On Tue, Apr 21, 2009 at 11:49:55AM +0900, Isaku Yamahata wrote:
> On Tue, Apr 21, 2009 at 11:19:06AM +0900, Isaku Yamahata wrote:
> > On Tue, Apr 21, 2009 at 10:27:02AM +0900, Akio Takebe wrote:
> > > Hi,
> > >
> > > The following changeset broke booting xen-ia64 on some kinds of ia64
> > > boxes.
> > > http://xenbits.xensource.com/ext/ia64/xen-unstable.hg/rev/3fd8f9b34941
> > >
> > > The tasklet_schedule call raise_softirq().
> > > Because raise_softirq() use per_cpu, if we access per_cpu before
> > > cpu_init()
> > > the behavior would be unexpected.
> > >
> > > I make the following patch for this investigation.
> > > It can boot xen-ia64 on the ia64 boxes.
> > > I'm not sure why Tiger4 can boot the latest xen-ia64.
> > > I didn't find a good-looking solution, what do you think about it?
> >
> > Unfortunately, it happened to boot on my tiger4 so that I pushed out
> > the change set.
> > I Understood the issue. Looking into the boot sequence, it seems
> > to somewhat difficult to move down init_console() after cpu_init()
> > and remove all the printk() before cpu_init().
> > Hmm, it needs some consideration.
> >
> > BTW, is there similar issue on ia64 linux case before?
>
> Yes, there was.
> commit 10617bbe84628eb18ab5f723d3ba35005adde143
> and
> commit c459ce8b5a7d933a3bcf6915ab17ac1e036e2ac4
>
> The mails were
> Jul 14 Christian Kande Initialization order problem
> and
> Aug 07 Luck, Tony [RFC] Fix early access to per-cpu variables
> thread.
I created the patch following ia64 linux way.
Could you try it?
This is not intrusive to the common code, and prevent
future similar breakage.
[IA64] fix early access to per cpu area.
The following changeset broke booting xen-ia64 on some kinds of ia64 boxes.
http://xenbits.xensource.com/ext/ia64/xen-unstable.hg/rev/3fd8f9b34941
The tasklet_schedule call raise_softirq().
Because raise_softirq() use per_cpu, if we access per_cpu before cpu_init()
the behavior would be unexpected.
There was a similar issueson Linux/ia64.
The following change sets resolved it.
10617bbe84628eb18ab5f723d3ba35005adde143
c459ce8b5a7d933a3bcf6915ab17ac1e036e2ac4
This patch fixes the issue following the linux/ia64 solution.
Allocate per cpu area for cpu0 in .data section and initialize
it early.
reported-by: Akio Takebe <takebe_akio@xxxxxxxxxxxxxx>
Signed-off-by: Isaku Yamahata <yamahata@xxxxxxxxxxxxx>
diff --git a/xen/arch/ia64/linux-xen/head.S b/xen/arch/ia64/linux-xen/head.S
--- a/xen/arch/ia64/linux-xen/head.S
+++ b/xen/arch/ia64/linux-xen/head.S
@@ -382,6 +382,35 @@ 1: // now we are in virtual mode
mov ar.rsc=0 // place RSE in enforced lazy mode
;;
loadrs // clear the dirty partition
+#ifdef XEN
+(isAP) br.few 2f
+ movl r19=__phys_per_cpu_start
+ mov r18=PERCPU_PAGE_SIZE
+#ifndef CONFIG_SMP
+ add r19=r19,r18
+ ;;
+#else
+ movl r20=__cpu0_per_cpu
+ ;;
+ shr.u r18=r18,3
+1:
+ ld8 r21=[r19],8 ;;
+ st8[r20]=r21,8
+ adds r18=-1,r18
+ ;;
+ cmp4.lt p7,p6=0,r18
+(p7) br.cond.dptk.few 1b
+ ;;
+#endif
+ movl r18=__per_cpu_offset
+ movl r19=__cpu0_per_cpu
+ movl r20=__per_cpu_start
+ ;;
+ sub r20=r19,r20
+ ;;
+ st8 [r18]=r20
+2:
+#endif
;;
mov ar.bspstore=r2 // establish the new RSE stack
;;
diff --git a/xen/arch/ia64/linux-xen/mm_contig.c
b/xen/arch/ia64/linux-xen/mm_contig.c
--- a/xen/arch/ia64/linux-xen/mm_contig.c
+++ b/xen/arch/ia64/linux-xen/mm_contig.c
@@ -183,7 +183,7 @@ void *percpu_area __initdata = NULL;
void* __init
per_cpu_allocate(void *xen_heap_start, unsigned long end_in_pa)
{
- int order = get_order(NR_CPUS * PERCPU_PAGE_SIZE);
+ int order = get_order((NR_CPUS - 1) * PERCPU_PAGE_SIZE);
unsigned long size = 1UL << (order + PAGE_SHIFT);
unsigned long start = ALIGN_UP((unsigned long)xen_heap_start,
PERCPU_PAGE_SIZE);
@@ -226,19 +226,31 @@ per_cpu_init (void)
*/
if (smp_processor_id() == 0) {
#ifdef XEN
+ void *cpu0_data = __cpu0_per_cpu;
+
+ __per_cpu_offset[0] = (char *)cpu0_data - __per_cpu_start;
