| Message ID | 1470672218-16059-5-git-send-email-cmetcalf@mellanox.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi, [adding Lorenzo] On Mon, Aug 08, 2016 at 12:03:38PM -0400, Chris Metcalf wrote: > When doing an nmi backtrace of many cores, most of which are idle, > the output is a little overwhelming and very uninformative. Suppress > messages for cpus that are idling when they are interrupted and just > emit one line, "NMI backtrace for N skipped: idling at pc 0xNNN". > > We do this by grouping all the cpuidle code together into a new > .cpuidle.text section, and then checking the address of the > interrupted PC to see if it lies within that section. > > This commit suitably tags x86, arm64, and tile idle routines, > and only adds in the minimal framework for other architectures. > diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S > index 659963d40bb4..fe7f93b7b11b 100644 > --- a/arch/arm64/kernel/vmlinux.lds.S > +++ b/arch/arm64/kernel/vmlinux.lds.S > @@ -122,6 +122,7 @@ SECTIONS > ENTRY_TEXT > TEXT_TEXT > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > KPROBES_TEXT > HYPERVISOR_TEXT > diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S > index 5bb61de23201..64f088ca3192 100644 > --- a/arch/arm64/mm/proc.S > +++ b/arch/arm64/mm/proc.S > @@ -48,11 +48,13 @@ > * > * Idle the processor (wait for interrupt). > */ > + .pushsection ".cpuidle.text","ax" > ENTRY(cpu_do_idle) > dsb sy // WFI may enter a low-power mode > wfi > ret > ENDPROC(cpu_do_idle) > + .popsection From a quick scan it looks like we only call this with interrupts disabled, and we have no NMI. So shouldn't we be annotating arch_cpu_idle(), which calls this and subsequently enables interrupts? I'm also not sure what you need to do for PSCI, which is the preferred (FW-backed) idle mechanism for arm64. The infrastrucure for that is spread over a few files: arch/arm64/kernel/sleep.S arch/arm64/kernel/smccc-call.S arch/arm64/kernel/suspend.c drivers/cpuidle/cpuidle-arm.c drivers/firmware/psci.c I'm not sure where we'd be an an interruptible state, and therefore I'm not immediately sure what we should annotate. Thanks, Mark.
On Mon, Aug 08, 2016 at 05:48:28PM +0100, Mark Rutland wrote: > Hi, > > [adding Lorenzo] > > On Mon, Aug 08, 2016 at 12:03:38PM -0400, Chris Metcalf wrote: > > When doing an nmi backtrace of many cores, most of which are idle, > > the output is a little overwhelming and very uninformative. Suppress > > messages for cpus that are idling when they are interrupted and just > > emit one line, "NMI backtrace for N skipped: idling at pc 0xNNN". > > > > We do this by grouping all the cpuidle code together into a new > > .cpuidle.text section, and then checking the address of the > > interrupted PC to see if it lies within that section. > > > > This commit suitably tags x86, arm64, and tile idle routines, > > and only adds in the minimal framework for other architectures. > > > diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S > > index 659963d40bb4..fe7f93b7b11b 100644 > > --- a/arch/arm64/kernel/vmlinux.lds.S > > +++ b/arch/arm64/kernel/vmlinux.lds.S > > @@ -122,6 +122,7 @@ SECTIONS > > ENTRY_TEXT > > TEXT_TEXT > > SCHED_TEXT > > + CPUIDLE_TEXT > > LOCK_TEXT > > KPROBES_TEXT > > HYPERVISOR_TEXT > > diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S > > index 5bb61de23201..64f088ca3192 100644 > > --- a/arch/arm64/mm/proc.S > > +++ b/arch/arm64/mm/proc.S > > @@ -48,11 +48,13 @@ > > * > > * Idle the processor (wait for interrupt). > > */ > > + .pushsection ".cpuidle.text","ax" > > ENTRY(cpu_do_idle) > > dsb sy // WFI may enter a low-power mode > > wfi > > ret > > ENDPROC(cpu_do_idle) > > + .popsection > > From a quick scan it looks like we only call this with interrupts > disabled, and we have no NMI. So shouldn't we be annotating > arch_cpu_idle(), which calls this and subsequently enables interrupts? > > I'm also not sure what you need to do for PSCI, which is the preferred > (FW-backed) idle mechanism for arm64. The infrastrucure for that is > spread over a few files: > > arch/arm64/kernel/sleep.S > arch/arm64/kernel/smccc-call.S > arch/arm64/kernel/suspend.c > drivers/cpuidle/cpuidle-arm.c > drivers/firmware/psci.c > > I'm not sure where we'd be an an interruptible state, and therefore I'm > not immediately sure what we should annotate. I am probably missing something here, but let me add that I am not sure I understand how this patch can be used on ARM/ARM64 systems so ARM platform idle back-end code annotation is basically useless given that it is code that can't be preempted anyway (and even if it could PC range check can even fail given that we may execute some code with MMU off so out of physical addresses). What's the purpose of this cpu idle tracking ? Can't it be implemented in a simpler way (ie RCU API) ? Lorenzo
On Mon 2016-08-08 12:03:38, Chris Metcalf wrote: > When doing an nmi backtrace of many cores, most of which are idle, > the output is a little overwhelming and very uninformative. Suppress > messages for cpus that are idling when they are interrupted and just > emit one line, "NMI backtrace for N skipped: idling at pc 0xNNN". > > We do this by grouping all the cpuidle code together into a new > .cpuidle.text section, and then checking the address of the > interrupted PC to see if it lies within that section. > > This commit suitably tags x86, arm64, and tile idle routines, > and only adds in the minimal framework for other architectures. > > Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> > Tested-by: Peter Zijlstra (Intel) <peterz@infradead.org> > Signed-off-by: Chris Metcalf <cmetcalf@mellanox.com> > --- > arch/alpha/kernel/vmlinux.lds.S | 1 + > arch/arc/kernel/vmlinux.lds.S | 1 + > arch/arm/kernel/vmlinux-xip.lds.S | 1 + > arch/arm/kernel/vmlinux.lds.S | 1 + > arch/arm64/kernel/vmlinux.lds.S | 1 + > arch/arm64/mm/proc.S | 2 ++ > arch/avr32/kernel/vmlinux.lds.S | 1 + > arch/blackfin/kernel/vmlinux.lds.S | 1 + > arch/c6x/kernel/vmlinux.lds.S | 1 + > arch/cris/kernel/vmlinux.lds.S | 1 + > arch/frv/kernel/vmlinux.lds.S | 1 + > arch/h8300/kernel/vmlinux.lds.S | 1 + > arch/hexagon/kernel/vmlinux.lds.S | 1 + > arch/ia64/kernel/vmlinux.lds.S | 1 + > arch/m32r/kernel/vmlinux.lds.S | 1 + > arch/m68k/kernel/vmlinux-nommu.lds | 1 + > arch/m68k/kernel/vmlinux-std.lds | 1 + > arch/m68k/kernel/vmlinux-sun3.lds | 1 + > arch/metag/kernel/vmlinux.lds.S | 1 + > arch/microblaze/kernel/vmlinux.lds.S | 1 + > arch/mips/kernel/vmlinux.lds.S | 1 + > arch/mn10300/kernel/vmlinux.lds.S | 1 + > arch/nios2/kernel/vmlinux.lds.S | 1 + > arch/openrisc/kernel/vmlinux.lds.S | 1 + > arch/parisc/kernel/vmlinux.lds.S | 1 + > arch/powerpc/kernel/vmlinux.lds.S | 1 + > arch/s390/kernel/vmlinux.lds.S | 1 + > arch/score/kernel/vmlinux.lds.S | 1 + > arch/sh/kernel/vmlinux.lds.S | 1 + > arch/sparc/kernel/vmlinux.lds.S | 1 + > arch/tile/kernel/entry.S | 2 +- > arch/tile/kernel/vmlinux.lds.S | 1 + > arch/um/kernel/dyn.lds.S | 1 + > arch/um/kernel/uml.lds.S | 1 + > arch/unicore32/kernel/vmlinux.lds.S | 1 + > arch/x86/kernel/acpi/cstate.c | 2 +- > arch/x86/kernel/process.c | 4 ++-- > arch/x86/kernel/vmlinux.lds.S | 1 + > arch/xtensa/kernel/vmlinux.lds.S | 3 +++ > drivers/acpi/processor_idle.c | 5 +++-- > drivers/cpuidle/driver.c | 5 +++-- > drivers/idle/intel_idle.c | 4 ++-- > include/asm-generic/vmlinux.lds.h | 6 ++++++ > include/linux/cpu.h | 5 +++++ > kernel/sched/idle.c | 13 +++++++++++-- > lib/nmi_backtrace.c | 16 +++++++++++----- > scripts/mod/modpost.c | 2 +- > scripts/recordmcount.c | 1 + > scripts/recordmcount.pl | 1 + > 49 files changed, 87 insertions(+), 18 deletions(-) > > diff --git a/arch/alpha/kernel/vmlinux.lds.S b/arch/alpha/kernel/vmlinux.lds.S > index 647b84c15382..cebecfb76fbf 100644 > --- a/arch/alpha/kernel/vmlinux.lds.S > +++ b/arch/alpha/kernel/vmlinux.lds.S > @@ -22,6 +22,7 @@ SECTIONS > HEAD_TEXT > TEXT_TEXT > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > *(.fixup) > *(.gnu.warning) > diff --git a/arch/arc/kernel/vmlinux.lds.S b/arch/arc/kernel/vmlinux.lds.S > index 894e696bddaa..65652160cfda 100644 > --- a/arch/arc/kernel/vmlinux.lds.S > +++ b/arch/arc/kernel/vmlinux.lds.S > @@ -97,6 +97,7 @@ SECTIONS > _text = .; > TEXT_TEXT > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > KPROBES_TEXT > *(.fixup) > diff --git a/arch/arm/kernel/vmlinux-xip.lds.S b/arch/arm/kernel/vmlinux-xip.lds.S > index cba1ec899a69..7fa487ef7e2f 100644 > --- a/arch/arm/kernel/vmlinux-xip.lds.S > +++ b/arch/arm/kernel/vmlinux-xip.lds.S > @@ -98,6 +98,7 @@ SECTIONS > IRQENTRY_TEXT > TEXT_TEXT > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > KPROBES_TEXT > *(.gnu.warning) > diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S > index d24e5dd2aa7a..f7f55df0bf7b 100644 > --- a/arch/arm/kernel/vmlinux.lds.S > +++ b/arch/arm/kernel/vmlinux.lds.S > @@ -111,6 +111,7 @@ SECTIONS > SOFTIRQENTRY_TEXT > TEXT_TEXT > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > HYPERVISOR_TEXT > KPROBES_TEXT > diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S > index 659963d40bb4..fe7f93b7b11b 100644 > --- a/arch/arm64/kernel/vmlinux.lds.S > +++ b/arch/arm64/kernel/vmlinux.lds.S > @@ -122,6 +122,7 @@ SECTIONS > ENTRY_TEXT > TEXT_TEXT > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > KPROBES_TEXT > HYPERVISOR_TEXT > diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S > index 5bb61de23201..64f088ca3192 100644 > --- a/arch/arm64/mm/proc.S > +++ b/arch/arm64/mm/proc.S > @@ -48,11 +48,13 @@ > * > * Idle the processor (wait for interrupt). > */ > + .pushsection ".cpuidle.text","ax" > ENTRY(cpu_do_idle) > dsb sy // WFI may enter a low-power mode > wfi > ret > ENDPROC(cpu_do_idle) > + .popsection > > #ifdef CONFIG_CPU_PM > /** > diff --git a/arch/avr32/kernel/vmlinux.lds.S b/arch/avr32/kernel/vmlinux.lds.S > index a4589176bed5..17f2730eb497 100644 > --- a/arch/avr32/kernel/vmlinux.lds.S > +++ b/arch/avr32/kernel/vmlinux.lds.S > @@ -52,6 +52,7 @@ SECTIONS > KPROBES_TEXT > TEXT_TEXT > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > *(.fixup) > *(.gnu.warning) > diff --git a/arch/blackfin/kernel/vmlinux.lds.S b/arch/blackfin/kernel/vmlinux.lds.S > index d920b959ff3a..68069a120055 100644 > --- a/arch/blackfin/kernel/vmlinux.lds.S > +++ b/arch/blackfin/kernel/vmlinux.lds.S > @@ -33,6 +33,7 @@ SECTIONS > #ifndef CONFIG_SCHEDULE_L1 > SCHED_TEXT > #endif > + CPUIDLE_TEXT > LOCK_TEXT > IRQENTRY_TEXT > SOFTIRQENTRY_TEXT > diff --git a/arch/c6x/kernel/vmlinux.lds.S b/arch/c6x/kernel/vmlinux.lds.S > index 50bc10f97bcb..a1a5c166bc9b 100644 > --- a/arch/c6x/kernel/vmlinux.lds.S > +++ b/arch/c6x/kernel/vmlinux.lds.S > @@ -70,6 +70,7 @@ SECTIONS > _stext = .; > TEXT_TEXT > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > IRQENTRY_TEXT > SOFTIRQENTRY_TEXT > diff --git a/arch/cris/kernel/vmlinux.lds.S b/arch/cris/kernel/vmlinux.lds.S > index 7552c2557506..979586261520 100644 > --- a/arch/cris/kernel/vmlinux.lds.S > +++ b/arch/cris/kernel/vmlinux.lds.S > @@ -43,6 +43,7 @@ SECTIONS > HEAD_TEXT > TEXT_TEXT > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > *(.fixup) > *(.text.__*) > diff --git a/arch/frv/kernel/vmlinux.lds.S b/arch/frv/kernel/vmlinux.lds.S > index 7e958d829ec9..aa6e573d57da 100644 > --- a/arch/frv/kernel/vmlinux.lds.S > +++ b/arch/frv/kernel/vmlinux.lds.S > @@ -63,6 +63,7 @@ SECTIONS > *(.text..tlbmiss) > TEXT_TEXT > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > #ifdef CONFIG_DEBUG_INFO > INIT_TEXT > diff --git a/arch/h8300/kernel/vmlinux.lds.S b/arch/h8300/kernel/vmlinux.lds.S > index cb5dfb02c88d..7f11da1b895e 100644 > --- a/arch/h8300/kernel/vmlinux.lds.S > +++ b/arch/h8300/kernel/vmlinux.lds.S > @@ -29,6 +29,7 @@ SECTIONS > _stext = . ; > TEXT_TEXT > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > #if defined(CONFIG_ROMKERNEL) > *(.int_redirect) > diff --git a/arch/hexagon/kernel/vmlinux.lds.S b/arch/hexagon/kernel/vmlinux.lds.S > index 5f268c1071b3..ec87e67feb19 100644 > --- a/arch/hexagon/kernel/vmlinux.lds.S > +++ b/arch/hexagon/kernel/vmlinux.lds.S > @@ -50,6 +50,7 @@ SECTIONS > _text = .; > TEXT_TEXT > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > KPROBES_TEXT > *(.fixup) > diff --git a/arch/ia64/kernel/vmlinux.lds.S b/arch/ia64/kernel/vmlinux.lds.S > index dc506b05ffbd..f89d20c97412 100644 > --- a/arch/ia64/kernel/vmlinux.lds.S > +++ b/arch/ia64/kernel/vmlinux.lds.S > @@ -46,6 +46,7 @@ SECTIONS { > __end_ivt_text = .; > TEXT_TEXT > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > KPROBES_TEXT > *(.gnu.linkonce.t*) > diff --git a/arch/m32r/kernel/vmlinux.lds.S b/arch/m32r/kernel/vmlinux.lds.S > index 018e4a711d79..ad1fe56455aa 100644 > --- a/arch/m32r/kernel/vmlinux.lds.S > +++ b/arch/m32r/kernel/vmlinux.lds.S > @@ -31,6 +31,7 @@ SECTIONS > HEAD_TEXT > TEXT_TEXT > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > *(.fixup) > *(.gnu.warning) > diff --git a/arch/m68k/kernel/vmlinux-nommu.lds b/arch/m68k/kernel/vmlinux-nommu.lds > index 06a763f49fd3..d2c8abf1c8c4 100644 > --- a/arch/m68k/kernel/vmlinux-nommu.lds > +++ b/arch/m68k/kernel/vmlinux-nommu.lds > @@ -45,6 +45,7 @@ SECTIONS { > HEAD_TEXT > TEXT_TEXT > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > *(.fixup) > . = ALIGN(16); > diff --git a/arch/m68k/kernel/vmlinux-std.lds b/arch/m68k/kernel/vmlinux-std.lds > index d0993594f558..5b5ce1e4d1ed 100644 > --- a/arch/m68k/kernel/vmlinux-std.lds > +++ b/arch/m68k/kernel/vmlinux-std.lds > @@ -16,6 +16,7 @@ SECTIONS > HEAD_TEXT > TEXT_TEXT > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > *(.fixup) > *(.gnu.warning) > diff --git a/arch/m68k/kernel/vmlinux-sun3.lds b/arch/m68k/kernel/vmlinux-sun3.lds > index 8080469ee6c1..fe5ea1974b16 100644 > --- a/arch/m68k/kernel/vmlinux-sun3.lds > +++ b/arch/m68k/kernel/vmlinux-sun3.lds > @@ -16,6 +16,7 @@ SECTIONS > HEAD_TEXT > TEXT_TEXT > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > *(.fixup) > *(.gnu.warning) > diff --git a/arch/metag/kernel/vmlinux.lds.S b/arch/metag/kernel/vmlinux.lds.S > index 150ace92c7ad..e6c700eaf207 100644 > --- a/arch/metag/kernel/vmlinux.lds.S > +++ b/arch/metag/kernel/vmlinux.lds.S > @@ -21,6 +21,7 @@ SECTIONS > .text : { > TEXT_TEXT > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > KPROBES_TEXT > IRQENTRY_TEXT > diff --git a/arch/microblaze/kernel/vmlinux.lds.S b/arch/microblaze/kernel/vmlinux.lds.S > index 0a47f0410554..289d0e7f3e3a 100644 > --- a/arch/microblaze/kernel/vmlinux.lds.S > +++ b/arch/microblaze/kernel/vmlinux.lds.S > @@ -33,6 +33,7 @@ SECTIONS { > EXIT_TEXT > EXIT_CALL > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > KPROBES_TEXT > IRQENTRY_TEXT > diff --git a/arch/mips/kernel/vmlinux.lds.S b/arch/mips/kernel/vmlinux.lds.S > index a82c178d0bb9..d5de67591735 100644 > --- a/arch/mips/kernel/vmlinux.lds.S > +++ b/arch/mips/kernel/vmlinux.lds.S > @@ -55,6 +55,7 @@ SECTIONS > .text : { > TEXT_TEXT > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > KPROBES_TEXT > IRQENTRY_TEXT > diff --git a/arch/mn10300/kernel/vmlinux.lds.S b/arch/mn10300/kernel/vmlinux.lds.S > index 13c4814c29f8..2d5f1c3f1afb 100644 > --- a/arch/mn10300/kernel/vmlinux.lds.S > +++ b/arch/mn10300/kernel/vmlinux.lds.S > @@ -30,6 +30,7 @@ SECTIONS > HEAD_TEXT > TEXT_TEXT > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > KPROBES_TEXT > *(.fixup) > diff --git a/arch/nios2/kernel/vmlinux.lds.S b/arch/nios2/kernel/vmlinux.lds.S > index e23e89539967..6a8045bb1a77 100644 > --- a/arch/nios2/kernel/vmlinux.lds.S > +++ b/arch/nios2/kernel/vmlinux.lds.S > @@ -37,6 +37,7 @@ SECTIONS > .text : { > TEXT_TEXT > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > IRQENTRY_TEXT > SOFTIRQENTRY_TEXT > diff --git a/arch/openrisc/kernel/vmlinux.lds.S b/arch/openrisc/kernel/vmlinux.lds.S > index d936de4c07ca..d68b9ede8423 100644 > --- a/arch/openrisc/kernel/vmlinux.lds.S > +++ b/arch/openrisc/kernel/vmlinux.lds.S > @@ -47,6 +47,7 @@ SECTIONS > _stext = .; > TEXT_TEXT > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > KPROBES_TEXT > IRQENTRY_TEXT > diff --git a/arch/parisc/kernel/vmlinux.lds.S b/arch/parisc/kernel/vmlinux.lds.S > index f3ead0b6ce46..9ec8ec075dae 100644 > --- a/arch/parisc/kernel/vmlinux.lds.S > +++ b/arch/parisc/kernel/vmlinux.lds.S > @@ -69,6 +69,7 @@ SECTIONS > .text ALIGN(PAGE_SIZE) : { > TEXT_TEXT > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > KPROBES_TEXT > IRQENTRY_TEXT > diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S > index b5fba689fca6..7ed59f0d947f 100644 > --- a/arch/powerpc/kernel/vmlinux.lds.S > +++ b/arch/powerpc/kernel/vmlinux.lds.S > @@ -52,6 +52,7 @@ SECTIONS > /* careful! __ftr_alt_* sections need to be close to .text */ > *(.text .fixup __ftr_alt_* .ref.text) > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > KPROBES_TEXT > IRQENTRY_TEXT > diff --git a/arch/s390/kernel/vmlinux.lds.S b/arch/s390/kernel/vmlinux.lds.S > index 429bfd111961..000e6e91f6a0 100644 > --- a/arch/s390/kernel/vmlinux.lds.S > +++ b/arch/s390/kernel/vmlinux.lds.S > @@ -35,6 +35,7 @@ SECTIONS > HEAD_TEXT > TEXT_TEXT > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > KPROBES_TEXT > IRQENTRY_TEXT > diff --git a/arch/score/kernel/vmlinux.lds.S b/arch/score/kernel/vmlinux.lds.S > index 7274b5c4287e..4117890b1db1 100644 > --- a/arch/score/kernel/vmlinux.lds.S > +++ b/arch/score/kernel/vmlinux.lds.S > @@ -40,6 +40,7 @@ SECTIONS > _text = .; /* Text and read-only data */ > TEXT_TEXT > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > KPROBES_TEXT > *(.text.*) > diff --git a/arch/sh/kernel/vmlinux.lds.S b/arch/sh/kernel/vmlinux.lds.S > index 235a4101999f..5b9a3cc90c58 100644 > --- a/arch/sh/kernel/vmlinux.lds.S > +++ b/arch/sh/kernel/vmlinux.lds.S > @@ -36,6 +36,7 @@ SECTIONS > TEXT_TEXT > EXTRA_TEXT > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > KPROBES_TEXT > IRQENTRY_TEXT > diff --git a/arch/sparc/kernel/vmlinux.lds.S b/arch/sparc/kernel/vmlinux.lds.S > index d79b3b734245..572db686f845 100644 > --- a/arch/sparc/kernel/vmlinux.lds.S > +++ b/arch/sparc/kernel/vmlinux.lds.S > @@ -49,6 +49,7 @@ SECTIONS > HEAD_TEXT > TEXT_TEXT > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > KPROBES_TEXT > IRQENTRY_TEXT > diff --git a/arch/tile/kernel/entry.S b/arch/tile/kernel/entry.S > index 670a3569450f..101de132e363 100644 > --- a/arch/tile/kernel/entry.S > +++ b/arch/tile/kernel/entry.S > @@ -50,7 +50,7 @@ STD_ENTRY(smp_nap) > * When interrupted at _cpu_idle_nap, we bump the PC forward 8, and > * as a result return to the function that called _cpu_idle(). > */ > -STD_ENTRY(_cpu_idle) > +STD_ENTRY_SECTION(_cpu_idle, .cpuidle.text) > movei r1, 1 > IRQ_ENABLE_LOAD(r2, r3) > mtspr INTERRUPT_CRITICAL_SECTION, r1 > diff --git a/arch/tile/kernel/vmlinux.lds.S b/arch/tile/kernel/vmlinux.lds.S > index 9d449caf8910..e1baf094fba4 100644 > --- a/arch/tile/kernel/vmlinux.lds.S > +++ b/arch/tile/kernel/vmlinux.lds.S > @@ -42,6 +42,7 @@ SECTIONS > .text : AT (ADDR(.text) - LOAD_OFFSET) { > HEAD_TEXT > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > KPROBES_TEXT > IRQENTRY_TEXT > diff --git a/arch/um/kernel/dyn.lds.S b/arch/um/kernel/dyn.lds.S > index adde088aeeff..4fdbcf958cd5 100644 > --- a/arch/um/kernel/dyn.lds.S > +++ b/arch/um/kernel/dyn.lds.S > @@ -68,6 +68,7 @@ SECTIONS > _stext = .; > TEXT_TEXT > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > *(.fixup) > *(.stub .text.* .gnu.linkonce.t.*) > diff --git a/arch/um/kernel/uml.lds.S b/arch/um/kernel/uml.lds.S > index 6899195602b7..1840f55ed042 100644 > --- a/arch/um/kernel/uml.lds.S > +++ b/arch/um/kernel/uml.lds.S > @@ -28,6 +28,7 @@ SECTIONS > _stext = .; > TEXT_TEXT > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > *(.fixup) > /* .gnu.warning sections are handled specially by elf32.em. */ > diff --git a/arch/unicore32/kernel/vmlinux.lds.S b/arch/unicore32/kernel/vmlinux.lds.S > index 77e407e49a63..56e788e8ee83 100644 > --- a/arch/unicore32/kernel/vmlinux.lds.S > +++ b/arch/unicore32/kernel/vmlinux.lds.S > @@ -37,6 +37,7 @@ SECTIONS > .text : { /* Real text segment */ > TEXT_TEXT > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > > *(.fixup) > diff --git a/arch/x86/kernel/acpi/cstate.c b/arch/x86/kernel/acpi/cstate.c > index bdfad642123f..af15f4444330 100644 > --- a/arch/x86/kernel/acpi/cstate.c > +++ b/arch/x86/kernel/acpi/cstate.c > @@ -152,7 +152,7 @@ int acpi_processor_ffh_cstate_probe(unsigned int cpu, > } > EXPORT_SYMBOL_GPL(acpi_processor_ffh_cstate_probe); > > -void acpi_processor_ffh_cstate_enter(struct acpi_processor_cx *cx) > +void __cpuidle acpi_processor_ffh_cstate_enter(struct acpi_processor_cx *cx) > { > unsigned int cpu = smp_processor_id(); > struct cstate_entry *percpu_entry; > diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c > index 62c0b0ea2ce4..c400e30831dc 100644 > --- a/arch/x86/kernel/process.c > +++ b/arch/x86/kernel/process.c > @@ -301,7 +301,7 @@ void arch_cpu_idle(void) > /* > * We use this if we don't have any better idle routine.. > */ > -void default_idle(void) > +void __cpuidle default_idle(void) > { > trace_cpu_idle_rcuidle(1, smp_processor_id()); > safe_halt(); > @@ -416,7 +416,7 @@ static int prefer_mwait_c1_over_halt(const struct cpuinfo_x86 *c) > * with interrupts enabled and no flags, which is backwards compatible with the > * original MWAIT implementation. > */ > -static void mwait_idle(void) > +static __cpuidle void mwait_idle(void) > { > if (!current_set_polling_and_test()) { > trace_cpu_idle_rcuidle(1, smp_processor_id()); > diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S > index 9297a002d8e5..dbf67f64d5ec 100644 > --- a/arch/x86/kernel/vmlinux.lds.S > +++ b/arch/x86/kernel/vmlinux.lds.S > @@ -97,6 +97,7 @@ SECTIONS > _stext = .; > TEXT_TEXT > SCHED_TEXT > + CPUIDLE_TEXT > LOCK_TEXT > KPROBES_TEXT > ENTRY_TEXT > diff --git a/arch/xtensa/kernel/vmlinux.lds.S b/arch/xtensa/kernel/vmlinux.lds.S > index c417cbe4ec87..18a174c7fb87 100644 > --- a/arch/xtensa/kernel/vmlinux.lds.S > +++ b/arch/xtensa/kernel/vmlinux.lds.S > @@ -93,6 +93,9 @@ SECTIONS > VMLINUX_SYMBOL(__sched_text_start) = .; > *(.sched.literal .sched.text) > VMLINUX_SYMBOL(__sched_text_end) = .; > + VMLINUX_SYMBOL(__cpuidle_text_start) = .; > + *(.cpuidle.literal .cpuidle.text) > + VMLINUX_SYMBOL(__cpuidle_text_end) = .; > VMLINUX_SYMBOL(__lock_text_start) = .; > *(.spinlock.literal .spinlock.text) > VMLINUX_SYMBOL(__lock_text_end) = .; > diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c > index cea52528aa18..2237d3f24f0e 100644 > --- a/drivers/acpi/processor_idle.c > +++ b/drivers/acpi/processor_idle.c > @@ -31,6 +31,7 @@ > #include <linux/sched.h> /* need_resched() */ > #include <linux/tick.h> > #include <linux/cpuidle.h> > +#include <linux/cpu.h> > #include <acpi/processor.h> > > /* > @@ -115,7 +116,7 @@ static const struct dmi_system_id processor_power_dmi_table[] = { > * Callers should disable interrupts before the call and enable > * interrupts after return. > */ > -static void acpi_safe_halt(void) > +static void __cpuidle acpi_safe_halt(void) > { > if (!tif_need_resched()) { > safe_halt(); > @@ -645,7 +646,7 @@ static int acpi_idle_bm_check(void) > * > * Caller disables interrupt before call and enables interrupt after return. > */ > -static void acpi_idle_do_entry(struct acpi_processor_cx *cx) > +static void __cpuidle acpi_idle_do_entry(struct acpi_processor_cx *cx) > { > if (cx->entry_method == ACPI_CSTATE_FFH) { > /* Call into architectural FFH based C-state */ > diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c > index 389ade4572be..ab264d393233 100644 > --- a/drivers/cpuidle/driver.c > +++ b/drivers/cpuidle/driver.c > @@ -14,6 +14,7 @@ > #include <linux/cpuidle.h> > #include <linux/cpumask.h> > #include <linux/tick.h> > +#include <linux/cpu.h> > > #include "cpuidle.h" > > @@ -178,8 +179,8 @@ static void __cpuidle_driver_init(struct cpuidle_driver *drv) > } > > #ifdef CONFIG_ARCH_HAS_CPU_RELAX > -static int poll_idle(struct cpuidle_device *dev, > - struct cpuidle_driver *drv, int index) > +static int __cpuidle poll_idle(struct cpuidle_device *dev, > + struct cpuidle_driver *drv, int index) > { > local_irq_enable(); > if (!current_set_polling_and_test()) { > diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c > index 67ec58f9ef99..4466a2f969d7 100644 > --- a/drivers/idle/intel_idle.c > +++ b/drivers/idle/intel_idle.c > @@ -863,8 +863,8 @@ static struct cpuidle_state dnv_cstates[] = { > * > * Must be called under local_irq_disable(). > */ > -static int intel_idle(struct cpuidle_device *dev, > - struct cpuidle_driver *drv, int index) > +static __cpuidle int intel_idle(struct cpuidle_device *dev, > + struct cpuidle_driver *drv, int index) > { > unsigned long ecx = 1; /* break on interrupt flag */ > struct cpuidle_state *state = &drv->states[index]; > diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h > index 24563970ff7b..3e42bcdd014b 100644 > --- a/include/asm-generic/vmlinux.lds.h > +++ b/include/asm-generic/vmlinux.lds.h > @@ -454,6 +454,12 @@ > *(.spinlock.text) \ > VMLINUX_SYMBOL(__lock_text_end) = .; > > +#define CPUIDLE_TEXT \ > + ALIGN_FUNCTION(); \ > + VMLINUX_SYMBOL(__cpuidle_text_start) = .; \ > + *(.cpuidle.text) \ > + VMLINUX_SYMBOL(__cpuidle_text_end) = .; > + > #define KPROBES_TEXT \ > ALIGN_FUNCTION(); \ > VMLINUX_SYMBOL(__kprobes_text_start) = .; \ > diff --git a/include/linux/cpu.h b/include/linux/cpu.h > index 797d9c8e9a1b..6babfa6db9d9 100644 > --- a/include/linux/cpu.h > +++ b/include/linux/cpu.h > @@ -239,6 +239,11 @@ void cpu_startup_entry(enum cpuhp_state state); > > void cpu_idle_poll_ctrl(bool enable); > > +/* Attach to any functions which should be considered cpuidle. */ > +#define __cpuidle __attribute__((__section__(".cpuidle.text"))) > + > +bool cpu_in_idle(unsigned long pc); > + > void arch_cpu_idle(void); > void arch_cpu_idle_prepare(void); > void arch_cpu_idle_enter(void); > diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c > index 9fb873cfc75c..1d8718d5300d 100644 > --- a/kernel/sched/idle.c > +++ b/kernel/sched/idle.c > @@ -16,6 +16,9 @@ > > #include "sched.h" > > +/* Linker adds these: start and end of __cpuidle functions */ > +extern char __cpuidle_text_start[], __cpuidle_text_end[]; > + > /** > * sched_idle_set_state - Record idle state for the current CPU. > * @idle_state: State to record. > @@ -53,7 +56,7 @@ static int __init cpu_idle_nopoll_setup(char *__unused) > __setup("hlt", cpu_idle_nopoll_setup); > #endif > > -static inline int cpu_idle_poll(void) > +static noinline int __cpuidle cpu_idle_poll(void) > { > rcu_idle_enter(); > trace_cpu_idle_rcuidle(0, smp_processor_id()); > @@ -84,7 +87,7 @@ void __weak arch_cpu_idle(void) > * > * To use when the cpuidle framework cannot be used. > */ > -void default_idle_call(void) > +void __cpuidle default_idle_call(void) > { > if (current_clr_polling_and_test()) { > local_irq_enable(); > @@ -271,6 +274,12 @@ static void cpu_idle_loop(void) > } > } > > +bool cpu_in_idle(unsigned long pc) > +{ > + return pc >= (unsigned long)__cpuidle_text_start && > + pc < (unsigned long)__cpuidle_text_end; > +} > + > void cpu_startup_entry(enum cpuhp_state state) > { > /* > diff --git a/lib/nmi_backtrace.c b/lib/nmi_backtrace.c > index 2933f0680174..de0d406e95cc 100644 > --- a/lib/nmi_backtrace.c > +++ b/lib/nmi_backtrace.c > @@ -16,6 +16,7 @@ > #include <linux/delay.h> > #include <linux/kprobes.h> > #include <linux/nmi.h> > +#include <linux/cpu.h> > > #ifdef arch_trigger_cpumask_backtrace > /* For reliability, we're prepared to waste bits here. */ > @@ -87,11 +88,16 @@ bool nmi_cpu_backtrace(struct pt_regs *regs) > int cpu = smp_processor_id(); > > if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) { > - pr_warn("NMI backtrace for cpu %d\n", cpu); > - if (regs) > - show_regs(regs); > - else > - dump_stack(); > + if (regs && cpu_in_idle(instruction_pointer(regs))) { > + pr_warn("NMI backtrace for cpu %d skipped: idling at pc %#lx\n", > + cpu, instruction_pointer(regs)); Hmm, I do not see this message even though the CPU is in the idle state: [ 7918.884535] CPU: 3 PID: 0 Comm: swapper/3 Not tainted 4.8.0-rc1-4-default+ #3088 [ 7918.884538] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 7918.884539] task: ffff88013a594380 task.stack: ffff88013a598000 [ 7918.884541] RIP: 0010:[<ffffffff81050bc6>] [<ffffffff81050bc6>] native_safe_halt+0x6/0x10 [ 7918.884543] RSP: 0018:ffff88013a59bea8 EFLAGS: 00000206 [ 7918.884544] RAX: ffff88013a594380 RBX: 0000000000000003 RCX: 0000000000000000 [ 7918.884546] RDX: ffff88013a594380 RSI: 0000000000000001 RDI: ffff88013a594380 [ 7918.884548] RBP: ffff88013a59bea8 R08: 0000000000000000 R09: 0000000000000000 [ 7918.884550] R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000003 [ 7918.884551] R13: 0000000000000000 R14: ffff88013a598000 R15: ffff88013a598000 [ 7918.884553] FS: 0000000000000000(0000) GS:ffff88013fd80000(0000) knlGS:0000000000000000 [ 7918.884554] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 7918.884556] CR2: 00007f8afc65e000 CR3: 00000001383b8000 CR4: 00000000000006e0 [ 7918.884557] Stack: [ 7918.884559] ffff88013a59bec8 ffffffff819573d3 0000000000000003 0000000000000000 [ 7918.884561] ffff88013a59bed8 ffffffff8102628f ffff88013a59bee8 ffffffff819579ea [ 7918.884562] ffff88013a59bf30 ffffffff810bfe1a ffff88013a598000 ffff88013a598000 [ 7918.884563] Call Trace: [ 7918.884565] [<ffffffff819573d3>] default_idle+0x23/0x170 [ 7918.884566] [<ffffffff8102628f>] arch_cpu_idle+0xf/0x20 [ 7918.884568] [<ffffffff819579ea>] default_idle_call+0x2a/0x50 [ 7918.884570] [<ffffffff810bfe1a>] cpu_startup_entry+0x16a/0x260 [ 7918.884571] [<ffffffff8103faf6>] start_secondary+0xf6/0x100 [ 7918.884573] Code: 00 00 00 00 00 55 48 89 e5 fa 5d c3 66 0f 1f 84 00 00 00 00 00 55 48 89 e5 fb 5d c3 66 0f 1f 84 00 00 00 00 00 55 48 89 e5 fb f4 <5d> c3 0f 1f 84 00 00 00 00 00 55 48 89 e5 f4 5d c3 66 0f 1f 84 Note that I test it in a virtual machine using qemu. The strange thing is that I do not see .cpuidle.text section in the vmlinux binary. But it is possible that I have misunderstood the concept. Best Regards, Petr
