Messages in this thread | | | Date | Mon, 20 May 2013 10:46:04 +0100 | From | Will Deacon <> | Subject | Re: [PATCH] arm64: extable: sort the exception table at build time |
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Hi David,
On Fri, May 17, 2013 at 07:33:53PM +0100, David Daney wrote: > On 05/17/2013 09:43 AM, Will Deacon wrote: > > As is done for other architectures, sort the exception table at > > build-time rather than during boot. > > > > Since sortextable appears to be a standalone C program relying on the > > host elf.h to provide EM_AARCH64, I've had to add a conditional check in > > order to allow cross-compilation on machines that aren't running a > > bleeding-edge libc-dev. > > > > Signed-off-by: Will Deacon <will.deacon@arm.com> > > --- > > arch/arm64/Kconfig | 1 + > > arch/arm64/kernel/vmlinux.lds.S | 15 +++++++-------- > > scripts/sortextable.c | 5 +++++ > > 3 files changed, 13 insertions(+), 8 deletions(-) > > > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > > index 48347dc..fb8fd90 100644 > > --- a/arch/arm64/Kconfig > > +++ b/arch/arm64/Kconfig > > @@ -7,6 +7,7 @@ config ARM64 > > select ARM_AMBA > > select ARM_ARCH_TIMER > > select ARM_GIC > > + select BUILDTIME_EXTABLE_SORT > > select CLONE_BACKWARDS > > select COMMON_CLK > > select GENERIC_CLOCKEVENTS > > diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S > > index 3fae2be..3d527726 100644 > > --- a/arch/arm64/kernel/vmlinux.lds.S > > +++ b/arch/arm64/kernel/vmlinux.lds.S > > @@ -57,6 +57,13 @@ SECTIONS > > > > RO_DATA(PAGE_SIZE) > > > > + . = ALIGN(8); > > + __ex_table : AT(ADDR(__ex_table) - LOAD_OFFSET) { > > + __start___ex_table = .; > > + *(__ex_table) > > + __stop___ex_table = .; > > + } > > + > > _etext = .; /* End of text and rodata section */ > > > You have moved this to rodata.
I don't think I have moved this to rodata. The RO_DATA macro expands to a bunch of sections, but it doesn't leave any of them open at the end.
> o Will the runtime sort still work like this? > > o Do we care? Maybe not.
For arm64 we'd be moving exclusively to build-time sorting, so I guess we *could* stick the thing in rodata if we wanted to. Not sure it's worth the linker script munging though.
Will
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