* [PATCH] arm64: remove redundant FRAME_POINTER kconfig option @ 2015-11-04 17:37 Yang Shi 2015-11-06 12:30 ` Will Deacon 0 siblings, 1 reply; 14+ messages in thread From: Yang Shi @ 2015-11-04 17:37 UTC (permalink / raw) To: catalin.marinas, will.deacon Cc: linux-kernel, linux-arm-kernel, linaro-kernel, yang.shi FRAME_POINTER is defined in lib/Kconfig.debug, it is unnecessary to redefine it in arch/arm64/Kconfig.debug. Signed-off-by: Yang Shi <yang.shi@linaro.org> --- arch/arm64/Kconfig.debug | 4 ---- 1 file changed, 4 deletions(-) diff --git a/arch/arm64/Kconfig.debug b/arch/arm64/Kconfig.debug index d6285ef..915dea7 100644 --- a/arch/arm64/Kconfig.debug +++ b/arch/arm64/Kconfig.debug @@ -2,10 +2,6 @@ menu "Kernel hacking" source "lib/Kconfig.debug" -config FRAME_POINTER - bool - default y - config ARM64_PTDUMP bool "Export kernel pagetable layout to userspace via debugfs" depends on DEBUG_KERNEL -- 2.0.2 ^ permalink raw reply related [flat|nested] 14+ messages in thread
* Re: [PATCH] arm64: remove redundant FRAME_POINTER kconfig option 2015-11-04 17:37 [PATCH] arm64: remove redundant FRAME_POINTER kconfig option Yang Shi @ 2015-11-06 12:30 ` Will Deacon 2015-11-06 12:50 ` Mark Rutland 2015-11-06 16:12 ` Catalin Marinas 0 siblings, 2 replies; 14+ messages in thread From: Will Deacon @ 2015-11-06 12:30 UTC (permalink / raw) To: Yang Shi; +Cc: catalin.marinas, linux-kernel, linux-arm-kernel, linaro-kernel On Wed, Nov 04, 2015 at 09:37:51AM -0800, Yang Shi wrote: > FRAME_POINTER is defined in lib/Kconfig.debug, it is unnecessary to redefine > it in arch/arm64/Kconfig.debug. It might be worth noting that this adds a dependency on DEBUG_KERNEL for building with frame pointers. I'm ok with that (it appears to be enabled in defconfig and follows the vast majority of other archs) but it is a change in behaviour. With that: Acked-by: Will Deacon <will.deacon@arm.com> Will > Signed-off-by: Yang Shi <yang.shi@linaro.org> > --- > arch/arm64/Kconfig.debug | 4 ---- > 1 file changed, 4 deletions(-) > > diff --git a/arch/arm64/Kconfig.debug b/arch/arm64/Kconfig.debug > index d6285ef..915dea7 100644 > --- a/arch/arm64/Kconfig.debug > +++ b/arch/arm64/Kconfig.debug > @@ -2,10 +2,6 @@ menu "Kernel hacking" > > source "lib/Kconfig.debug" > > -config FRAME_POINTER > - bool > - default y > - > config ARM64_PTDUMP > bool "Export kernel pagetable layout to userspace via debugfs" > depends on DEBUG_KERNEL > -- > 2.0.2 > ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] arm64: remove redundant FRAME_POINTER kconfig option 2015-11-06 12:30 ` Will Deacon @ 2015-11-06 12:50 ` Mark Rutland 2015-11-06 15:42 ` Will Deacon 2015-11-06 16:21 ` Catalin Marinas 2015-11-06 16:12 ` Catalin Marinas 1 sibling, 2 replies; 14+ messages in thread From: Mark Rutland @ 2015-11-06 12:50 UTC (permalink / raw) To: Will Deacon Cc: Yang Shi, catalin.marinas, linaro-kernel, linux-kernel, linux-arm-kernel On Fri, Nov 06, 2015 at 12:30:09PM +0000, Will Deacon wrote: > On Wed, Nov 04, 2015 at 09:37:51AM -0800, Yang Shi wrote: > > FRAME_POINTER is defined in lib/Kconfig.debug, it is unnecessary to redefine > > it in arch/arm64/Kconfig.debug. > > It might be worth noting that this adds a dependency on DEBUG_KERNEL > for building with frame pointers. I'm ok with that (it appears to be > enabled in defconfig and follows the vast majority of other archs) but > it is a change in behaviour. > > With that: > > Acked-by: Will Deacon <will.deacon@arm.com> The code in arch/arm64/kernel/stacktrace.c assumes we have frame pointers regardless of FRAME_POINTER. Depending on what the compiler decides to use x29 for, we could get some weird fake unwinding and/or dodgy memory accesses. I think we should first audit the uses of frame pointers to ensure that they are guarded for !FRAME_POINTER. Thanks, Mark. ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] arm64: remove redundant FRAME_POINTER kconfig option 2015-11-06 12:50 ` Mark Rutland @ 2015-11-06 15:42 ` Will Deacon 2015-11-06 16:21 ` Catalin Marinas 1 sibling, 0 replies; 14+ messages in thread From: Will Deacon @ 2015-11-06 15:42 UTC (permalink / raw) To: Mark Rutland Cc: Yang Shi, catalin.marinas, linaro-kernel, linux-kernel, linux-arm-kernel On Fri, Nov 06, 2015 at 12:50:02PM +0000, Mark Rutland wrote: > On Fri, Nov 06, 2015 at 12:30:09PM +0000, Will Deacon wrote: > > On Wed, Nov 04, 2015 at 09:37:51AM -0800, Yang Shi wrote: > > > FRAME_POINTER is defined in lib/Kconfig.debug, it is unnecessary to redefine > > > it in arch/arm64/Kconfig.debug. > > > > It might be worth noting that this adds a dependency on DEBUG_KERNEL > > for building with frame pointers. I'm ok with that (it appears to be > > enabled in defconfig and follows the vast majority of other archs) but > > it is a change in behaviour. > > > > With that: > > > > Acked-by: Will Deacon <will.deacon@arm.com> > > The code in arch/arm64/kernel/stacktrace.c assumes we have frame > pointers regardless of FRAME_POINTER. Depending on what the compiler > decides to use x29 for, we could get some weird fake unwinding and/or > dodgy memory accesses. > > I think we should first audit the uses of frame pointers to ensure that > they are guarded for !FRAME_POINTER. Good point. The perf callchain code suffers from a similar issue. Will ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] arm64: remove redundant FRAME_POINTER kconfig option 2015-11-06 12:50 ` Mark Rutland 2015-11-06 15:42 ` Will Deacon @ 2015-11-06 16:21 ` Catalin Marinas 2015-11-06 16:25 ` Will Deacon 1 sibling, 1 reply; 14+ messages in thread From: Catalin Marinas @ 2015-11-06 16:21 UTC (permalink / raw) To: Mark Rutland Cc: Will Deacon, Yang Shi, linaro-kernel, linux-kernel, linux-arm-kernel On Fri, Nov 06, 2015 at 12:50:02PM +0000, Mark Rutland wrote: > On Fri, Nov 06, 2015 at 12:30:09PM +0000, Will Deacon wrote: > > On Wed, Nov 04, 2015 at 09:37:51AM -0800, Yang Shi wrote: > > > FRAME_POINTER is defined in lib/Kconfig.debug, it is unnecessary to redefine > > > it in arch/arm64/Kconfig.debug. > > > > It might be worth noting that this adds a dependency on DEBUG_KERNEL > > for building with frame pointers. I'm ok with that (it appears to be > > enabled in defconfig and follows the vast majority of other archs) but > > it is a change in behaviour. > > > > With that: > > > > Acked-by: Will Deacon <will.deacon@arm.com> > > The code in arch/arm64/kernel/stacktrace.c assumes we have frame > pointers regardless of FRAME_POINTER. Depending on what the compiler > decides to use x29 for, we could get some weird fake unwinding and/or > dodgy memory accesses. > > I think we should first audit the uses of frame pointers to ensure that > they are guarded for !FRAME_POINTER. Or we just select FRAME_POINTER in the ARM64 Kconfig entry. -- Catalin ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] arm64: remove redundant FRAME_POINTER kconfig option 2015-11-06 16:21 ` Catalin Marinas @ 2015-11-06 16:25 ` Will Deacon 2015-11-06 17:23 ` Shi, Yang 0 siblings, 1 reply; 14+ messages in thread From: Will Deacon @ 2015-11-06 16:25 UTC (permalink / raw) To: Catalin Marinas Cc: Mark Rutland, Yang Shi, linaro-kernel, linux-kernel, linux-arm-kernel On Fri, Nov 06, 2015 at 04:21:09PM +0000, Catalin Marinas wrote: > On Fri, Nov 06, 2015 at 12:50:02PM +0000, Mark Rutland wrote: > > On Fri, Nov 06, 2015 at 12:30:09PM +0000, Will Deacon wrote: > > > On Wed, Nov 04, 2015 at 09:37:51AM -0800, Yang Shi wrote: > > > > FRAME_POINTER is defined in lib/Kconfig.debug, it is unnecessary to redefine > > > > it in arch/arm64/Kconfig.debug. > > > > > > It might be worth noting that this adds a dependency on DEBUG_KERNEL > > > for building with frame pointers. I'm ok with that (it appears to be > > > enabled in defconfig and follows the vast majority of other archs) but > > > it is a change in behaviour. > > > > > > With that: > > > > > > Acked-by: Will Deacon <will.deacon@arm.com> > > > > The code in arch/arm64/kernel/stacktrace.c assumes we have frame > > pointers regardless of FRAME_POINTER. Depending on what the compiler > > decides to use x29 for, we could get some weird fake unwinding and/or > > dodgy memory accesses. > > > > I think we should first audit the uses of frame pointers to ensure that > > they are guarded for !FRAME_POINTER. > > Or we just select FRAME_POINTER in the ARM64 Kconfig entry. Yang, did you see any benefit disabling frame pointers, or was this patch purely based on you spotting a duplicate Kconfig entry? Will ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] arm64: remove redundant FRAME_POINTER kconfig option 2015-11-06 16:25 ` Will Deacon @ 2015-11-06 17:23 ` Shi, Yang 2015-11-06 17:35 ` Catalin Marinas 0 siblings, 1 reply; 14+ messages in thread From: Shi, Yang @ 2015-11-06 17:23 UTC (permalink / raw) To: Will Deacon, Catalin Marinas Cc: Mark Rutland, linaro-kernel, linux-kernel, linux-arm-kernel On 11/6/2015 8:25 AM, Will Deacon wrote: > On Fri, Nov 06, 2015 at 04:21:09PM +0000, Catalin Marinas wrote: >> On Fri, Nov 06, 2015 at 12:50:02PM +0000, Mark Rutland wrote: >>> On Fri, Nov 06, 2015 at 12:30:09PM +0000, Will Deacon wrote: >>>> On Wed, Nov 04, 2015 at 09:37:51AM -0800, Yang Shi wrote: >>>>> FRAME_POINTER is defined in lib/Kconfig.debug, it is unnecessary to redefine >>>>> it in arch/arm64/Kconfig.debug. >>>> >>>> It might be worth noting that this adds a dependency on DEBUG_KERNEL >>>> for building with frame pointers. I'm ok with that (it appears to be >>>> enabled in defconfig and follows the vast majority of other archs) but >>>> it is a change in behaviour. >>>> >>>> With that: >>>> >>>> Acked-by: Will Deacon <will.deacon@arm.com> >>> >>> The code in arch/arm64/kernel/stacktrace.c assumes we have frame >>> pointers regardless of FRAME_POINTER. Depending on what the compiler >>> decides to use x29 for, we could get some weird fake unwinding and/or >>> dodgy memory accesses. >>> >>> I think we should first audit the uses of frame pointers to ensure that >>> they are guarded for !FRAME_POINTER. >> >> Or we just select FRAME_POINTER in the ARM64 Kconfig entry. > > Yang, did you see any benefit disabling frame pointers, or was this patch > purely based on you spotting a duplicate Kconfig entry? It just spots a duplicate Kconfig entry. FRAME_POINTER is defined in both lib/Kconfig.debug and arch/arm64/Kconfig.debug. The lib/Kconfig.debug one looks like: config