diff options
| -rw-r--r-- | arch/arm64/include/asm/efi.h | 8 | ||||
| -rw-r--r-- | arch/arm64/kernel/efi-rt-wrapper.S | 32 | ||||
| -rw-r--r-- | arch/arm64/kernel/efi.c | 22 | ||||
| -rw-r--r-- | arch/arm64/mm/fault.c | 4 | ||||
| -rw-r--r-- | drivers/firmware/efi/runtime-wrappers.c | 1 |
5 files changed, 62 insertions, 5 deletions
diff --git a/arch/arm64/include/asm/efi.h b/arch/arm64/include/asm/efi.h index 1c408ec3c8b3..31d13a6001df 100644 --- a/arch/arm64/include/asm/efi.h +++ b/arch/arm64/include/asm/efi.h @@ -14,8 +14,16 @@ #ifdef CONFIG_EFI extern void efi_init(void); + +bool efi_runtime_fixup_exception(struct pt_regs *regs, const char *msg); #else #define efi_init() + +static inline +bool efi_runtime_fixup_exception(struct pt_regs *regs, const char *msg) +{ + return false; +} #endif int efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md); diff --git a/arch/arm64/kernel/efi-rt-wrapper.S b/arch/arm64/kernel/efi-rt-wrapper.S index b2786b968fee..a00886410537 100644 --- a/arch/arm64/kernel/efi-rt-wrapper.S +++ b/arch/arm64/kernel/efi-rt-wrapper.S @@ -6,7 +6,7 @@ #include <linux/linkage.h> SYM_FUNC_START(__efi_rt_asm_wrapper) - stp x29, x30, [sp, #-32]! + stp x29, x30, [sp, #-112]! mov x29, sp /* @@ -16,11 +16,21 @@ SYM_FUNC_START(__efi_rt_asm_wrapper) */ stp x1, x18, [sp, #16] + /* + * Preserve all callee saved registers and preserve the stack pointer + * value at the base of the EFI runtime stack so we can recover from + * synchronous exceptions occurring while executing the firmware + * routines. + */ + stp x19, x20, [sp, #32] + stp x21, x22, [sp, #48] + stp x23, x24, [sp, #64] + stp x25, x26, [sp, #80] + stp x27, x28, [sp, #96] + ldr_l x16, efi_rt_stack_top mov sp, x16 -#ifdef CONFIG_SHADOW_CALL_STACK - str x18, [sp, #-16]! -#endif + stp x18, x29, [sp, #-16]! /* * We are lucky enough that no EFI runtime services take more than @@ -38,7 +48,7 @@ SYM_FUNC_START(__efi_rt_asm_wrapper) mov sp, x29 ldp x1, x2, [sp, #16] cmp x2, x18 - ldp x29, x30, [sp], #32 + ldp x29, x30, [sp], #112 b.ne 0f ret 0: @@ -56,3 +66,15 @@ SYM_FUNC_START(__efi_rt_asm_wrapper) b efi_handle_corrupted_x18 // tail call SYM_FUNC_END(__efi_rt_asm_wrapper) + +SYM_CODE_START(__efi_rt_asm_recover) + mov sp, x30 + + ldp x19, x20, [sp, #32] + ldp x21, x22, [sp, #48] + ldp x23, x24, [sp, #64] + ldp x25, x26, [sp, #80] + ldp x27, x28, [sp, #96] + ldp x29, x30, [sp], #112 + ret +SYM_CODE_END(__efi_rt_asm_recover) diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c index 386bd81ca12b..fab05de2e12d 100644 --- a/arch/arm64/kernel/efi.c +++ b/arch/arm64/kernel/efi.c @@ -149,6 +149,28 @@ DEFINE_SPINLOCK(efi_rt_lock); asmlinkage u64 *efi_rt_stack_top __ro_after_init; +asmlinkage efi_status_t __efi_rt_asm_recover(void); + +bool efi_runtime_fixup_exception(struct pt_regs *regs, const char *msg) +{ + /* Check whether the exception occurred while running the firmware */ + if (current_work() != &efi_rts_work.work || regs->pc >= TASK_SIZE_64) + return false; + + pr_err(FW_BUG "Unable to handle %s in EFI runtime service\n", msg); + add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_STILL_OK); + clear_bit(EFI_RUNTIME_SERVICES, &efi.flags); + + regs->regs[0] = EFI_ABORTED; + regs->regs[30] = efi_rt_stack_top[-1]; + regs->pc = (u64)__efi_rt_asm_recover; + + if (IS_ENABLED(CONFIG_SHADOW_CALL_STACK)) + regs->regs[18] = efi_rt_stack_top[-2]; + + return true; +} + /* EFI requires 8 KiB of stack space for runtime services */ static_assert(THREAD_SIZE >= SZ_8K); diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index 5b391490e045..3e9cf9826417 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -30,6 +30,7 @@ #include <asm/bug.h> #include <asm/cmpxchg.h> #include <asm/cpufeature.h> +#include <asm/efi.h> #include <asm/exception.h> #include <asm/daifflags.h> #include <asm/debug-monitors.h> @@ -391,6 +392,9 @@ static void __do_kernel_fault(unsigned long addr, unsigned long esr, msg = "paging request"; } + if (efi_runtime_fixup_exception(regs, msg)) + return; + die_kernel_fault(msg, addr, esr, regs); } diff --git a/drivers/firmware/efi/runtime-wrappers.c b/drivers/firmware/efi/runtime-wrappers.c index f3e54f6616f0..7feee3d9c2bf 100644 --- a/drivers/firmware/efi/runtime-wrappers.c +++ b/drivers/firmware/efi/runtime-wrappers.c @@ -83,6 +83,7 @@ struct efi_runtime_work efi_rts_work; else \ pr_err("Failed to queue work to efi_rts_wq.\n"); \ \ + WARN_ON_ONCE(efi_rts_work.status == EFI_ABORTED); \ exit: \ efi_rts_work.efi_rts_id = EFI_NONE; \ efi_rts_work.status; \ |