WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-changelog

[Xen-changelog] [xen-unstable] linux 2.6.18: eliminate Xen special: alte

To: xen-changelog@xxxxxxxxxxxxxxxxxxx
Subject: [Xen-changelog] [xen-unstable] linux 2.6.18: eliminate Xen special: alternative.c
From: Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>
Date: Wed, 07 Mar 2007 11:30:47 -0800
Delivery-date: Wed, 07 Mar 2007 11:32:54 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
List-help: <mailto:xen-changelog-request@lists.xensource.com?subject=help>
List-id: BK change log <xen-changelog.lists.xensource.com>
List-post: <mailto:xen-changelog@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-changelog>, <mailto:xen-changelog-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-changelog>, <mailto:xen-changelog-request@lists.xensource.com?subject=unsubscribe>
Reply-to: xen-devel@xxxxxxxxxxxxxxxxxxx
Sender: xen-changelog-bounces@xxxxxxxxxxxxxxxxxxx
# HG changeset patch
# User kfraser@xxxxxxxxxxxxxxxxxxxxx
# Date 1173101570 0
# Node ID 192b59b472bcb9bfff88d71549cb50bb8a4ca746
# Parent  c371b6b267531cf2d61cd83deaf24d4df58a1d12
linux 2.6.18: eliminate Xen special: alternative.c

The sole (x86-64 specific) difference of
arch/i386/kernel/alternative-xen.c
over its native original can be eliminated by slightly adjusting
x86-64's make_readonly(), and the Xen special can then be removed.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>
---
 linux-2.6-xen-sparse/arch/i386/kernel/alternative-xen.c |  389 ----------------
 linux-2.6-xen-sparse/arch/x86_64/kernel/Makefile        |    1 
 linux-2.6-xen-sparse/arch/x86_64/mm/init-xen.c          |    8 
 3 files changed, 6 insertions(+), 392 deletions(-)

