mapping
+        */
+#ifdef CONFIG_XEN
+       movl r16=XSI_IFA
+       ;;
+       ld8 r16=[r16]
+#ifdef CONFIG_HUGETLB_PAGE
+       movl r18=PAGE_SHIFT
+       movl r25=XSI_ITIR
+       ;;
+       ld8 r25=[r25]
+#endif
+#else
+       mov r16=cr.ifa                          // get address that caused the 
TLB miss
+#ifdef CONFIG_HUGETLB_PAGE
+       movl r18=PAGE_SHIFT
+       mov r25=cr.itir
+#endif
+#endif
+       ;;
+#ifdef CONFIG_XEN
+       XEN_HYPER_RSM_PSR_DT;
+#else
+       rsm psr.dt                              // use physical addressing for 
data
+#endif
+       mov r31=pr                              // save the predicate registers
+       mov r19=IA64_KR(PT_BASE)                // get page table base address
+       shl r21=r16,3                           // shift bit 60 into sign bit
+       shr.u r17=r16,61                        // get the region number into 
r17
+       ;;
+       shr.u r22=r21,3
+#ifdef CONFIG_HUGETLB_PAGE
+       extr.u r26=r25,2,6
+       ;;
+       cmp.ne p8,p0=r18,r26
+       sub r27=r26,r18
+       ;;
+(p8)   dep r25=r18,r25,2,6
+(p8)   shr r22=r22,r27
+#endif
+       ;;
+       cmp.eq p6,p7=5,r17                      // is IFA pointing into to 
region 5?
+       shr.u r18=r22,PGDIR_SHIFT               // get bottom portion of pgd 
index bit
+       ;;
+(p7)   dep r17=r17,r19,(PAGE_SHIFT-3),3        // put region number bits in 
place
+
+       srlz.d
+       LOAD_PHYSICAL(p6, r19, swapper_pg_dir)  // region 5 is rooted at 
swapper_pg_dir
+
+       .pred.rel "mutex", p6, p7
+(p6)   shr.u r21=r21,PGDIR_SHIFT+PAGE_SHIFT
+(p7)   shr.u r21=r21,PGDIR_SHIFT+PAGE_SHIFT-3
+       ;;
+(p6)   dep r17=r18,r19,3,(PAGE_SHIFT-3)        // r17=pgd_offset for region 5
+(p7)   dep r17=r18,r17,3,(PAGE_SHIFT-6)        // r17=pgd_offset for 
region[0-4]
+       cmp.eq p7,p6=0,r21                      // unused address bits all 
zeroes?
+#ifdef CONFIG_PGTABLE_4
+       shr.u r28=r22,PUD_SHIFT                 // shift pud index into position
+#else
+       shr.u r18=r22,PMD_SHIFT                 // shift pmd index into position
+#endif
+       ;;
+       ld8 r17=[r17]                           // get *pgd (may be 0)
+       ;;
+(p7)   cmp.eq p6,p7=r17,r0                     // was pgd_present(*pgd) == 
NULL?
+#ifdef CONFIG_PGTABLE_4
+       dep r28=r28,r17,3,(PAGE_SHIFT-3)        // r28=pud_offset(pgd,addr)
+       ;;
+       shr.u r18=r22,PMD_SHIFT                 // shift pmd index into position
+(p7)   ld8 r29=[r28]                           // get *pud (may be 0)
+       ;;
+(p7)   cmp.eq.or.andcm p6,p7=r29,r0            // was pud_present(*pud) == 
NULL?
+       dep r17=r18,r29,3,(PAGE_SHIFT-3)        // r17=pmd_offset(pud,addr)
+#else
+       dep r17=r18,r17,3,(PAGE_SHIFT-3)        // r17=pmd_offset(pgd,addr)
+#endif
+       ;;
+(p7)   ld8 r20=[r17]                           // get *pmd (may be 0)
+       shr.u r19=r22,PAGE_SHIFT                // shift pte index into position
+       ;;
+(p7)   cmp.eq.or.andcm p6,p7=r20,r0            // was pmd_present(*pmd) == 
NULL?
+       dep r21=r19,r20,3,(PAGE_SHIFT-3)        // r21=pte_offset(pmd,addr)
+       ;;
+(p7)   ld8 r18=[r21]                           // read *pte
+#ifdef CONFIG_XEN
+       movl r19=XSI_ISR
+       ;;
+       ld8 r19=[r19]
+#else
+       mov r19=cr.isr                          // cr.isr bit 32 tells us if 
this is an insn miss
+#endif
+       ;;
+(p7)   tbit.z p6,p7=r18,_PAGE_P_BIT            // page present bit cleared?
+#ifdef CONFIG_XEN
+       movl r22=XSI_IHA
+       ;;
+       ld8 r22=[r22]
+#else
+       mov r22=cr.iha                          // get the VHPT address that 
caused the TLB miss
+#endif
+       ;;                                      // avoid RAW on p7
+(p7)   tbit.nz.unc p10,p11=r19,32              // is it an instruction TLB 
miss?
+       dep r23=0,r20,0,PAGE_SHIFT              // clear low bits to get page 
address
+       ;;
+#ifdef CONFIG_XEN
+       mov r24=r8
+       mov r8=r18
+       ;;
+(p10)  XEN_HYPER_ITC_I
+       ;;
+(p11)  XEN_HYPER_ITC_D
+       ;;
+       mov r8=r24
+       ;;
+#else
+(p10)  itc.i r18                               // insert the instruction TLB 
entry
+(p11)  itc.d r18                               // insert the data TLB entry
+#endif
+(p6)   br.cond.spnt.many page_fault            // handle bad address/page not 
present (page fault)
+#ifdef CONFIG_XEN
+       movl r24=XSI_IFA
+       ;;
+       st8 [r24]=r22
+       ;;
+#ifdef CONFIG_HUGETLB_PAGE
+(p8)   movl r24=XSI_ITIR
+       ;;
+(p8)   st8 [r24]=r25
+#endif
+#else
+       mov cr.ifa=r22
+
+#ifdef CONFIG_HUGETLB_PAGE
+(p8)   mov cr.itir=r25                         // change to default page-size 
for VHPT
+#endif
+#endif
+
+       /*
+        * Now compute and insert the TLB entry for the virtual page table.  We 
never
+        * execute in a page table page so there is no need to set the 
exception deferral
+        * bit.
+        */
+       adds r24=__DIRTY_BITS_NO_ED|_PAGE_PL_0|_PAGE_AR_RW,r23
+       ;;
+#ifdef CONFIG_XEN
+(p7)   mov r25=r8
+(p7)   mov r8=r24
+       ;;
+(p7)   XEN_HYPER_ITC_D
+       ;;
+(p7)   mov r8=r25
+       ;;
+#else
+(p7)   itc.d r24
+#endif
+       ;;
+#ifdef CONFIG_SMP
+       /*
+        * Tell the assemblers dependency-violation checker that the above 
"itc" instructions
+        * cannot possibly affect the following loads:
+        */
+       dv_serialize_data
+
+       /*
+        * Re-check pagetable entry.  If they changed, we may have received a 
ptc.g
+        * between reading the pagetable and the "itc".  If so, flush the entry 
we
+        * inserted and retry.  At this point, we have:
+        *
+        * r28 = equivalent of pud_offset(pgd, ifa)
+        * r17 = equivalent of pmd_offset(pud, ifa)
+        * r21 = equivalent of pte_offset(pmd, ifa)
+        *
+        * r29 = *pud
+        * r20 = *pmd
+        * r18 = *pte
+        */
+       ld8 r25=[r21]                           // read *pte again
+       ld8 r26=[r17]                           // read *pmd again
+#ifdef CONFIG_PGTABLE_4
+       ld8 r19=[r28]                           // read *pud again
+#endif
+       cmp.ne p6,p7=r0,r0
+       ;;
+       cmp.ne.or.andcm p6,p7=r26,r20           // did *pmd change
+#ifdef CONFIG_PGTABLE_4
+       cmp.ne.or.andcm p6,p7=r19,r29           // did *pud change
+#endif
+       mov r27=PAGE_SHIFT<<2
+       ;;
+(p6)   ptc.l r22,r27                           // purge PTE page translation
+(p7)   cmp.ne.or.andcm p6,p7=r25,r18           // did *pte change
+       ;;
+(p6)   ptc.l r16,r27                           // purge translation
+#endif
+
+       mov pr=r31,-1                           // restore predicate registers
+#ifdef CONFIG_XEN
+       XEN_HYPER_RFI
+       dv_serialize_data
+#else
+       rfi
+#endif
+END(vhpt_miss)
+
+       .org ia64_ivt+0x400
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x0400 Entry 1 (size 64 bundles) ITLB (21)
+ENTRY(itlb_miss)
+       DBG_FAULT(1)
+       /*
+        * The ITLB handler accesses the PTE via the virtually mapped linear
+        * page table.  If a nested TLB miss occurs, we switch into physical
+        * mode, walk the page table, and then re-execute the PTE read and
+        * go on normally after that.
+        */
+#ifdef CONFIG_XEN
+       movl r16=XSI_IFA
+       ;;
+       ld8 r16=[r16]
+#else
+       mov r16=cr.ifa                          // get virtual address
+#endif
+       mov r29=b0                              // save b0
+       mov r31=pr                              // save predicates
+.itlb_fault:
+#ifdef CONFIG_XEN
+       movl r17=XSI_IHA
+       ;;
+       ld8 r17=[r17]                           // get virtual address of L3 PTE
+#else
+       mov r17=cr.iha                          // get virtual address of PTE
+#endif
+       movl r30=1f                             // load nested fault 
continuation point
+       ;;
+1:     ld8 r18=[r17]                           // read *pte
+       ;;
+       mov b0=r29
+       tbit.z p6,p0=r18,_PAGE_P_BIT            // page present bit cleared?
