[PATCH v1 12/27] x86/paravirt: Adapt assembly for PIE support
From: Thomas Garnier via Virtualization <hidden>
Date: 2017-10-11 20:30:12
Subsystem:
paravirt_ops interface, the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Juergen Gross, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
if PIE is enabled, switch the paravirt assembly constraints to be compatible. The %c/i constrains generate smaller code so is kept by default. Position Independent Executable (PIE) support will allow to extended the KASLR randomization range below the -2G memory limit. Signed-off-by: Thomas Garnier <redacted> --- arch/x86/include/asm/paravirt_types.h | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index 280d94c36dad..e6961f8a74aa 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h@@ -335,9 +335,17 @@ extern struct pv_lock_ops pv_lock_ops; #define PARAVIRT_PATCH(x) \ (offsetof(struct paravirt_patch_template, x) / sizeof(void *)) +#ifdef CONFIG_X86_PIE +#define paravirt_opptr_call "a" +#define paravirt_opptr_type "p" +#else +#define paravirt_opptr_call "c" +#define paravirt_opptr_type "i" +#endif + #define paravirt_type(op) \ [paravirt_typenum] "i" (PARAVIRT_PATCH(op)), \ - [paravirt_opptr] "i" (&(op)) + [paravirt_opptr] paravirt_opptr_type (&(op)) #define paravirt_clobber(clobber) \ [paravirt_clobber] "i" (clobber)
@@ -391,7 +399,7 @@ int paravirt_disable_iospace(void); * offset into the paravirt_patch_template structure, and can therefore be * freely converted back into a structure offset. */ -#define PARAVIRT_CALL "call *%c[paravirt_opptr];" +#define PARAVIRT_CALL "call *%" paravirt_opptr_call "[paravirt_opptr];" /* * These macros are intended to wrap calls through one of the paravirt
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2.15.0.rc0.271.g36b669edcc-goog