diff -r c371b6b26753 -r 192b59b472bc 
linux-2.6-xen-sparse/arch/i386/kernel/alternative-xen.c
--- a/linux-2.6-xen-sparse/arch/i386/kernel/alternative-xen.c   Mon Mar 05 
13:30:52 2007 +0000
+++ /dev/null   Thu Jan 01 00:00:00 1970 +0000
@@ -1,389 +0,0 @@
-#include <linux/module.h>
-#include <linux/spinlock.h>
-#include <linux/list.h>
-#include <asm/alternative.h>
-#include <asm/sections.h>
-
-static int no_replacement    = 0;
-static int smp_alt_once      = 0;
-static int debug_alternative = 0;
-
-static int __init noreplacement_setup(char *s)
-{
-       no_replacement = 1;
-       return 1;
-}
-static int __init bootonly(char *str)
-{
-       smp_alt_once = 1;
-       return 1;
-}
-static int __init debug_alt(char *str)
-{
-       debug_alternative = 1;
-       return 1;
-}
-
-__setup("noreplacement", noreplacement_setup);
-__setup("smp-alt-boot", bootonly);
-__setup("debug-alternative", debug_alt);
-
-#define DPRINTK(fmt, args...) if (debug_alternative) \
-       printk(KERN_DEBUG fmt, args)
-
-#ifdef GENERIC_NOP1
-/* Use inline assembly to define this because the nops are defined
-   as inline assembly strings in the include files and we cannot
-   get them easily into strings. */
-asm("\t.data\nintelnops: "
-       GENERIC_NOP1 GENERIC_NOP2 GENERIC_NOP3 GENERIC_NOP4 GENERIC_NOP5 
GENERIC_NOP6
-       GENERIC_NOP7 GENERIC_NOP8);
-extern unsigned char intelnops[];
-static unsigned char *intel_nops[ASM_NOP_MAX+1] = {
-       NULL,
-       intelnops,
-       intelnops + 1,
-       intelnops + 1 + 2,
-       intelnops + 1 + 2 + 3,
-       intelnops + 1 + 2 + 3 + 4,
-       intelnops + 1 + 2 + 3 + 4 + 5,
-       intelnops + 1 + 2 + 3 + 4 + 5 + 6,
-       intelnops + 1 + 2 + 3 + 4 + 5 + 6 + 7,
-};
-#endif
-
-#ifdef K8_NOP1
-asm("\t.data\nk8nops: "
-       K8_NOP1 K8_NOP2 K8_NOP3 K8_NOP4 K8_NOP5 K8_NOP6
-       K8_NOP7 K8_NOP8);
-extern unsigned char k8nops[];
-static unsigned char *k8_nops[ASM_NOP_MAX+1] = {
-       NULL,
-       k8nops,
-       k8nops + 1,
-       k8nops + 1 + 2,
-       k8nops + 1 + 2 + 3,
-       k8nops + 1 + 2 + 3 + 4,
-       k8nops + 1 + 2 + 3 + 4 + 5,
-       k8nops + 1 + 2 + 3 + 4 + 5 + 6,
-       k8nops + 1 + 2 + 3 + 4 + 5 + 6 + 7,
-};
-#endif
-
-#ifdef K7_NOP1
-asm("\t.data\nk7nops: "
-       K7_NOP1 K7_NOP2 K7_NOP3 K7_NOP4 K7_NOP5 K7_NOP6
-       K7_NOP7 K7_NOP8);
-extern unsigned char k7nops[];
-static unsigned char *k7_nops[ASM_NOP_MAX+1] = {
-       NULL,
-       k7nops,
-       k7nops + 1,
-       k7nops + 1 + 2,
-       k7nops + 1 + 2 + 3,
-       k7nops + 1 + 2 + 3 + 4,
-       k7nops + 1 + 2 + 3 + 4 + 5,
-       k7nops + 1 + 2 + 3 + 4 + 5 + 6,
-       k7nops + 1 + 2 + 3 + 4 + 5 + 6 + 7,
-};
-#endif
-
-#ifdef CONFIG_X86_64
-
-extern char __vsyscall_0;
-static inline unsigned char** find_nop_table(void)
-{
-       return k8_nops;
-}
-
-#else /* CONFIG_X86_64 */
-
-static struct nop {
-       int cpuid;
-       unsigned char **noptable;
-} noptypes[] = {
-       { X86_FEATURE_K8, k8_nops },
-       { X86_FEATURE_K7, k7_nops },
-       { -1, NULL }
-};
-
-static unsigned char** find_nop_table(void)
-{
-       unsigned char **noptable = intel_nops;
-       int i;
-
-       for (i = 0; noptypes[i].cpuid >= 0; i++) {
-               if (boot_cpu_has(noptypes[i].cpuid)) {
-                       noptable = noptypes[i].noptable;
-                       break;
-               }
-       }
-       return noptable;
-}
-
-#endif /* CONFIG_X86_64 */
-
-extern struct alt_instr __alt_instructions[], __alt_instructions_end[];
-extern struct alt_instr __smp_alt_instructions[], __smp_alt_instructions_end[];
-extern u8 *__smp_locks[], *__smp_locks_end[];
-
-extern u8 __smp_alt_begin[], __smp_alt_end[];
-
-/* Replace instructions with better alternatives for this CPU type.
-   This runs before SMP is initialized to avoid SMP problems with
-   self modifying code. This implies that assymetric systems where
-   APs have less capabilities than the boot processor are not handled.
-   Tough. Make sure you disable such features by hand. */
-
-void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
-{
-       unsigned char **noptable = find_nop_table();
-       struct alt_instr *a;
-       u8 *instr;
-       int diff, i, k;
-
-       DPRINTK("%s: alt table %p -> %p\n", __FUNCTION__, start, end);
-       for (a = start; a < end; a++) {
-               BUG_ON(a->replacementlen > a->instrlen);
-               if (!boot_cpu_has(a->cpuid))
-                       continue;
-               instr = a->instr;
-#ifdef CONFIG_X86_64
-               /* vsyscall code is not mapped yet. resolve it manually. */
