2007-02-03 02:52:00

by Chris Wright

[permalink] [raw]
Subject: [patch 27/59] x86: Work around gcc 4.2 over aggressive optimizer

-stable review patch. If anyone has any objections, please let us know.
------------------

From: Andi Kleen <[email protected]>

The new PDA code uses a dummy _proxy_pda variable to describe
memory references to the PDA. It is never referenced
in inline assembly, but exists as input/output arguments.
gcc 4.2 in some cases can CSE references to this which causes
unresolved symbols. Define it to zero to avoid this.

Signed-off-by: Andi Kleen <[email protected]>
Signed-off-by: Chris Wright <[email protected]>
---
arch/i386/kernel/vmlinux.lds.S | 1 +
arch/x86_64/kernel/vmlinux.lds.S | 1 +
2 files changed, 2 insertions(+)

--- linux-2.6.19.2.orig/arch/i386/kernel/vmlinux.lds.S
+++ linux-2.6.19.2/arch/i386/kernel/vmlinux.lds.S
@@ -13,6 +13,7 @@ OUTPUT_FORMAT("elf32-i386", "elf32-i386"
OUTPUT_ARCH(i386)
ENTRY(phys_startup_32)
jiffies = jiffies_64;
+_proxy_pda = 0;

PHDRS {
text PT_LOAD FLAGS(5); /* R_E */
--- linux-2.6.19.2.orig/arch/x86_64/kernel/vmlinux.lds.S
+++ linux-2.6.19.2/arch/x86_64/kernel/vmlinux.lds.S
@@ -13,6 +13,7 @@ OUTPUT_FORMAT("elf64-x86-64", "elf64-x86
OUTPUT_ARCH(i386:x86-64)
ENTRY(phys_startup_64)
jiffies_64 = jiffies;
+_proxy_pda = 0;
PHDRS {
text PT_LOAD FLAGS(5); /* R_E */
data PT_LOAD FLAGS(7); /* RWE */

--