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From: Luis R. Rodriguez on 5 Mar 2010 13:50
Upstream commit: 811a0fff5d6e80e18e06be88e0fb685f3924bf8f

This patch included on 2.6.25 is required to be backported to compile
both the 2.6.23 and 2.6.24 kernels on x86_64 systems with a modern
toolchain. Otherwise you get this pesky assembly error:

arch/i386/boot/boot.h: Assembler messages:
arch/i386/boot/boot.h:112: Error: bad register name `%dil'

Author: H. Peter Anvin <hpa(a)zytor.com>
Date: Wed Jan 30 13:33:02 2008 +0100

x86 setup: fix constraints in segment accessor functions

Fix the operand constraints for the segment accessor functions,
{rd,wr}{fs,gs}*. In particular, the 8-bit functions used "r"
constraints instead of "q" constraints.

Signed-off-by: H. Peter Anvin <hpa(a)zytor.com>
Signed-off-by: Ingo Molnar <mingo(a)elte.hu>
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>

Signed-off-by: Luis R. Rodriguez <lrodriguez(a)atheros.com>
---

This patch is not likely to be applied upstream as 2.6.23.y and 2.6.24.y
are both dead now. Use at least the latest 2.6.27.y as that is the latest
supported kernel. I put this out there though in case someone also is looking
for a solution and does not have an option to upgrade. May the google cache
be with you.

--- arch/i386/boot/boot.h.orig 2010-01-05 17:03:12.000000000 -0800
+++ arch/i386/boot/boot.h 2010-01-06 00:14:04.000000000 -0800
@@ -109,7 +109,7 @@
static inline u8 rdfs8(addr_t addr)
{
u8 v;
- asm volatile("movb %%fs:%1,%0" : "=r" (v) : "m" (*(u8 *)addr));
+ asm volatile("movb %%fs:%1,%0" : "=q" (v) : "m" (*(u8 *)addr));
return v;
}
static inline u16 rdfs16(addr_t addr)
@@ -127,21 +127,21 @@

static inline void wrfs8(u8 v, addr_t addr)
{
- asm volatile("movb %1,%%fs:%0" : "+m" (*(u8 *)addr) : "r" (v));
+ asm volatile("movb %1,%%fs:%0" : "+m" (*(u8 *)addr) : "qi" (v));
}
static inline void wrfs16(u16 v, addr_t addr)
{
- asm volatile("movw %1,%%fs:%0" : "+m" (*(u16 *)addr) : "r" (v));
+ asm volatile("movw %1,%%fs:%0" : "+m" (*(u16 *)addr) : "ri" (v));
}
static inline void wrfs32(u32 v, addr_t addr)
{
- asm volatile("movl %1,%%fs:%0" : "+m" (*(u32 *)addr) : "r" (v));
+ asm volatile("movl %1,%%fs:%0" : "+m" (*(u32 *)addr) : "ri" (v));
}

static inline u8 rdgs8(addr_t addr)
{
u8 v;
- asm volatile("movb %%gs:%1,%0" : "=r" (v) : "m" (*(u8 *)addr));
+ asm volatile("movb %%gs:%1,%0" : "=q" (v) : "m" (*(u8 *)addr));
return v;
}
static inline u16 rdgs16(addr_t addr)
@@ -159,15 +159,15 @@

static inline void wrgs8(u8 v, addr_t addr)
{
- asm volatile("movb %1,%%gs:%0" : "+m" (*(u8 *)addr) : "r" (v));
+ asm volatile("movb %1,%%gs:%0" : "+m" (*(u8 *)addr) : "qi" (v));
}
static inline void wrgs16(u16 v, addr_t addr)
{
- asm volatile("movw %1,%%gs:%0" : "+m" (*(u16 *)addr) : "r" (v));
+ asm volatile("movw %1,%%gs:%0" : "+m" (*(u16 *)addr) : "ri" (v));
}
static inline void wrgs32(u32 v, addr_t addr)
{
- asm volatile("movl %1,%%gs:%0" : "+m" (*(u32 *)addr) : "r" (v));
+ asm volatile("movl %1,%%gs:%0" : "+m" (*(u32 *)addr) : "ri" (v));
}

/* Note: these only return true/false, not a signed return value! */
--
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