-               if (instr >= (u8 *)VSYSCALL_START && instr < (u8*)VSYSCALL_END) 
{
-                       instr -= VSYSCALL_START - (unsigned long)&__vsyscall_0;
-                       DPRINTK("%s: vsyscall fixup: %p => %p\n",
-                               __FUNCTION__, a->instr, instr);
-               }
-#endif
-               memcpy(instr, a->replacement, a->replacementlen);
-               diff = a->instrlen - a->replacementlen;
-               /* Pad the rest with nops */
-               for (i = a->replacementlen; diff > 0; diff -= k, i += k) {
-                       k = diff;
-                       if (k > ASM_NOP_MAX)
-                               k = ASM_NOP_MAX;
-                       memcpy(a->instr + i, noptable[k], k);
-               }
-       }
-}
-
-#ifdef CONFIG_SMP
-
-static void alternatives_smp_save(struct alt_instr *start, struct alt_instr 
*end)
-{
-       struct alt_instr *a;
-
-       DPRINTK("%s: alt table %p-%p\n", __FUNCTION__, start, end);
-       for (a = start; a < end; a++) {
-               memcpy(a->replacement + a->replacementlen,
-                      a->instr,
-                      a->instrlen);
-       }
-}
-
-static void alternatives_smp_apply(struct alt_instr *start, struct alt_instr 
*end)
-{
-       struct alt_instr *a;
-
-       for (a = start; a < end; a++) {
-               memcpy(a->instr,
-                      a->replacement + a->replacementlen,
-                      a->instrlen);
-       }
-}
-
-static void alternatives_smp_lock(u8 **start, u8 **end, u8 *text, u8 *text_end)
-{
-       u8 **ptr;
-
-       for (ptr = start; ptr < end; ptr++) {
-               if (*ptr < text)
-                       continue;
-               if (*ptr > text_end)
-                       continue;
-               **ptr = 0xf0; /* lock prefix */
-       };
-}
-
-static void alternatives_smp_unlock(u8 **start, u8 **end, u8 *text, u8 
*text_end)
-{
-       unsigned char **noptable = find_nop_table();
-       u8 **ptr;
-
-       for (ptr = start; ptr < end; ptr++) {
-               if (*ptr < text)
-                       continue;
-               if (*ptr > text_end)
-                       continue;
-               **ptr = noptable[1][0];
-       };
-}
-
-struct smp_alt_module {
-       /* what is this ??? */
-       struct module   *mod;
-       char            *name;
-
-       /* ptrs to lock prefixes */
-       u8              **locks;
-       u8              **locks_end;
-
-       /* .text segment, needed to avoid patching init code ;) */
-       u8              *text;
-       u8              *text_end;
-
-       struct list_head next;
-};
-static LIST_HEAD(smp_alt_modules);
-static DEFINE_SPINLOCK(smp_alt);
-
-void alternatives_smp_module_add(struct module *mod, char *name,
-                                void *locks, void *locks_end,
-                                void *text,  void *text_end)
-{
-       struct smp_alt_module *smp;
-       unsigned long flags;
-
-       if (no_replacement)
-               return;
-
-       if (smp_alt_once) {
-               if (boot_cpu_has(X86_FEATURE_UP))
-                       alternatives_smp_unlock(locks, locks_end,
-                                               text, text_end);
-               return;
-       }
-
-       smp = kzalloc(sizeof(*smp), GFP_KERNEL);
-       if (NULL == smp)
-               return; /* we'll run the (safe but slow) SMP code then ... */
-
-       smp->mod        = mod;
-       smp->name       = name;
-       smp->locks      = locks;
-       smp->locks_end  = locks_end;
-       smp->text       = text;
-       smp->text_end   = text_end;
-       DPRINTK("%s: locks %p -> %p, text %p -> %p, name %s\n",
-               __FUNCTION__, smp->locks, smp->locks_end,
-               smp->text, smp->text_end, smp->name);
-
-       spin_lock_irqsave(&smp_alt, flags);
-       list_add_tail(&smp->next, &smp_alt_modules);
-       if (boot_cpu_has(X86_FEATURE_UP))
-               alternatives_smp_unlock(smp->locks, smp->locks_end,
-                                       smp->text, smp->text_end);
-       spin_unlock_irqrestore(&smp_alt, flags);
-}
-
-void alternatives_smp_module_del(struct module *mod)
-{
-       struct smp_alt_module *item;
-       unsigned long flags;
-
-       if (no_replacement || smp_alt_once)
-               return;
-
-       spin_lock_irqsave(&smp_alt, flags);
-       list_for_each_entry(item, &smp_alt_modules, next) {
-               if (mod != item->mod)
-                       continue;
-               list_del(&item->next);
-               spin_unlock_irqrestore(&smp_alt, flags);
