This change adds per-CPU shadow call stacks for the SDEI handler. Similarly to how the kernel stacks are handled, we add separate shadow stacks for normal and critical events. Signed-off-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx> Reviewed-by: James Morse <james.morse@xxxxxxx> Tested-by: James Morse <james.morse@xxxxxxx> --- arch/arm64/kernel/entry.S | 14 +++++++++++++- arch/arm64/kernel/scs.c | 5 +++++ 2 files changed, 18 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 14f0ff763b39..9f7be489d26d 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -1058,13 +1058,16 @@ SYM_CODE_START(__sdei_asm_handler) mov x19, x1 +#if defined(CONFIG_VMAP_STACK) || defined(CONFIG_SHADOW_CALL_STACK) + ldrb w4, [x19, #SDEI_EVENT_PRIORITY] +#endif + #ifdef CONFIG_VMAP_STACK /* * entry.S may have been using sp as a scratch register, find whether * this is a normal or critical event and switch to the appropriate * stack for this CPU. */ - ldrb w4, [x19, #SDEI_EVENT_PRIORITY] cbnz w4, 1f ldr_this_cpu dst=x5, sym=sdei_stack_normal_ptr, tmp=x6 b 2f @@ -1074,6 +1077,15 @@ SYM_CODE_START(__sdei_asm_handler) mov sp, x5 #endif +#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 + b 4f +3: adr_this_cpu dst=x18, sym=sdei_shadow_call_stack_critical, tmp=x6 +4: +#endif + /* * We may have interrupted userspace, or a guest, or exit-from or * return-to either of these. We can't trust sp_el0, restore it. diff --git a/arch/arm64/kernel/scs.c b/arch/arm64/kernel/scs.c index 086ad97bba86..656262736eca 100644 --- a/arch/arm64/kernel/scs.c +++ b/arch/arm64/kernel/scs.c @@ -14,3 +14,8 @@ __aligned(SCS_SIZE) DEFINE_SCS(irq_shadow_call_stack); + +#ifdef CONFIG_ARM_SDE_INTERFACE +DEFINE_SCS(sdei_shadow_call_stack_normal); +DEFINE_SCS(sdei_shadow_call_stack_critical); +#endif -- 2.26.1.301.g55bc3eb7cb9-goog
