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| author | Becky Bruce <becky.bruce@freescale.com> | 2007-11-09 23:17:49 +0100 |
|---|---|---|
| committer | Paul Mackerras <paulus@samba.org> | 2007-11-13 06:22:43 +0100 |
| commit | b64f87c16f3c00fe593f632e1ee5798ba3f4f3f4 (patch) | |
| tree | 1e0c63707b73c4b2f316a01b2e3c6ebd82c6356a /arch/powerpc/kernel/entry_32.S | |
| parent | Merge branch 'for-2.6.24' of master.kernel.org:/pub/scm/linux/kernel/git/gala... (diff) | |
| download | linux-b64f87c16f3c00fe593f632e1ee5798ba3f4f3f4.tar.xz linux-b64f87c16f3c00fe593f632e1ee5798ba3f4f3f4.zip | |
[POWERPC] Avoid unpaired stwcx. on some processors
The context switch code in the kernel issues a dummy stwcx. to clear the
reservation, as recommended by the architecture. However, some processors
can have issues if this stwcx to address A occurs while the reservation
is already held to a different address B. To avoid this problem, the dummy
stwcx. needs to be paired with a dummy lwarx to the same address.
This adds the dummy lwarx, and creates a cpu feature bit to indicate
which cpus are affected. Tested on mpc8641_hpcn_defconfig in
arch/powerpc; build tested in arch/ppc.
Signed-off-by: Becky Bruce <becky.bruce@freescale.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/powerpc/kernel/entry_32.S')
| -rw-r--r-- | arch/powerpc/kernel/entry_32.S | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S index a7572cf464bd..69a91bd46115 100644 --- a/arch/powerpc/kernel/entry_32.S +++ b/arch/powerpc/kernel/entry_32.S @@ -251,6 +251,9 @@ syscall_exit_cont: bne- 2f 1: #endif /* CONFIG_44x */ +BEGIN_FTR_SECTION + lwarx r7,0,r1 +END_FTR_SECTION_IFSET(CPU_FTR_NEED_PAIRED_STWCX) stwcx. r0,0,r1 /* to clear the reservation */ lwz r4,_LINK(r1) lwz r5,_CCR(r1) @@ -717,6 +720,9 @@ restore: mtctr r11 PPC405_ERR77(0,r1) +BEGIN_FTR_SECTION + lwarx r11,0,r1 +END_FTR_SECTION_IFSET(CPU_FTR_NEED_PAIRED_STWCX) stwcx. r0,0,r1 /* to clear the reservation */ #if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE)) |