+ per_cpu(local_per_cpu_offset, 0) = __per_cpu_offset[0];
+
cpu_data = get_per_cpu_area();
if (cpu_data == NULL)
panic("can't allocate per cpu area.\n");
+
+ for (cpu = 1; cpu < NR_CPUS; cpu++) {
+ memcpy(cpu_data, __phys_per_cpu_start, __per_cpu_end -
__per_cpu_start);
+ __per_cpu_offset[cpu] = (char *) cpu_data -
__per_cpu_start;
+ cpu_data += PERCPU_PAGE_SIZE;
+ per_cpu(local_per_cpu_offset, cpu) =
__per_cpu_offset[cpu];
+ }
#else
cpu_data = __alloc_bootmem(PERCPU_PAGE_SIZE * NR_CPUS,
PERCPU_PAGE_SIZE,
__pa(MAX_DMA_ADDRESS));
-#endif
for (cpu = 0; cpu < NR_CPUS; cpu++) {
memcpy(cpu_data, __phys_per_cpu_start, __per_cpu_end -
__per_cpu_start);
__per_cpu_offset[cpu] = (char *) cpu_data -
__per_cpu_start;
cpu_data += PERCPU_PAGE_SIZE;
per_cpu(local_per_cpu_offset, cpu) =
__per_cpu_offset[cpu];
}
+#endif
}
return __per_cpu_start + __per_cpu_offset[smp_processor_id()];
}
diff --git a/xen/arch/ia64/linux-xen/smpboot.c
b/xen/arch/ia64/linux-xen/smpboot.c
--- a/xen/arch/ia64/linux-xen/smpboot.c
+++ b/xen/arch/ia64/linux-xen/smpboot.c
@@ -449,8 +449,8 @@ start_secondary (void *unused)
{
/* Early console may use I/O ports */
ia64_set_kr(IA64_KR_IO_BASE, __pa(ia64_iobase));
+#ifndef XEN
Dprintk("start_secondary: starting CPU 0x%x\n",
hard_smp_processor_id());
-#ifndef XEN
efi_map_pal_code();
#endif
cpu_init();
diff --git a/xen/arch/ia64/xen/xen.lds.S b/xen/arch/ia64/xen/xen.lds.S
--- a/xen/arch/ia64/xen/xen.lds.S
+++ b/xen/arch/ia64/xen/xen.lds.S
@@ -195,7 +195,17 @@ SECTIONS
data : { } :data
.data : AT(ADDR(.data) - LOAD_OFFSET)
- { *(.data) *(.data1) *(.gnu.linkonce.d*) CONSTRUCTORS }
+ {
+#ifdef CONFIG_SMP
+ . = ALIGN(PERCPU_PAGE_SIZE);
+ __cpu0_per_cpu = .;
+ . = . + PERCPU_PAGE_SIZE; /* cpu0 per-cpu space */
+#endif
+ *(.data)
+ *(.data1)
+ *(.gnu.linkonce.d*)
+ CONSTRUCTORS
+ }
. = ALIGN(16); /* gp must be 16-byte aligned for exc. table */
.got : AT(ADDR(.got) - LOAD_OFFSET)
diff --git a/xen/include/asm-ia64/linux-xen/asm/README.origin
b/xen/include/asm-ia64/linux-xen/asm/README.origin
--- a/xen/include/asm-ia64/linux-xen/asm/README.origin
+++ b/xen/include/asm-ia64/linux-xen/asm/README.origin
@@ -22,6 +22,7 @@ pgtable.h -> linux/include/asm-ia64/pgt
processor.h -> linux/include/asm-ia64/processor.h
ptrace.h -> linux/include/asm-ia64/ptrace.h
sal.h -> linux/include/asm-ia64/sal.h
+sections.h -> linux/include/asm-ia64/sections.h
smp.h -> linux/include/asm-ia64/smp.h
spinlock.h -> linux/include/asm-ia64/spinlock.h
system.h -> linux/include/asm-ia64/system.h
diff --git a/xen/include/asm-ia64/linux/asm/sections.h
b/xen/include/asm-ia64/linux-xen/asm/sections.h
rename from xen/include/asm-ia64/linux/asm/sections.h
rename to xen/include/asm-ia64/linux-xen/asm/sections.h
--- a/xen/include/asm-ia64/linux/asm/sections.h
+++ b/xen/include/asm-ia64/linux-xen/asm/sections.h
@@ -9,6 +9,9 @@
#include <asm-generic/sections.h>
extern char __per_cpu_start[], __per_cpu_end[], __phys_per_cpu_start[];
+#ifdef CONFIG_SMP
+extern char __cpu0_per_cpu[];
+#endif
extern char __start___vtop_patchlist[], __end___vtop_patchlist[];
extern char __start___mckinley_e9_bundles[], __end___mckinley_e9_bundles[];
extern char __start_gate_section[];
diff --git a/xen/include/asm-ia64/linux/asm/README.origin
b/xen/include/asm-ia64/linux/asm/README.origin
--- a/xen/include/asm-ia64/linux/asm/README.origin
+++ b/xen/include/asm-ia64/linux/asm/README.origin
@@ -29,7 +29,6 @@ param.h -> linux/include/asm-ia64/para
patch.h -> linux/include/asm-ia64/patch.h
pci.h -> linux/include/asm-ia64/pci.h
rse.h -> linux/include/asm-ia64/rse.h
-sections.h -> linux/include/asm-ia64/sections.h
setup.h -> linux/include/asm-ia64/setup.h
string.h -> linux/include/asm-ia64/string.h
thread_info.h -> linux/include/asm-ia64/thread_info.h
--
yamahata
cpu0-per-cpu.patch
Description: Text Data
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