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| author | Ard Biesheuvel <ardb@kernel.org> | 2022-11-30 17:37:17 +0100 |
|---|---|---|
| committer | Ard Biesheuvel <ardb@kernel.org> | 2022-12-01 14:48:26 +0100 |
| commit | 7572ac3c979d4d0fb42d73a72d2608656516ff4f (patch) | |
| tree | 1f5d452d5b93e3ac525dbaa04ed9106aa9ba4b18 /arch/arm64/kernel/efi-rt-wrapper.S | |
| parent | arm64: efi: Fix handling of misaligned runtime regions and drop warning (diff) | |
| download | linux-7572ac3c979d4d0fb42d73a72d2608656516ff4f.tar.xz linux-7572ac3c979d4d0fb42d73a72d2608656516ff4f.zip | |
arm64: efi: Revert "Recover from synchronous exceptions ..."
This reverts commit 23715a26c8d81291, which introduced some code in
assembler that manipulates both the ordinary and the shadow call stack
pointer in a way that could potentially be taken advantage of. So let's
revert it, and do a better job the next time around.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Diffstat (limited to 'arch/arm64/kernel/efi-rt-wrapper.S')
| -rw-r--r-- | arch/arm64/kernel/efi-rt-wrapper.S | 33 |
1 files changed, 2 insertions, 31 deletions
diff --git a/arch/arm64/kernel/efi-rt-wrapper.S b/arch/arm64/kernel/efi-rt-wrapper.S index 67babd5f04c2..75691a2641c1 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, #-112]! + stp x29, x30, [sp, #-32]! mov x29, sp /* @@ -17,20 +17,6 @@ SYM_FUNC_START(__efi_rt_asm_wrapper) stp x1, x18, [sp, #16] /* - * Preserve all callee saved registers and record the stack pointer - * value in a per-CPU variable so we can recover from synchronous - * exceptions occurring while running 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] - - adr_this_cpu x8, __efi_rt_asm_recover_sp, x9 - str x29, [x8] - - /* * We are lucky enough that no EFI runtime services take more than * 5 arguments, so all are passed in registers rather than via the * stack. @@ -45,7 +31,7 @@ SYM_FUNC_START(__efi_rt_asm_wrapper) ldp x1, x2, [sp, #16] cmp x2, x18 - ldp x29, x30, [sp], #112 + ldp x29, x30, [sp], #32 b.ne 0f ret 0: @@ -59,18 +45,3 @@ SYM_FUNC_START(__efi_rt_asm_wrapper) mov x18, x2 b efi_handle_corrupted_x18 // tail call SYM_FUNC_END(__efi_rt_asm_wrapper) - -SYM_FUNC_START(__efi_rt_asm_recover) - ldr_this_cpu x8, __efi_rt_asm_recover_sp, x9 - mov sp, x8 - - ldp x0, x18, [sp, #16] - 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 - - b efi_handle_runtime_exception -SYM_FUNC_END(__efi_rt_asm_recover) |