Convert pvops invocations to use non-speculative call sequences, when
CONFIG_RETPOLINE is enabled.
There is scope for future optimisation here — once the pvops methods are
actually set, we could just turn the damn things into *direct* jumps.
But this is perfectly sufficient for now, without that added complexity.
Signed-off-by: David Woodhouse <d...@amazon.co.uk>
---
arch/x86/include/asm/paravirt_types.h | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/paravirt_types.h
b/arch/x86/include/asm/paravirt_types.h
index 6ec54d01972d..54b735b8ae12 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -336,11 +336,17 @@ extern struct pv_lock_ops pv_lock_ops;
#define PARAVIRT_PATCH(x) \
(offsetof(struct paravirt_patch_template, x) / sizeof(void *))
+#define paravirt_clobber(clobber) \
+ [paravirt_clobber] "i" (clobber)
+#ifdef CONFIG_RETPOLINE
+#define paravirt_type(op) \
+ [paravirt_typenum] "i" (PARAVIRT_PATCH(op)), \
+ [paravirt_opptr] "r" ((op))
+#else
#define paravirt_type(op) \
[paravirt_typenum] "i" (PARAVIRT_PATCH(op)), \
[paravirt_opptr] "i" (&(op))
-#define paravirt_clobber(clobber) \
- [paravirt_clobber] "i" (clobber)
+#endif
/*
* Generate some code, and mark it as patchable by the
@@ -392,7 +398,11 @@ int paravirt_disable_iospace(void);
* offset into the paravirt_patch_template structure, and can therefore be
* freely converted back into a structure offset.
*/
+#ifdef CONFIG_RETPOLINE
+#define PARAVIRT_CALL "call __x86.indirect_thunk.%V[paravirt_opptr];"
+#else
#define PARAVIRT_CALL "call *%c[paravirt_opptr];"
+#endif
/*
* These macros are intended to wrap calls through one of the paravirt
--
2.14.3
