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[RFC,06/43] x86/CPU: Adapt assembly for PIE support

Message ID 86defd5e8ee1328bbfbe7f6b293bacb4f1b7d23a.1682673543.git.houwenlong.hwl@antgroup.com
State New
Headers
Series x86/pie: Make kernel image's virtual address flexible |

Commit Message

Hou Wenlong April 28, 2023, 9:50 a.m. UTC 
  From: Thomas Garnier <thgarnie@chromium.org>

From: Thomas Garnier <thgarnie@chromium.org>

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

Signed-off-by: Thomas Garnier <thgarnie@chromium.org>
Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com>
Cc: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Cc: Kees Cook <keescook@chromium.org>
---
 arch/x86/include/asm/sync_core.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)
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Patch

diff --git a/arch/x86/include/asm/sync_core.h b/arch/x86/include/asm/sync_core.h
index ab7382f92aff..fa5b1fe1a692 100644
--- a/arch/x86/include/asm/sync_core.h
+++ b/arch/x86/include/asm/sync_core.h
@@ -31,10 +31,12 @@  static inline void iret_to_self(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"
 		"1:"
-		: "=&r" (tmp), ASM_CALL_CONSTRAINT : : "cc", "memory");
+		: "=&r" (tmp), ASM_CALL_CONSTRAINT
+		: : "cc", "memory");
 }
 #endif /* CONFIG_X86_32 */