+(p6)   br.cond.spnt page_fault
+       ;;
+#ifdef CONFIG_XEN
+       mov r19=r8
+       mov r8=r18
+       ;;
+       XEN_HYPER_ITC_I
+       ;;
+       mov r8=r19
+#else
+       itc.i r18
+#endif
+       ;;
+#ifdef CONFIG_SMP
+       /*
+        * Tell the assemblers dependency-violation checker that the above 
"itc" instructions
+        * cannot possibly affect the following loads:
+        */
+       dv_serialize_data
+
+       ld8 r19=[r17]                           // read *pte again and see if 
same
+       mov r20=PAGE_SHIFT<<2                   // setup page size for purge
+       ;;
+       cmp.ne p7,p0=r18,r19
+       ;;
+(p7)   ptc.l r16,r20
+#endif
+       mov pr=r31,-1
+#ifdef CONFIG_XEN
+       XEN_HYPER_RFI
+       dv_serialize_data
+#else
+       rfi
+#endif
+END(itlb_miss)
+
+       .org ia64_ivt+0x0800
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x0800 Entry 2 (size 64 bundles) DTLB (9,48)
+ENTRY(dtlb_miss)
+       DBG_FAULT(2)
+       /*
+        * The DTLB handler accesses the PTE via the virtually mapped linear
+        * page table.  If a nested TLB miss occurs, we switch into physical
+        * mode, walk the page table, and then re-execute the PTE read and
+        * go on normally after that.
+        */
+#ifdef CONFIG_XEN
+       movl r16=XSI_IFA
+       ;;
+       ld8 r16=[r16]
+#else
+       mov r16=cr.ifa                          // get virtual address
+#endif
+       mov r29=b0                              // save b0
+       mov r31=pr                              // save predicates
+dtlb_fault:
+#ifdef CONFIG_XEN
+       movl r17=XSI_IHA
+       ;;
+       ld8 r17=[r17]                           // get virtual address of L3 PTE
+#else
+       mov r17=cr.iha                          // get virtual address of PTE
+#endif
+       movl r30=1f                             // load nested fault 
continuation point
+       ;;
+1:     ld8 r18=[r17]                           // read *pte
+       ;;
+       mov b0=r29
+       tbit.z p6,p0=r18,_PAGE_P_BIT            // page present bit cleared?
+(p6)   br.cond.spnt page_fault
+       ;;
+#ifdef CONFIG_XEN
+       mov r19=r8
+       mov r8=r18
+       ;;
+       XEN_HYPER_ITC_D
+       ;;
+       mov r8=r19
+       ;;
+#else
+       itc.d r18
+#endif
+       ;;
+#ifdef CONFIG_SMP
+       /*
+        * Tell the assemblers dependency-violation checker that the above 
"itc" instructions
+        * cannot possibly affect the following loads:
+        */
+       dv_serialize_data
+
+       ld8 r19=[r17]                           // read *pte again and see if 
same
+       mov r20=PAGE_SHIFT<<2                   // setup page size for purge
+       ;;
+       cmp.ne p7,p0=r18,r19
+       ;;
+(p7)   ptc.l r16,r20
+#endif
+       mov pr=r31,-1
+#ifdef CONFIG_XEN
+       XEN_HYPER_RFI
+       dv_serialize_data
+#else
+       rfi
+#endif
+END(dtlb_miss)
+
+       .org ia64_ivt+0x0c00
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x0c00 Entry 3 (size 64 bundles) Alt ITLB (19)
+ENTRY(alt_itlb_miss)
+       DBG_FAULT(3)
+#ifdef CONFIG_XEN
+       movl r31=XSI_IPSR
+       ;;
+       ld8 r21=[r31],XSI_IFA_OFS-XSI_IPSR_OFS  // get ipsr, point to ifa
+       movl r17=PAGE_KERNEL
+       ;;
+       ld8 r16=[r31]           // get ifa
+#else
+       mov r16=cr.ifa          // get address that caused the TLB miss
+       movl r17=PAGE_KERNEL
+       mov r21=cr.ipsr
+#endif
+       movl r19=(((1 << IA64_MAX_PHYS_BITS) - 1) & ~0xfff)
+       mov r31=pr
+       ;;
+#ifdef CONFIG_DISABLE_VHPT
+       shr.u r22=r16,61                        // get the region number into 
r21
+       ;;
+       cmp.gt p8,p0=6,r22                      // user mode
+       ;;
+#ifdef CONFIG_XEN
+       //XXX notyet
+#else
+(p8)   thash r17=r16
+       ;;
+(p8)   mov cr.iha=r17
+#endif
+(p8)   mov r29=b0                              // save b0
+(p8)   br.cond.dptk .itlb_fault
+#endif
+       extr.u r23=r21,IA64_PSR_CPL0_BIT,2      // extract psr.cpl
+       and r19=r19,r16         // clear ed, reserved bits, and PTE control bits
+       shr.u r18=r16,57        // move address bit 61 to bit 4
+       ;;
+       andcm r18=0x10,r18      // bit 4=~address-bit(61)
+       cmp.ne p8,p0=r0,r23     // psr.cpl != 0?
+       or r19=r17,r19          // insert PTE control bits into r19
+       ;;
+       or r19=r19,r18          // set bit 4 (uncached) if the access was to 
region 6
+(p8)   br.cond.spnt page_fault
+       ;;
+#ifdef CONFIG_XEN
+       mov r18=r8
+       mov r8=r19
+       ;;
+       XEN_HYPER_ITC_I
+       ;;
+       mov r8=r18
+       ;;
+       mov pr=r31,-1
+       ;;
+       XEN_HYPER_RFI;
+#else
+       itc.i r19               // insert the TLB entry
+       mov pr=r31,-1
+       rfi
+#endif
+END(alt_itlb_miss)
+
+       .org ia64_ivt+0x1000
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x1000 Entry 4 (size 64 bundles) Alt DTLB (7,46)
+ENTRY(alt_dtlb_miss)
+       DBG_FAULT(4)
+#ifdef CONFIG_XEN
+       movl r31=XSI_IPSR
+       ;;
+       ld8 r21=[r31],XSI_ISR_OFS-XSI_IPSR_OFS  // get ipsr, point to isr
+       movl r17=PAGE_KERNEL
+       ;;
+       ld8 r20=[r31],XSI_IFA_OFS-XSI_ISR_OFS   // get isr, point to ifa
+       movl r19=(((1 << IA64_MAX_PHYS_BITS) - 1) & ~0xfff)
+       ;;
+       ld8 r16=[r31]           // get ifa
+#else
+       mov r16=cr.ifa          // get address that caused the TLB miss
+       movl r17=PAGE_KERNEL
+       mov r20=cr.isr
+       movl r19=(((1 << IA64_MAX_PHYS_BITS) - 1) & ~0xfff)
+       mov r21=cr.ipsr
+#endif
+       mov r31=pr
+       mov r24=PERCPU_ADDR
+       ;;
+#ifdef CONFIG_DISABLE_VHPT
+       shr.u r22=r16,61                        // get the region number into 
r21
+       ;;
+       cmp.gt p8,p0=6,r22                      // access to region 0-5
+       ;;
+#ifdef CONFIG_XEN
+       //XXX notyet
+#else
+(p8)   thash r17=r16
+       ;;
+(p8)   mov cr.iha=r17
+#endif
+(p8)   mov r29=b0                              // save b0
+(p8)   br.cond.dptk dtlb_fault
+#endif
+       cmp.ge p10,p11=r16,r24                  // access to per_cpu_data?
+       tbit.z p12,p0=r16,61                    // access to region 6?
+       mov r25=PERCPU_PAGE_SHIFT << 2
+       mov r26=PERCPU_PAGE_SIZE
+       nop.m 0
+       nop.b 0
+       ;;
+(p10)  mov r19=IA64_KR(PER_CPU_DATA)
+(p11)  and r19=r19,r16                         // clear non-ppn fields
+       extr.u r23=r21,IA64_PSR_CPL0_BIT,2      // extract psr.cpl
+       and r22=IA64_ISR_CODE_MASK,r20          // get the isr.code field
+       tbit.nz p6,p7=r20,IA64_ISR_SP_BIT       // is speculation bit on?
+       tbit.nz p9,p0=r20,IA64_ISR_NA_BIT       // is non-access bit on?
+       ;;
+(p10)  sub r19=r19,r26
+#ifdef CONFIG_XEN
+(p10)  movl r24=XSI_ITIR
+       ;;
+(p10)  st8 [r24]=r25
+#else
+(p10)  mov cr.itir=r25
+#endif
+       cmp.ne p8,p0=r0,r23
+(p9)   cmp.eq.or.andcm p6,p7=IA64_ISR_CODE_LFETCH,r22  // check isr.code field
+(p12)  dep r17=-1,r17,4,1                      // set ma=UC for region 6 addr
+(p8)   br.cond.spnt page_fault
+
+       dep r21=-1,r21,IA64_PSR_ED_BIT,1
+       ;;
+       or r19=r19,r17          // insert PTE control bits into r19
+(p6)   mov cr.ipsr=r21
+       ;;
+#ifdef CONFIG_XEN
+(p7)   mov r18=r8
+(p7)   mov r8=r19
+       ;;
+(p7)   XEN_HYPER_ITC_D
+       ;;
+(p7)   mov r8=r18
+       ;;
+       mov pr=r31,-1
+       ;;
+       XEN_HYPER_RFI;
+#else
+(p7)   itc.d r19               // insert the TLB entry
+       mov pr=r31,-1
+       rfi
+#endif
+END(alt_dtlb_miss)
+
+       .org ia64_ivt+0x1400
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x1400 Entry 5 (size 64 bundles) Data nested TLB (6,45)
+ENTRY(nested_dtlb_miss)
+       /*
+        * In the absence of kernel bugs, we get here when the virtually mapped 
linear
+        * page table is accessed non-speculatively (e.g., in the Dirty-bit, 
Instruction
+        * Access-bit, or Data Access-bit faults).  If the DTLB entry for the 
virtual page
+        * table is missing, a nested TLB miss fault is triggered and control is
+        * transferred to this point.  When this happens, we lookup the pte for 
the
+        * faulting address by walking the page table in physical mode and 
return to the
+        * continuation point passed in register r30 (or call page_fault if the 
address is
+        * not mapped).
