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x86: convert pda ops to wrappers around x86 percpu accessors

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pda is now a percpu variable and there's no reason it can't use plain
x86 percpu accessors.  Add x86_test_and_clear_bit_percpu() and replace
pda op implementations with wrappers around x86 percpu accessors.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Tejun Heo 2009-01-13 20:41:35 +09:00 committed by Ingo Molnar
parent b12d8db8fb
commit 49357d19e4
4 changed files with 16 additions and 85 deletions
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88
arch/x86/include/asm/pda.h
View File

@ -45,91 +45,15 @@ extern void pda_init(int);
#define cpu_pda(cpu) (&per_cpu(__pda, cpu))
/*
* There is no fast way to get the base address of the PDA, all the accesses
* have to mention %fs/%gs. So it needs to be done this Torvaldian way.
*/
extern void __bad_pda_field(void) __attribute__((noreturn));
/*
* proxy_pda doesn't actually exist, but tell gcc it is accessed for
* all PDA accesses so it gets read/write dependencies right.
*/
extern struct x8664_pda _proxy_pda;
#define pda_offset(field) offsetof(struct x8664_pda, field)
#define pda_to_op(op, field, val) \
do { \
typedef typeof(_proxy_pda.field) T__; \
if (0) { T__ tmp__; tmp__ = (val); } /* type checking */ \
switch (sizeof(_proxy_pda.field)) { \
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; \
case 8: \
asm(op "q %1,%%gs:%c2": \
"+m" (_proxy_pda.field) : \
"r" ((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 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; \
case 8: \
asm(op "q %%gs:%c1,%0": \
"=r" (ret__) : \
"i" (pda_offset(field)), \
"m" (_proxy_pda.field)); \
break; \
default: \
__bad_pda_field(); \
} \
ret__; \
})
#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)
#define read_pda(field) x86_read_percpu(__pda.field)
#define write_pda(field, val) x86_write_percpu(__pda.field, val)
#define add_pda(field, val) x86_add_percpu(__pda.field, val)
#define sub_pda(field, val) x86_sub_percpu(__pda.field, val)
#define or_pda(field, val) x86_or_percpu(__pda.field, val)
/* This is not atomic against other CPUs -- CPU preemption needs to be off */
#define test_and_clear_bit_pda(bit, field) \
({ \
int old__; \
asm volatile("btr %2,%%gs:%c3\n\tsbbl %0,%0" \
: "=r" (old__), "+m" (_proxy_pda.field) \
: "dIr" (bit), "i" (pda_offset(field)) : "memory");\
old__; \
})
x86_test_and_clear_bit_percpu(bit, __pda.field)
#endif

10
arch/x86/include/asm/percpu.h
View File

@ -121,6 +121,16 @@ do { \
#define x86_sub_percpu(var, val) percpu_to_op("sub", per_cpu__##var, val)
#define x86_or_percpu(var, val) percpu_to_op("or", per_cpu__##var, val)
/* This is not atomic against other CPUs -- CPU preemption needs to be off */
#define x86_test_and_clear_bit_percpu(bit, var) \
({ \
int old__; \
asm volatile("btr %1,"__percpu_seg_str"%c2\n\tsbbl %0,%0" \
: "=r" (old__) \
: "dIr" (bit), "i" (&per_cpu__##var) : "memory"); \
old__; \
})
#ifdef CONFIG_X86_64
extern void load_pda_offset(int cpu);
#else

1
arch/x86/kernel/vmlinux_64.lds.S
View File

@ -14,7 +14,6 @@ OUTPUT_FORMAT("elf64-x86-64", "elf64-x86-64", "elf64-x86-64")
OUTPUT_ARCH(i386:x86-64)
ENTRY(phys_startup_64)
jiffies_64 = jiffies;
_proxy_pda = 1;
PHDRS {
text PT_LOAD FLAGS(5); /* R_E */
data PT_LOAD FLAGS(7); /* RWE */

2
arch/x86/kernel/x8664_ksyms_64.c
View File

@ -58,5 +58,3 @@ EXPORT_SYMBOL(__memcpy);
EXPORT_SYMBOL(empty_zero_page);
EXPORT_SYMBOL(init_level4_pgt);
EXPORT_SYMBOL(load_gs_index);
EXPORT_SYMBOL(_proxy_pda);