On 8/9/2016 6:37 AM, Lorenzo Pieralisi wrote: > On Mon, Aug 08, 2016 at 05:48:28PM +0100, Mark Rutland wrote: >> Hi, >> >> [adding Lorenzo] >> >> On Mon, Aug 08, 2016 at 12:03:38PM -0400, Chris Metcalf wrote: >>> When doing an nmi backtrace of many cores, most of which are idle, >>> the output is a little overwhelming and very uninformative. Suppress >>> messages for cpus that are idling when they are interrupted and just >>> emit one line, "NMI backtrace for N skipped: idling at pc 0xNNN". >>> >>> We do this by grouping all the cpuidle code together into a new >>> .cpuidle.text section, and then checking the address of the >>> interrupted PC to see if it lies within that section. >>> >>> This commit suitably tags x86, arm64, and tile idle routines, >>> and only adds in the minimal framework for other architectures. >>> diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S >>> index 659963d40bb4..fe7f93b7b11b 100644 >>> --- a/arch/arm64/kernel/vmlinux.lds.S >>> +++ b/arch/arm64/kernel/vmlinux.lds.S >>> @@ -122,6 +122,7 @@ SECTIONS >>> ENTRY_TEXT >>> TEXT_TEXT >>> SCHED_TEXT >>> + CPUIDLE_TEXT >>> LOCK_TEXT >>> KPROBES_TEXT >>> HYPERVISOR_TEXT >>> diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S >>> index 5bb61de23201..64f088ca3192 100644 >>> --- a/arch/arm64/mm/proc.S >>> +++ b/arch/arm64/mm/proc.S >>> @@ -48,11 +48,13 @@ >>> * >>> * Idle the processor (wait for interrupt). >>> */ >>> + .pushsection ".cpuidle.text","ax" >>> ENTRY(cpu_do_idle) >>> dsb sy // WFI may enter a low-power mode >>> wfi >>> ret >>> ENDPROC(cpu_do_idle) >>> + .popsection >> From a quick scan it looks like we only call this with interrupts >> disabled, and we have no NMI. So shouldn't we be annotating >> arch_cpu_idle(), which calls this and subsequently enables interrupts? You're right - I made a quick mental mapping between the arch/tile _cpu_idle assembly and the arch/arm64 cpu_do_idle. But on tile the way it works is we can racelessly enable interrupts and then issue the "nap" instruction; it is similar to WFI except that you actually take the interrupt right from the nap instruction itself, and then have to manually bump forward the PC in the handler if you want the nap to act more like a WFI. I see on closer examination that you're right, we won't interrupt in the cpu_do_idle assembly anyway. You're also right that there is no support for remote stack dump on arm64 right now. I added the arm64 "support" just because I am hacking on arm64 most of the day at this point anyway, and felt like the cpu_idle tracking knowledge might as well be there if/when support for some kind of NMI-style remote interrupt was added to the Linux implementation. The Tile architecture also has no "NMI" per se, but we use individual bitmasks to enable and disable interrupts, so the Linux irq_disable() just amounts to "write a particular bitmask into the enable register". The bitmask itself is just a per-cpu variable that changes as interrupt sources are configured, and there are a few (a couple of performance interrupts, and a synthetic one used for cross-core ipi) that we never mark as maskable. >> I'm also not sure what you need to do for PSCI, which is the preferred >> (FW-backed) idle mechanism for arm64. The infrastrucure for that is >> spread over a few files: >> >> arch/arm64/kernel/sleep.S >> arch/arm64/kernel/smccc-call.S >> arch/arm64/kernel/suspend.c >> drivers/cpuidle/cpuidle-arm.c >> drivers/firmware/psci.c >> >> I'm not sure where we'd be an an interruptible state, and therefore I'm >> not immediately sure what we should annotate. > I am probably missing something here, but let me add that I am not > sure I understand how this patch can be used on ARM/ARM64 systems > so ARM platform idle back-end code annotation is basically useless > given that it is code that can't be preempted anyway (and even if > it could PC range check can even fail given that we may execute some > code with MMU off so out of physical addresses). I think this is all fair enough, and I will back out the arm64 "support" for my next patch series. > What's the purpose of this cpu idle tracking ? Can't it be implemented > in a simpler way (ie RCU API) ? The cpu idle tracking here is done solely to make the "backtrace all cpus" output less crazy-verbose. We annotate functions because claiming "there's nothing interesting to see here; go away" is not something you want to do unless you're really quite sure that there's nothing interesting going on there. In particular, if the RCU stuff is screwed up, you want to see backtraces out of the RCU code if you happen to be somehow stuck there, even if some RCU state claims you are idle. See e.g. the discussion with Peter Ziljstra starting around here: https://lkml.org/lkml/2016/3/7/681 Thanks!
On 8/9/2016 8:43 AM, Petr Mladek wrote: > On Mon 2016-08-08 12:03:38, Chris Metcalf wrote: >> When doing an nmi backtrace of many cores, most of which are idle, >> the output is a little overwhelming and very uninformative. Suppress >> messages for cpus that are idling when they are interrupted and just >> emit one line, "NMI backtrace for N skipped: idling at pc 0xNNN". > Hmm, I do not see this message even though the CPU is in the idle state: > > [ 7918.884535] CPU: 3 PID: 0 Comm: swapper/3 Not tainted 4.8.0-rc1-4-default+ #3088 > [ 7918.884538] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 > [ 7918.884539] task: ffff88013a594380 task.stack: ffff88013a598000 > [ 7918.884541] RIP: 0010:[<ffffffff81050bc6>] [<ffffffff81050bc6>] native_safe_halt+0x6/0x10 > [ 7918.884543] RSP: 0018:ffff88013a59bea8 EFLAGS: 00000206 > [ 7918.884544] RAX: ffff88013a594380 RBX: 0000000000000003 RCX: 0000000000000000 > [ 7918.884546] RDX: ffff88013a594380 RSI: 0000000000000001 RDI: ffff88013a594380 > [ 7918.884548] RBP: ffff88013a59bea8 R08: 0000000000000000 R09: 0000000000000000 > [ 7918.884550] R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000003 > [ 7918.884551] R13: 0000000000000000 R14: ffff88013a598000 R15: ffff88013a598000 > [ 7918.884553] FS: 0000000000000000(0000) GS:ffff88013fd80000(0000) knlGS:0000000000000000 > [ 7918.884554] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 7918.884556] CR2: 00007f8afc65e000 CR3: 00000001383b8000 CR4: 00000000000006e0 > [ 7918.884557] Stack: > [ 7918.884559] ffff88013a59bec8 ffffffff819573d3 0000000000000003 0000000000000000 > [ 7918.884561] ffff88013a59bed8 ffffffff8102628f ffff88013a59bee8 ffffffff819579ea > [ 7918.884562] ffff88013a59bf30 ffffffff810bfe1a ffff88013a598000 ffff88013a598000 > [ 7918.884563] Call Trace: > [ 7918.884565] [<ffffffff819573d3>] default_idle+0x23/0x170 > [ 7918.884566] [<ffffffff8102628f>] arch_cpu_idle+0xf/0x20 > [ 7918.884568] [<ffffffff819579ea>] default_idle_call+0x2a/0x50 > [ 7918.884570] [<ffffffff810bfe1a>] cpu_startup_entry+0x16a/0x260 > [ 7918.884571] [<ffffffff8103faf6>] start_secondary+0xf6/0x100 > [ 7918.884573] Code: 00 00 00 00 00 55 48 89 e5 fa 5d c3 66 0f 1f 84 00 00 00 00 00 55 48 89 e5 fb 5d c3 66 0f 1f 84 00 00 00 00 00 55 48 89 e5 fb f4 <5d> c3 0f 1f 84 00 00 00 00 00 55 > 48 89 e5 f4 5d c3 66 0f 1f 84 > > Note that I test it in a virtual machine using qemu. > > The strange thing is that I do not see .cpuidle.text section in > the vmlinux binary. But it is possible that I have misunderstood > the concept. The .cpuidle.text sections are merged into the final kernel's overall text segment. What you should see is something like this in the "nm -n" output from the built vmlinux: [...] ffffffff81922aa8 T __cpuidle_text_start ffffffff81922ab0 T default_idle ffffffff81922b90 t mwait_idle ffffffff81922d20 T acpi_processor_ffh_cstate_enter ffffffff81922df0 T default_idle_call ffffffff81922e30 t cpu_idle_poll ffffffff81922f50 t intel_idle ffffffff81923085 t acpi_idle_do_entry ffffffff819230d0 t poll_idle ffffffff81923143 T __cpuidle_text_end [...] In other words, all the cpuidle functions grouped together and bracketed by the __cpuidle_text_{start,end} symbols. Perhaps you were running with a kernel that didn't have the actual patch 4/4 applied, but just the earlier patches? Or perhaps your host Linux has been patched, but not the guest Linux running in qemu? Or perhaps you are ending up doing an NMI backtrace on the host kernel, not the guest? Thanks for your other reviews as well. I have incorporated all of your suggestions into a v8 patch series and pushed it up to kernel.org. I will just wait to repost it until we sort out this issue that you've reported here.
diff --git a/arch/alpha/kernel/vmlinux.lds.S b/arch/alpha/kernel/vmlinux.lds.S index 647b84c15382..cebecfb76fbf 100644 --- a/arch/alpha/kernel/vmlinux.lds.S +++ b/arch/alpha/kernel/vmlinux.lds.S @@ -22,6 +22,7 @@ SECTIONS HEAD_TEXT TEXT_TEXT SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT *(.fixup) *(.gnu.warning) diff --git a/arch/arc/kernel/vmlinux.lds.S b/arch/arc/kernel/vmlinux.lds.S index 894e696bddaa..65652160cfda 100644 --- a/arch/arc/kernel/vmlinux.lds.S +++ b/arch/arc/kernel/vmlinux.lds.S @@ -97,6 +97,7 @@ SECTIONS _text = .; TEXT_TEXT SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT KPROBES_TEXT *(.fixup) diff --git a/arch/arm/kernel/vmlinux-xip.lds.S b/arch/arm/kernel/vmlinux-xip.lds.S index cba1ec899a69..7fa487ef7e2f 100644 --- a/arch/arm/kernel/vmlinux-xip.lds.S +++ b/arch/arm/kernel/vmlinux-xip.lds.S @@ -98,6 +98,7 @@ SECTIONS IRQENTRY_TEXT TEXT_TEXT SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT KPROBES_TEXT *(.gnu.warning) diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S index d24e5dd2aa7a..f7f55df0bf7b 100644 --- a/arch/arm/kernel/vmlinux.lds.S +++ b/arch/arm/kernel/vmlinux.lds.S @@ -111,6 +111,7 @@ SECTIONS SOFTIRQENTRY_TEXT TEXT_TEXT SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT HYPERVISOR_TEXT KPROBES_TEXT diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S index 659963d40bb4..fe7f93b7b11b 100644 --- a/arch/arm64/kernel/vmlinux.lds.S +++ b/arch/arm64/kernel/vmlinux.lds.S @@ -122,6 +122,7 @@ SECTIONS ENTRY_TEXT TEXT_TEXT SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT KPROBES_TEXT HYPERVISOR_TEXT diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S index 5bb61de23201..64f088ca3192 100644 --- a/arch/arm64/mm/proc.S +++ b/arch/arm64/mm/proc.S @@ -48,11 +48,13 @@ * * Idle the processor (wait for interrupt). */ + .pushsection ".cpuidle.text","ax" ENTRY(cpu_do_idle) dsb sy // WFI may enter a low-power mode wfi ret ENDPROC(cpu_do_idle) + .popsection #ifdef CONFIG_CPU_PM /** diff --git a/arch/avr32/kernel/vmlinux.lds.S b/arch/avr32/kernel/vmlinux.lds.S index a4589176bed5..17f2730eb497 100644 --- a/arch/avr32/kernel/vmlinux.lds.S +++ b/arch/avr32/kernel/vmlinux.lds.S @@ -52,6 +52,7 @@ SECTIONS KPROBES_TEXT TEXT_TEXT SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT *(.fixup) *(.gnu.warning) diff --git a/arch/blackfin/kernel/vmlinux.lds.S b/arch/blackfin/kernel/vmlinux.lds.S index d920b959ff3a..68069a120055 100644 --- a/arch/blackfin/kernel/vmlinux.lds.S +++ b/arch/blackfin/kernel/vmlinux.lds.S @@ -33,6 +33,7 @@ SECTIONS #ifndef CONFIG_SCHEDULE_L1 SCHED_TEXT #endif + CPUIDLE_TEXT LOCK_TEXT IRQENTRY_TEXT SOFTIRQENTRY_TEXT diff --git a/arch/c6x/kernel/vmlinux.lds.S b/arch/c6x/kernel/vmlinux.lds.S index 50bc10f97bcb..a1a5c166bc9b 100644 --- a/arch/c6x/kernel/vmlinux.lds.S +++ b/arch/c6x/kernel/vmlinux.lds.S @@ -70,6 +70,7 @@ SECTIONS _stext = .; TEXT_TEXT SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT IRQENTRY_TEXT SOFTIRQENTRY_TEXT diff --git a/arch/cris/kernel/vmlinux.lds.S b/arch/cris/kernel/vmlinux.lds.S index 7552c2557506..979586261520 100644 --- a/arch/cris/kernel/vmlinux.lds.S +++ b/arch/cris/kernel/vmlinux.lds.S @@ -43,6 +43,7 @@ SECTIONS HEAD_TEXT TEXT_TEXT SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT *(.fixup) *(.text.__*) diff --git a/arch/frv/kernel/vmlinux.lds.S b/arch/frv/kernel/vmlinux.lds.S index 7e958d829ec9..aa6e573d57da 100644 --- a/arch/frv/kernel/vmlinux.lds.S +++ b/arch/frv/kernel/vmlinux.lds.S @@ -63,6 +63,7 @@ SECTIONS *(.text..tlbmiss) TEXT_TEXT SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT #ifdef CONFIG_DEBUG_INFO INIT_TEXT diff --git a/arch/h8300/kernel/vmlinux.lds.S b/arch/h8300/kernel/vmlinux.lds.S index cb5dfb02c88d..7f11da1b895e 100644 --- a/arch/h8300/kernel/vmlinux.lds.S +++ b/arch/h8300/kernel/vmlinux.lds.S @@ -29,6 +29,7 @@ SECTIONS _stext = . ; TEXT_TEXT SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT #if defined(CONFIG_ROMKERNEL) *(.int_redirect) diff --git a/arch/hexagon/kernel/vmlinux.lds.S b/arch/hexagon/kernel/vmlinux.lds.S index 5f268c1071b3..ec87e67feb19 100644 --- a/arch/hexagon/kernel/vmlinux.lds.S +++ b/arch/hexagon/kernel/vmlinux.lds.S @@ -50,6 +50,7 @@ SECTIONS _text = .; TEXT_TEXT SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT KPROBES_TEXT *(.fixup) diff --git a/arch/ia64/kernel/vmlinux.lds.S b/arch/ia64/kernel/vmlinux.lds.S index dc506b05ffbd..f89d20c97412 100644 --- a/arch/ia64/kernel/vmlinux.lds.S +++ b/arch/ia64/kernel/vmlinux.lds.S @@ -46,6 +46,7 @@ SECTIONS { __end_ivt_text = .; TEXT_TEXT SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT KPROBES_TEXT *(.gnu.linkonce.t*) diff --git a/arch/m32r/kernel/vmlinux.lds.S b/arch/m32r/kernel/vmlinux.lds.S index 018e4a711d79..ad1fe56455aa 100644 --- a/arch/m32r/kernel/vmlinux.lds.S +++ b/arch/m32r/kernel/vmlinux.lds.S @@ -31,6 +31,7 @@ SECTIONS HEAD_TEXT TEXT_TEXT SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT *(.fixup) *(.gnu.warning) diff --git a/arch/m68k/kernel/vmlinux-nommu.lds b/arch/m68k/kernel/vmlinux-nommu.lds index 06a763f49fd3..d2c8abf1c8c4 100644 --- a/arch/m68k/kernel/vmlinux-nommu.lds +++ b/arch/m68k/kernel/vmlinux-nommu.lds @@ -45,6 +45,7 @@ SECTIONS { HEAD_TEXT TEXT_TEXT SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT *(.fixup) . = ALIGN(16); diff --git a/arch/m68k/kernel/vmlinux-std.lds b/arch/m68k/kernel/vmlinux-std.lds index d0993594f558..5b5ce1e4d1ed 100644 --- a/arch/m68k/kernel/vmlinux-std.lds +++ b/arch/m68k/kernel/vmlinux-std.lds @@ -16,6 +16,7 @@ SECTIONS HEAD_TEXT TEXT_TEXT SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT *(.fixup) *(.gnu.warning) diff --git a/arch/m68k/kernel/vmlinux-sun3.lds b/arch/m68k/kernel/vmlinux-sun3.lds index 8080469ee6c1..fe5ea1974b16 100644 --- a/arch/m68k/kernel/vmlinux-sun3.lds +++ b/arch/m68k/kernel/vmlinux-sun3.lds @@ -16,6 +16,7 @@ SECTIONS HEAD_TEXT TEXT_TEXT SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT *(.fixup) *(.gnu.warning) diff --git a/arch/metag/kernel/vmlinux.lds.S b/arch/metag/kernel/vmlinux.lds.S index 150ace92c7ad..e6c700eaf207 100644 --- a/arch/metag/kernel/vmlinux.lds.S +++ b/arch/metag/kernel/vmlinux.lds.S @@ -21,6 +21,7 @@ SECTIONS .text : { TEXT_TEXT SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT KPROBES_TEXT IRQENTRY_TEXT diff --git a/arch/microblaze/kernel/vmlinux.lds.S b/arch/microblaze/kernel/vmlinux.lds.S index 0a47f0410554..289d0e7f3e3a 100644 --- a/arch/microblaze/kernel/vmlinux.lds.S +++ b/arch/microblaze/kernel/vmlinux.lds.S @@ -33,6 +33,7 @@ SECTIONS { EXIT_TEXT EXIT_CALL SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT KPROBES_TEXT IRQENTRY_TEXT diff --git a/arch/mips/kernel/vmlinux.lds.S b/arch/mips/kernel/vmlinux.lds.S index a82c178d0bb9..d5de67591735 100644 --- a/arch/mips/kernel/vmlinux.lds.S +++ b/arch/mips/kernel/vmlinux.lds.S @@ -55,6 +55,7 @@ SECTIONS .text : { TEXT_TEXT SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT KPROBES_TEXT IRQENTRY_TEXT diff --git a/arch/mn10300/kernel/vmlinux.lds.S b/arch/mn10300/kernel/vmlinux.lds.S index 13c4814c29f8..2d5f1c3f1afb 100644 --- a/arch/mn10300/kernel/vmlinux.lds.S +++ b/arch/mn10300/kernel/vmlinux.lds.S @@ -30,6 +30,7 @@ SECTIONS HEAD_TEXT TEXT_TEXT SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT KPROBES_TEXT *(.fixup) diff --git a/arch/nios2/kernel/vmlinux.lds.S b/arch/nios2/kernel/vmlinux.lds.S index e23e89539967..6a8045bb1a77 100644 --- a/arch/nios2/kernel/vmlinux.lds.S +++ b/arch/nios2/kernel/vmlinux.lds.S @@ -37,6 +37,7 @@ SECTIONS .text : { TEXT_TEXT SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT IRQENTRY_TEXT SOFTIRQENTRY_TEXT diff --git a/arch/openrisc/kernel/vmlinux.lds.S b/arch/openrisc/kernel/vmlinux.lds.S index d936de4c07ca..d68b9ede8423 100644 --- a/arch/openrisc/kernel/vmlinux.lds.S +++ b/arch/openrisc/kernel/vmlinux.lds.S @@ -47,6 +47,7 @@ SECTIONS _stext = .; TEXT_TEXT SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT KPROBES_TEXT IRQENTRY_TEXT diff --git a/arch/parisc/kernel/vmlinux.lds.S b/arch/parisc/kernel/vmlinux.lds.S index f3ead0b6ce46..9ec8ec075dae 100644 --- a/arch/parisc/kernel/vmlinux.lds.S +++ b/arch/parisc/kernel/vmlinux.lds.S @@ -69,6 +69,7 @@ SECTIONS .text ALIGN(PAGE_SIZE) : { TEXT_TEXT SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT KPROBES_TEXT IRQENTRY_TEXT diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S index b5fba689fca6..7ed59f0d947f 100644 --- a/arch/powerpc/kernel/vmlinux.lds.S +++ b/arch/powerpc/kernel/vmlinux.lds.S @@ -52,6 +52,7 @@ SECTIONS /* careful! __ftr_alt_* sections need to be close to .text */ *(.text .fixup __ftr_alt_* .ref.text) SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT KPROBES_TEXT IRQENTRY_TEXT diff --git a/arch/s390/kernel/vmlinux.lds.S b/arch/s390/kernel/vmlinux.lds.S index 429bfd111961..000e6e91f6a0 100644 --- a/arch/s390/kernel/vmlinux.lds.S +++ b/arch/s390/kernel/vmlinux.lds.S @@ -35,6 +35,7 @@ SECTIONS HEAD_TEXT TEXT_TEXT SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT KPROBES_TEXT IRQENTRY_TEXT diff --git a/arch/score/kernel/vmlinux.lds.S b/arch/score/kernel/vmlinux.lds.S index 7274b5c4287e..4117890b1db1 100644 --- a/arch/score/kernel/vmlinux.lds.S +++ b/arch/score/kernel/vmlinux.lds.S @@ -40,6 +40,7 @@ SECTIONS _text = .; /* Text and read-only data */ TEXT_TEXT SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT KPROBES_TEXT *(.text.*) diff --git a/arch/sh/kernel/vmlinux.lds.S b/arch/sh/kernel/vmlinux.lds.S index 235a4101999f..5b9a3cc90c58 100644 --- a/arch/sh/kernel/vmlinux.lds.S +++ b/arch/sh/kernel/vmlinux.lds.S @@ -36,6 +36,7 @@ SECTIONS TEXT_TEXT EXTRA_TEXT SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT KPROBES_TEXT IRQENTRY_TEXT diff --git a/arch/sparc/kernel/vmlinux.lds.S b/arch/sparc/kernel/vmlinux.lds.S index d79b3b734245..572db686f845 100644 --- a/arch/sparc/kernel/vmlinux.lds.S +++ b/arch/sparc/kernel/vmlinux.lds.S @@ -49,6 +49,7 @@ SECTIONS HEAD_TEXT TEXT_TEXT SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT KPROBES_TEXT IRQENTRY_TEXT diff --git a/arch/tile/kernel/entry.S b/arch/tile/kernel/entry.S index 670a3569450f..101de132e363 100644 --- a/arch/tile/kernel/entry.S +++ b/arch/tile/kernel/entry.S @@ -50,7 +50,7 @@ STD_ENTRY(smp_nap) * When interrupted at _cpu_idle_nap, we bump the PC forward 8, and * as a result return to the function that called _cpu_idle(). */ -STD_ENTRY(_cpu_idle) +STD_ENTRY_SECTION(_cpu_idle, .cpuidle.text) movei r1, 1 IRQ_ENABLE_LOAD(r2, r3) mtspr INTERRUPT_CRITICAL_SECTION, r1 diff --git a/arch/tile/kernel/vmlinux.lds.S b/arch/tile/kernel/vmlinux.lds.S index 9d449caf8910..e1baf094fba4 100644 --- a/arch/tile/kernel/vmlinux.lds.S +++ b/arch/tile/kernel/vmlinux.lds.S @@ -42,6 +42,7 @@ SECTIONS .text : AT (ADDR(.text) - LOAD_OFFSET) { HEAD_TEXT SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT KPROBES_TEXT IRQENTRY_TEXT diff --git a/arch/um/kernel/dyn.lds.S b/arch/um/kernel/dyn.lds.S index adde088aeeff..4fdbcf958cd5 100644 --- a/arch/um/kernel/dyn.lds.S +++ b/arch/um/kernel/dyn.lds.S @@ -68,6 +68,7 @@ SECTIONS _stext = .; TEXT_TEXT SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT *(.fixup) *(.stub .text.* .gnu.linkonce.t.*) diff --git a/arch/um/kernel/uml.lds.S b/arch/um/kernel/uml.lds.S index 6899195602b7..1840f55ed042 100644 --- a/arch/um/kernel/uml.lds.S +++ b/arch/um/kernel/uml.lds.S @@ -28,6 +28,7 @@ SECTIONS _stext = .; TEXT_TEXT SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT *(.fixup) /* .gnu.warning sections are handled specially by elf32.em. */ diff --git a/arch/unicore32/kernel/vmlinux.lds.S b/arch/unicore32/kernel/vmlinux.lds.S index 77e407e49a63..56e788e8ee83 100644 --- a/arch/unicore32/kernel/vmlinux.lds.S +++ b/arch/unicore32/kernel/vmlinux.lds.S @@ -37,6 +37,7 @@ SECTIONS .text : { /* Real text segment */ TEXT_TEXT SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT *(.fixup) diff --git a/arch/x86/kernel/acpi/cstate.c b/arch/x86/kernel/acpi/cstate.c index bdfad642123f..af15f4444330 100644 --- a/arch/x86/kernel/acpi/cstate.c +++ b/arch/x86/kernel/acpi/cstate.c @@ -152,7 +152,7 @@ int acpi_processor_ffh_cstate_probe(unsigned int cpu, } EXPORT_SYMBOL_GPL(acpi_processor_ffh_cstate_probe); -void acpi_processor_ffh_cstate_enter(struct acpi_processor_cx *cx) +void __cpuidle acpi_processor_ffh_cstate_enter(struct acpi_processor_cx *cx) { unsigned int cpu = smp_processor_id(); struct cstate_entry *percpu_entry; diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 62c0b0ea2ce4..c400e30831dc 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -301,7 +301,7 @@ void arch_cpu_idle(void) /* * We use this if we don't have any better idle routine.. */ -void default_idle(void) +void __cpuidle default_idle(void) { trace_cpu_idle_rcuidle(1, smp_processor_id()); safe_halt(); @@ -416,7 +416,7 @@ static int prefer_mwait_c1_over_halt(const struct cpuinfo_x86 *c) * with interrupts enabled and no flags, which is backwards compatible with the * original MWAIT implementation. */ -static void mwait_idle(void) +static __cpuidle void mwait_idle(void) { if (!current_set_polling_and_test()) { trace_cpu_idle_rcuidle(1, smp_processor_id()); diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index 