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x86/traps: Simplify pagefault tracing logic

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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>
This commit is contained in:
Thomas Gleixner 2017-08-28 08:47:22 +02:00 committed by Ingo Molnar
parent 2feb1b316d
commit 11a7ffb017
5 changed files with 16 additions and 66 deletions
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8
arch/x86/entry/entry_32.S
View File

@ -891,14 +891,6 @@ BUILD_INTERRUPT3(hyperv_callback_vector, HYPERVISOR_CALLBACK_VECTOR,
#endif /* CONFIG_HYPERV */
#ifdef CONFIG_TRACING
ENTRY(trace_page_fault)
ASM_CLAC
pushl $trace_do_page_fault
jmp common_exception
END(trace_page_fault)
#endif
ENTRY(page_fault)
ASM_CLAC
pushl $do_page_fault

13
arch/x86/entry/entry_64.S
View File

@ -918,17 +918,6 @@ ENTRY(\sym)
END(\sym)
.endm
#ifdef CONFIG_TRACING
.macro trace_idtentry sym do_sym has_error_code:req
idtentry trace(\sym) trace(\do_sym) has_error_code=\has_error_code
idtentry \sym \do_sym has_error_code=\has_error_code
.endm
#else
.macro trace_idtentry sym do_sym has_error_code:req
idtentry \sym \do_sym has_error_code=\has_error_code
.endm
#endif
idtentry divide_error do_divide_error has_error_code=0
idtentry overflow do_overflow has_error_code=0
idtentry bounds do_bounds has_error_code=0
@ -1096,7 +1085,7 @@ idtentry xen_stack_segment do_stack_segment has_error_code=1
#endif
idtentry general_protection do_general_protection has_error_code=1
trace_idtentry page_fault do_page_fault has_error_code=1
idtentry page_fault do_page_fault has_error_code=1
#ifdef CONFIG_KVM_GUEST
idtentry async_page_fault do_async_page_fault has_error_code=1

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

@ -39,7 +39,6 @@ asmlinkage void machine_check(void);
asmlinkage void simd_coprocessor_error(void);
#ifdef CONFIG_TRACING
asmlinkage void trace_page_fault(void);
#define trace_stack_segment stack_segment
#define trace_divide_error divide_error
#define trace_bounds bounds
@ -54,6 +53,7 @@ asmlinkage void trace_page_fault(void);
#define trace_alignment_check alignment_check
#define trace_simd_coprocessor_error simd_coprocessor_error
#define trace_async_page_fault async_page_fault
#define trace_page_fault page_fault
#endif
dotraplinkage void do_divide_error(struct pt_regs *, long);
@ -74,14 +74,6 @@ asmlinkage struct pt_regs *sync_regs(struct pt_regs *);
#endif
dotraplinkage void do_general_protection(struct pt_regs *, long);
dotraplinkage void do_page_fault(struct pt_regs *, unsigned long);
#ifdef CONFIG_TRACING
dotraplinkage void trace_do_page_fault(struct pt_regs *, unsigned long);
#else
static inline void trace_do_page_fault(struct pt_regs *regs, unsigned long error)
{
do_page_fault(regs, error);
}
#endif
dotraplinkage void do_spurious_interrupt_bug(struct pt_regs *, long);
dotraplinkage void do_coprocessor_error(struct pt_regs *, long);
dotraplinkage void do_alignment_check(struct pt_regs *, long);

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

@ -263,7 +263,7 @@ do_async_page_fault(struct pt_regs *regs, unsigned long error_code)
switch (kvm_read_and_reset_pf_reason()) {
default:
trace_do_page_fault(regs, error_code);
do_page_fault(regs, error_code);
break;
case KVM_PV_REASON_PAGE_NOT_PRESENT:
/* page is swapped out by the host. */

49
arch/x86/mm/fault.c
View File

@ -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);