From: Song Liu Date: Wed, 6 Sep 2023 17:52:15 +0000 (-0700) Subject: x86/build: Fix linker fill bytes quirk/incompatibility for ld.lld X-Git-Url: http://git.hungrycats.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=604b1b6ee09c1312223e585d12219effd10ad8ff;p=linux x86/build: Fix linker fill bytes quirk/incompatibility for ld.lld commit 65e710899fd19f435f40268f3a92dfaa11f14470 upstream. 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. Signed-off-by: Song Liu Signed-off-by: Ingo Molnar Reviewed-by: Kees Cook Acked-by: Peter Zijlstra (Intel) Fixes: 7705dc855797 ("x86/vmlinux: Use INT3 instead of NOP for linker fill bytes") Link: https://lore.kernel.org/r/20230906175215.2236033-1-song@kernel.org Signed-off-by: Greg Kroah-Hartman --- diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index 83d41c2601d7..f15fb71f280e 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 = .;