diff options
| author | Masami Hiramatsu <mhiramat@kernel.org> | 2018-01-19 01:14:21 +0900 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2018-01-19 16:31:28 +0100 |
| commit | 736e80a4213e9bbce40a7c050337047128b472ac (patch) | |
| tree | 1aedc475ad8df60cc8b0654e77ce7050179980a8 | |
| parent | 6f41c34d69eb005e7848716bbcafc979b35037d5 (diff) | |
retpoline: Introduce start/end markers of indirect thunk
Introduce start/end markers of __x86_indirect_thunk_* functions.
To make it easy, consolidate .text.__x86.indirect_thunk.* sections
to one .text.__x86.indirect_thunk section and put it in the
end of kernel text section and adds __indirect_thunk_start/end
so that other subsystem (e.g. kprobes) can identify it.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: David Woodhouse <dwmw@amazon.co.uk>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linux-foundation.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/151629206178.10241.6828804696410044771.stgit@devbox
| -rw-r--r-- | arch/x86/include/asm/nospec-branch.h | 3 | ||||
| -rw-r--r-- | arch/x86/kernel/vmlinux.lds.S | 6 | ||||
| -rw-r--r-- | arch/x86/lib/retpoline.S | 2 |
3 files changed, 10 insertions, 1 deletions
diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h index 7b45d8424150..19ba5ad19c65 100644 --- a/arch/x86/include/asm/nospec-branch.h +++ b/arch/x86/include/asm/nospec-branch.h @@ -194,6 +194,9 @@ enum spectre_v2_mitigation { SPECTRE_V2_IBRS, }; +extern char __indirect_thunk_start[]; +extern char __indirect_thunk_end[]; + /* * On VMEXIT we must ensure that no RSB predictions learned in the guest * can be followed in the host, by overwriting the RSB completely. Both diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index 1e413a9326aa..9b138a06c1a4 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -124,6 +124,12 @@ SECTIONS ASSERT(. - _entry_trampoline == PAGE_SIZE, "entry trampoline is too big"); #endif +#ifdef CONFIG_RETPOLINE + __indirect_thunk_start = .; + *(.text.__x86.indirect_thunk) + __indirect_thunk_end = .; +#endif + /* End of text section */ _etext = .; } :text = 0x9090 diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S index cb45c6cb465f..d3415dc30f82 100644 --- a/arch/x86/lib/retpoline.S +++ b/arch/x86/lib/retpoline.S @@ -9,7 +9,7 @@ #include <asm/nospec-branch.h> .macro THUNK reg - .section .text.__x86.indirect_thunk.\reg + .section .text.__x86.indirect_thunk ENTRY(__x86_indirect_thunk_\reg) CFI_STARTPROC |