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Date: Thu, 10 Aug 2017 10:26:02 -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>,
	Arnd Bergmann <arnd@...db.de>,
	Thomas Garnier <thgarnie@...gle.com>,
	Matthias Kaehlcke <mka@...omium.org>,
	Boris Ostrovsky <boris.ostrovsky@...cle.com>,
	Juergen Gross <jgross@...e.com>,
	Paolo Bonzini <pbonzini@...hat.com>,
	Radim Krčmář <rkrcmar@...hat.com>,
	Joerg Roedel <joro@...tes.org>,
	Tom Lendacky <thomas.lendacky@....com>,
	Andy Lutomirski <luto@...nel.org>,
	Borislav Petkov <bp@...e.de>,
	Brian Gerst <brgerst@...il.com>,
	"Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>,
	"Rafael J . Wysocki" <rjw@...ysocki.net>,
	Len Brown <len.brown@...el.com>,
	Pavel Machek <pavel@....cz>,
	Tejun Heo <tj@...nel.org>,
	Christoph Lameter <cl@...ux.com>,
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	Andrew Morton <akpm@...ux-foundation.org>,
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	Christopher Li <sparse@...isli.org>,
	"Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
	Lukas Wunner <lukas@...ner.de>,
	Mika Westerberg <mika.westerberg@...ux.intel.com>,
	Dou Liyang <douly.fnst@...fujitsu.com>,
	Daniel Borkmann <daniel@...earbox.net>,
	Alexei Starovoitov <ast@...nel.org>,
	Masahiro Yamada <yamada.masahiro@...ionext.com>,
	Markus Trippelsdorf <markus@...ppelsdorf.de>,
	Steven Rostedt <rostedt@...dmis.org>,
	Kees Cook <keescook@...omium.org>,
	Rik van Riel <riel@...hat.com>,
	David Howells <dhowells@...hat.com>,
	Waiman Long <longman@...hat.com>,
	Kyle Huey <me@...ehuey.com>,
	Peter Foley <pefoley2@...oley.com>,
	Tim Chen <tim.c.chen@...ux.intel.com>,
	Catalin Marinas <catalin.marinas@....com>,
	Ard Biesheuvel <ard.biesheuvel@...aro.org>,
	Michal Hocko <mhocko@...e.com>,
	Matthew Wilcox <mawilcox@...rosoft.com>,
	"H . J . Lu" <hjl.tools@...il.com>,
	Paul Bolle <pebolle@...cali.nl>,
	Rob Landley <rob@...dley.net>,
	Baoquan He <bhe@...hat.com>,
	Daniel Micay <danielmicay@...il.com>
Cc: x86@...nel.org,
	linux-crypto@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	xen-devel@...ts.xenproject.org,
	kvm@...r.kernel.org,
	linux-pm@...r.kernel.org,
	linux-arch@...r.kernel.org,
	linux-sparse@...r.kernel.org,
	kernel-hardening@...ts.openwall.com
Subject: [RFC v2 10/23] 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_GET_PTR macro instead of
the 'mov $symbol, %dst' construct to not have an absolute reference.

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 | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index c1352771b2f6..14fc21e2df08 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -49,7 +49,7 @@ static inline void *current_text_addr(void)
 {
 	void *pc;
 
-	asm volatile("mov $1f, %0; 1:":"=r" (pc));
+	asm volatile(_ASM_GET_PTR(1f, %0) "; 1:":"=r" (pc));
 
 	return pc;
 }
@@ -689,6 +689,7 @@ static inline void sync_core(void)
 		: "+r" (__sp) : : "memory");
 #else
 	unsigned int tmp;
+	unsigned long tmp2;
 
 	asm volatile (
 		UNWIND_HINT_SAVE
@@ -699,11 +700,12 @@ 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), "+r" (__sp) : : "cc", "memory");
+		: "=&r" (tmp), "=&r" (tmp2), "+r" (__sp) : : "cc", "memory");
 #endif
 }
 
-- 
2.14.0.434.g98096fd7a8-goog

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