-               DPRINTK("%s: %s\n", __FUNCTION__, item->name);
-               kfree(item);
-               return;
-       }
-       spin_unlock_irqrestore(&smp_alt, flags);
-}
-
-void alternatives_smp_switch(int smp)
-{
-       struct smp_alt_module *mod;
-       unsigned long flags;
-
-#ifdef CONFIG_LOCKDEP
-       /*
-        * A not yet fixed binutils section handling bug prevents
-        * alternatives-replacement from working reliably, so turn
-        * it off:
-        */
-       printk("lockdep: not fixing up alternatives.\n");
-       return;
-#endif
-
-       if (no_replacement || smp_alt_once)
-               return;
-       BUG_ON(!smp && (num_online_cpus() > 1));
-
-       spin_lock_irqsave(&smp_alt, flags);
-       if (smp) {
-               printk(KERN_INFO "SMP alternatives: switching to SMP code\n");
-               clear_bit(X86_FEATURE_UP, boot_cpu_data.x86_capability);
-               clear_bit(X86_FEATURE_UP, cpu_data[0].x86_capability);
-               alternatives_smp_apply(__smp_alt_instructions,
-                                      __smp_alt_instructions_end);
-               list_for_each_entry(mod, &smp_alt_modules, next)
-                       alternatives_smp_lock(mod->locks, mod->locks_end,
-                                             mod->text, mod->text_end);
-       } else {
-               printk(KERN_INFO "SMP alternatives: switching to UP code\n");
-               set_bit(X86_FEATURE_UP, boot_cpu_data.x86_capability);
-               set_bit(X86_FEATURE_UP, cpu_data[0].x86_capability);
-               apply_alternatives(__smp_alt_instructions,
-                                  __smp_alt_instructions_end);
-               list_for_each_entry(mod, &smp_alt_modules, next)
-                       alternatives_smp_unlock(mod->locks, mod->locks_end,
-                                               mod->text, mod->text_end);
-       }
-       spin_unlock_irqrestore(&smp_alt, flags);
-}
-
-#endif
-
-void __init alternative_instructions(void)
-{
-       if (no_replacement) {
-               printk(KERN_INFO "(SMP-)alternatives turned off\n");
-               free_init_pages("SMP alternatives",
-                               (unsigned long)__smp_alt_begin,
-                               (unsigned long)__smp_alt_end);
-               return;
-       }
-       apply_alternatives(__alt_instructions, __alt_instructions_end);
-
-       /* switch to patch-once-at-boottime-only mode and free the
-        * tables in case we know the number of CPUs will never ever
-        * change */
-#ifdef CONFIG_HOTPLUG_CPU
-       if (num_possible_cpus() < 2)
-               smp_alt_once = 1;
-#else
-       smp_alt_once = 1;
-#endif
-
-#ifdef CONFIG_SMP
-       if (smp_alt_once) {
-               if (1 == num_possible_cpus()) {
-                       printk(KERN_INFO "SMP alternatives: switching to UP 
code\n");
-                       set_bit(X86_FEATURE_UP, boot_cpu_data.x86_capability);
-                       set_bit(X86_FEATURE_UP, cpu_data[0].x86_capability);
-                       apply_alternatives(__smp_alt_instructions,
-                                          __smp_alt_instructions_end);
-                       alternatives_smp_unlock(__smp_locks, __smp_locks_end,
-                                               _text, _etext);
-               }
-               free_init_pages("SMP alternatives",
-                               (unsigned long)__smp_alt_begin,
-                               (unsigned long)__smp_alt_end);
-       } else {
-               alternatives_smp_save(__smp_alt_instructions,
-                                     __smp_alt_instructions_end);
-               alternatives_smp_module_add(NULL, "core kernel",
-                                           __smp_locks, __smp_locks_end,
-                                           _text, _etext);
-               alternatives_smp_switch(0);
-       }
-#endif
-}
diff -r c371b6b26753 -r 192b59b472bc 
linux-2.6-xen-sparse/arch/x86_64/kernel/Makefile
--- a/linux-2.6-xen-sparse/arch/x86_64/kernel/Makefile  Mon Mar 05 13:30:52 
2007 +0000
+++ b/linux-2.6-xen-sparse/arch/x86_64/kernel/Makefile  Mon Mar 05 13:32:50 
2007 +0000
@@ -62,7 +62,6 @@ pci-dma-y                     += ../../i386/kernel/pci-dma
 pci-dma-y                      += ../../i386/kernel/pci-dma-xen.o
 microcode-$(subst m,y,$(CONFIG_MICROCODE))  := 
../../i386/kernel/microcode-xen.o
 quirks-y                       := ../../i386/kernel/quirks-xen.o
-alternative-y                  := ../../i386/kernel/alternative-xen.o
 
