diff options
| author | Petr Pavlu <petr.pavlu@suse.com> | 2023-07-11 11:19:51 +0200 |
|---|---|---|
| committer | Borislav Petkov (AMD) <bp@alien8.de> | 2023-08-14 11:44:19 +0200 |
| commit | 79cd2a11224eab86d6673fe8a11d2046ae9d2757 (patch) | |
| tree | 0ee936d47ffbfd103a1a109a87bcc794f7007f2d /arch/x86/kernel/vmlinux.lds.S | |
| parent | x86/srso: Disable the mitigation on unaffected configurations (diff) | |
| download | linux-79cd2a11224eab86d6673fe8a11d2046ae9d2757.tar.xz linux-79cd2a11224eab86d6673fe8a11d2046ae9d2757.zip | |
x86/retpoline,kprobes: Fix position of thunk sections with CONFIG_LTO_CLANG
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
Diffstat (limited to 'arch/x86/kernel/vmlinux.lds.S')
| -rw-r--r-- | arch/x86/kernel/vmlinux.lds.S | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index ef06211bae4c..dfb8783cb4c7 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -134,15 +134,15 @@ SECTIONS SOFTIRQENTRY_TEXT #ifdef CONFIG_RETPOLINE __indirect_thunk_start = .; - *(.text.__x86.indirect_thunk) - *(.text.__x86.return_thunk) + *(.text..__x86.indirect_thunk) + *(.text..__x86.return_thunk) __indirect_thunk_end = .; #endif STATIC_CALL_TEXT ALIGN_ENTRY_TEXT_BEGIN #ifdef CONFIG_CPU_SRSO - *(.text.__x86.rethunk_untrain) + *(.text..__x86.rethunk_untrain) #endif ENTRY_TEXT @@ -153,7 +153,7 @@ SECTIONS * definition. */ . = srso_untrain_ret_alias | (1 << 2) | (1 << 8) | (1 << 14) | (1 << 20); - *(.text.__x86.rethunk_safe) + *(.text..__x86.rethunk_safe) #endif ALIGN_ENTRY_TEXT_END *(.gnu.warning) |