+        *
+        * Input:       r16:    faulting address
+        *              r29:    saved b0
+        *              r30:    continuation address
+        *              r31:    saved pr
+        *
+        * Output:      r17:    physical address of PTE of faulting address
+        *              r29:    saved b0
+        *              r30:    continuation address
+        *              r31:    saved pr
+        *
+        * Clobbered:   b0, r18, r19, r21, r22, psr.dt (cleared)
+        */
+#ifdef CONFIG_XEN
+       XEN_HYPER_RSM_PSR_DT;
+#else
+       rsm psr.dt                              // switch to using physical 
data addressing
+#endif
+       mov r19=IA64_KR(PT_BASE)                // get the page table base 
address
+       shl r21=r16,3                           // shift bit 60 into sign bit
+#ifdef CONFIG_XEN
+       movl r18=XSI_ITIR
+       ;;
+       ld8 r18=[r18]
+#else
+       mov r18=cr.itir
+#endif
+       ;;
+       shr.u r17=r16,61                        // get the region number into 
r17
+       extr.u r18=r18,2,6                      // get the faulting page size
+       ;;
+       cmp.eq p6,p7=5,r17                      // is faulting address in 
region 5?
+       add r22=-PAGE_SHIFT,r18                 // adjustment for hugetlb 
address
+       add r18=PGDIR_SHIFT-PAGE_SHIFT,r18
+       ;;
+       shr.u r22=r16,r22
+       shr.u r18=r16,r18
+(p7)   dep r17=r17,r19,(PAGE_SHIFT-3),3        // put region number bits in 
place
+
+       srlz.d
+       LOAD_PHYSICAL(p6, r19, swapper_pg_dir)  // region 5 is rooted at 
swapper_pg_dir
+
+       .pred.rel "mutex", p6, p7
+(p6)   shr.u r21=r21,PGDIR_SHIFT+PAGE_SHIFT
+(p7)   shr.u r21=r21,PGDIR_SHIFT+PAGE_SHIFT-3
+       ;;
+(p6)   dep r17=r18,r19,3,(PAGE_SHIFT-3)        // r17=pgd_offset for region 5
+(p7)   dep r17=r18,r17,3,(PAGE_SHIFT-6)        // r17=pgd_offset for 
region[0-4]
+       cmp.eq p7,p6=0,r21                      // unused address bits all 
zeroes?
+#ifdef CONFIG_PGTABLE_4
+       shr.u r18=r22,PUD_SHIFT                 // shift pud index into position
+#else
+       shr.u r18=r22,PMD_SHIFT                 // shift pmd index into position
+#endif
+       ;;
+       ld8 r17=[r17]                           // get *pgd (may be 0)
+       ;;
+(p7)   cmp.eq p6,p7=r17,r0                     // was pgd_present(*pgd) == 
NULL?
+       dep r17=r18,r17,3,(PAGE_SHIFT-3)        // r17=p[u|m]d_offset(pgd,addr)
+       ;;
+#ifdef CONFIG_PGTABLE_4
+(p7)   ld8 r17=[r17]                           // get *pud (may be 0)
+       shr.u r18=r22,PMD_SHIFT                 // shift pmd index into position
+       ;;
+(p7)   cmp.eq.or.andcm p6,p7=r17,r0            // was pud_present(*pud) == 
NULL?
+       dep r17=r18,r17,3,(PAGE_SHIFT-3)        // r17=pmd_offset(pud,addr)
+       ;;
+#endif
+(p7)   ld8 r17=[r17]                           // get *pmd (may be 0)
+       shr.u r19=r22,PAGE_SHIFT                // shift pte index into position
+       ;;
+(p7)   cmp.eq.or.andcm p6,p7=r17,r0            // was pmd_present(*pmd) == 
NULL?
+       dep r17=r19,r17,3,(PAGE_SHIFT-3)        // r17=pte_offset(pmd,addr);
+(p6)   br.cond.spnt page_fault
+       mov b0=r30
+       br.sptk.many b0                         // return to continuation point
+END(nested_dtlb_miss)
+
+       .org ia64_ivt+0x1800
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x1800 Entry 6 (size 64 bundles) Instruction Key Miss (24)
+ENTRY(ikey_miss)
+       DBG_FAULT(6)
+       FAULT(6)
+END(ikey_miss)
+
+       
//-----------------------------------------------------------------------------------
+       // call do_page_fault (predicates are in r31, psr.dt may be off, r16 is 
faulting address)
+ENTRY(page_fault)
+#ifdef CONFIG_XEN
+       XEN_HYPER_SSM_PSR_DT
+#else
+       ssm psr.dt
+       ;;
+       srlz.i
+#endif
+       ;;
+       SAVE_MIN_WITH_COVER
+       alloc r15=ar.pfs,0,0,3,0
+#ifdef CONFIG_XEN
+       movl r3=XSI_ISR
+       ;;
+       ld8 out1=[r3],XSI_IFA_OFS-XSI_ISR_OFS   // get vcr.isr, point to ifa
+       ;;
+       ld8 out0=[r3]                           // get vcr.ifa
+       mov r14=1
+       ;;
+       add r3=XSI_PSR_IC_OFS-XSI_IFA_OFS, r3   // point to vpsr.ic
+       ;;
+       st4 [r3]=r14                            // vpsr.ic = 1
+       adds r3=8,r2                            // set up second base pointer
+       ;;
+#else
+       mov out0=cr.ifa
+       mov out1=cr.isr
+       adds r3=8,r2                            // set up second base pointer
+       ;;
+       ssm psr.ic | PSR_DEFAULT_BITS
+       ;;
+       srlz.i                                  // guarantee that interruption 
collectin is on
+       ;;
+#endif
+#ifdef CONFIG_XEN
+
+#define MASK_TO_PEND_OFS    (-1)
+
+(p15)  movl r14=XSI_PSR_I_ADDR
+       ;;
+(p15)  ld8 r14=[r14]
+       ;;
+(p15)  st1 [r14]=r0,MASK_TO_PEND_OFS           // if (p15) vpsr.i = 1
+       ;;              // if (p15) (vcpu->vcpu_info->evtchn_upcall_mask)=0
+(p15)  ld1 r14=[r14]   // if (vcpu->vcpu_info->evtchn_upcall_pending)
+       ;;
+(p15)  cmp.ne  p15,p0=r14,r0
+       ;;
+(p15)  XEN_HYPER_SSM_I
+#else
+(p15)  ssm psr.i                               // restore psr.i
+#endif
+       movl r14=ia64_leave_kernel
+       ;;
+       SAVE_REST
+       mov rp=r14
+       ;;
+       adds out2=16,r12                        // out2 = pointer to pt_regs
+       br.call.sptk.many b6=ia64_do_page_fault // ignore return address
+END(page_fault)
+
+       .org ia64_ivt+0x1c00
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x1c00 Entry 7 (size 64 bundles) Data Key Miss (12,51)
+ENTRY(dkey_miss)
+       DBG_FAULT(7)
+       FAULT(7)
+END(dkey_miss)
+
+       .org ia64_ivt+0x2000
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x2000 Entry 8 (size 64 bundles) Dirty-bit (54)
+ENTRY(dirty_bit)
+       DBG_FAULT(8)
+       /*
+        * What we do here is to simply turn on the dirty bit in the PTE.  We 
need to
+        * update both the page-table and the TLB entry.  To efficiently access 
the PTE,
+        * we address it through the virtual page table.  Most likely, the TLB 
entry for
+        * the relevant virtual page table page is still present in the TLB so 
we can
+        * normally do this without additional TLB misses.  In case the 
necessary virtual
+        * page table TLB entry isn't present, we take a nested TLB miss hit 
where we look
+        * up the physical address of the L3 PTE and then continue at label 1 
below.
+        */
+#ifdef CONFIG_XEN
+       movl r16=XSI_IFA
+       ;;
+       ld8 r16=[r16]
+       ;;
+#else
+       mov r16=cr.ifa                          // get the address that caused 
the fault
+#endif
+       movl r30=1f                             // load continuation point in 
case of nested fault
+       ;;
+#ifdef CONFIG_XEN
+       mov r18=r8;
+       mov r8=r16;
+       XEN_HYPER_THASH;;
+       mov r17=r8;
+       mov r8=r18;;
+#else
+       thash r17=r16                           // compute virtual address of 
L3 PTE
+#endif
+       mov r29=b0                              // save b0 in case of nested 
fault
+       mov r31=pr                              // save pr
+#ifdef CONFIG_SMP
+       mov r28=ar.ccv                          // save ar.ccv
+       ;;
+1:     ld8 r18=[r17]
+       ;;                                      // avoid RAW on r18
+       mov ar.ccv=r18                          // set compare value for cmpxchg
+       or r25=_PAGE_D|_PAGE_A,r18              // set the dirty and accessed 
bits
+       tbit.z p7,p6 = r18,_PAGE_P_BIT          // Check present bit
+       ;;
+(p6)   cmpxchg8.acq r26=[r17],r25,ar.ccv       // Only update if page is 
present
+       mov r24=PAGE_SHIFT<<2
+       ;;
+(p6)   cmp.eq p6,p7=r26,r18                    // Only compare if page is 
present
+       ;;
+#ifdef CONFIG_XEN
+(p6)   mov r18=r8
+(p6)   mov r8=r25
+       ;;
+(p6)   XEN_HYPER_ITC_D
+       ;;
+(p6)   mov r8=r18
+#else
+(p6)   itc.d r25                               // install updated PTE
+#endif
+       ;;
+       /*
+        * Tell the assemblers dependency-violation checker that the above 
"itc" instructions
+        * cannot possibly affect the following loads:
+        */
+       dv_serialize_data
+
+       ld8 r18=[r17]                           // read PTE again
+       ;;
+       cmp.eq p6,p7=r18,r25                    // is it same as the newly 
installed
+       ;;
+(p7)   ptc.l r16,r24
+       mov b0=r29                              // restore b0
+       mov ar.ccv=r28
+#else
+       ;;
+1:     ld8 r18=[r17]
+       ;;                                      // avoid RAW on r18
+       or r18=_PAGE_D|_PAGE_A,r18              // set the dirty and accessed 
bits
+       mov b0=r29                              // restore b0
+       ;;
+       st8 [r17]=r18                           // store back updated PTE
+       itc.d r18                               // install updated PTE
+#endif
+       mov pr=r31,-1                           // restore pr
+#ifdef CONFIG_XEN
+       XEN_HYPER_RFI
+       dv_serialize_data
+#else
+       rfi
+#endif
+END(dirty_bit)
+
+       .org ia64_ivt+0x2400
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x2400 Entry 9 (size 64 bundles) Instruction Access-bit (27)
+ENTRY(iaccess_bit)
+       DBG_FAULT(9)
+       // Like Entry 8, except for instruction access
+#ifdef CONFIG_XEN
+       movl r16=XSI_IFA
+       ;;
+       ld8 r16=[r16]
+       ;;
+#else
+       mov r16=cr.ifa                          // get the address that caused 
the fault
+#endif
+       movl r30=1f                             // load continuation point in 
case of nested fault
+       mov r31=pr                              // save predicates
+#ifdef CONFIG_ITANIUM
+       /*
+        * Erratum 10 (IFA may contain incorrect address) has "NoFix" status.
