Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Thomas Garnier <thgarnie@chromium.org>
To:     kernel-hardening@lists.openwall.com
Cc:     kristen@linux.intel.com, keescook@chromium.org,
        Thomas Garnier <thgarnie@chromium.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        "H. Peter Anvin" <hpa@zytor.com>, x86@kernel.org,
        "Peter Zijlstra (Intel)" <peterz@infradead.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Len Brown <len.brown@intel.com>,
        Andy Lutomirski <luto@kernel.org>, linux-kernel@vger.kernel.org
Subject: [PATCH v9 06/11] x86/CPU: Adapt assembly for PIE support
Date:   Tue, 30 Jul 2019 12:12:50 -0700
Message-Id: <20190730191303.206365-7-thgarnie@chromium.org>
In-Reply-To: <20190730191303.206365-1-thgarnie@chromium.org>
References: <20190730191303.206365-1-thgarnie@chromium.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Change the assembly code to use only relative references of symbols for the
kernel to be PIE compatible.

Position Independent Executable (PIE) support will allow to extend the
KASLR randomization range below 0xffffffff80000000.

Signed-off-by: Thomas Garnier <thgarnie@chromium.org>
---
 arch/x86/include/asm/processor.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 6e0a3b43d027..bf333d62889e 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -713,11 +713,13 @@ 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), %q0\n\t"
+		"pushq %q0\n\t"
 		"iretq\n\t"
 		UNWIND_HINT_RESTORE
 		"1:"
-		: "=&r" (tmp), ASM_CALL_CONSTRAINT : : "cc", "memory");
+		: "=&r" (tmp), ASM_CALL_CONSTRAINT
+		: : "cc", "memory");
 #endif
 }
 
-- 
2.22.0.770.g0f2c4a37fd-goog