Commit-ID: 736e80a4213e9bbce40a7c050337047128b472ac Gitweb: https://git.kernel.org/tip/736e80a4213e9bbce40a7c050337047128b472ac Author: Masami Hiramatsu <mhira...@kernel.org> AuthorDate: Fri, 19 Jan 2018 01:14:21 +0900 Committer: Thomas Gleixner <t...@linutronix.de> CommitDate: Fri, 19 Jan 2018 16:31:28 +0100
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 <mhira...@kernel.org> Signed-off-by: Thomas Gleixner <t...@linutronix.de> Acked-by: David Woodhouse <d...@amazon.co.uk> Cc: Andi Kleen <a...@linux.intel.com> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Ananth N Mavinakayanahalli <ana...@linux.vnet.ibm.com> Cc: Arjan van de Ven <ar...@linux.intel.com> Cc: Greg Kroah-Hartman <gre...@linux-foundation.org> Cc: sta...@vger.kernel.org Link: https://lkml.kernel.org/r/151629206178.10241.6828804696410044771.stgit@devbox --- arch/x86/include/asm/nospec-branch.h | 3 +++ arch/x86/kernel/vmlinux.lds.S | 6 ++++++ arch/x86/lib/retpoline.S | 2 +- 3 files changed, 10 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h index 7b45d84..19ba5ad 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 1e413a93..9b138a0 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 cb45c6c..d3415dc 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