+        */
+       mov r17=cr.ipsr
+       ;;
+       mov r18=cr.iip
+       tbit.z p6,p0=r17,IA64_PSR_IS_BIT        // IA64 instruction set?
+       ;;
+(p6)   mov r16=r18                             // if so, use cr.iip instead of 
cr.ifa
+#endif /* CONFIG_ITANIUM */
+       ;;
+#ifdef CONFIG_XEN
+       mov r18=r8;
+       mov r8=r16;
+       XEN_HYPER_THASH;;
+       mov r17=r8;
+       mov r8=r18;;
+#else
+       thash r17=r16                           // compute virtual address of 
L3 PTE
+#endif
+       mov r29=b0                              // save b0 in case of nested 
fault)
+#ifdef CONFIG_SMP
+       mov r28=ar.ccv                          // save ar.ccv
+       ;;
+1:     ld8 r18=[r17]
+       ;;
+       mov ar.ccv=r18                          // set compare value for cmpxchg
+       or r25=_PAGE_A,r18                      // set the accessed bit
+       tbit.z p7,p6 = r18,_PAGE_P_BIT          // Check present bit
+       ;;
+(p6)   cmpxchg8.acq r26=[r17],r25,ar.ccv       // Only if page present
+       mov r24=PAGE_SHIFT<<2
+       ;;
+(p6)   cmp.eq p6,p7=r26,r18                    // Only if page present
+       ;;
+#ifdef CONFIG_XEN
+       mov r26=r8
+       mov r8=r25
+       ;;
+(p6)   XEN_HYPER_ITC_I
+       ;;
+       mov r8=r26
+       ;;
+#else
+(p6)   itc.i r25                               // install updated PTE
+#endif
+       ;;
+       /*
+        * Tell the assemblers dependency-violation checker that the above 
"itc" instructions
+        * cannot possibly affect the following loads:
+        */
+       dv_serialize_data
+
+       ld8 r18=[r17]                           // read PTE again
+       ;;
+       cmp.eq p6,p7=r18,r25                    // is it same as the newly 
installed
+       ;;
+(p7)   ptc.l r16,r24
+       mov b0=r29                              // restore b0
+       mov ar.ccv=r28
+#else /* !CONFIG_SMP */
+       ;;
+1:     ld8 r18=[r17]
+       ;;
+       or r18=_PAGE_A,r18                      // set the accessed bit
+       mov b0=r29                              // restore b0
+       ;;
+       st8 [r17]=r18                           // store back updated PTE
+       itc.i r18                               // install updated PTE
+#endif /* !CONFIG_SMP */
+       mov pr=r31,-1
+#ifdef CONFIG_XEN
+       XEN_HYPER_RFI
+       dv_serialize_data
+#else
+       rfi
+#endif
+END(iaccess_bit)
+
+       .org ia64_ivt+0x2800
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x2800 Entry 10 (size 64 bundles) Data Access-bit (15,55)
+ENTRY(daccess_bit)
+       DBG_FAULT(10)
+       // Like Entry 8, except for data access
+#ifdef CONFIG_XEN
+       movl r16=XSI_IFA
+       ;;
+       ld8 r16=[r16]
+       ;;
+#else
+       mov r16=cr.ifa                          // get the address that caused 
the fault
+#endif
+       movl r30=1f                             // load continuation point in 
case of nested fault
+       ;;
+#ifdef CONFIG_XEN
+       mov r18=r8
+       mov r8=r16
+       XEN_HYPER_THASH
+       ;;
+       mov r17=r8
+       mov r8=r18
+       ;;
+#else
+       thash r17=r16                           // compute virtual address of 
L3 PTE
+#endif
+       mov r31=pr
+       mov r29=b0                              // save b0 in case of nested 
fault)
+#ifdef CONFIG_SMP
+       mov r28=ar.ccv                          // save ar.ccv
+       ;;
+1:     ld8 r18=[r17]
+       ;;                                      // avoid RAW on r18
+       mov ar.ccv=r18                          // set compare value for cmpxchg
+       or r25=_PAGE_A,r18                      // set the dirty bit
+       tbit.z p7,p6 = r18,_PAGE_P_BIT          // Check present bit
+       ;;
+(p6)   cmpxchg8.acq r26=[r17],r25,ar.ccv       // Only if page is present
+       mov r24=PAGE_SHIFT<<2
+       ;;
+(p6)   cmp.eq p6,p7=r26,r18                    // Only if page is present
+       ;;
+#ifdef CONFIG_XEN
+       mov r26=r8
+       mov r8=r25
+       ;;
+(p6)   XEN_HYPER_ITC_D
+       ;;
+       mov r8=r26
+       ;;
+#else
+(p6)   itc.d r25                               // install updated PTE
+#endif
+       /*
+        * Tell the assemblers dependency-violation checker that the above 
"itc" instructions
+        * cannot possibly affect the following loads:
+        */
+       dv_serialize_data
+       ;;
+       ld8 r18=[r17]                           // read PTE again
+       ;;
+       cmp.eq p6,p7=r18,r25                    // is it same as the newly 
installed
+       ;;
+(p7)   ptc.l r16,r24
+       mov ar.ccv=r28
+#else
+       ;;
+1:     ld8 r18=[r17]
+       ;;                                      // avoid RAW on r18
+       or r18=_PAGE_A,r18                      // set the accessed bit
+       ;;
+       st8 [r17]=r18                           // store back updated PTE
+       itc.d r18                               // install updated PTE
+#endif
+       mov b0=r29                              // restore b0
+       mov pr=r31,-1
+#ifdef CONFIG_XEN
+       XEN_HYPER_RFI
+       dv_serialize_data
+#else
+       rfi
+#endif
+END(daccess_bit)
+
+       .org ia64_ivt+0x2c00
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x2c00 Entry 11 (size 64 bundles) Break instruction (33)
+ENTRY(break_fault)
+       /*
+        * The streamlined system call entry/exit paths only save/restore the 
initial part
+        * of pt_regs.  This implies that the callers of system-calls must 
adhere to the
+        * normal procedure calling conventions.
+        *
+        *   Registers to be saved & restored:
+        *      CR registers: cr.ipsr, cr.iip, cr.ifs
+        *      AR registers: ar.unat, ar.pfs, ar.rsc, ar.rnat, ar.bspstore, 
ar.fpsr
+        *      others: pr, b0, b6, loadrs, r1, r11, r12, r13, r15
+        *   Registers to be restored only:
+        *      r8-r11: output value from the system call.
+        *
+        * During system call exit, scratch registers (including r15) are 
modified/cleared
+        * to prevent leaking bits from kernel to user level.
+        */
+       DBG_FAULT(11)
+       mov.m r16=IA64_KR(CURRENT)              // M2 r16 <- current task (12 
cyc)
+#ifdef CONFIG_XEN
+       movl r22=XSI_IPSR
+       ;;
+       ld8 r29=[r22],XSI_IIM_OFS-XSI_IPSR_OFS  // get ipsr, point to iip
+#else
+       mov r29=cr.ipsr                         // M2 (12 cyc)
+#endif
+       mov r31=pr                              // I0 (2 cyc)
+
+#ifdef CONFIG_XEN
+       ;;
+       ld8 r17=[r22],XSI_IIP_OFS-XSI_IIM_OFS
+#else
+       mov r17=cr.iim                          // M2 (2 cyc)
+#endif
+       mov.m r27=ar.rsc                        // M2 (12 cyc)
+       mov r18=__IA64_BREAK_SYSCALL            // A
+
+       mov.m ar.rsc=0                          // M2
+       mov.m r21=ar.fpsr                       // M2 (12 cyc)
+       mov r19=b6                              // I0 (2 cyc)
+       ;;
+       mov.m r23=ar.bspstore                   // M2 (12 cyc)
+       mov.m r24=ar.rnat                       // M2 (5 cyc)
+       mov.i r26=ar.pfs                        // I0 (2 cyc)
+
+       invala                                  // M0|1
+       nop.m 0                                 // M
+       mov r20=r1                              // A                    save r1
+
+       nop.m 0
+       movl r30=sys_call_table                 // X
+
+#ifdef CONFIG_XEN
+       ld8 r28=[r22]
+#else
+       mov r28=cr.iip                          // M2 (2 cyc)
+#endif
+       cmp.eq p0,p7=r18,r17                    // I0 is this a system call?
+(p7)   br.cond.spnt non_syscall                // B  no ->
+       //
+       // From this point on, we are definitely on the syscall-path
+       // and we can use (non-banked) scratch registers.
+       //
+///////////////////////////////////////////////////////////////////////
+       mov r1=r16                              // A    move task-pointer to 
"addl"-addressable reg
+       mov r2=r16                              // A    setup r2 for 
ia64_syscall_setup
+       add r9=TI_FLAGS+IA64_TASK_SIZE,r16      // A    r9 = 
&current_thread_info()->flags
+
+       adds r16=IA64_TASK_THREAD_ON_USTACK_OFFSET,r16
+       adds r15=-1024,r15                      // A    subtract 1024 from 
syscall number
+       mov r3=NR_syscalls - 1
+       ;;
+       ld1.bias r17=[r16]                      // M0|1 r17 = 
current->thread.on_ustack flag
+       ld4 r9=[r9]                             // M0|1 r9 = 
current_thread_info()->flags
+       extr.u r8=r29,41,2                      // I0   extract ei field from 
cr.ipsr
+
+       shladd r30=r15,3,r30                    // A    r30 = sys_call_table + 
8*(syscall-1024)
+       addl r22=IA64_RBS_OFFSET,r1             // A    compute base of RBS
+       cmp.leu p6,p7=r15,r3                    // A    syscall number in range?
