ret_fast_syscall runs when user space makes a syscall. However it
needs to be marked as such so the ELF information is correct. Before
it was:
101: 8000f300 0 NOTYPE LOCAL DEFAULT 2 ret_fast_syscall
But with this change it correctly shows as:
101: 8000f300 96 FUNC LOCAL DEFAULT 2 ret_fast_syscall
I see this function when using perf to unwind call stacks from kernel
space to user space. Without this change I would need to add some
special case logic when using the vmlinux ELF information.
Signed-off-by: Drew Richardson <[email protected]>
---
arch/arm/kernel/entry-common.S | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index 92828a1dec80..b48dd4f37f80 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -61,6 +61,7 @@ work_pending:
movlt scno, #(__NR_restart_syscall - __NR_SYSCALL_BASE)
ldmia sp, {r0 - r6} @ have to reload r0 - r6
b local_restart @ ... and off we go
+ENDPROC(ret_fast_syscall)
/*
* "slow" syscall return path. "why" tells us if this was a real syscall.
--
2.1.4
On Tue, Jul 14, 2015 at 01:45:57PM +0100, Drew Richardson wrote:
> ret_fast_syscall runs when user space makes a syscall. However it
> needs to be marked as such so the ELF information is correct. Before
> it was:
>
> 101: 8000f300 0 NOTYPE LOCAL DEFAULT 2 ret_fast_syscall
>
> But with this change it correctly shows as:
>
> 101: 8000f300 96 FUNC LOCAL DEFAULT 2 ret_fast_syscall
>
> I see this function when using perf to unwind call stacks from kernel
> space to user space. Without this change I would need to add some
> special case logic when using the vmlinux ELF information.
>
> Signed-off-by: Drew Richardson <[email protected]>
I haven't heard any further comments on this, did this get merged and
I just didn't notice? Or did I forget to add someone?
Thanks,
Drew
On Thu, 6 Aug 2015, Drew Richardson wrote:
> On Tue, Jul 14, 2015 at 01:45:57PM +0100, Drew Richardson wrote:
> > ret_fast_syscall runs when user space makes a syscall. However it
> > needs to be marked as such so the ELF information is correct. Before
> > it was:
> >
> > 101: 8000f300 0 NOTYPE LOCAL DEFAULT 2 ret_fast_syscall
> >
> > But with this change it correctly shows as:
> >
> > 101: 8000f300 96 FUNC LOCAL DEFAULT 2 ret_fast_syscall
> >
> > I see this function when using perf to unwind call stacks from kernel
> > space to user space. Without this change I would need to add some
> > special case logic when using the vmlinux ELF information.
> >
> > Signed-off-by: Drew Richardson <[email protected]>
>
> I haven't heard any further comments on this, did this get merged and
> I just didn't notice? Or did I forget to add someone?
Most likely that it is so trivial that nobody paid much attention.
FWIW, you can add
Acked-by: Nicolas Pitre <[email protected]>
and submit it here: http://www.arm.linux.org.uk/developer/patches/
Nicolas
On Thu, Aug 06, 2015 at 06:30:40PM +0100, Nicolas Pitre wrote:
> On Thu, 6 Aug 2015, Drew Richardson wrote:
>
> > On Tue, Jul 14, 2015 at 01:45:57PM +0100, Drew Richardson wrote:
> > > ret_fast_syscall runs when user space makes a syscall. However it
> > > needs to be marked as such so the ELF information is correct. Before
> > > it was:
> > >
> > > 101: 8000f300 0 NOTYPE LOCAL DEFAULT 2 ret_fast_syscall
> > >
> > > But with this change it correctly shows as:
> > >
> > > 101: 8000f300 96 FUNC LOCAL DEFAULT 2 ret_fast_syscall
> > >
> > > I see this function when using perf to unwind call stacks from kernel
> > > space to user space. Without this change I would need to add some
> > > special case logic when using the vmlinux ELF information.
> > >
> > > Signed-off-by: Drew Richardson <[email protected]>
> >
> > I haven't heard any further comments on this, did this get merged and
> > I just didn't notice? Or did I forget to add someone?
>
> Most likely that it is so trivial that nobody paid much attention.
>
> FWIW, you can add
>
> Acked-by: Nicolas Pitre <[email protected]>
>
> and submit it here: http://www.arm.linux.org.uk/developer/patches/
>
>
> Nicolas
>
Done, thanks.