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Date: Thu, 10 Aug 2017 10:25:55 -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>,
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	"Rafael J . Wysocki" <rjw@...ysocki.net>,
	Len Brown <len.brown@...el.com>,
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	Lukas Wunner <lukas@...ner.de>,
	Mika Westerberg <mika.westerberg@...ux.intel.com>,
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	Daniel Borkmann <daniel@...earbox.net>,
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	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>,
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	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>,
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	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 03/23] x86: Use symbol name in jump table for PIE support

Replace the %c constraint with %P. The %c is incompatible with PIE
because it implies an immediate value whereas %P reference a symbol.

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/jump_label.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/jump_label.h b/arch/x86/include/asm/jump_label.h
index adc54c12cbd1..6e558e4524dc 100644
--- a/arch/x86/include/asm/jump_label.h
+++ b/arch/x86/include/asm/jump_label.h
@@ -36,9 +36,9 @@ static __always_inline bool arch_static_branch(struct static_key *key, bool bran
 		".byte " __stringify(STATIC_KEY_INIT_NOP) "\n\t"
 		".pushsection __jump_table,  \"aw\" \n\t"
 		_ASM_ALIGN "\n\t"
-		_ASM_PTR "1b, %l[l_yes], %c0 + %c1 \n\t"
+		_ASM_PTR "1b, %l[l_yes], %P0 \n\t"
 		".popsection \n\t"
-		: :  "i" (key), "i" (branch) : : l_yes);
+		: :  "X" (&((char *)key)[branch]) : : l_yes);
 
 	return false;
 l_yes:
@@ -52,9 +52,9 @@ static __always_inline bool arch_static_branch_jump(struct static_key *key, bool
 		"2:\n\t"
 		".pushsection __jump_table,  \"aw\" \n\t"
 		_ASM_ALIGN "\n\t"
-		_ASM_PTR "1b, %l[l_yes], %c0 + %c1 \n\t"
+		_ASM_PTR "1b, %l[l_yes], %P0 \n\t"
 		".popsection \n\t"
-		: :  "i" (key), "i" (branch) : : l_yes);
+		: :  "X" (&((char *)key)[branch]) : : l_yes);
 
 	return false;
 l_yes:
-- 
2.14.0.434.g98096fd7a8-goog

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