+       ;;
+
+       lfetch.fault.excl.nt1 [r22]             // M0|1 prefetch RBS
+(p6)   ld8 r30=[r30]                           // M0|1 load address of syscall 
entry point
+       tnat.nz.or p7,p0=r15                    // I0   is syscall nr a NaT?
+
+       mov.m ar.bspstore=r22                   // M2   switch to kernel RBS
+       cmp.eq p8,p9=2,r8                       // A    isr.ei==2?
+       ;;
+
+(p8)   mov r8=0                                // A    clear ei to 0
+(p7)   movl r30=sys_ni_syscall                 // X
+
+(p8)   adds r28=16,r28                         // A    switch cr.iip to next 
bundle
+(p9)   adds r8=1,r8                            // A    increment ei to next 
slot
+       nop.i 0
+       ;;
+
+       mov.m r25=ar.unat                       // M2 (5 cyc)
+       dep r29=r8,r29,41,2                     // I0   insert new ei into 
cr.ipsr
+       adds r15=1024,r15                       // A    restore original 
syscall number
+       //
+       // If any of the above loads miss in L1D, we'll stall here until
+       // the data arrives.
+       //
+///////////////////////////////////////////////////////////////////////
+       st1 [r16]=r0                            // M2|3 clear 
current->thread.on_ustack flag
+       mov b6=r30                              // I0   setup syscall handler 
branch reg early
+       cmp.eq pKStk,pUStk=r0,r17               // A    were we on kernel 
stacks already?
+
+       and r9=_TIF_SYSCALL_TRACEAUDIT,r9       // A    mask trace or audit
+       mov r18=ar.bsp                          // M2 (12 cyc)
+(pKStk)        br.cond.spnt .break_fixup               // B    we're already 
in kernel-mode -- fix up RBS
+       ;;
+.back_from_break_fixup:
+(pUStk)        addl r1=IA64_STK_OFFSET-IA64_PT_REGS_SIZE,r1 // A    compute 
base of memory stack
+       cmp.eq p14,p0=r9,r0                     // A    are syscalls being 
traced/audited?
+       br.call.sptk.many b7=ia64_syscall_setup // B
+1:
+       mov ar.rsc=0x3                          // M2   set eager mode, pl 0, 
LE, loadrs=0
+       nop 0
+#ifdef CONFIG_XEN
+       mov r2=b0; br.call.sptk b0=xen_bsw1;; mov b0=r2;;
+#else
+       bsw.1                                   // B (6 cyc) regs are saved, 
switch to bank 1
+#endif
+       ;;
+
+#ifdef CONFIG_XEN
+       movl r16=XSI_PSR_IC
+       mov r3=1
+       ;;
+       st4 [r16]=r3,XSI_PSR_I_ADDR_OFS-XSI_PSR_IC_OFS  // vpsr.ic = 1
+#else
+       ssm psr.ic | PSR_DEFAULT_BITS           // M2   now it's safe to 
re-enable intr.-collection
+#endif
+       movl r3=ia64_ret_from_syscall           // X
+       ;;
+
+       srlz.i                                  // M0   ensure interruption 
collection is on
+       mov rp=r3                               // I0   set the real return addr
+(p10)  br.cond.spnt.many ia64_ret_from_syscall // B    return if bad 
call-frame or r15 is a NaT
+
+#ifdef CONFIG_XEN
+(p15)  ld8 r16=[r16]                           // vpsr.i
+       ;;
+(p15)  st1 [r16]=r0,MASK_TO_PEND_OFS           // if (p15) vpsr.i = 1
+       ;;              // if (p15) (vcpu->vcpu_info->evtchn_upcall_mask)=0
+(p15)  ld1 r2=[r16]    // if (vcpu->vcpu_info->evtchn_upcall_pending)
+       ;;
+(p15)  cmp.ne.unc p6,p0=r2,r0
+       ;;
+(p6)   XEN_HYPER_SSM_I                         //   do a real ssm psr.i
+#else
+(p15)  ssm psr.i                               // M2   restore psr.i
+#endif
+(p14)  br.call.sptk.many b6=b6                 // B    invoke syscall-handker 
(ignore return addr)
+       br.cond.spnt.many ia64_trace_syscall    // B    do syscall-tracing 
thingamagic
+       // NOT REACHED
+///////////////////////////////////////////////////////////////////////
+       // On entry, we optimistically assumed that we're coming from 
user-space.
+       // For the rare cases where a system-call is done from within the 
kernel,
+       // we fix things up at this point:
+.break_fixup:
+       add r1=-IA64_PT_REGS_SIZE,sp            // A    allocate space for 
pt_regs structure
+       mov ar.rnat=r24                         // M2   restore kernel's AR.RNAT
+       ;;
+       mov ar.bspstore=r23                     // M2   restore kernel's 
AR.BSPSTORE
+       br.cond.sptk .back_from_break_fixup
+END(break_fault)
+
+       .org ia64_ivt+0x3000
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x3000 Entry 12 (size 64 bundles) External Interrupt (4)
+ENTRY(interrupt)
+       DBG_FAULT(12)
+       mov r31=pr              // prepare to save predicates
+       ;;
+       SAVE_MIN_WITH_COVER     // uses r31; defines r2 and r3
+#ifdef CONFIG_XEN
+       movl r3=XSI_PSR_IC
+       mov r14=1
+       ;;
+       st4 [r3]=r14
+#else
+       ssm psr.ic | PSR_DEFAULT_BITS
+#endif
+       ;;
+       adds r3=8,r2            // set up second base pointer for SAVE_REST
+       srlz.i                  // ensure everybody knows psr.ic is back on
+       ;;
+       SAVE_REST
+       ;;
+       MCA_RECOVER_RANGE(interrupt)
+       alloc r14=ar.pfs,0,0,2,0 // must be first in an insn group
+#ifdef CONFIG_XEN
+       ;;
+       XEN_HYPER_GET_IVR
+       ;;
+       mov out0=r8             // pass cr.ivr as first arg
+#else
+       mov out0=cr.ivr         // pass cr.ivr as first arg
+#endif
+       add out1=16,sp          // pass pointer to pt_regs as second arg
+       ;;
+       srlz.d                  // make sure we see the effect of cr.ivr
+       movl r14=ia64_leave_kernel
+       ;;
+       mov rp=r14
+       br.call.sptk.many b6=ia64_handle_irq
+END(interrupt)
+
+       .org ia64_ivt+0x3400
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x3400 Entry 13 (size 64 bundles) Reserved
+       DBG_FAULT(13)
+       FAULT(13)
+
+       .org ia64_ivt+0x3800
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x3800 Entry 14 (size 64 bundles) Reserved
+       DBG_FAULT(14)
+       FAULT(14)
+
+       /*
+        * There is no particular reason for this code to be here, other than 
that
+        * there happens to be space here that would go unused otherwise.  If 
this
+        * fault ever gets "unreserved", simply moved the following code to a 
more
+        * suitable spot...
+        *
+        * ia64_syscall_setup() is a separate subroutine so that it can
+        *      allocate stacked registers so it can safely demine any
+        *      potential NaT values from the input registers.
+        *
+        * On entry:
+        *      - executing on bank 0 or bank 1 register set (doesn't matter)
+        *      -  r1: stack pointer
+        *      -  r2: current task pointer
+        *      -  r3: preserved
+        *      - r11: original contents (saved ar.pfs to be saved)
+        *      - r12: original contents (sp to be saved)
+        *      - r13: original contents (tp to be saved)
+        *      - r15: original contents (syscall # to be saved)
+        *      - r18: saved bsp (after switching to kernel stack)
+        *      - r19: saved b6
+        *      - r20: saved r1 (gp)
+        *      - r21: saved ar.fpsr
+        *      - r22: kernel's register backing store base (krbs_base)
+        *      - r23: saved ar.bspstore
+        *      - r24: saved ar.rnat
+        *      - r25: saved ar.unat
+        *      - r26: saved ar.pfs
+        *      - r27: saved ar.rsc
+        *      - r28: saved cr.iip
+        *      - r29: saved cr.ipsr
+        *      - r31: saved pr
+        *      -  b0: original contents (to be saved)
+        * On exit:
+        *      -  p10: TRUE if syscall is invoked with more than 8 out
+        *              registers or r15's Nat is true
+        *      -  r1: kernel's gp
+        *      -  r3: preserved (same as on entry)
+        *      -  r8: -EINVAL if p10 is true
+        *      - r12: points to kernel stack
+        *      - r13: points to current task
+        *      - r14: preserved (same as on entry)
+        *      - p13: preserved
+        *      - p15: TRUE if interrupts need to be re-enabled
+        *      - ar.fpsr: set to kernel settings
+        *      -  b6: preserved (same as on entry)
+        */
+#ifndef CONFIG_XEN
+GLOBAL_ENTRY(ia64_syscall_setup)
+#if PT(B6) != 0
+# error This code assumes that b6 is the first field in pt_regs.
