5.4-stable review patch. If anyone has any objections, please let me know.
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From: Rui Qi qirui.001@bytedance.com
commit 8afd1c7da2b0 ("x86/speculation: Change FILL_RETURN_BUFFER to work with objtool") does not support intra-function call stack validation, which causes kernel live patching to fail. This commit adds support for this, and after testing, the kernel live patching feature is restored to normal.
Fixes: 8afd1c7da2b0 ("x86/speculation: Change FILL_RETURN_BUFFER to work with objtool") Cc: stable@vger.kernel.org # v5.4.250+ Signed-off-by: Rui Qi qirui.001@bytedance.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/include/asm/nospec-branch.h | 7 +++++++ arch/x86/include/asm/unwind_hints.h | 2 +- 2 files changed, 8 insertions(+), 1 deletion(-)
--- a/arch/x86/include/asm/nospec-branch.h +++ b/arch/x86/include/asm/nospec-branch.h @@ -13,6 +13,8 @@ #include <asm/unwind_hints.h> #include <asm/percpu.h>
+#include <linux/frame.h> +#include <asm/unwind_hints.h> /* * This should be used immediately before a retpoline alternative. It tells * objtool where the retpolines are so that it can make sense of the control @@ -51,14 +53,18 @@ #define __FILL_RETURN_BUFFER(reg, nr, sp) \ mov $(nr/2), reg; \ 771: \ + ANNOTATE_INTRA_FUNCTION_CALL; \ call 772f; \ 773: /* speculation trap */ \ + UNWIND_HINT_EMPTY; \ pause; \ lfence; \ jmp 773b; \ 772: \ + ANNOTATE_INTRA_FUNCTION_CALL; \ call 774f; \ 775: /* speculation trap */ \ + UNWIND_HINT_EMPTY; \ pause; \ lfence; \ jmp 775b; \ @@ -152,6 +158,7 @@ .endm
.macro ISSUE_UNBALANCED_RET_GUARD + ANNOTATE_INTRA_FUNCTION_CALL; call .Lunbalanced_ret_guard_@ int3 .Lunbalanced_ret_guard_@: --- a/arch/x86/include/asm/unwind_hints.h +++ b/arch/x86/include/asm/unwind_hints.h @@ -101,7 +101,7 @@ ".popsection\n\t"
#define UNWIND_HINT_SAVE UNWIND_HINT(0, 0, UNWIND_HINT_TYPE_SAVE, 0) - +#define UNWIND_HINT_EMPTY #define UNWIND_HINT_RESTORE UNWIND_HINT(0, 0, UNWIND_HINT_TYPE_RESTORE, 0)
#endif /* __ASSEMBLY__ */