a0f7ab8a6a
cherry-pick from upstream 4.14
218 lines
7.8 KiB
Diff
218 lines
7.8 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Thomas Gleixner <tglx@linutronix.de>
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Date: Mon, 28 Aug 2017 08:47:22 +0200
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Subject: [PATCH] x86/traps: Simplify pagefault tracing logic
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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CVE-2017-5754
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Make use of the new irqvector tracing static key and remove the duplicated
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trace_do_pagefault() implementation.
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If irq vector tracing is disabled, then the overhead of this is a single
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NOP5, which is a reasonable tradeoff to avoid duplicated code and the
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unholy macro mess.
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Cc: Andy Lutomirski <luto@kernel.org>
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Cc: Borislav Petkov <bp@alien8.de>
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Cc: Linus Torvalds <torvalds@linux-foundation.org>
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Cc: Peter Zijlstra <peterz@infradead.org>
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Cc: Steven Rostedt <rostedt@goodmis.org>
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Link: http://lkml.kernel.org/r/20170828064956.672965407@linutronix.de
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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(cherry picked from commit 11a7ffb01703c3bbb1e9b968893f4487a1b0b5a8)
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Signed-off-by: Andy Whitcroft <apw@canonical.com>
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Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
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(cherry picked from commit 8478bb5608747fd64c9fd4a2f5422fb4af756a50)
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Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
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---
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arch/x86/include/asm/traps.h | 10 +--------
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arch/x86/kernel/kvm.c | 2 +-
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arch/x86/mm/fault.c | 49 ++++++++++++--------------------------------
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arch/x86/entry/entry_32.S | 8 --------
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arch/x86/entry/entry_64.S | 13 +-----------
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5 files changed, 16 insertions(+), 66 deletions(-)
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diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h
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index 01fd0a7f48cd..b4f322d6c95f 100644
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--- a/arch/x86/include/asm/traps.h
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+++ b/arch/x86/include/asm/traps.h
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@@ -39,7 +39,6 @@ asmlinkage void machine_check(void);
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asmlinkage void simd_coprocessor_error(void);
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#ifdef CONFIG_TRACING
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-asmlinkage void trace_page_fault(void);
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#define trace_stack_segment stack_segment
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#define trace_divide_error divide_error
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#define trace_bounds bounds
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@@ -54,6 +53,7 @@ asmlinkage void trace_page_fault(void);
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#define trace_alignment_check alignment_check
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#define trace_simd_coprocessor_error simd_coprocessor_error
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#define trace_async_page_fault async_page_fault
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+#define trace_page_fault page_fault
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#endif
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dotraplinkage void do_divide_error(struct pt_regs *, long);
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@@ -74,14 +74,6 @@ asmlinkage struct pt_regs *sync_regs(struct pt_regs *);
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#endif
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dotraplinkage void do_general_protection(struct pt_regs *, long);
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dotraplinkage void do_page_fault(struct pt_regs *, unsigned long);
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-#ifdef CONFIG_TRACING
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-dotraplinkage void trace_do_page_fault(struct pt_regs *, unsigned long);
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-#else
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-static inline void trace_do_page_fault(struct pt_regs *regs, unsigned long error)
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-{
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- do_page_fault(regs, error);
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-}
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-#endif
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dotraplinkage void do_spurious_interrupt_bug(struct pt_regs *, long);
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dotraplinkage void do_coprocessor_error(struct pt_regs *, long);
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dotraplinkage void do_alignment_check(struct pt_regs *, long);
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diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
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index e5e4306e4546..9e3798b00e40 100644
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--- a/arch/x86/kernel/kvm.c
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+++ b/arch/x86/kernel/kvm.c
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@@ -270,7 +270,7 @@ do_async_page_fault(struct pt_regs *regs, unsigned long error_code)
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switch (kvm_read_and_reset_pf_reason()) {
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default:
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- trace_do_page_fault(regs, error_code);
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+ do_page_fault(regs, error_code);
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break;
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case KVM_PV_REASON_PAGE_NOT_PRESENT:
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/* page is swapped out by the host. */
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diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
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index 955be01dd9cc..4ee9eb916826 100644
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--- a/arch/x86/mm/fault.c
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+++ b/arch/x86/mm/fault.c
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@@ -1253,10 +1253,6 @@ static inline bool smap_violation(int error_code, struct pt_regs *regs)
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* This routine handles page faults. It determines the address,
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* and the problem, and then passes it off to one of the appropriate
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* routines.
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- *
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- * This function must have noinline because both callers
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- * {,trace_}do_page_fault() have notrace on. Having this an actual function
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- * guarantees there's a function trace entry.