FRAME_POINTER bool "Compile the kernel with frame pointers" depends on DEBUG_KERNEL && \ (CRIS || M68K || FRV || UML || \ AVR32 || SUPERH || BLACKFIN || MN10300 || METAG) || \ ARCH_WANT_FRAME_POINTERS default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS help If you say Y here the resulting kernel image will be slightly larger and slower, but it gives very useful debugging information in case of kernel bugs. (precise oopses/stacktraces/warnings) The common one just depends on DEBUG_KERNEL && ARCH_WANT_FRAME_POINTERS. ARCH_WANT_FRAME_POINTERS is selected by ARM64 kconfig entry. To answer Catalin's question about: > However, the patch would allow one to > disable FRAME_POINTERS (not sure it has any effect on the aarch64 gcc > though). No, it doesn't. Actually, FRAME_POINTER could be disabled regardless of the patch. Thanks, Yang > > Will > ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] arm64: remove redundant FRAME_POINTER kconfig option 2015-11-06 17:23 ` Shi, Yang @ 2015-11-06 17:35 ` Catalin Marinas 2015-11-06 17:39 ` Shi, Yang 0 siblings, 1 reply; 14+ messages in thread From: Catalin Marinas @ 2015-11-06 17:35 UTC (permalink / raw) To: Shi, Yang Cc: Will Deacon, Mark Rutland, linaro-kernel, linux-kernel, linux-arm-kernel On Fri, Nov 06, 2015 at 09:23:38AM -0800, Shi, Yang wrote: > On 11/6/2015 8:25 AM, Will Deacon wrote: > >However, the patch would allow one to > >disable FRAME_POINTERS (not sure it has any effect on the aarch64 gcc > >though). > > No, it doesn't. Actually, FRAME_POINTER could be disabled regardless of the > patch. In which case I suggest that we always select it just as a clearer statement that the feature cannot be disabled (and you never know what the compiler people decide to do in the future). -- Catalin ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] arm64: remove redundant FRAME_POINTER kconfig option 2015-11-06 17:35 ` Catalin Marinas @ 2015-11-06 17:39 ` Shi, Yang 2015-11-06 17:51 ` Catalin Marinas 0 siblings, 1 reply; 14+ messages in thread From: Shi, Yang @ 2015-11-06 17:39 UTC (permalink / raw) To: Catalin Marinas Cc: Will Deacon, Mark Rutland, linaro-kernel, linux-kernel, linux-arm-kernel On 11/6/2015 9:35 AM, Catalin Marinas wrote: > On Fri, Nov 06, 2015 at 09:23:38AM -0800, Shi, Yang wrote: >> On 11/6/2015 8:25 AM, Will Deacon wrote: >>> However, the patch would allow one to >>> disable FRAME_POINTERS (not sure it has any effect on the aarch64 gcc >>> though). >> >> No, it doesn't. Actually, FRAME_POINTER could be disabled regardless of the >> patch. > > In which case I suggest that we always select it just as a clearer > statement that the feature cannot be disabled (and you never know what > the compiler people decide to do in the future). Do you mean select FRAME_POINTER in ARCH_WANT_FRAME_POINTERS? Yes, we could, but this may cause other architectures which select ARCH_WANT_FRAME_POINTERS to have FRAME_POINTER selected too. Or we could do: select FRAME_POINTER is ARM64 Thanks, Yang > ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] arm64: remove redundant FRAME_POINTER kconfig option 2015-11-06 17:39 ` Shi, Yang @ 2015-11-06 17:51 ` Catalin Marinas 2015-11-06 17:55 ` Shi, Yang 0 siblings, 1 reply; 14+ messages in thread From: Catalin Marinas @ 2015-11-06 17:51 UTC (permalink / raw) To: Shi, Yang Cc: Mark Rutland, linaro-kernel, Will Deacon, linux-kernel, linux-arm-kernel On Fri, Nov 06, 2015 at 09:39:07AM -0800, Shi, Yang wrote: > On 