+#endif
+       st8 [r1]=r19                            // save b6
+       add r16=PT(CR_IPSR),r1                  // initialize first base pointer
+       add r17=PT(R11),r1                      // initialize second base 
pointer
+       ;;
+       alloc r19=ar.pfs,8,0,0,0                // ensure in0-in7 are writable
+       st8 [r16]=r29,PT(AR_PFS)-PT(CR_IPSR)    // save cr.ipsr
+       tnat.nz p8,p0=in0
+
+       st8.spill [r17]=r11,PT(CR_IIP)-PT(R11)  // save r11
+       tnat.nz p9,p0=in1
+(pKStk)        mov r18=r0                              // make sure r18 isn't 
NaT
+       ;;
+
+       st8 [r16]=r26,PT(CR_IFS)-PT(AR_PFS)     // save ar.pfs
+       st8 [r17]=r28,PT(AR_UNAT)-PT(CR_IIP)    // save cr.iip
+       mov r28=b0                              // save b0 (2 cyc)
+       ;;
+
+       st8 [r17]=r25,PT(AR_RSC)-PT(AR_UNAT)    // save ar.unat
+       dep r19=0,r19,38,26                     // clear all bits but 0..37 [I0]
+(p8)   mov in0=-1
+       ;;
+
+       st8 [r16]=r19,PT(AR_RNAT)-PT(CR_IFS)    // store ar.pfs.pfm in cr.ifs
+       extr.u r11=r19,7,7      // I0           // get sol of ar.pfs
+       and r8=0x7f,r19         // A            // get sof of ar.pfs
+
+       st8 [r17]=r27,PT(AR_BSPSTORE)-PT(AR_RSC)// save ar.rsc
+       tbit.nz p15,p0=r29,IA64_PSR_I_BIT // I0
+(p9)   mov in1=-1
+       ;;
+
+(pUStk) sub r18=r18,r22                                // r18=RSE.ndirty*8
+       tnat.nz p10,p0=in2
+       add r11=8,r11
+       ;;
+(pKStk) adds r16=PT(PR)-PT(AR_RNAT),r16                // skip over ar_rnat 
field
+(pKStk) adds r17=PT(B0)-PT(AR_BSPSTORE),r17    // skip over ar_bspstore field
+       tnat.nz p11,p0=in3
+       ;;
+(p10)  mov in2=-1
+       tnat.nz p12,p0=in4                              // [I0]
+(p11)  mov in3=-1
+       ;;
+(pUStk) st8 [r16]=r24,PT(PR)-PT(AR_RNAT)       // save ar.rnat
+(pUStk) st8 [r17]=r23,PT(B0)-PT(AR_BSPSTORE)   // save ar.bspstore
+       shl r18=r18,16                          // compute ar.rsc to be used 
for "loadrs"
+       ;;
+       st8 [r16]=r31,PT(LOADRS)-PT(PR)         // save predicates
+       st8 [r17]=r28,PT(R1)-PT(B0)             // save b0
+       tnat.nz p13,p0=in5                              // [I0]
+       ;;
+       st8 [r16]=r18,PT(R12)-PT(LOADRS)        // save ar.rsc value for 
"loadrs"
+       st8.spill [r17]=r20,PT(R13)-PT(R1)      // save original r1
+(p12)  mov in4=-1
+       ;;
+
+.mem.offset 0,0; st8.spill [r16]=r12,PT(AR_FPSR)-PT(R12)       // save r12
+.mem.offset 8,0; st8.spill [r17]=r13,PT(R15)-PT(R13)           // save r13
+(p13)  mov in5=-1
+       ;;
+       st8 [r16]=r21,PT(R8)-PT(AR_FPSR)        // save ar.fpsr
+       tnat.nz p13,p0=in6
+       cmp.lt p10,p9=r11,r8    // frame size can't be more than local+8
+       ;;
+       mov r8=1
+(p9)   tnat.nz p10,p0=r15
+       adds r12=-16,r1         // switch to kernel memory stack (with 16 bytes 
of scratch)
+
+       st8.spill [r17]=r15                     // save r15
+       tnat.nz p8,p0=in7
+       nop.i 0
+
+       mov r13=r2                              // establish `current'
+       movl r1=__gp                            // establish kernel global 
pointer
+       ;;
+       st8 [r16]=r8            // ensure pt_regs.r8 != 0 (see 
handle_syscall_error)
+(p13)  mov in6=-1
+(p8)   mov in7=-1
+
+       cmp.eq pSys,pNonSys=r0,r0               // set pSys=1, pNonSys=0
+       movl r17=FPSR_DEFAULT
+       ;;
+       mov.m ar.fpsr=r17                       // set ar.fpsr to kernel 
default value
+(p10)  mov r8=-EINVAL
+       br.ret.sptk.many b7
+END(ia64_syscall_setup)
+#endif
+
+       .org ia64_ivt+0x3c00
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x3c00 Entry 15 (size 64 bundles) Reserved
+       DBG_FAULT(15)
+       FAULT(15)
+
+       /*
+        * Squatting in this space ...
+        *
+        * This special case dispatcher for illegal operation faults allows 
preserved
+        * registers to be modified through a callback function (asm only) that 
is handed
+        * back from the fault handler in r8. Up to three arguments can be 
passed to the
+        * callback function by returning an aggregate with the callback as its 
first
+        * element, followed by the arguments.
+        */
+ENTRY(dispatch_illegal_op_fault)
+       .prologue
+       .body
+       SAVE_MIN_WITH_COVER
+       ssm psr.ic | PSR_DEFAULT_BITS
+       ;;
+       srlz.i          // guarantee that interruption collection is on
+       ;;
+(p15)  ssm psr.i       // restore psr.i
+       adds r3=8,r2    // set up second base pointer for SAVE_REST
+       ;;
+       alloc r14=ar.pfs,0,0,1,0        // must be first in insn group
+       mov out0=ar.ec
+       ;;
+       SAVE_REST
+       PT_REGS_UNWIND_INFO(0)
+       ;;
+       br.call.sptk.many rp=ia64_illegal_op_fault
+.ret0: ;;
+       alloc r14=ar.pfs,0,0,3,0        // must be first in insn group
+       mov out0=r9
+       mov out1=r10
+       mov out2=r11
+       movl r15=ia64_leave_kernel
+       ;;
+       mov rp=r15
+       mov b6=r8
+       ;;
+       cmp.ne p6,p0=0,r8
+(p6)   br.call.dpnt.many b6=b6         // call returns to ia64_leave_kernel
+       br.sptk.many ia64_leave_kernel
+END(dispatch_illegal_op_fault)
+
+       .org ia64_ivt+0x4000
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x4000 Entry 16 (size 64 bundles) Reserved
+       DBG_FAULT(16)
+       FAULT(16)
+
+       .org ia64_ivt+0x4400
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x4400 Entry 17 (size 64 bundles) Reserved
+       DBG_FAULT(17)
+       FAULT(17)
+
+ENTRY(non_syscall)
+       mov ar.rsc=r27                  // restore ar.rsc before 
SAVE_MIN_WITH_COVER
+       ;;
+       SAVE_MIN_WITH_COVER
+
+       // There is no particular reason for this code to be here, other than 
that
+       // there happens to be space here that would go unused otherwise.  If 
this
+       // fault ever gets "unreserved", simply moved the following code to a 
more
+       // suitable spot...
+
+       alloc r14=ar.pfs,0,0,2,0
+       mov out0=cr.iim
+       add out1=16,sp
+       adds r3=8,r2                    // set up second base pointer for 
SAVE_REST
+
+       ssm psr.ic | PSR_DEFAULT_BITS
+       ;;
+       srlz.i                          // guarantee that interruption 
collection is on
+       ;;
+(p15)  ssm psr.i                       // restore psr.i
+       movl r15=ia64_leave_kernel
+       ;;
+       SAVE_REST
+       mov rp=r15
+       ;;
+       br.call.sptk.many b6=ia64_bad_break     // avoid WAW on CFM and ignore 
return addr
+END(non_syscall)
+
+       .org ia64_ivt+0x4800
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x4800 Entry 18 (size 64 bundles) Reserved
+       DBG_FAULT(18)
+       FAULT(18)
+
+       /*
+        * There is no particular reason for this code to be here, other than 
that
+        * there happens to be space here that would go unused otherwise.  If 
this
+        * fault ever gets "unreserved", simply moved the following code to a 
more
+        * suitable spot...
+        */
+
+ENTRY(dispatch_unaligned_handler)
+       SAVE_MIN_WITH_COVER
+       ;;
+       alloc r14=ar.pfs,0,0,2,0                // now it's safe (must be first 
in insn group!)
+       mov out0=cr.ifa
+       adds out1=16,sp
+
+       ssm psr.ic | PSR_DEFAULT_BITS
+       ;;
+       srlz.i                                  // guarantee that interruption 
collection is on
+       ;;
+(p15)  ssm psr.i                               // restore psr.i
+       adds r3=8,r2                            // set up second base pointer
+       ;;
+       SAVE_REST
+       movl r14=ia64_leave_kernel
+       ;;
+       mov rp=r14
+       br.sptk.many ia64_prepare_handle_unaligned
+END(dispatch_unaligned_handler)
+
+       .org ia64_ivt+0x4c00
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x4c00 Entry 19 (size 64 bundles) Reserved
+       DBG_FAULT(19)
+       FAULT(19)
+
+       /*
+        * There is no particular reason for this code to be here, other than 
that
+        * there happens to be space here that would go unused otherwise.  If 
this
+        * fault ever gets "unreserved", simply moved the following code to a 
more
+        * suitable spot...
+        */
+
+ENTRY(dispatch_to_fault_handler)
+       /*
+        * Input:
+        *      psr.ic: off
+        *      r19:    fault vector number (e.g., 24 for General Exception)
+        *      r31:    contains saved predicates (pr)
+        */
+       SAVE_MIN_WITH_COVER_R19
+       alloc r14=ar.pfs,0,0,5,0
+       mov out0=r15
+#ifdef CONFIG_XEN
+       movl out1=XSI_ISR
+       ;;
+       adds out2=XSI_IFA-XSI_ISR,out1
+       adds out3=XSI_IIM-XSI_ISR,out1
+       adds out4=XSI_ITIR-XSI_ISR,out1
+       ;;
+       ld8 out1=[out1]
+       ld8 out2=[out2]
+       ld8 out3=[out4]
+       ld8 out4=[out4]
+       ;;
+#else
+       mov out1=cr.isr
+       mov out2=cr.ifa
+       mov out3=cr.iim
+       mov out4=cr.itir
+       ;;
+#endif
+       ssm psr.ic | PSR_DEFAULT_BITS
+       ;;
+       srlz.i                                  // guarantee that interruption 
collection is on
+       ;;
+(p15)  ssm psr.i                               // restore psr.i
+       adds r3=8,r2                            // set up second base pointer 
for SAVE_REST
+       ;;
+       SAVE_REST
+       movl r14=ia64_leave_kernel
+       ;;
+       mov rp=r14
+       br.call.sptk.many b6=ia64_fault
+END(dispatch_to_fault_handler)
+
+//
+// --- End of long entries, Beginning of short entries
+//
+
+       .org ia64_ivt+0x5000
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x5000 Entry 20 (size 16 bundles) Page Not Present (10,22,49)
+ENTRY(page_not_present)
+       DBG_FAULT(20)
+       mov r16=cr.ifa
+       rsm psr.dt
+       /*
+        * The Linux page fault handler doesn't expect non-present pages to be 
in
+        * the TLB.  Flush the existing entry now, so we meet that expectation.
