Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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kernel
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linux
[AVR32] optimize pagefault path
Avoid the costly notifier list in the pagefault path and call
the kprobes code directly. The same change went into the 2.6.22
cycle for powerpc, 2s390 and sparc64 already.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
authored by Christoph Hellwig and committed by Haavard Skinnemoen 9caebec7 5d1938c8
+1
-6
arch/avr32/kernel/kprobes.c
+1
-6
arch/avr32/kernel/kprobes.c
···
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return 1;
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}
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-
static int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
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+
int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
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{
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struct kprobe *cur = kprobe_running();
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···
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break;
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case DIE_SSTEP:
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if (post_kprobe_handler(args->regs))
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-
ret = NOTIFY_STOP;
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-
break;
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-
case DIE_FAULT:
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-
if (kprobe_running()
221
-
&& kprobe_fault_handler(args->regs, args->trapnr))
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ret = NOTIFY_STOP;
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break;
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default:
+12
-24
arch/avr32/mm/fault.c
+12
-24
arch/avr32/mm/fault.c
···
12
12
#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/pagemap.h>
15
-
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#include <linux/kdebug.h>
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+
#include <linux/kprobes.h>
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+
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#include <asm/mmu_context.h>
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#include <asm/sysreg.h>
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#include <asm/tlb.h>
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#include <asm/uaccess.h>
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#ifdef CONFIG_KPROBES
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-
ATOMIC_NOTIFIER_HEAD(notify_page_fault_chain);
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-
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-
/* Hook to register for page fault notifications */
26
-
int register_page_fault_notifier(struct notifier_block *nb)
24
+
static inline int notify_page_fault(struct pt_regs *regs, int trap)
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25
{
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-
return atomic_notifier_chain_register(¬ify_page_fault_chain, nb);
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-
}
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+
int ret = 0;
30
27
31
-
int unregister_page_fault_notifier(struct notifier_block *nb)
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-
{
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-
return atomic_notifier_chain_unregister(¬ify_page_fault_chain, nb);
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-
}
28
+
if (!user_mode(regs)) {
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+
if (kprobe_running() && kprobe_fault_handler(regs, trap))
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+
ret = 1;
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+
}
35
32
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-
static inline int notify_page_fault(enum die_val val, struct pt_regs *regs,
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-
int trap, int sig)
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-
{
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-
struct die_args args = {
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-
.regs = regs,
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-
.trapnr = trap,
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-
};
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-
return atomic_notifier_call_chain(¬ify_page_fault_chain, val, &args);
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+
return ret;
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34
}
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#else
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-
static inline int notify_page_fault(enum die_val val, struct pt_regs *regs,
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-
int trap, int sig)
36
+
static inline int notify_page_fault(struct pt_regs *regs, int trap)
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37
{
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-
return NOTIFY_DONE;
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+
return 0;
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}
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40
#endif
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41
···
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long signr;
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int code;
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78
68
-
if (notify_page_fault(DIE_PAGE_FAULT, regs,
69
-
ecr, SIGSEGV) == NOTIFY_STOP)
79
+
if (notify_page_fault(regs, ecr))
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return;
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address = sysreg_read(TLBEAR);
+13
-4
include/asm-avr32/kdebug.h
+13
-4
include/asm-avr32/kdebug.h
···
5
5
6
6
/* Grossly misnamed. */
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7
enum die_val {
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-
DIE_FAULT,
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8
DIE_BREAKPOINT,
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9
DIE_SSTEP,
11
-
DIE_PAGE_FAULT,
12
10
};
13
11
14
-
int register_page_fault_notifier(struct notifier_block *nb);
15
-
int unregister_page_fault_notifier(struct notifier_block *nb);
12
+
/*
13
+
* These are only here because kprobes.c wants them to implement a
14
+
* blatant layering violation. Will hopefully go away soon once all
15
+
* architectures are updated.
16
+
*/
17
+
static inline int register_page_fault_notifier(struct notifier_block *nb)
18
+
{
19
+
return 0;
20
+
}
21
+
static inline int unregister_page_fault_notifier(struct notifier_block *nb)
22
+
{
23
+
return 0;
24
+
}
16
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17
26
#endif /* __ASM_AVR32_KDEBUG_H */