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>
---
Changes in v2:
- Consolidate .text.__x86.indirect_thunk.* sections to
one .text.__x86.indirect_thunk section. (Thanks David!)
---
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 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
