3.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Will Deacon <will.deacon@xxxxxxx>
commit bf3f0f332f76a85ff3a0b393aaded5a8533769c0 upstream.
Commit ae8a8b9553bd ("ARM: 7691/1: mm: kill unused TLB_CAN_READ_FROM_L1_CACHE
and use ALT_SMP instead") added early function returns for page table
cache flushing operations on ARMv7 SMP CPUs.
Unfortunately, when targetting Thumb-2, these `mov pc, lr' sequences
assemble to 2 bytes which can lead to corruption of the instruction
stream after code patching.
This patch fixes the alternates to use wide (32-bit) instructions for
Thumb-2, therefore ensuring that the patching code works correctly.
Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm/mm/proc-v7-2level.S | 2 +-
arch/arm/mm/proc-v7-3level.S | 2 +-
arch/arm/mm/proc-v7.S | 11 ++++++-----
3 files changed, 8 insertions(+), 7 deletions(-)
--- a/arch/arm/mm/proc-v7-2level.S
+++ b/arch/arm/mm/proc-v7-2level.S
@@ -110,7 +110,7 @@ ENTRY(cpu_v7_set_pte_ext)
ARM( str r3, [r0, #2048]! )
THUMB( add r0, r0, #2048 )
THUMB( str r3, [r0] )
- ALT_SMP(mov pc,lr)
+ ALT_SMP(W(nop))
ALT_UP (mcr p15, 0, r0, c7, c10, 1) @ flush_pte
#endif
mov pc, lr
--- a/arch/arm/mm/proc-v7-3level.S
+++ b/arch/arm/mm/proc-v7-3level.S
@@ -73,7 +73,7 @@ ENTRY(cpu_v7_set_pte_ext)
tst r3, #1 << (55 - 32) @ L_PTE_DIRTY
orreq r2, #L_PTE_RDONLY
1: strd r2, r3, [r0]
- ALT_SMP(mov pc, lr)
+ ALT_SMP(W(nop))
ALT_UP (mcr p15, 0, r0, c7, c10, 1) @ flush_pte
#endif
mov pc, lr
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -75,13 +75,14 @@ ENTRY(cpu_v7_do_idle)
ENDPROC(cpu_v7_do_idle)
ENTRY(cpu_v7_dcache_clean_area)
- ALT_SMP(mov pc, lr) @ MP extensions imply L1 PTW
- ALT_UP(W(nop))
- dcache_line_size r2, r3
-1: mcr p15, 0, r0, c7, c10, 1 @ clean D entry
+ ALT_SMP(W(nop)) @ MP extensions imply L1 PTW
+ ALT_UP_B(1f)
+ mov pc, lr
+1: dcache_line_size r2, r3
+2: mcr p15, 0, r0, c7, c10, 1 @ clean D entry
add r0, r0, r2
subs r1, r1, r2
- bhi 1b
+ bhi 2b
dsb
mov pc, lr
ENDPROC(cpu_v7_dcache_clean_area)
--
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