9297a002d8e5..dbf67f64d5ec 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -97,6 +97,7 @@ SECTIONS _stext = .; TEXT_TEXT SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT KPROBES_TEXT ENTRY_TEXT diff --git a/arch/xtensa/kernel/vmlinux.lds.S b/arch/xtensa/kernel/vmlinux.lds.S index c417cbe4ec87..18a174c7fb87 100644 --- a/arch/xtensa/kernel/vmlinux.lds.S +++ b/arch/xtensa/kernel/vmlinux.lds.S @@ -93,6 +93,9 @@ SECTIONS VMLINUX_SYMBOL(__sched_text_start) = .; *(.sched.literal .sched.text) VMLINUX_SYMBOL(__sched_text_end) = .; + VMLINUX_SYMBOL(__cpuidle_text_start) = .; + *(.cpuidle.literal .cpuidle.text) + VMLINUX_SYMBOL(__cpuidle_text_end) = .; VMLINUX_SYMBOL(__lock_text_start) = .; *(.spinlock.literal .spinlock.text) VMLINUX_SYMBOL(__lock_text_end) = .; diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index cea52528aa18..2237d3f24f0e 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -31,6 +31,7 @@ #include <linux/sched.h> /* need_resched() */ #include <linux/tick.h> #include <linux/cpuidle.h> +#include <linux/cpu.h> #include <acpi/processor.h> /* @@ -115,7 +116,7 @@ static const struct dmi_system_id processor_power_dmi_table[] = { * Callers should disable interrupts before the call and enable * interrupts after return. */ -static void acpi_safe_halt(void) +static void __cpuidle acpi_safe_halt(void) { if (!tif_need_resched()) { safe_halt(); @@ -645,7 +646,7 @@ static int acpi_idle_bm_check(void) * * Caller disables interrupt before call and enables interrupt after return. */ -static void acpi_idle_do_entry(struct acpi_processor_cx *cx) +static void __cpuidle acpi_idle_do_entry(struct acpi_processor_cx *cx) { if (cx->entry_method == ACPI_CSTATE_FFH) { /* Call into architectural FFH based C-state */ diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c index 389ade4572be..ab264d393233 100644 --- a/drivers/cpuidle/driver.c +++ b/drivers/cpuidle/driver.c @@ -14,6 +14,7 @@ #include <linux/cpuidle.h> #include <linux/cpumask.h> #include <linux/tick.h> +#include <linux/cpu.h> #include "cpuidle.h" @@ -178,8 +179,8 @@ static void __cpuidle_driver_init(struct cpuidle_driver *drv) } #ifdef CONFIG_ARCH_HAS_CPU_RELAX -static int poll_idle(struct cpuidle_device *dev, - struct cpuidle_driver *drv, int index) +static int __cpuidle poll_idle(struct cpuidle_device *dev, + struct cpuidle_driver *drv, int index) { local_irq_enable(); if (!current_set_polling_and_test()) { diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c index 67ec58f9ef99..4466a2f969d7 100644 --- a/drivers/idle/intel_idle.c +++ b/drivers/idle/intel_idle.c @@ -863,8 +863,8 @@ static struct cpuidle_state dnv_cstates[] = { * * Must be called under local_irq_disable(). */ -static int intel_idle(struct cpuidle_device *dev, - struct cpuidle_driver *drv, int index) +static __cpuidle int intel_idle(struct cpuidle_device *dev, + struct cpuidle_driver *drv, int index) { unsigned long ecx = 1; /* break on interrupt flag */ struct cpuidle_state *state = &drv->states[index]; diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 24563970ff7b..3e42bcdd014b 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -454,6 +454,12 @@ *(.spinlock.text) \ VMLINUX_SYMBOL(__lock_text_end) = .; +#define CPUIDLE_TEXT \ + ALIGN_FUNCTION(); \ + VMLINUX_SYMBOL(__cpuidle_text_start) = .; \ + *(.cpuidle.text) \ + VMLINUX_SYMBOL(__cpuidle_text_end) = .; + #define KPROBES_TEXT \ ALIGN_FUNCTION(); \ VMLINUX_SYMBOL(__kprobes_text_start) = .; \ diff --git a/include/linux/cpu.h b/include/linux/cpu.h index 797d9c8e9a1b..6babfa6db9d9 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -239,6 +239,11 @@ void cpu_startup_entry(enum cpuhp_state state); void cpu_idle_poll_ctrl(bool enable); +/* Attach to any functions which should be considered cpuidle. */ +#define __cpuidle __attribute__((__section__(".cpuidle.text"))) + +bool cpu_in_idle(unsigned long pc); + void arch_cpu_idle(void); void arch_cpu_idle_prepare(void); void arch_cpu_idle_enter(void); diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c index 9fb873cfc75c..1d8718d5300d 100644 --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -16,6 +16,9 @@ #include "sched.h" +/* Linker adds these: start and end of __cpuidle functions */ +extern char __cpuidle_text_start[], __cpuidle_text_end[]; + /** * sched_idle_set_state - Record idle state for the current CPU. * @idle_state: State to record. @@ -53,7 +56,7 @@ static int __init cpu_idle_nopoll_setup(char *__unused) __setup("hlt", cpu_idle_nopoll_setup); #endif -static inline int cpu_idle_poll(void) +static noinline int __cpuidle cpu_idle_poll(void) { rcu_idle_enter(); trace_cpu_idle_rcuidle(0, smp_processor_id()); @@ -84,7 +87,7 @@ void __weak arch_cpu_idle(void) * * To use when the cpuidle framework cannot be used. */ -void default_idle_call(void) +void __cpuidle default_idle_call(void) { if (current_clr_polling_and_test()) { local_irq_enable(); @@ -271,6 +274,12 @@ static void cpu_idle_loop(void) } } +bool cpu_in_idle(unsigned long pc) +{ + return pc >= (unsigned long)__cpuidle_text_start && + pc < (unsigned long)__cpuidle_text_end; +} + void cpu_startup_entry(enum cpuhp_state state) { /* diff --git a/lib/nmi_backtrace.c b/lib/nmi_backtrace.c index 2933f0680174..de0d406e95cc 100644 --- a/lib/nmi_backtrace.c +++ b/lib/nmi_backtrace.c @@ -16,6 +16,7 @@ #include <linux/delay.h> #include <linux/kprobes.h> #include <linux/nmi.h> +#include <linux/cpu.h> #ifdef arch_trigger_cpumask_backtrace /* For reliability, we're prepared to waste bits here. */ @@ -87,11 +88,16 @@ bool nmi_cpu_backtrace(struct pt_regs *regs) int cpu = smp_processor_id(); if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) { - pr_warn("NMI backtrace for cpu %d\n", cpu); - if (regs) - show_regs(regs); - else - dump_stack(); + if (regs && cpu_in_idle(instruction_pointer(regs))) { + pr_warn("NMI backtrace for cpu %d skipped: idling at pc %#lx\n", + cpu, instruction_pointer(regs)); + } else { + pr_warn("NMI backtrace for cpu %d\n", cpu); + if (regs) + show_regs(regs); + else + dump_stack(); + } cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask)); return true; } diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 48958d3cec9e..bd8349759095 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -888,7 +888,7 @@ static void check_section(const char *modname, struct elf_info *elf, #define DATA_SECTIONS ".data", ".data.rel" #define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \ - ".kprobes.text" + ".kprobes.text", ".cpuidle.text" #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \ ".fixup", ".entry.text", ".exception.text", ".text.*", \ ".coldtext" diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c index 42396a74405d..c0222107cf58 100644 --- a/scripts/recordmcount.c +++ b/scripts/recordmcount.c @@ -364,6 +364,7 @@ is_mcounted_section_name(char const *const txtname) strcmp(".spinlock.text", txtname) == 0 || strcmp(".irqentry.text", txtname) == 0 || strcmp(".kprobes.text", txtname) == 0 || + strcmp(".cpuidle.text", txtname) == 0 || strcmp(".text.unlikely", txtname) == 0; } diff --git a/scripts/recordmcount.pl b/scripts/recordmcount.pl index 96e2486a6fc4..29cecf9b504f 100755 --- a/scripts/recordmcount.pl +++ b/scripts/recordmcount.pl @@ -135,6 +135,7 @@ my %text_sections = ( ".spinlock.text" => 1, ".irqentry.text" => 1, ".kprobes.text" => 1, + ".cpuidle.text" => 1, ".text.unlikely" => 1, );