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x86/entry: Move paranoid irq tracing out of ASM code 

The last step to remove the irq tracing cruft from ASM. Ignore #DF as the
maschine is going to die anyway.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20200521202120.414043330@linutronix.de
This commit is contained in:
Thomas Gleixner 2020-05-21 22:05:51 +02:00
parent 9628f26bae
commit 3ffdfdcec1
4 changed files with 17 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

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

@ -16,7 +16,6 @@
*
* Some macro usage:
* - SYM_FUNC_START/END:Define functions in the symbol table.
* - TRACE_IRQ_*: Trace hardirq state for lock debugging.
* - idtentry: Define exception entry points.
*/
#include <linux/linkage.h>
@ -107,11 +106,6 @@ SYM_CODE_END(native_usergs_sysret64)
SYM_CODE_START(entry_SYSCALL_64)
UNWIND_HINT_EMPTY
/*
* Interrupts are off on entry.
* We do not frame this tiny irq-off block with TRACE_IRQS_OFF/ON,
* it is too small to ever cause noticeable irq latency.
*/
swapgs
/* tss.sp2 is scratch space. */
@ -462,8 +456,6 @@ SYM_CODE_START(\asmsym)
UNWIND_HINT_REGS
TRACE_IRQS_OFF
movq %rsp, %rdi /* pt_regs pointer */
.if \vector == X86_TRAP_DB
@ -881,17 +873,13 @@ SYM_CODE_END(paranoid_entry)
*/
SYM_CODE_START_LOCAL(paranoid_exit)
UNWIND_HINT_REGS
DISABLE_INTERRUPTS(CLBR_ANY)
TRACE_IRQS_OFF
testl %ebx, %ebx /* swapgs needed? */
jnz .Lparanoid_exit_no_swapgs
TRACE_IRQS_IRETQ
/* Always restore stashed CR3 value (see paranoid_entry) */
RESTORE_CR3 scratch_reg=%rbx save_reg=%r14
SWAPGS_UNSAFE_STACK
jmp restore_regs_and_return_to_kernel
.Lparanoid_exit_no_swapgs:
TRACE_IRQS_IRETQ
/* Always restore stashed CR3 value (see paranoid_entry) */
RESTORE_CR3 scratch_reg=%rbx save_reg=%r14
jmp restore_regs_and_return_to_kernel
@ -1292,7 +1280,6 @@ end_repeat_nmi:
call paranoid_entry
UNWIND_HINT_REGS
/* paranoidentry exc_nmi(), 0; without TRACE_IRQS_OFF */
movq %rsp, %rdi
movq $-1, %rsi
call exc_nmi

3
arch/x86/kernel/cpu/mce/core.c
View File

@ -1922,7 +1922,10 @@ static __always_inline void exc_machine_check_kernel(struct pt_regs *regs)
* that out because it's an indirect call. Annotate it.
*/
instrumentation_begin();
trace_hardirqs_off_prepare();
machine_check_vector(regs);
if (regs->flags & X86_EFLAGS_IF)
trace_hardirqs_on_prepare();
instrumentation_end();
nmi_exit();
}

3
arch/x86/kernel/nmi.c
View File

@ -330,6 +330,7 @@ static noinstr void default_do_nmi(struct pt_regs *regs)
__this_cpu_write(last_nmi_rip, regs->ip);
instrumentation_begin();
trace_hardirqs_off_prepare();
handled = nmi_handle(NMI_LOCAL, regs);
__this_cpu_add(nmi_stats.normal, handled);
@ -416,6 +417,8 @@ static noinstr void default_do_nmi(struct pt_regs *regs)
unknown_nmi_error(reason, regs);
out:
if (regs->flags & X86_EFLAGS_IF)
trace_hardirqs_on_prepare();
instrumentation_end();
}

11
arch/x86/kernel/traps.c
View File

@ -634,8 +634,11 @@ DEFINE_IDTENTRY_RAW(exc_int3)
} else {
nmi_enter();
instrumentation_begin();
trace_hardirqs_off_prepare();
if (!do_int3(regs))
die("int3", regs, 0);
if (regs->flags & X86_EFLAGS_IF)
trace_hardirqs_on_prepare();
instrumentation_end();
nmi_exit();
}
@ -850,6 +853,10 @@ static __always_inline void exc_debug_kernel(struct pt_regs *regs,
unsigned long dr6)
{
nmi_enter();
instrumentation_begin();
trace_hardirqs_off_prepare();
instrumentation_end();
/*
* The SDM says "The processor clears the BTF flag when it
* generates a debug exception." Clear TIF_BLOCKSTEP to keep
@ -871,6 +878,10 @@ static __always_inline void exc_debug_kernel(struct pt_regs *regs,
if (dr6)
handle_debug(regs, dr6, false);
instrumentation_begin();
if (regs->flags & X86_EFLAGS_IF)
trace_hardirqs_on_prepare();
instrumentation_end();
nmi_exit();
}