From: Thomas Garnier via Virtualization Subject: [PATCH v2 03/27] x86: Use symbol name in jump table for PIE support Date: Tue, 13 Mar 2018 13:59:21 -0700 Message-ID: <20180313205945.245105-4-thgarnie@google.com> References: <20180313205945.245105-1-thgarnie@google.com> Reply-To: Thomas Garnier Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: linux-arch@vger.kernel.org, kvm@vger.kernel.org, linux-pm@vger.kernel.org, x86@kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-sparse@vger.kernel.org, linux-crypto@vger.kernel.org, kernel-hardening@lists.openwall.com, xen-devel@lists.xenproject.org To: Herbert Xu , "David S . Miller" , Thomas Gleixner , Ingo Molnar , "H . Peter Anvin" , Peter Zijlstra , Josh Poimboeuf , Greg Kroah-Hartman , Kate Stewart , Thomas Garnier , Arnd Bergmann , Philippe Ombredanne , Arnaldo Carvalho de Melo , Andrey Ryabinin , Matthias Kaehlcke , Kees Cook , Tom Lendacky , "Kirill A . Shutemov" , Andy Lutomirski , Dominik Brodowski , Borislav Petkov , Borislav Petkov , "Raf Return-path: In-Reply-To: <20180313205945.245105-1-thgarnie@google.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org List-Id: linux-crypto.vger.kernel.org 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 --- 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 8c0de4282659..dfdcdc39604a 100644 --- a/arch/x86/include/asm/jump_label.h +++ b/arch/x86/include/asm/jump_label.h @@ -37,9 +37,9 @@ 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: @@ -53,9 +53,9 @@ 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: -- 2.16.2.660.g709887971b-goog