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| author | Thomas Gleixner <tglx@linutronix.de> | 2017-08-28 08:47:22 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-08-29 11:42:23 +0200 |
| commit | 11a7ffb01703c3bbb1e9b968893f4487a1b0b5a8 (patch) | |
| tree | 938e6fb9f52b79afbf4a8d25eac25cfa5d315178 /arch/x86/mm | |
| parent | 2feb1b316d48004d905278c02a55902cab0be8be (diff) | |
| download | linux-11a7ffb01703c3bbb1e9b968893f4487a1b0b5a8.tar.bz2 | |
x86/traps: Simplify pagefault tracing logic
Make use of the new irqvector tracing static key and remove the duplicated
trace_do_pagefault() implementation.
If irq vector tracing is disabled, then the overhead of this is a single
NOP5, which is a reasonable tradeoff to avoid duplicated code and the
unholy macro mess.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20170828064956.672965407@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/mm')
| -rw-r--r-- | arch/x86/mm/fault.c | 49 |
1 files changed, 13 insertions, 36 deletions
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 2a1fa10c6a98..58d7b3a4ec2e 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -1254,10 +1254,6 @@ static inline bool smap_violation(int error_code, struct pt_regs *regs) * This routine handles page faults. It determines the address, * and the problem, and then passes it off to one of the appropriate * routines. - * - * This function must have noinline because both callers - * {,trace_}do_page_fault() have notrace on. Having this an actual function - * guarantees there's a function trace entry. */ static noinline void __do_page_fault(struct pt_regs *regs, unsigned long error_code, @@ -1490,27 +1486,6 @@ good_area: } NOKPROBE_SYMBOL(__do_page_fault); -dotraplinkage void notrace -do_page_fault(struct pt_regs *regs, unsigned long error_code) -{ - unsigned long address = read_cr2(); /* Get the faulting address */ - enum ctx_state prev_state; - - /* - * We must have this function tagged with __kprobes, notrace and call - * read_cr2() before calling anything else. To avoid calling any kind - * of tracing machinery before we've observed the CR2 value. - * - * exception_{enter,exit}() contain all sorts of tracepoints. - */ - - prev_state = exception_enter(); - __do_page_fault(regs, error_code, address); - exception_exit(prev_state); -} -NOKPROBE_SYMBOL(do_page_fault); - -#ifdef CONFIG_TRACING static nokprobe_inline void trace_page_fault_entries(unsigned long address, struct pt_regs *regs, unsigned long error_code) @@ -1521,22 +1496,24 @@ trace_page_fault_entries(unsigned long address, struct pt_regs *regs, trace_page_fault_kernel(address, regs, error_code); } +/* + * We must have this function blacklisted from kprobes, tagged with notrace + * and call read_cr2() before calling anything else. To avoid calling any + * kind of tracing machinery before we've observed the CR2 value. + * + * exception_{enter,exit}() contains all sorts of tracepoints. + */ dotraplinkage void notrace -trace_do_page_fault(struct pt_regs *regs, unsigned long error_code) +do_page_fault(struct pt_regs *regs, unsigned long error_code) { - /* - * The exception_enter and tracepoint processing could - * trigger another page faults (user space callchain - * reading) and destroy the original cr2 value, so read - * the faulting address now. - */ - unsigned long address = read_cr2(); + unsigned long address = read_cr2(); /* Get the faulting address */ enum ctx_state prev_state; prev_state = exception_enter(); - trace_page_fault_entries(address, regs, error_code); + if (trace_irqvectors_enabled()) + trace_page_fault_entries(address, regs, error_code); + __do_page_fault(regs, error_code, address); exception_exit(prev_state); } -NOKPROBE_SYMBOL(trace_do_page_fault); -#endif /* CONFIG_TRACING */ +NOKPROBE_SYMBOL(do_page_fault); |