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Message-Id: <20170718223333.110371-4-thgarnie@google.com> Date: Tue, 18 Jul 2017 15:33:14 -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>, Thomas Garnier <thgarnie@...gle.com>, Arnd Bergmann <arnd@...db.de>, 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>, Andy Lutomirski <luto@...nel.org>, Borislav Petkov <bp@...en8.de>, "Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>, Brian Gerst <brgerst@...il.com>, Borislav Petkov <bp@...e.de>, Christian Borntraeger <borntraeger@...ibm.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>, Kees Cook <keescook@...omium.org>, Paul Gortmaker <paul.gortmaker@...driver.com>, Chris Metcalf <cmetcalf@...lanox.com>, "Paul E . McKenney" <paulmck@...ux.vnet.ibm.com>, Andrew Morton <akpm@...ux-foundation.org>, Christopher Li <sparse@...isli.org>, Dou Liyang <douly.fnst@...fujitsu.com>, Masahiro Yamada <yamada.masahiro@...ionext.com>, Daniel Borkmann <daniel@...earbox.net>, Markus Trippelsdorf <markus@...ppelsdorf.de>, Peter Foley <pefoley2@...oley.com>, Steven Rostedt <rostedt@...dmis.org>, Tim Chen <tim.c.chen@...ux.intel.com>, Ard Biesheuvel <ard.biesheuvel@...aro.org>, Catalin Marinas <catalin.marinas@....com>, Matthew Wilcox <mawilcox@...rosoft.com>, Michal Hocko <mhocko@...e.com>, Rob Landley <rob@...dley.net>, Jiri Kosina <jkosina@...e.cz>, "H . J . Lu" <hjl.tools@...il.com>, Paul Bolle <pebolle@...cali.nl>, 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 03/22] 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: -- 2.13.2.932.g7449e964c-goog
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