11/6/2015 9:35 AM, Catalin Marinas wrote: > >On Fri, Nov 06, 2015 at 09:23:38AM -0800, Shi, Yang wrote: > >>On 11/6/2015 8:25 AM, Will Deacon wrote: > >>>However, the patch would allow one to > >>>disable FRAME_POINTERS (not sure it has any effect on the aarch64 gcc > >>>though). > >> > >>No, it doesn't. Actually, FRAME_POINTER could be disabled regardless of the > >>patch. > > > >In which case I suggest that we always select it just as a clearer > >statement that the feature cannot be disabled (and you never know what > >the compiler people decide to do in the future). > > Do you mean select FRAME_POINTER in ARCH_WANT_FRAME_POINTERS? > > Yes, we could, but this may cause other architectures which select > ARCH_WANT_FRAME_POINTERS to have FRAME_POINTER selected too. This would have been the ideal option, something like: --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -322,7 +322,7 @@ config ARCH_WANT_FRAME_POINTERS help config FRAME_POINTER - bool "Compile the kernel with frame pointers" + bool "Compile the kernel with frame pointers" if !ARCH_WANT_FRAME_POINTERS depends on DEBUG_KERNEL && \ (CRIS || M68K || FRV || UML || \ AVR32 || SUPERH || BLACKFIN || MN10300 || METAG) || \ But, as you said, we would need to check the other architectures selecting ARCH_WANT_FRAME_POINTERS. In the meantime: --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -27,6 +27,7 @@ config ARM64 select CPU_PM if (SUSPEND || CPU_IDLE) select DCACHE_WORD_ACCESS select EDAC_SUPPORT + select FRAME_POINTER select GENERIC_ALLOCATOR select GENERIC_CLOCKEVENTS select GENERIC_CLOCKEVENTS_BROADCAST -- Catalin ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] arm64: remove redundant FRAME_POINTER kconfig option 2015-11-06 17:51 ` Catalin Marinas @ 2015-11-06 17:55 ` Shi, Yang 2015-11-09 15:58 ` Catalin Marinas 0 siblings, 1 reply; 14+ messages in thread From: Shi, Yang @ 2015-11-06 17:55 UTC (permalink / raw) To: Catalin Marinas Cc: Mark Rutland, linaro-kernel, Will Deacon, linux-kernel, linux-arm-kernel On 11/6/2015 9:51 AM, Catalin Marinas wrote: > On Fri, Nov 06, 2015 at 09:39:07AM -0800, Shi, Yang wrote: >> On 11/6/2015 9:35 AM, Catalin Marinas wrote: >>> On Fri, Nov 06, 2015 at 09:23:38AM -0800, Shi, Yang wrote: >>>> On 11/6/2015 8:25 AM, Will Deacon wrote: >>>>> However, the patch would allow one to >>>>> disable FRAME_POINTERS (not sure it has any effect on the aarch64 gcc >>>>> though). >>>> >>>> No, it doesn't. Actually, FRAME_POINTER could be disabled regardless of the >>>> patch. >>> >>> In which case I suggest that we always select it just as a clearer >>> statement that the feature cannot be disabled (and you never know what >>> the compiler people decide to do in the future). >> >> Do you mean select FRAME_POINTER in ARCH_WANT_FRAME_POINTERS? >> >> Yes, we could, but this may cause other architectures which select >> ARCH_WANT_FRAME_POINTERS to have FRAME_POINTER selected too. > > This would have been the ideal option, something like: > > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -322,7 +322,7 @@ config ARCH_WANT_FRAME_POINTERS > help > > config FRAME_POINTER > - bool "Compile the kernel with frame pointers" > + bool "Compile the kernel with frame pointers" if !ARCH_WANT_FRAME_POINTERS > depends on DEBUG_KERNEL && \ > (CRIS || M68K || FRV || UML || \ > AVR32 || SUPERH || BLACKFIN || MN10300 || METAG) || \ > > But, as you said, we would need to check the other architectures > selecting