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| author | Peter Zijlstra <peterz@infradead.org> | 2022-03-08 16:30:56 +0100 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2022-03-15 10:32:47 +0100 |
| commit | ed53a0d971926e484d86cce617ec02a7ee85c3fe (patch) | |
| tree | 1423484f3912113c56c0b77fa5b0397113040828 /scripts/link-vmlinux.sh | |
| parent | 89bc853eae4ad125030ef99f207ba76c2f00a26e (diff) | |
| download | linux-ed53a0d971926e484d86cce617ec02a7ee85c3fe.tar.gz linux-ed53a0d971926e484d86cce617ec02a7ee85c3fe.tar.bz2 linux-ed53a0d971926e484d86cce617ec02a7ee85c3fe.zip | |
x86/alternative: Use .ibt_endbr_seal to seal indirect calls
Objtool's --ibt option generates .ibt_endbr_seal which lists
superfluous ENDBR instructions. That is those instructions for which
the function is never indirectly called.
Overwrite these ENDBR instructions with a NOP4 such that these
function can never be indirect called, reducing the number of viable
ENDBR targets in the kernel.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154319.822545231@infradead.org
Diffstat (limited to 'scripts/link-vmlinux.sh')
| -rwxr-xr-x | scripts/link-vmlinux.sh | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index 9b08dca26f99..f704034ebbe6 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -108,7 +108,9 @@ objtool_link() local objtoolcmd; local objtoolopt; - if is_enabled CONFIG_LTO_CLANG && is_enabled CONFIG_STACK_VALIDATION; then + if is_enabled CONFIG_STACK_VALIDATION && \ + ( is_enabled CONFIG_LTO_CLANG || is_enabled CONFIG_X86_KERNEL_IBT ); then + # Don't perform vmlinux validation unless explicitly requested, # but run objtool on vmlinux.o now that we have an object file. if is_enabled CONFIG_UNWINDER_ORC; then @@ -117,6 +119,10 @@ objtool_link() objtoolopt="${objtoolopt} --lto" + if is_enabled CONFIG_X86_KERNEL_IBT; then + objtoolopt="${objtoolopt} --ibt" + fi + if is_enabled CONFIG_FTRACE_MCOUNT_USE_OBJTOOL; then objtoolopt="${objtoolopt} --mcount" fi @@ -168,7 +174,7 @@ vmlinux_link() # skip output file argument shift - if is_enabled CONFIG_LTO_CLANG; then + if is_enabled CONFIG_LTO_CLANG || is_enabled CONFIG_X86_KERNEL_IBT; then # Use vmlinux.o instead of performing the slow LTO link again. objs=vmlinux.o libs= |