+        */
+       mov r17=PAGE_SHIFT<<2
+       ;;
+       ptc.l r16,r17
+       ;;
+       mov r31=pr
+       srlz.d
+       br.sptk.many page_fault
+END(page_not_present)
+
+       .org ia64_ivt+0x5100
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x5100 Entry 21 (size 16 bundles) Key Permission (13,25,52)
+ENTRY(key_permission)
+       DBG_FAULT(21)
+       mov r16=cr.ifa
+       rsm psr.dt
+       mov r31=pr
+       ;;
+       srlz.d
+       br.sptk.many page_fault
+END(key_permission)
+
+       .org ia64_ivt+0x5200
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x5200 Entry 22 (size 16 bundles) Instruction Access Rights (26)
+ENTRY(iaccess_rights)
+       DBG_FAULT(22)
+       mov r16=cr.ifa
+       rsm psr.dt
+       mov r31=pr
+       ;;
+       srlz.d
+       br.sptk.many page_fault
+END(iaccess_rights)
+
+       .org ia64_ivt+0x5300
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x5300 Entry 23 (size 16 bundles) Data Access Rights (14,53)
+ENTRY(daccess_rights)
+       DBG_FAULT(23)
+#ifdef CONFIG_XEN
+       movl r16=XSI_IFA
+       ;;
+       ld8 r16=[r16]
+       ;;
+       XEN_HYPER_RSM_PSR_DT
+#else
+       mov r16=cr.ifa
+       rsm psr.dt
+#endif
+       mov r31=pr
+       ;;
+       srlz.d
+       br.sptk.many page_fault
+END(daccess_rights)
+
+       .org ia64_ivt+0x5400
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x5400 Entry 24 (size 16 bundles) General Exception (5,32,34,36,38,39)
+ENTRY(general_exception)
+       DBG_FAULT(24)
+       mov r16=cr.isr
+       mov r31=pr
+       ;;
+       cmp4.eq p6,p0=0,r16
+(p6)   br.sptk.many dispatch_illegal_op_fault
+       ;;
+       mov r19=24              // fault number
+       br.sptk.many dispatch_to_fault_handler
+END(general_exception)
+
+       .org ia64_ivt+0x5500
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x5500 Entry 25 (size 16 bundles) Disabled FP-Register (35)
+ENTRY(disabled_fp_reg)
+       DBG_FAULT(25)
+       rsm psr.dfh             // ensure we can access fph
+       ;;
+       srlz.d
+       mov r31=pr
+       mov r19=25
+       br.sptk.many dispatch_to_fault_handler
+END(disabled_fp_reg)
+
+       .org ia64_ivt+0x5600
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x5600 Entry 26 (size 16 bundles) Nat Consumption (11,23,37,50)
+ENTRY(nat_consumption)
+       DBG_FAULT(26)
+
+       mov r16=cr.ipsr
+       mov r17=cr.isr
+       mov r31=pr                              // save PR
+       ;;
+       and r18=0xf,r17                         // r18 = cr.ipsr.code{3:0}
+       tbit.z p6,p0=r17,IA64_ISR_NA_BIT
+       ;;
+       cmp.ne.or p6,p0=IA64_ISR_CODE_LFETCH,r18
+       dep r16=-1,r16,IA64_PSR_ED_BIT,1
+(p6)   br.cond.spnt 1f         // branch if (cr.ispr.na == 0 || 
cr.ipsr.code{3:0} != LFETCH)
+       ;;
+       mov cr.ipsr=r16         // set cr.ipsr.na
+       mov pr=r31,-1
+       ;;
+       rfi
+
+1:     mov pr=r31,-1
+       ;;
+       FAULT(26)
+END(nat_consumption)
+
+       .org ia64_ivt+0x5700
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x5700 Entry 27 (size 16 bundles) Speculation (40)
+ENTRY(speculation_vector)
+       DBG_FAULT(27)
+       /*
+        * A [f]chk.[as] instruction needs to take the branch to the recovery 
code but
+        * this part of the architecture is not implemented in hardware on some 
CPUs, such
+        * as Itanium.  Thus, in general we need to emulate the behavior.  IIM 
contains
+        * the relative target (not yet sign extended).  So after sign 
extending it we
+        * simply add it to IIP.  We also need to reset the EI field of the 
IPSR to zero,
+        * i.e., the slot to restart into.
+        *
+        * cr.imm contains zero_ext(imm21)
+        */
+       mov r18=cr.iim
+       ;;
+       mov r17=cr.iip
+       shl r18=r18,43                  // put sign bit in position (43=64-21)
+       ;;
+
+       mov r16=cr.ipsr
+       shr r18=r18,39                  // sign extend (39=43-4)
+       ;;
+
+       add r17=r17,r18                 // now add the offset
+       ;;
+       mov cr.iip=r17
+       dep r16=0,r16,41,2              // clear EI
+       ;;
+
+       mov cr.ipsr=r16
+       ;;
+
+#ifdef CONFIG_XEN
+       XEN_HYPER_RFI;
+#else
+       rfi                             // and go back
+#endif
+END(speculation_vector)
+
+       .org ia64_ivt+0x5800
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x5800 Entry 28 (size 16 bundles) Reserved
+       DBG_FAULT(28)
+       FAULT(28)
+
+       .org ia64_ivt+0x5900
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x5900 Entry 29 (size 16 bundles) Debug (16,28,56)
+ENTRY(debug_vector)
+       DBG_FAULT(29)
+       FAULT(29)
+END(debug_vector)
+
+       .org ia64_ivt+0x5a00
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x5a00 Entry 30 (size 16 bundles) Unaligned Reference (57)
+ENTRY(unaligned_access)
+       DBG_FAULT(30)
+       mov r31=pr              // prepare to save predicates
+       ;;
+       br.sptk.many dispatch_unaligned_handler
+END(unaligned_access)
+
+       .org ia64_ivt+0x5b00
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x5b00 Entry 31 (size 16 bundles) Unsupported Data Reference (57)
+ENTRY(unsupported_data_reference)
+       DBG_FAULT(31)
+       FAULT(31)
+END(unsupported_data_reference)
+
+       .org ia64_ivt+0x5c00
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x5c00 Entry 32 (size 16 bundles) Floating-Point Fault (64)
+ENTRY(floating_point_fault)
+       DBG_FAULT(32)
+       FAULT(32)
+END(floating_point_fault)
+
+       .org ia64_ivt+0x5d00
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x5d00 Entry 33 (size 16 bundles) Floating Point Trap (66)
+ENTRY(floating_point_trap)
+       DBG_FAULT(33)
+       FAULT(33)
+END(floating_point_trap)
+
+       .org ia64_ivt+0x5e00
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x5e00 Entry 34 (size 16 bundles) Lower Privilege Transfer Trap (66)
+ENTRY(lower_privilege_trap)
+       DBG_FAULT(34)
+       FAULT(34)
+END(lower_privilege_trap)
+
+       .org ia64_ivt+0x5f00
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x5f00 Entry 35 (size 16 bundles) Taken Branch Trap (68)
+ENTRY(taken_branch_trap)
+       DBG_FAULT(35)
+       FAULT(35)
+END(taken_branch_trap)
+
+       .org ia64_ivt+0x6000
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x6000 Entry 36 (size 16 bundles) Single Step Trap (69)
+ENTRY(single_step_trap)
+       DBG_FAULT(36)
+       FAULT(36)
+END(single_step_trap)
+
+       .org ia64_ivt+0x6100
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x6100 Entry 37 (size 16 bundles) Reserved
+       DBG_FAULT(37)
+       FAULT(37)
+
+       .org ia64_ivt+0x6200
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x6200 Entry 38 (size 16 bundles) Reserved
+       DBG_FAULT(38)
+       FAULT(38)
+
+       .org ia64_ivt+0x6300
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x6300 Entry 39 (size 16 bundles) Reserved
+       DBG_FAULT(39)
+       FAULT(39)
+
+       .org ia64_ivt+0x6400
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x6400 Entry 40 (size 16 bundles) Reserved
+       DBG_FAULT(40)
+       FAULT(40)
+
+       .org ia64_ivt+0x6500
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x6500 Entry 41 (size 16 bundles) Reserved
+       DBG_FAULT(41)
+       FAULT(41)
+
+       .org ia64_ivt+0x6600
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x6600 Entry 42 (size 16 bundles) Reserved
+       DBG_FAULT(42)
+       FAULT(42)
+
+       .org ia64_ivt+0x6700
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x6700 Entry 43 (size 16 bundles) Reserved
+       DBG_FAULT(43)
+       FAULT(43)
+
+       .org ia64_ivt+0x6800
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x6800 Entry 44 (size 16 bundles) Reserved
+       DBG_FAULT(44)
+       FAULT(44)
+
+       .org ia64_ivt+0x6900
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x6900 Entry 45 (size 16 bundles) IA-32 Exeception 
(17,18,29,41,42,43,44,58,60,61,62,72,73,75,76,77)
+ENTRY(ia32_exception)
+       DBG_FAULT(45)
+       FAULT(45)
+END(ia32_exception)
+
+       .org ia64_ivt+0x6a00
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x6a00 Entry 46 (size 16 bundles) IA-32 Intercept  (30,31,59,70,71)
+ENTRY(ia32_intercept)
+       DBG_FAULT(46)
+#ifdef CONFIG_IA32_SUPPORT
+       mov r31=pr
+       mov r16=cr.isr
+       ;;
+       extr.u r17=r16,16,8     // get ISR.code
+       mov r18=ar.eflag
+       mov r19=cr.iim          // old eflag value
+       ;;
+       cmp.ne p6,p0=2,r17
+(p6)   br.cond.spnt 1f         // not a system flag fault
+       xor r16=r18,r19
+       ;;
+       extr.u r17=r16,18,1     // get the eflags.ac bit
+       ;;
+       cmp.eq p6,p0=0,r17
+(p6)   br.cond.spnt 1f         // eflags.ac bit didn't change
+       ;;
+       mov pr=r31,-1           // restore predicate registers
+#ifdef CONFIG_XEN
+       XEN_HYPER_RFI;
+#else
+       rfi
+#endif
+
+1:
+#endif // CONFIG_IA32_SUPPORT