ARCH_WANT_FRAME_POINTERS. How about: diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 1d1521c..709255a 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -319,6 +319,7 @@ config DEBUG_SECTION_MISMATCH # config ARCH_WANT_FRAME_POINTERS bool + select FRAME_POINTER if ARM64 help config FRAME_POINTER If other architectures want the same behavior, they could easily append to the is statement. If all arches which selects ARCH_WANT_FRAME_POINTERS, the if statement could be just removed. Yang > > In the meantime: > > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -27,6 +27,7 @@ config ARM64 > select CPU_PM if (SUSPEND || CPU_IDLE) > select DCACHE_WORD_ACCESS > select EDAC_SUPPORT > + select FRAME_POINTER > select GENERIC_ALLOCATOR > select GENERIC_CLOCKEVENTS > select GENERIC_CLOCKEVENTS_BROADCAST > ^ permalink raw reply related [flat|nested] 14+ messages in thread
* Re: [PATCH] arm64: remove redundant FRAME_POINTER kconfig option 2015-11-06 17:55 ` Shi, Yang @ 2015-11-09 15:58 ` Catalin Marinas 0 siblings, 0 replies; 14+ messages in thread From: Catalin Marinas @ 2015-11-09 15:58 UTC (permalink / raw) To: Shi, Yang Cc: Mark Rutland, linaro-kernel, Will Deacon, linux-kernel, linux-arm-kernel On Fri, Nov 06, 2015 at 09:55:54AM -0800, Shi, Yang wrote: > On 11/6/2015 9:51 AM, Catalin Marinas wrote: > >On Fri, Nov 06, 2015 at 09:39:07AM -0800, Shi, Yang wrote: > >>On 11/6/2015 9:35 AM, Catalin Marinas wrote: > >>>On Fri, Nov 06, 2015 at 09:23:38AM -0800, Shi, Yang wrote: > >>>>On 11/6/2015 8:25 AM, Will Deacon wrote: > >>>>>However, the patch would allow one to > >>>>>disable FRAME_POINTERS (not sure it has any effect on the aarch64 gcc > >>>>>though). > >>>> > >>>>No, it doesn't. Actually, FRAME_POINTER could be disabled regardless of the > >>>>patch. > >>> > >>>In which case I suggest that we always select it just as a clearer > >>>statement that the feature cannot be disabled (and you never know what > >>>the compiler people decide to do in the future). > >> > >>Do you mean select FRAME_POINTER in ARCH_WANT_FRAME_POINTERS? > >> > >>Yes, we could, but this may cause other architectures which select > >>ARCH_WANT_FRAME_POINTERS to have FRAME_POINTER selected too. > > > >This would have been the ideal option, something like: > > > >--- a/lib/Kconfig.debug > >+++ b/lib/Kconfig.debug > >@@ -322,7 +322,7 @@ config ARCH_WANT_FRAME_POINTERS > > help > > > > config FRAME_POINTER > >- bool "Compile the kernel with frame pointers" > >+ bool "Compile the kernel with frame pointers" if !ARCH_WANT_FRAME_POINTERS > > depends on DEBUG_KERNEL && \ > > (CRIS || M68K || FRV || UML || \ > > AVR32 || SUPERH || BLACKFIN || MN10300 || METAG) || \ > > > >But, as you said, we would need to check the other architectures > >selecting ARCH_WANT_FRAME_POINTERS. > > How about: > > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index 1d1521c..709255a 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -319,6 +319,7 @@ config DEBUG_SECTION_MISMATCH > # > config ARCH_WANT_FRAME_POINTERS > bool > + select FRAME_POINTER if ARM64 > help > > config FRAME_POINTER > > If other architectures want the same behavior, they could easily append to > the is statement. If all arches which selects ARCH_WANT_FRAME_POINTERS, the > if statement could be just removed. I prefer the select in the ARM64 Kconfig entry as below: > >--- a/arch/arm64/Kconfig > >+++ b/arch/arm64/Kconfig > >@@ -27,6 +27,7 @@ config ARM64 > > select CPU_PM if (SUSPEND || CPU_IDLE) > > select DCACHE_WORD_ACCESS > > select EDAC_SUPPORT > >+ select FRAME_POINTER > > select GENERIC_ALLOCATOR > > select GENERIC_CLOCKEVENTS > > select GENERIC_CLOCKEVENTS_BROADCAST > > -- Catalin ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] arm64: remove redundant FRAME_POINTER kconfig option 2015-11-06 12:30 ` Will Deacon 2015-11-06 12:50 ` Mark Rutland @ 2015-11-06 16:12 ` Catalin Marinas 2015-11-06 16:19 ` Will Deacon 1 sibling, 1 reply; 14+ messages in thread From: Catalin Marinas @ 2015-11-06 16:12 UTC (permalink / raw) To: Will Deacon; +Cc: Yang Shi, linaro-kernel, linux-kernel, linux-arm-kernel On Fri, Nov 06, 2015 at 12:30:09PM +0000, Will Deacon wrote: > On Wed, Nov 04, 2015 at 09:37:51AM -0800, Yang Shi wrote: > > FRAME_POINTER is defined in lib/Kconfig.debug, it is unnecessary to redefine > > it in arch/arm64/Kconfig.debug. > > It might be worth noting that this adds a dependency on DEBUG_KERNEL > for building with frame pointers. I'm ok with that (it appears to be > enabled in defconfig and follows the vast majority of other archs) but > it is a change in behaviour. We shouldn't have the dependency on DEBUG_KERNEL since we select ARCH_WANT_FRAME_POINTERS on arm64. However, the patch would allow one to disable FRAME_POINTERS (not sure it has any effect on the aarch64 gcc though). -- Catalin ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] arm64: remove redundant FRAME_POINTER kconfig option 2015-11-06 16:12 ` Catalin Marinas @ 2015-11-06 16:19 ` Will Deacon 0 siblings, 0 replies; 14+ messages in thread From: Will Deacon @ 2015-11-06 16:19 UTC (permalink / raw) To: Catalin Marinas; +Cc: Yang Shi, linaro-kernel, linux-kernel, linux-arm-kernel On Fri, Nov 06, 2015 at 04:12:14PM +0000, Catalin Marinas wrote: > On Fri, Nov 06, 2015 at 12:30:09PM +0000, Will Deacon wrote: > > On Wed, Nov 04, 2015 at 09:37:51AM -0800, Yang Shi wrote: > > > FRAME_POINTER is defined in lib/Kconfig.debug, it is unnecessary to redefine > > > it in arch/arm64/Kconfig.debug. > > > > It might be worth noting that this adds a dependency on DEBUG_KERNEL > > for building with frame pointers. I'm ok with that (it appears to be > > enabled in defconfig and follows the vast majority of other archs) but > > it is a change in behaviour. > > We shouldn't have the dependency on DEBUG_KERNEL since we select > ARCH_WANT_FRAME_POINTERS on arm64. However, the patch would allow one to > disable FRAME_POINTERS (not sure it has any effect on the aarch64 gcc > though). Ah yes, you're right about DEBUG_KERNEL. I completely misread the brackets and the left-associativity of &&/|| works out. I still think Rutland has a valid point wrt junk frame pointers, though. Will ^ permalink raw reply [flat|nested] 14+ messages in thread
end of thread, other threads:[~2015-11-09 15:58 UTC | newest] Thread overview: 14+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2015-11-04 17:37 [PATCH] arm64: remove redundant FRAME_POINTER kconfig option Yang Shi 2015-11-06 12:30 ` Will Deacon 2015-11-06 12:50 ` Mark Rutland 2015-11-06 15:42 ` Will Deacon 2015-11-06 16:21 ` Catalin Marinas 2015-11-06 16:25 ` Will Deacon 2015-11-06 17:23 ` Shi, Yang 2015-11-06 17:35 ` Catalin Marinas 2015-11-06 17:39 ` Shi, Yang 2015-11-06 17:51 ` Catalin Marinas 2015-11-06 17:55 ` Shi, Yang 2015-11-09 15:58 ` Catalin Marinas 2015-11-06 16:12 ` Catalin Marinas 2015-11-06 16:19 ` Will Deacon
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