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[PATCH] i386: Basic definitions for i386-pda 

This patch has the basic definitions of struct i386_pda, and the segment
selector in the GDT.

asm-i386/pda.h is more or less a direct copy of asm-x86_64/pda.h.  The most
interesting difference is the use of _proxy_pda, which is used to give gcc a
model for the actual memory operations on the real pda structure.  No actual
reference is ever made to _proxy_pda, so it is never defined.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Chuck Ebbert <76306.1226@compuserve.com>
Cc: Zachary Amsden <zach@vmware.com>
Cc: Jan Beulich <jbeulich@novell.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
hifive-unleashed-5.1
Jeremy Fitzhardinge 2006-12-07 02:14:02 +01:00 committed by Andi Kleen
parent eb5b7b9d86
commit 9ca36101a8
3 changed files with 100 additions and 2 deletions
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2
arch/i386/kernel/head.S
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@ -585,7 +585,7 @@ ENTRY(cpu_gdt_table)
.quad 0x004092000000ffff /* 0xc8 APM DS data */
.quad 0x00c0920000000000 /* 0xd0 - ESPFIX SS */
.quad 0x0000000000000000 /* 0xd8 - unused */
.quad 0x0000000000000000 /* 0xd8 - PDA */
.quad 0x0000000000000000 /* 0xe0 - unused */
.quad 0x0000000000000000 /* 0xe8 - unused */
.quad 0x0000000000000000 /* 0xf0 - unused */

95
include/asm-i386/pda.h 100644
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@ -0,0 +1,95 @@
/*
Per-processor Data Areas
Jeremy Fitzhardinge <jeremy@goop.org> 2006
Based on asm-x86_64/pda.h by Andi Kleen.
*/
#ifndef _I386_PDA_H
#define _I386_PDA_H
#include <linux/stddef.h>
struct i386_pda
{
struct i386_pda *_pda; /* pointer to self */
};
extern struct i386_pda *_cpu_pda[];
#define cpu_pda(i) (_cpu_pda[i])
#define pda_offset(field) offsetof(struct i386_pda, field)
extern void __bad_pda_field(void);
/* This variable is never instantiated. It is only used as a stand-in
for the real per-cpu PDA memory, so that gcc can understand what
memory operations the inline asms() below are performing. This
eliminates the need to make the asms volatile or have memory
clobbers, so gcc can readily analyse them. */
extern struct i386_pda _proxy_pda;
#define pda_to_op(op,field,val) \
do { \
typedef typeof(_proxy_pda.field) T__; \
if (0) { T__ tmp__; tmp__ = (val); } \
switch (sizeof(_proxy_pda.field)) { \
case 1: \
asm(op "b %1,%%gs:%c2" \
: "+m" (_proxy_pda.field) \
:"ri" ((T__)val), \
"i"(pda_offset(field))); \
break; \
case 2: \
asm(op "w %1,%%gs:%c2" \
: "+m" (_proxy_pda.field) \
:"ri" ((T__)val), \
"i"(pda_offset(field))); \
break; \
case 4: \
asm(op "l %1,%%gs:%c2" \
: "+m" (_proxy_pda.field) \
:"ri" ((T__)val), \
"i"(pda_offset(field))); \
break; \
default: __bad_pda_field(); \
} \
} while (0)
#define pda_from_op(op,field) \
({ \
typeof(_proxy_pda.field) ret__; \
switch (sizeof(_proxy_pda.field)) { \
case 1: \
asm(op "b %%gs:%c1,%0" \
: "=r" (ret__) \
: "i" (pda_offset(field)), \
"m" (_proxy_pda.field)); \
break; \
case 2: \
asm(op "w %%gs:%c1,%0" \
: "=r" (ret__) \
: "i" (pda_offset(field)), \
"m" (_proxy_pda.field)); \
break; \
case 4: \
asm(op "l %%gs:%c1,%0" \
: "=r" (ret__) \
: "i" (pda_offset(field)), \
"m" (_proxy_pda.field)); \
break; \
default: __bad_pda_field(); \
} \
ret__; })
/* Return a pointer to a pda field */
#define pda_addr(field) \
((typeof(_proxy_pda.field) *)((unsigned char *)read_pda(_pda) + \
pda_offset(field)))
#define read_pda(field) pda_from_op("mov",field)
#define write_pda(field,val) pda_to_op("mov",field,val)
#define add_pda(field,val) pda_to_op("add",field,val)
#define sub_pda(field,val) pda_to_op("sub",field,val)
#define or_pda(field,val) pda_to_op("or",field,val)
#endif /* _I386_PDA_H */

5
include/asm-i386/segment.h
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@ -39,7 +39,7 @@
* 25 - APM BIOS support
*
* 26 - ESPFIX small SS
* 27 - unused
* 27 - PDA [ per-cpu private data area ]
* 28 - unused
* 29 - unused
* 30 - unused
@ -74,6 +74,9 @@
#define GDT_ENTRY_ESPFIX_SS (GDT_ENTRY_KERNEL_BASE + 14)
#define __ESPFIX_SS (GDT_ENTRY_ESPFIX_SS * 8)
#define GDT_ENTRY_PDA (GDT_ENTRY_KERNEL_BASE + 15)
#define __KERNEL_PDA (GDT_ENTRY_PDA * 8)
#define GDT_ENTRY_DOUBLEFAULT_TSS 31
/*