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| author | Ingo Molnar <mingo@kernel.org> | 2025-05-13 11:47:10 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2025-05-13 11:47:10 +0300 |
| commit | c4070e1996e05dd2eb5e08ee68d0d00553ae08f7 (patch) | |
| tree | 180e4a4bae29635fd54bf7e7ca29f5e15ff0b8fc /arch/x86/lib/retpoline.S | |
| parent | 7d40efd67dd313826a12dc4b03635ece97bb6d04 (diff) | |
| parent | 6f5bf947bab06f37ff931c359fd5770c4d9cbf87 (diff) | |
| download | linux-c4070e1996e05dd2eb5e08ee68d0d00553ae08f7.tar.xz | |
Merge commit 'its-for-linus-20250509-merge' into x86/core, to resolve conflicts
Conflicts:
Documentation/admin-guide/hw-vuln/index.rst
arch/x86/include/asm/cpufeatures.h
arch/x86/kernel/alternative.c
arch/x86/kernel/cpu/bugs.c
arch/x86/kernel/cpu/common.c
drivers/base/cpu.c
include/linux/cpu.h
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/lib/retpoline.S')
| -rw-r--r-- | arch/x86/lib/retpoline.S | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S index 9f3116609c8c..d78d769a02bd 100644 --- a/arch/x86/lib/retpoline.S +++ b/arch/x86/lib/retpoline.S @@ -368,6 +368,54 @@ SYM_FUNC_END(call_depth_return_thunk) #endif /* CONFIG_MITIGATION_CALL_DEPTH_TRACKING */ +#ifdef CONFIG_MITIGATION_ITS + +.macro ITS_THUNK reg + +/* + * If CFI paranoid is used then the ITS thunk starts with opcodes (0xea; jne 1b) + * that complete the fineibt_paranoid caller sequence. + */ +1: .byte 0xea +SYM_INNER_LABEL(__x86_indirect_paranoid_thunk_\reg, SYM_L_GLOBAL) + UNWIND_HINT_UNDEFINED + ANNOTATE_NOENDBR + jne 1b +SYM_INNER_LABEL(__x86_indirect_its_thunk_\reg, SYM_L_GLOBAL) + UNWIND_HINT_UNDEFINED + ANNOTATE_NOENDBR + ANNOTATE_RETPOLINE_SAFE + jmp *%\reg + int3 + .align 32, 0xcc /* fill to the end of the line */ + .skip 32 - (__x86_indirect_its_thunk_\reg - 1b), 0xcc /* skip to the next upper half */ +.endm + +/* ITS mitigation requires thunks be aligned to upper half of cacheline */ +.align 64, 0xcc +.skip 29, 0xcc + +#define GEN(reg) ITS_THUNK reg +#include <asm/GEN-for-each-reg.h> +#undef GEN + + .align 64, 0xcc +SYM_FUNC_ALIAS(__x86_indirect_its_thunk_array, __x86_indirect_its_thunk_rax) +SYM_CODE_END(__x86_indirect_its_thunk_array) + +.align 64, 0xcc +.skip 32, 0xcc +SYM_CODE_START(its_return_thunk) + UNWIND_HINT_FUNC + ANNOTATE_NOENDBR + ANNOTATE_UNRET_SAFE + ret + int3 +SYM_CODE_END(its_return_thunk) +EXPORT_SYMBOL(its_return_thunk) + +#endif /* CONFIG_MITIGATION_ITS */ + /* * This function name is magical and is used by -mfunction-return=thunk-extern * for the compiler to generate JMPs to it. |