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Message-Id: <20180625224014.134829-4-thgarnie@google.com>
Date: Mon, 25 Jun 2018 15:38:51 -0700
From: Thomas Garnier <thgarnie@...gle.com>
To: kernel-hardening@...ts.openwall.com
Cc: Thomas Garnier <thgarnie@...gle.com>, Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, "H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
Kate Stewart <kstewart@...uxfoundation.org>, Philippe Ombredanne <pombredanne@...b.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>, linux-kernel@...r.kernel.org
Subject: [PATCH v5 03/27] 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 extend the
KASLR randomization range 0xffffffff80000000.
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 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:
--
2.18.0.rc2.346.g013aa6912e-goog
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