+       FAULT(46)
+END(ia32_intercept)
+
+       .org ia64_ivt+0x6b00
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x6b00 Entry 47 (size 16 bundles) IA-32 Interrupt  (74)
+ENTRY(ia32_interrupt)
+       DBG_FAULT(47)
+#ifdef CONFIG_IA32_SUPPORT
+       mov r31=pr
+       br.sptk.many dispatch_to_ia32_handler
+#else
+       FAULT(47)
+#endif
+END(ia32_interrupt)
+
+       .org ia64_ivt+0x6c00
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x6c00 Entry 48 (size 16 bundles) Reserved
+       DBG_FAULT(48)
+       FAULT(48)
+
+       .org ia64_ivt+0x6d00
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x6d00 Entry 49 (size 16 bundles) Reserved
+       DBG_FAULT(49)
+       FAULT(49)
+
+       .org ia64_ivt+0x6e00
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x6e00 Entry 50 (size 16 bundles) Reserved
+       DBG_FAULT(50)
+       FAULT(50)
+
+       .org ia64_ivt+0x6f00
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x6f00 Entry 51 (size 16 bundles) Reserved
+       DBG_FAULT(51)
+       FAULT(51)
+
+       .org ia64_ivt+0x7000
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x7000 Entry 52 (size 16 bundles) Reserved
+       DBG_FAULT(52)
+       FAULT(52)
+
+       .org ia64_ivt+0x7100
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x7100 Entry 53 (size 16 bundles) Reserved
+       DBG_FAULT(53)
+       FAULT(53)
+
+       .org ia64_ivt+0x7200
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x7200 Entry 54 (size 16 bundles) Reserved
+       DBG_FAULT(54)
+       FAULT(54)
+
+       .org ia64_ivt+0x7300
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x7300 Entry 55 (size 16 bundles) Reserved
+       DBG_FAULT(55)
+       FAULT(55)
+
+       .org ia64_ivt+0x7400
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x7400 Entry 56 (size 16 bundles) Reserved
+       DBG_FAULT(56)
+       FAULT(56)
+
+       .org ia64_ivt+0x7500
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x7500 Entry 57 (size 16 bundles) Reserved
+       DBG_FAULT(57)
+       FAULT(57)
+
+       .org ia64_ivt+0x7600
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x7600 Entry 58 (size 16 bundles) Reserved
+       DBG_FAULT(58)
+       FAULT(58)
+
+       .org ia64_ivt+0x7700
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x7700 Entry 59 (size 16 bundles) Reserved
+       DBG_FAULT(59)
+       FAULT(59)
+
+       .org ia64_ivt+0x7800
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x7800 Entry 60 (size 16 bundles) Reserved
+       DBG_FAULT(60)
+       FAULT(60)
+
+       .org ia64_ivt+0x7900
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x7900 Entry 61 (size 16 bundles) Reserved
+       DBG_FAULT(61)
+       FAULT(61)
+
+       .org ia64_ivt+0x7a00
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x7a00 Entry 62 (size 16 bundles) Reserved
+       DBG_FAULT(62)
+       FAULT(62)
+
+       .org ia64_ivt+0x7b00
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x7b00 Entry 63 (size 16 bundles) Reserved
+       DBG_FAULT(63)
+       FAULT(63)
+
+       .org ia64_ivt+0x7c00
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x7c00 Entry 64 (size 16 bundles) Reserved
+       DBG_FAULT(64)
+       FAULT(64)
+
+       .org ia64_ivt+0x7d00
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x7d00 Entry 65 (size 16 bundles) Reserved
+       DBG_FAULT(65)
+       FAULT(65)
+
+       .org ia64_ivt+0x7e00
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x7e00 Entry 66 (size 16 bundles) Reserved
+       DBG_FAULT(66)
+       FAULT(66)
+
+       .org ia64_ivt+0x7f00
+/////////////////////////////////////////////////////////////////////////////////////////
+// 0x7f00 Entry 67 (size 16 bundles) Reserved
+       DBG_FAULT(67)
+       FAULT(67)
+
+#ifdef CONFIG_IA32_SUPPORT
+
+       /*
+        * There is no particular reason for this code to be here, other than 
that
+        * there happens to be space here that would go unused otherwise.  If 
this
+        * fault ever gets "unreserved", simply moved the following code to a 
more
+        * suitable spot...
+        */
+
+       // IA32 interrupt entry point
+
+ENTRY(dispatch_to_ia32_handler)
+       SAVE_MIN
+       ;;
+       mov r14=cr.isr
+       ssm psr.ic | PSR_DEFAULT_BITS
+       ;;
+       srlz.i                                  // guarantee that interruption 
collection is on
+       ;;
+(p15)  ssm psr.i
+       adds r3=8,r2            // Base pointer for SAVE_REST
+       ;;
+       SAVE_REST
+       ;;
+       mov r15=0x80
+       shr r14=r14,16          // Get interrupt number
+       ;;
+       cmp.ne p6,p0=r14,r15
+(p6)   br.call.dpnt.many b6=non_ia32_syscall
+
+       adds r14=IA64_PT_REGS_R8_OFFSET + 16,sp // 16 byte hole per SW 
conventions
+       adds r15=IA64_PT_REGS_R1_OFFSET + 16,sp
+       ;;
+       cmp.eq pSys,pNonSys=r0,r0 // set pSys=1, pNonSys=0
+       ld8 r8=[r14]            // get r8
+       ;;
+       st8 [r15]=r8            // save original EAX in r1 (IA32 procs don't 
use the GP)
+       ;;
+       alloc r15=ar.pfs,0,0,6,0        // must first in an insn group
+       ;;
+       ld4 r8=[r14],8          // r8 == eax (syscall number)
+       mov r15=IA32_NR_syscalls
+       ;;
+       cmp.ltu.unc p6,p7=r8,r15
+       ld4 out1=[r14],8        // r9 == ecx
+       ;;
+       ld4 out2=[r14],8        // r10 == edx
+       ;;
+       ld4 out0=[r14]          // r11 == ebx
+       adds r14=(IA64_PT_REGS_R13_OFFSET) + 16,sp
+       ;;
+       ld4 out5=[r14],PT(R14)-PT(R13)  // r13 == ebp
+       ;;
+       ld4 out3=[r14],PT(R15)-PT(R14)  // r14 == esi
+       adds r2=TI_FLAGS+IA64_TASK_SIZE,r13
+       ;;
+       ld4 out4=[r14]          // r15 == edi
+       movl r16=ia32_syscall_table
+       ;;
+(p6)   shladd r16=r8,3,r16     // force ni_syscall if not valid syscall number
+       ld4 r2=[r2]             // r2 = current_thread_info()->flags
+       ;;
+       ld8 r16=[r16]
+       and r2=_TIF_SYSCALL_TRACEAUDIT,r2       // mask trace or audit
+       ;;
+       mov b6=r16
+       movl r15=ia32_ret_from_syscall
+       cmp.eq p8,p0=r2,r0
+       ;;
+       mov rp=r15
+(p8)   br.call.sptk.many b6=b6
+       br.cond.sptk ia32_trace_syscall
+
+non_ia32_syscall:
+       alloc r15=ar.pfs,0,0,2,0
+       mov out0=r14                            // interrupt #
+       add out1=16,sp                          // pointer to pt_regs
+       ;;                      // avoid WAW on CFM
+       br.call.sptk.many rp=ia32_bad_interrupt
+.ret1: movl r15=ia64_leave_kernel
+       ;;
+       mov rp=r15
+       br.ret.sptk.many rp
+END(dispatch_to_ia32_handler)
+#endif /* CONFIG_IA32_SUPPORT */
+
+#ifdef CONFIG_XEN
+       .section .text,"ax"
+GLOBAL_ENTRY(xen_event_callback)
+       mov r31=pr              // prepare to save predicates
+       ;;
+       SAVE_MIN_WITH_COVER     // uses r31; defines r2 and r3
+       ;;
+       movl r3=XSI_PSR_IC
+       mov r14=1
+       ;;
+       st4 [r3]=r14
+       ;;
+       adds r3=8,r2            // set up second base pointer for SAVE_REST
+       srlz.i                  // ensure everybody knows psr.ic is back on
+       ;;
+       SAVE_REST
+       ;;
+1:
+       alloc r14=ar.pfs,0,0,1,0 // must be first in an insn group
+       add out0=16,sp          // pass pointer to pt_regs as first arg
+       ;;
+       br.call.sptk.many b0=xen_evtchn_do_upcall
+       ;;
+       movl r20=XSI_PSR_I_ADDR
+       ;;
+       ld8 r20=[r20]
+       ;;
+       adds r20=-1,r20         // vcpu_info->evtchn_upcall_pending
+       ;;
+       ld1 r20=[r20]
+       ;;
+       cmp.ne p6,p0=r20,r0     // if there are pending events,
+       (p6) br.spnt.few 1b     // call evtchn_do_upcall again.
+       br.sptk.many ia64_leave_kernel
+END(xen_event_callback)
+
+
+       /*
+        * There is no particular reason for this code to be here, other than 
that
+        * there happens to be space here that would go unused otherwise.  If 
this
+        * fault ever gets "unreserved", simply moved the following code to a 
more
+        * suitable spot...
+        */
+
+GLOBAL_ENTRY(xen_bsw1)
+       /* FIXME: THIS CODE IS NOT NaT SAFE! */
+       mov r14=ar.unat
+       movl r30=XSI_B1NAT
+       ;;
+       ld8 r30=[r30];;
+       mov ar.unat=r30
+       movl r30=XSI_BANKNUM;
+       mov r31=1;;
+       st4 [r30]=r31;
+       movl r30=XSI_BANK1_R16;
+       movl r31=XSI_BANK1_R16+8;;
+       ld8.fill r16=[r30],16; ld8.fill r17=[r31],16;;
+       ld8.fill r18=[r30],16; ld8.fill r19=[r31],16;;
+       ld8.fill r20=[r30],16; ld8.fill r21=[r31],16;;
+       ld8.fill r22=[r30],16; ld8.fill r23=[r31],16;;
+       ld8.fill r24=[r30],16; ld8.fill r25=[r31],16;;
+       ld8.fill r26=[r30],16; ld8.fill r27=[r31],16;;
+       ld8.fill r28=[r30],16; ld8.fill r29=[r31],16;;
+       ld8.fill r30=[r30]; ld8.fill r31=[r31];;
+       mov ar.unat=r14
+       br.ret.sptk.many b0
+END(xen_bsw1)
+
+#endif
-- 
1.5.3


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