Messages in this thread Patch in this message | | | From | Song Liu <> | Subject | [PATCH] x86/vmlinux: Fix linker fill bytes for ld.lld | Date | Wed, 6 Sep 2023 10:52:15 -0700 |
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With ":text =0xcccc", ld.lld fills unused text area with 0xcccc0000. Example objdump -D output:
ffffffff82b04203: 00 00 add %al,(%rax) ffffffff82b04205: cc int3 ffffffff82b04206: cc int3 ffffffff82b04207: 00 00 add %al,(%rax) ffffffff82b04209: cc int3 ffffffff82b0420a: cc int3
Replace it with ":text =0xcccccccc", so we get the following instead:
ffffffff82b04203: cc int3 ffffffff82b04204: cc int3 ffffffff82b04205: cc int3 ffffffff82b04206: cc int3 ffffffff82b04207: cc int3 ffffffff82b04208: cc int3
gcc/ld doesn't seem to have the same issue. The generated code stays the same for gcc/ld.
Cc: Kees Cook <keescook@chromium.org> Cc: x86@kernel.org Signed-off-by: Song Liu <song@kernel.org> --- arch/x86/kernel/vmlinux.lds.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index 83d41c2601d7..41d56fb9bf92 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -156,7 +156,7 @@ SECTIONS ALIGN_ENTRY_TEXT_END *(.gnu.warning) - } :text =0xcccc + } :text =0xcccccccc /* End of text section, which should occupy whole number of pages */ _etext = .; -- 2.34.1
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