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*/
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static noinline void
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__do_page_fault(struct pt_regs *regs, unsigned long error_code,
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@@ -1491,27 +1487,6 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code,
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}
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NOKPROBE_SYMBOL(__do_page_fault);
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-dotraplinkage void notrace
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-do_page_fault(struct pt_regs *regs, unsigned long error_code)
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-{
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- unsigned long address = read_cr2(); /* Get the faulting address */
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- enum ctx_state prev_state;
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-
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- /*
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- * We must have this function tagged with __kprobes, notrace and call
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- * read_cr2() before calling anything else. To avoid calling any kind
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- * of tracing machinery before we've observed the CR2 value.
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- *
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- * exception_{enter,exit}() contain all sorts of tracepoints.
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- */
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-
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- prev_state = exception_enter();
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- __do_page_fault(regs, error_code, address);
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- exception_exit(prev_state);
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-}
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-NOKPROBE_SYMBOL(do_page_fault);
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-
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-#ifdef CONFIG_TRACING
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static nokprobe_inline void
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trace_page_fault_entries(unsigned long address, struct pt_regs *regs,
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unsigned long error_code)
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@@ -1522,22 +1497,24 @@ trace_page_fault_entries(unsigned long address, struct pt_regs *regs,
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trace_page_fault_kernel(address, regs, error_code);
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}
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+/*
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+ * We must have this function blacklisted from kprobes, tagged with notrace
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+ * and call read_cr2() before calling anything else. To avoid calling any
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+ * kind of tracing machinery before we've observed the CR2 value.
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+ *
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+ * exception_{enter,exit}() contains all sorts of tracepoints.
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+ */
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dotraplinkage void notrace
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-trace_do_page_fault(struct pt_regs *regs, unsigned long error_code)
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+do_page_fault(struct pt_regs *regs, unsigned long error_code)
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{
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- /*
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- * The exception_enter and tracepoint processing could
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- * trigger another page faults (user space callchain
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- * reading) and destroy the original cr2 value, so read
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- * the faulting address now.
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- */
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- unsigned long address = read_cr2();
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+ unsigned long address = read_cr2(); /* Get the faulting address */
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enum ctx_state prev_state;
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prev_state = exception_enter();
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- trace_page_fault_entries(address, regs, error_code);
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+ if (trace_irqvectors_enabled())
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+ trace_page_fault_entries(address, regs, error_code);
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+
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__do_page_fault(regs, error_code, address);
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exception_exit(prev_state);
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}
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-NOKPROBE_SYMBOL(trace_do_page_fault);
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-#endif /* CONFIG_TRACING */
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+NOKPROBE_SYMBOL(do_page_fault);
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diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
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index 48ef7bb32c42..0092da1c056f 100644
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--- a/arch/x86/entry/entry_32.S
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+++ b/arch/x86/entry/entry_32.S
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@@ -891,14 +891,6 @@ BUILD_INTERRUPT3(hyperv_callback_vector, HYPERVISOR_CALLBACK_VECTOR,
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#endif /* CONFIG_HYPERV */
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-#ifdef CONFIG_TRACING
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-ENTRY(trace_page_fault)
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- ASM_CLAC
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- pushl $trace_do_page_fault
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- jmp common_exception
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-END(trace_page_fault)
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-#endif
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-
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ENTRY(page_fault)
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ASM_CLAC
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pushl $do_page_fault
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diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
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index ca0b250eefc4..dfabcbf8e813 100644
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--- a/arch/x86/entry/entry_64.S
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+++ b/arch/x86/entry/entry_64.S
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@@ -913,17 +913,6 @@ ENTRY(\sym)
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END(\sym)
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.endm
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-#ifdef CONFIG_TRACING
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-.macro trace_idtentry sym do_sym has_error_code:req
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-idtentry trace(\sym) trace(\do_sym) has_error_code=\has_error_code
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-idtentry \sym \do_sym has_error_code=\has_error_code
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-.endm
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-#else
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-.macro trace_idtentry sym do_sym has_error_code:req
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-idtentry \sym \do_sym has_error_code=\has_error_code
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-.endm
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-#endif
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-
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idtentry divide_error do_divide_error has_error_code=0
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idtentry overflow do_overflow has_error_code=0
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idtentry bounds do_bounds has_error_code=0
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@@ -1091,7 +1080,7 @@ idtentry xen_stack_segment do_stack_segment has_error_code=1
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#endif
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idtentry general_protection do_general_protection has_error_code=1
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-trace_idtentry page_fault do_page_fault has_error_code=1
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+idtentry page_fault do_page_fault has_error_code=1
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#ifdef CONFIG_KVM_GUEST
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idtentry async_page_fault do_async_page_fault has_error_code=1
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--
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2.14.2
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