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Subject[tip: x86/entry] x86/entry: Move paranoid irq tracing out of ASM code
The following commit has been merged into the x86/entry branch of tip:

Commit-ID: 290e14a71d0fab4dad25ad2fee2e78e3bd6aef79
Gitweb: https://git.kernel.org/tip/290e14a71d0fab4dad25ad2fee2e78e3bd6aef79
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Thu, 21 May 2020 22:05:51 +02:00
Committer: Ingo Molnar <mingo@kernel.org>
CommitterDate: Tue, 26 May 2020 19:06:29 +02:00

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
---
arch/x86/entry/entry_64.S | 13 -------------
arch/x86/kernel/cpu/mce/core.c | 3 +++
arch/x86/kernel/nmi.c | 3 +++
arch/x86/kernel/traps.c | 11 +++++++++++
4 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index fb7f126..2566554 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -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
diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index c47f004..068e6ca 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -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();
}
diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
index d18ec18..1c58454 100644
--- a/arch/x86/kernel/nmi.c
+++ b/arch/x86/kernel/nmi.c
@@ -334,6 +334,7 @@ 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);
@@ -420,6 +421,8 @@ 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();
}

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index f28be3e..50fb9cd 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -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();
}

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