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| author | Peter Zijlstra <peterz@infradead.org> | 2022-03-08 18:30:55 +0300 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2022-03-15 12:32:47 +0300 |
| commit | 89bc853eae4ad125030ef99f207ba76c2f00a26e (patch) | |
| tree | 7f3aa0f233858f04ee61872e4ae3a795433b4fa4 /arch/x86/kernel/vmlinux.lds.S | |
| parent | 08f87a93c8ec709698edba66a5167077181fc978 (diff) | |
| download | linux-89bc853eae4ad125030ef99f207ba76c2f00a26e.tar.xz | |
objtool: Find unused ENDBR instructions
Find all ENDBR instructions which are never referenced and stick them
in a section such that the kernel can poison them, sealing the
functions from ever being an indirect call target.
This removes about 1-in-4 ENDBR instructions.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154319.763643193@infradead.org
Diffstat (limited to 'arch/x86/kernel/vmlinux.lds.S')
| -rw-r--r-- | arch/x86/kernel/vmlinux.lds.S | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index 27f830345b6f..7fda7f27e762 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -285,6 +285,15 @@ SECTIONS } #endif +#ifdef CONFIG_X86_KERNEL_IBT + . = ALIGN(8); + .ibt_endbr_seal : AT(ADDR(.ibt_endbr_seal) - LOAD_OFFSET) { + __ibt_endbr_seal = .; + *(.ibt_endbr_seal) + __ibt_endbr_seal_end = .; + } +#endif + /* * struct alt_inst entries. From the header (alternative.h): * "Alternative instructions for different CPU types or capabilities" |