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authorNicholas Piggin <npiggin@gmail.com>2020-10-07 10:06:05 +0200
committerMichael Ellerman <mpe@ellerman.id.au>2020-10-08 03:50:52 +0200
commit792254a77201453d9a77479e63dc216ad90462d2 (patch)
tree705bc1471240d76c54be84a457c51fb18e9439ff /arch/powerpc/kernel/entry_64.S
parentpowerpc/hv-gpci: Add sysfs files inside hv-gpci device to show cpumask (diff)
downloadlinux-792254a77201453d9a77479e63dc216ad90462d2.tar.xz
linux-792254a77201453d9a77479e63dc216ad90462d2.zip
powerpc/security: Fix link stack flush instruction
The inline execution path for the hardware assisted branch flush instruction failed to set CTR to the correct value before bcctr, causing a crash when the feature is enabled. Fixes: 4d24e21cc694 ("powerpc/security: Allow for processors that flush the link stack using the special bcctr") Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20201007080605.64423-1-npiggin@gmail.com
Diffstat (limited to 'arch/powerpc/kernel/entry_64.S')
-rw-r--r--arch/powerpc/kernel/entry_64.S8
1 files changed, 6 insertions, 2 deletions
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index 733e40eba4eb..2f3846192ec7 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -430,7 +430,11 @@ _ASM_NOKPROBE_SYMBOL(save_nvgprs);
#define FLUSH_COUNT_CACHE \
1: nop; \
- patch_site 1b, patch__call_flush_branch_caches
+ patch_site 1b, patch__call_flush_branch_caches1; \
+1: nop; \
+ patch_site 1b, patch__call_flush_branch_caches2; \
+1: nop; \
+ patch_site 1b, patch__call_flush_branch_caches3
.macro nops number
.rept \number
@@ -512,7 +516,7 @@ _GLOBAL(_switch)
kuap_check_amr r9, r10
- FLUSH_COUNT_CACHE
+ FLUSH_COUNT_CACHE /* Clobbers r9, ctr */
/*
* On SMP kernels, care must be taken because a task may be