x18 holds the SCS stack pointer value, so introduce a register alias to make this easier to read in assembly code.
Signed-off-by: Will Deacon <[email protected]> --- arch/arm64/include/asm/scs.h | 6 ++++-- arch/arm64/kernel/entry.S | 10 +++++----- arch/arm64/kernel/head.S | 2 +- 3 files changed, 10 insertions(+), 8 deletions(-) diff --git a/arch/arm64/include/asm/scs.h b/arch/arm64/include/asm/scs.h index 6b8cf4352fe3..d46efdd2060a 100644 --- a/arch/arm64/include/asm/scs.h +++ b/arch/arm64/include/asm/scs.h @@ -7,12 +7,14 @@ #include <asm/asm-offsets.h> #ifdef CONFIG_SHADOW_CALL_STACK + scs_sp .req x18 + .macro scs_load tsk, tmp - ldr x18, [\tsk, #TSK_TI_SCS_SP] + ldr scs_sp, [\tsk, #TSK_TI_SCS_SP] .endm .macro scs_save tsk, tmp - str x18, [\tsk, #TSK_TI_SCS_SP] + str scs_sp, [\tsk, #TSK_TI_SCS_SP] .endm #else .macro scs_load tsk, tmp diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index cb0516e6f963..741faf0706f1 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -394,7 +394,7 @@ alternative_insn eret, nop, ARM64_UNMAP_KERNEL_AT_EL0 .macro irq_stack_entry mov x19, sp // preserve the original sp #ifdef CONFIG_SHADOW_CALL_STACK - mov x24, x18 // preserve the original shadow stack + mov x24, scs_sp // preserve the original shadow stack #endif /* @@ -416,7 +416,7 @@ alternative_insn eret, nop, ARM64_UNMAP_KERNEL_AT_EL0 #ifdef CONFIG_SHADOW_CALL_STACK /* also switch to the irq shadow stack */ - adr_this_cpu x18, irq_shadow_call_stack, x26 + adr_this_cpu scs_sp, irq_shadow_call_stack, x26 #endif 9998: @@ -430,7 +430,7 @@ alternative_insn eret, nop, ARM64_UNMAP_KERNEL_AT_EL0 .macro irq_stack_exit mov sp, x19 #ifdef CONFIG_SHADOW_CALL_STACK - mov x18, x24 + mov scs_sp, x24 #endif .endm @@ -1071,9 +1071,9 @@ SYM_CODE_START(__sdei_asm_handler) #ifdef CONFIG_SHADOW_CALL_STACK /* Use a separate shadow call stack for normal and critical events */ cbnz w4, 3f - adr_this_cpu dst=x18, sym=sdei_shadow_call_stack_normal, tmp=x6 + adr_this_cpu dst=scs_sp, sym=sdei_shadow_call_stack_normal, tmp=x6 b 4f -3: adr_this_cpu dst=x18, sym=sdei_shadow_call_stack_critical, tmp=x6 +3: adr_this_cpu dst=scs_sp, sym=sdei_shadow_call_stack_critical, tmp=x6 4: #endif diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index 2b01c19c5483..1293baddfd20 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -426,7 +426,7 @@ SYM_FUNC_START_LOCAL(__primary_switched) mov x29, sp #ifdef CONFIG_SHADOW_CALL_STACK - adr_l x18, init_shadow_call_stack // Set shadow call stack + adr_l scs_sp, init_shadow_call_stack // Set shadow call stack #endif str_l x21, __fdt_pointer, x5 // Save FDT pointer -- 2.26.2.761.g0e0b3e54be-goog
