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Date: Tue, 13 Mar 2018 13:59:26 -0700
From: Thomas Garnier <thgarnie@...gle.com>
To: Herbert Xu <herbert@...dor.apana.org.au>,
	"David S . Miller" <davem@...emloft.net>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H . Peter Anvin" <hpa@...or.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Josh Poimboeuf <jpoimboe@...hat.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Kate Stewart <kstewart@...uxfoundation.org>,
	Thomas Garnier <thgarnie@...gle.com>,
	Arnd Bergmann <arnd@...db.de>,
	Philippe Ombredanne <pombredanne@...b.com>,
	Arnaldo Carvalho de Melo <acme@...hat.com>,
	Andrey Ryabinin <aryabinin@...tuozzo.com>,
	Matthias Kaehlcke <mka@...omium.org>,
	Kees Cook <keescook@...omium.org>,
	Tom Lendacky <thomas.lendacky@....com>,
	"Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>,
	Andy Lutomirski <luto@...nel.org>,
	Dominik Brodowski <linux@...inikbrodowski.net>,
	Borislav Petkov <bp@...en8.de>,
	Borislav Petkov <bp@...e.de>,
	"Rafael J . Wysocki" <rjw@...ysocki.net>,
	Len Brown <len.brown@...el.com>,
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	Alexey Dobriyan <adobriyan@...il.com>,
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	Andrew Morton <akpm@...ux-foundation.org>,
	Nicolas Pitre <nicolas.pitre@...aro.org>,
	Randy Dunlap <rdunlap@...radead.org>,
	"Luis R . Rodriguez" <mcgrof@...nel.org>,
	Christopher Li <sparse@...isli.org>,
	Jason Baron <jbaron@...mai.com>,
	Ashish Kalra <ashish@...estacks.com>,
	Kyle McMartin <kyle@...hat.com>,
	Dou Liyang <douly.fnst@...fujitsu.com>,
	Lukas Wunner <lukas@...ner.de>,
	Petr Mladek <pmladek@...e.com>,
	Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
	Masahiro Yamada <yamada.masahiro@...ionext.com>,
	Ingo Molnar <mingo@...nel.org>,
	Nicholas Piggin <npiggin@...il.com>,
	Cao jin <caoj.fnst@...fujitsu.com>,
	"H . J . Lu" <hjl.tools@...il.com>,
	Paolo Bonzini <pbonzini@...hat.com>,
	Radim Krčmář <rkrcmar@...hat.com>,
	Joerg Roedel <joro@...tes.org>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	Rik van Riel <riel@...hat.com>,
	Jia Zhang <qianyue.zj@...baba-inc.com>,
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	Kyle Huey <me@...ehuey.com>,
	Jonathan Corbet <corbet@....net>,
	Matthew Wilcox <mawilcox@...rosoft.com>,
	Michal Hocko <mhocko@...e.com>,
	Rob Landley <rob@...dley.net>,
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	Daniel Micay <danielmicay@...il.com>,
	Jan H . Schönherr <jschoenh@...zon.de>
Cc: x86@...nel.org,
	linux-crypto@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-pm@...r.kernel.org,
	virtualization@...ts.linux-foundation.org,
	xen-devel@...ts.xenproject.org,
	linux-arch@...r.kernel.org,
	linux-sparse@...r.kernel.org,
	kvm@...r.kernel.org,
	linux-doc@...r.kernel.org,
	kernel-hardening@...ts.openwall.com
Subject: [PATCH v2 08/27] x86/CPU: Adapt assembly for PIE support

Change the assembly code to use only relative references of symbols for the
kernel to be PIE compatible. Use the new _ASM_MOVABS macro instead of
the 'mov $symbol, %dst' construct.

Position Independent Executable (PIE) support will allow to extended the
KASLR randomization range below the -2G memory limit.

Signed-off-by: Thomas Garnier <thgarnie@...gle.com>
---
 arch/x86/include/asm/processor.h | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index b0ccd4847a58..1b9488b1018a 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -50,7 +50,7 @@ static inline void *current_text_addr(void)
 {
 	void *pc;
 
-	asm volatile("mov $1f, %0; 1:":"=r" (pc));
+	asm volatile(_ASM_MOVABS " $1f, %0; 1:":"=r" (pc));
 
 	return pc;
 }
@@ -710,6 +710,7 @@ static inline void sync_core(void)
 		: ASM_CALL_CONSTRAINT : : "memory");
 #else
 	unsigned int tmp;
+	unsigned long tmp2;
 
 	asm volatile (
 		UNWIND_HINT_SAVE
@@ -720,11 +721,13 @@ static inline void sync_core(void)
 		"pushfq\n\t"
 		"mov %%cs, %0\n\t"
 		"pushq %q0\n\t"
-		"pushq $1f\n\t"
+		"leaq 1f(%%rip), %1\n\t"
+		"pushq %1\n\t"
 		"iretq\n\t"
 		UNWIND_HINT_RESTORE
 		"1:"
-		: "=&r" (tmp), ASM_CALL_CONSTRAINT : : "cc", "memory");
+		: "=&r" (tmp), "=&r" (tmp2), ASM_CALL_CONSTRAINT
+		: : "cc", "memory");
 #endif
 }
 
-- 
2.16.2.660.g709887971b-goog

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