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Message-Id: <20180529221625.33541-13-thgarnie@google.com>
Date: Tue, 29 May 2018 15:15:13 -0700
From: Thomas Garnier <thgarnie@...gle.com>
To: kernel-hardening@...ts.openwall.com
Cc: Thomas Garnier <thgarnie@...gle.com>,
Juergen Gross <jgross@...e.com>,
Alok Kataria <akataria@...are.com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
"H. Peter Anvin" <hpa@...or.com>,
x86@...nel.org,
virtualization@...ts.linux-foundation.org,
linux-kernel@...r.kernel.org
Subject: [PATCH v4 12/27] x86/paravirt: Adapt assembly for PIE support
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 extend the
KASLR randomization range 0xffffffff80000000.
Signed-off-by: Thomas Garnier <thgarnie@...gle.com>
---
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 180bc0bff0fb..140747a98d94 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -337,9 +337,17 @@ 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)
@@ -395,7 +403,7 @@ int paravirt_disable_iospace(void);
*/
#define PARAVIRT_CALL \
ANNOTATE_RETPOLINE_SAFE \
- "call *%c[paravirt_opptr];"
+ "call *%" paravirt_opptr_call "[paravirt_opptr];"
/*
* These macros are intended to wrap calls through one of the paravirt
--
2.17.0.921.gf22659ad46-goog
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