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authorPetr Pavlu2023-07-11 11:19:51 +0200
committerGreg Kroah-Hartman2023-08-26 13:27:00 +0200
commitc8b056a3b4ebb33adbb873cab152ed499d1a1dcb (patch)
treef9347e7d68fae58cff5459043df0272d05ed8f6e /tools
parentdae93ed961a8a315cefe64491e8573c5d9e3484e (diff)
x86/retpoline,kprobes: Fix position of thunk sections with CONFIG_LTO_CLANG
commit 79cd2a11224eab86d6673fe8a11d2046ae9d2757 upstream. The linker script arch/x86/kernel/vmlinux.lds.S matches the thunk sections ".text.__x86.*" from arch/x86/lib/retpoline.S as follows: .text { [...] TEXT_TEXT [...] __indirect_thunk_start = .; *(.text.__x86.*) __indirect_thunk_end = .; [...] } Macro TEXT_TEXT references TEXT_MAIN which normally expands to only ".text". However, with CONFIG_LTO_CLANG, TEXT_MAIN becomes ".text .text.[0-9a-zA-Z_]*" which wrongly matches also the thunk sections. The output layout is then different than expected. For instance, the currently defined range [__indirect_thunk_start, __indirect_thunk_end] becomes empty. Prevent the problem by using ".." as the first separator, for example, ".text..__x86.indirect_thunk". This pattern is utilized by other explicit section names which start with one of the standard prefixes, such as ".text" or ".data", and that need to be individually selected in the linker script. [ nathan: Fix conflicts with SRSO and fold in fix issue brought up by Andrew Cooper in post-review: https://lore.kernel.org/20230803230323.1478869-1-andrew.cooper3@citrix.com ] Fixes: dc5723b02e52 ("kbuild: add support for Clang LTO") Signed-off-by: Petr Pavlu <petr.pavlu@suse.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/20230711091952.27944-2-petr.pavlu@suse.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'tools')
-rw-r--r--tools/objtool/check.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 8ec97762b607..7c4e61cbefaa 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -379,7 +379,7 @@ static int decode_instructions(struct objtool_file *file)
if (!strcmp(sec->name, ".noinstr.text") ||
!strcmp(sec->name, ".entry.text") ||
- !strncmp(sec->name, ".text.__x86.", 12))
+ !strncmp(sec->name, ".text..__x86.", 13))
sec->noinstr = true;
for (offset = 0; offset < sec->sh.sh_size; offset += insn->len) {