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x86: multi-byte single instruction NOPs

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Add support for and use the multi-byte NOPs recently documented to be
available on all PentiumPro and later processors.

This patch only applies cleanly on top of the "x86: misc.
constifications" patch sent earlier.

[ tglx: arch/x86 adaptation ]

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

 arch/x86/kernel/alternative.c  |   23 ++++++++++++++++++++++-
 include/asm-x86/processor_32.h |   22 ++++++++++++++++++++++
 include/asm-x86/processor_64.h |   22 ++++++++++++++++++++++
 3 files changed, 66 insertions(+), 1 deletion(-)
This commit is contained in:
Jan Beulich 2007-10-17 18:04:41 +02:00 committed by Thomas Gleixner
parent c861eff88c
commit 32c464f5d9
3 changed files with 66 additions and 1 deletions
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23
arch/x86/kernel/alternative.c
View File

@ -116,12 +116,31 @@ static const unsigned char *const k7_nops[ASM_NOP_MAX+1] = {
};
#endif
#ifdef P6_NOP1
asm("\t.section .rodata, \"a\"\np6nops: "
P6_NOP1 P6_NOP2 P6_NOP3 P6_NOP4 P6_NOP5 P6_NOP6
P6_NOP7 P6_NOP8);
extern const unsigned char p6nops[];
static const unsigned char *const p6_nops[ASM_NOP_MAX+1] = {
NULL,
p6nops,
p6nops + 1,
p6nops + 1 + 2,
p6nops + 1 + 2 + 3,
p6nops + 1 + 2 + 3 + 4,
p6nops + 1 + 2 + 3 + 4 + 5,
p6nops + 1 + 2 + 3 + 4 + 5 + 6,
p6nops + 1 + 2 + 3 + 4 + 5 + 6 + 7,
};
#endif
#ifdef CONFIG_X86_64
extern char __vsyscall_0;
static inline const unsigned char*const * find_nop_table(void)
{
return k8_nops;
return boot_cpu_data.x86_vendor != X86_VENDOR_INTEL ||
boot_cpu_data.x86 < 6 ? k8_nops : p6_nops;
}
#else /* CONFIG_X86_64 */
@ -132,6 +151,8 @@ static const struct nop {
} noptypes[] = {
{ X86_FEATURE_K8, k8_nops },
{ X86_FEATURE_K7, k7_nops },
{ X86_FEATURE_P4, p6_nops },
{ X86_FEATURE_P3, p6_nops },
{ -1, NULL }
};

22
include/asm-x86/processor_32.h
View File

@ -677,6 +677,17 @@ static inline unsigned int cpuid_edx(unsigned int op)
#define K7_NOP7 ".byte 0x8D,0x04,0x05,0,0,0,0\n"
#define K7_NOP8 K7_NOP7 ASM_NOP1
/* P6 nops */
/* uses eax dependencies (Intel-recommended choice) */
#define P6_NOP1 GENERIC_NOP1
#define P6_NOP2 ".byte 0x66,0x90\n"
#define P6_NOP3 ".byte 0x0f,0x1f,0x00\n"
#define P6_NOP4 ".byte 0x0f,0x1f,0x40,0\n"
#define P6_NOP5 ".byte 0x0f,0x1f,0x44,0x00,0\n"
#define P6_NOP6 ".byte 0x66,0x0f,0x1f,0x44,0x00,0\n"
#define P6_NOP7 ".byte 0x0f,0x1f,0x80,0,0,0,0\n"
#define P6_NOP8 ".byte 0x0f,0x1f,0x84,0x00,0,0,0,0\n"
#ifdef CONFIG_MK8
#define ASM_NOP1 K8_NOP1
#define ASM_NOP2 K8_NOP2
@ -695,6 +706,17 @@ static inline unsigned int cpuid_edx(unsigned int op)
#define ASM_NOP6 K7_NOP6
#define ASM_NOP7 K7_NOP7
#define ASM_NOP8 K7_NOP8
#elif defined(CONFIG_M686) || defined(CONFIG_MPENTIUMII) || \
defined(CONFIG_MPENTIUMIII) || defined(CONFIG_MPENTIUMM) || \
defined(CONFIG_MCORE2) || defined(CONFIG_PENTIUM4)
#define ASM_NOP1 P6_NOP1
#define ASM_NOP2 P6_NOP2
#define ASM_NOP3 P6_NOP3
#define ASM_NOP4 P6_NOP4
#define ASM_NOP5 P6_NOP5
#define ASM_NOP6 P6_NOP6
#define ASM_NOP7 P6_NOP7
#define ASM_NOP8 P6_NOP8
#else
#define ASM_NOP1 GENERIC_NOP1
#define ASM_NOP2 GENERIC_NOP2

22
include/asm-x86/processor_64.h
View File

@ -334,6 +334,16 @@ struct extended_sigtable {
};
#if defined(CONFIG_MPSC) || defined(CONFIG_MCORE2)
#define ASM_NOP1 P6_NOP1
#define ASM_NOP2 P6_NOP2
#define ASM_NOP3 P6_NOP3
#define ASM_NOP4 P6_NOP4
#define ASM_NOP5 P6_NOP5
#define ASM_NOP6 P6_NOP6
#define ASM_NOP7 P6_NOP7
#define ASM_NOP8 P6_NOP8
#else
#define ASM_NOP1 K8_NOP1
#define ASM_NOP2 K8_NOP2
#define ASM_NOP3 K8_NOP3
@ -342,6 +352,7 @@ struct extended_sigtable {
#define ASM_NOP6 K8_NOP6
#define ASM_NOP7 K8_NOP7
#define ASM_NOP8 K8_NOP8
#endif
/* Opteron nops */
#define K8_NOP1 ".byte 0x90\n"
@ -353,6 +364,17 @@ struct extended_sigtable {
#define K8_NOP7 K8_NOP4 K8_NOP3
#define K8_NOP8 K8_NOP4 K8_NOP4
/* P6 nops */
/* uses eax dependencies (Intel-recommended choice) */
#define P6_NOP1 ".byte 0x90\n"
#define P6_NOP2 ".byte 0x66,0x90\n"
#define P6_NOP3 ".byte 0x0f,0x1f,0x00\n"
#define P6_NOP4 ".byte 0x0f,0x1f,0x40,0\n"
#define P6_NOP5 ".byte 0x0f,0x1f,0x44,0x00,0\n"
#define P6_NOP6 ".byte 0x66,0x0f,0x1f,0x44,0x00,0\n"
#define P6_NOP7 ".byte 0x0f,0x1f,0x80,0,0,0,0\n"
#define P6_NOP8 ".byte 0x0f,0x1f,0x84,0x00,0,0,0,0\n"
#define ASM_NOP_MAX 8
/* REP NOP (PAUSE) is a good thing to insert into busy-wait loops. */