lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Merge branches 'perf-fixes-for-linus' and 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

Browse Source 
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  jump label: Add work around to i386 gcc asm goto bug
  x86, ftrace: Use safe noops, drop trap test
  jump_label: Fix unaligned traps on sparc.
  jump label: Make arch_jump_label_text_poke_early() optional
  jump label: Fix error with preempt disable holding mutex
  oprofile: Remove deprecated use of flush_scheduled_work()
  oprofile: Fix the hang while taking the cpu offline
  jump label: Fix deadlock b/w jump_label_mutex vs. text_mutex
  jump label: Fix module __init section race

* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: Check irq_remapped instead of remapping_enabled in destroy_irq()
This commit is contained in:
Linus Torvalds
2010-10-30 11:43:26 -07:00
parent 925d169f5b 169ed55bd3 7b79462a20
commit f02a38d86a
12 changed files with 153 additions and 82 deletions
Download Patch File Download Diff File Expand all files Collapse all files

69
arch/x86/kernel/alternative.c
View File

@ -644,65 +644,26 @@ void *__kprobes text_poke_smp(void *addr, const void *opcode, size_t len)
#if defined(CONFIG_DYNAMIC_FTRACE) || defined(HAVE_JUMP_LABEL)
unsigned char ideal_nop5[IDEAL_NOP_SIZE_5];
#ifdef CONFIG_X86_64
unsigned char ideal_nop5[5] = { 0x66, 0x66, 0x66, 0x66, 0x90 };
#else
unsigned char ideal_nop5[5] = { 0x3e, 0x8d, 0x74, 0x26, 0x00 };
#endif
void __init arch_init_ideal_nop5(void)
{
extern const unsigned char ftrace_test_p6nop[];
extern const unsigned char ftrace_test_nop5[];
extern const unsigned char ftrace_test_jmp[];
int faulted = 0;
/*
* There is no good nop for all x86 archs.
* We will default to using the P6_NOP5, but first we
* will test to make sure that the nop will actually
* work on this CPU. If it faults, we will then
* go to a lesser efficient 5 byte nop. If that fails
* we then just use a jmp as our nop. This isn't the most
* efficient nop, but we can not use a multi part nop
* since we would then risk being preempted in the middle
* of that nop, and if we enabled tracing then, it might
* cause a system crash.
* There is no good nop for all x86 archs. This selection
* algorithm should be unified with the one in find_nop_table(),
* but this should be good enough for now.
*
* TODO: check the cpuid to determine the best nop.
* For cases other than the ones below, use the safe (as in
* always functional) defaults above.
*/
asm volatile (
"ftrace_test_jmp:"
"jmp ftrace_test_p6nop\n"
"nop\n"
"nop\n"
"nop\n" /* 2 byte jmp + 3 bytes */
"ftrace_test_p6nop:"
P6_NOP5
"jmp 1f\n"
"ftrace_test_nop5:"
".byte 0x66,0x66,0x66,0x66,0x90\n"
"1:"
".section .fixup, \"ax\"\n"
"2: movl $1, %0\n"
" jmp ftrace_test_nop5\n"
"3: movl $2, %0\n"
" jmp 1b\n"
".previous\n"
_ASM_EXTABLE(ftrace_test_p6nop, 2b)
_ASM_EXTABLE(ftrace_test_nop5, 3b)
: "=r"(faulted) : "0" (faulted));
switch (faulted) {
case 0:
pr_info("converting mcount calls to 0f 1f 44 00 00\n");
memcpy(ideal_nop5, ftrace_test_p6nop, IDEAL_NOP_SIZE_5);
break;
case 1:
pr_info("converting mcount calls to 66 66 66 66 90\n");
memcpy(ideal_nop5, ftrace_test_nop5, IDEAL_NOP_SIZE_5);
break;
case 2:
pr_info("converting mcount calls to jmp . + 5\n");
memcpy(ideal_nop5, ftrace_test_jmp, IDEAL_NOP_SIZE_5);
break;
}
#ifdef CONFIG_X86_64
/* Don't use these on 32 bits due to broken virtualizers */
if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL)
memcpy(ideal_nop5, p6_nops[5], 5);
#endif
}
#endif