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-rw-r--r--arch/arm/kernel/entry-header.S29
1 files changed, 15 insertions, 14 deletions
diff --git a/arch/arm/kernel/entry-header.S b/arch/arm/kernel/entry-header.S
index 8db307d0954..2fdf8679b46 100644
--- a/arch/arm/kernel/entry-header.S
+++ b/arch/arm/kernel/entry-header.S
@@ -208,26 +208,21 @@
#endif
.endif
msr spsr_cxsf, \rpsr
-#if defined(CONFIG_CPU_V6)
- ldr r0, [sp]
- strex r1, r2, [sp] @ clear the exclusive monitor
- ldmib sp, {r1 - pc}^ @ load r1 - pc, cpsr
-#elif defined(CONFIG_CPU_32v6K)
- clrex @ clear the exclusive monitor
- ldmia sp, {r0 - pc}^ @ load r0 - pc, cpsr
-#else
- ldmia sp, {r0 - pc}^ @ load r0 - pc, cpsr
+#if defined(CONFIG_CPU_V6) || defined(CONFIG_CPU_32v6K)
+ @ We must avoid clrex due to Cortex-A15 erratum #830321
+ sub r0, sp, #4 @ uninhabited address
+ strex r1, r2, [r0] @ clear the exclusive monitor
#endif
+ ldmia sp, {r0 - pc}^ @ load r0 - pc, cpsr
.endm
.macro restore_user_regs, fast = 0, offset = 0
ldr r1, [sp, #\offset + S_PSR] @ get calling cpsr
ldr lr, [sp, #\offset + S_PC]! @ get pc
msr spsr_cxsf, r1 @ save in spsr_svc
-#if defined(CONFIG_CPU_V6)
+#if defined(CONFIG_CPU_V6) || defined(CONFIG_CPU_32v6K)
+ @ We must avoid clrex due to Cortex-A15 erratum #830321
strex r1, r2, [sp] @ clear the exclusive monitor
-#elif defined(CONFIG_CPU_32v6K)
- clrex @ clear the exclusive monitor
#endif
.if \fast
ldmdb sp, {r1 - lr}^ @ get calling r1 - lr
@@ -261,7 +256,10 @@
.endif
ldr lr, [sp, #S_SP] @ top of the stack
ldrd r0, r1, [sp, #S_LR] @ calling lr and pc
- clrex @ clear the exclusive monitor
+
+ @ We must avoid clrex due to Cortex-A15 erratum #830321
+ strex r2, r1, [sp, #S_LR] @ clear the exclusive monitor
+
stmdb lr!, {r0, r1, \rpsr} @ calling lr and rfe context
ldmia sp, {r0 - r12}
mov sp, lr
@@ -282,13 +280,16 @@
.endm
#else /* ifdef CONFIG_CPU_V7M */
.macro restore_user_regs, fast = 0, offset = 0
- clrex @ clear the exclusive monitor
mov r2, sp
load_user_sp_lr r2, r3, \offset + S_SP @ calling sp, lr
ldr r1, [sp, #\offset + S_PSR] @ get calling cpsr
ldr lr, [sp, #\offset + S_PC] @ get pc
add sp, sp, #\offset + S_SP
msr spsr_cxsf, r1 @ save in spsr_svc
+
+ @ We must avoid clrex due to Cortex-A15 erratum #830321
+ strex r1, r2, [sp] @ clear the exclusive monitor
+
.if \fast
ldmdb sp, {r1 - r12} @ get calling r1 - r12
.else