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| author |  Josh Poimboeuf <jpoimboe@kernel.org>
| 2024-01-03 19:36:26 +0100 |
|---|---|---|
| committer |  Borislav Petkov (AMD) <bp@alien8.de>
| 2024-02-12 11:42:15 +0100 |
| commit | 4461438a8405e800f90e0e40409e5f3d07eed381 (patch) | |
| tree | 1c660616f321919a56e80cac4fd9e0e980065a68 /arch/x86/entry/thunk_64.S | |
| parent | x86/bugs: Rename CONFIG_RETHUNK => CONFIG_MITIGATION_RETHUNK (diff) | |
| download | linux-4461438a8405e800f90e0e40409e5f3d07eed381.tar.gz linux-4461438a8405e800f90e0e40409e5f3d07eed381.tar.bz2 linux-4461438a8405e800f90e0e40409e5f3d07eed381.zip | |
x86/retpoline: Ensure default return thunk isn't used at runtime
Make sure the default return thunk is not used after all return
instructions have been patched by the alternatives because the default
return thunk is insufficient when it comes to mitigating Retbleed or
SRSO.
Fix based on an earlier version by David Kaplan <david.kaplan@amd.com>.
[ bp: Fix the compilation error of warn_thunk_thunk being an invisible
symbol, hoist thunk macro into calling.h ]
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Co-developed-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20231010171020.462211-4-david.kaplan@amd.com
Link: https://lore.kernel.org/r/20240104132446.GEZZaxnrIgIyat0pqf@fat_crate.local
Diffstat (limited to 'arch/x86/entry/thunk_64.S')
| -rw-r--r-- | arch/x86/entry/thunk_64.S | 33 |
1 files changed, 0 insertions, 33 deletions
diff --git a/arch/x86/entry/thunk_64.S b/arch/x86/entry/thunk_64.S index 416b400f39db..119ebdc3d362 100644 --- a/arch/x86/entry/thunk_64.S +++ b/arch/x86/entry/thunk_64.S @@ -9,39 +9,6 @@ #include "calling.h" #include <asm/asm.h> - /* rdi: arg1 ... normal C conventions. rax is saved/restored. */ - .macro THUNK name, func -SYM_FUNC_START(\name) - pushq %rbp - movq %rsp, %rbp - - pushq %rdi - pushq %rsi - pushq %rdx - pushq %rcx - pushq %rax - pushq %r8 - pushq %r9 - pushq %r10 - pushq %r11 - - call \func - - popq %r11 - popq %r10 - popq %r9 - popq %r8 - popq %rax - popq %rcx - popq %rdx - popq %rsi - popq %rdi - popq %rbp - RET -SYM_FUNC_END(\name) - _ASM_NOKPROBE(\name) - .endm - THUNK preempt_schedule_thunk, preempt_schedule THUNK preempt_schedule_notrace_thunk, preempt_schedule_notrace EXPORT_SYMBOL(preempt_schedule_thunk) |