 n-obj-xen := i8259.o reboot.o i8237.o smpboot.o trampoline.o
 
diff -r c371b6b26753 -r 192b59b472bc 
linux-2.6-xen-sparse/arch/x86_64/mm/init-xen.c
--- a/linux-2.6-xen-sparse/arch/x86_64/mm/init-xen.c    Mon Mar 05 13:30:52 
2007 +0000
+++ b/linux-2.6-xen-sparse/arch/x86_64/mm/init-xen.c    Mon Mar 05 13:32:50 
2007 +0000
@@ -410,6 +410,7 @@ static inline void __set_pte(pte_t *dst,
 
 static inline int make_readonly(unsigned long paddr)
 {
+       extern char __vsyscall_0;
        int readonly = 0;
 
        /* Make new page tables read-only. */
@@ -426,9 +427,12 @@ static inline int make_readonly(unsigned
        /*
         * No need for writable mapping of kernel image. This also ensures that
         * page and descriptor tables embedded inside don't have writable
-        * mappings. 
+        * mappings. Exclude the vsyscall area here, allowing alternative
+        * instruction patching to work.
         */
-       if ((paddr >= __pa_symbol(&_text)) && (paddr < __pa_symbol(&_end)))
+       if ((paddr >= __pa_symbol(&_text)) && (paddr < __pa_symbol(&_end))
+           && !(paddr >= __pa_symbol(&__vsyscall_0)
+                && paddr < __pa_symbol(&__vsyscall_0) + PAGE_SIZE))
                readonly = 1;
 
        return readonly;

_______________________________________________
Xen-changelog mailing list
Xen-changelog@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-changelog

<Prev in Thread] Current Thread [Next in Thread>
  • [Xen-changelog] [xen-unstable] linux 2.6.18: eliminate Xen special: alternative.c, Xen patchbot-unstable <=