lkml.org 
[lkml]   [2022]   [Feb]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH] xtensa: Implement "current_stack_pointer"
On Wed, Feb 23, 2022 at 10:22:59PM -0800, Max Filippov wrote:
> On Wed, Feb 23, 2022 at 10:05 PM Kees Cook <keescook@chromium.org> wrote:
> >
> > To follow the existing per-arch conventions replace open-coded uses
> > of asm "sp" as "current_stack_pointer". This will let it be used in
> > non-arch places (like HARDENED_USERCOPY).
> >
> > Cc: Chris Zankel <chris@zankel.net>
> > Cc: Max Filippov <jcmvbkbc@gmail.com>
> > Cc: Marc Zyngier <maz@kernel.org>
> > Cc: linux-xtensa@linux-xtensa.org
> > Signed-off-by: Kees Cook <keescook@chromium.org>
> > ---
> > arch/xtensa/Kconfig | 1 +
> > arch/xtensa/include/asm/current.h | 2 ++
> > arch/xtensa/include/asm/stacktrace.h | 2 +-
> > arch/xtensa/kernel/irq.c | 3 +--
> > 4 files changed, 5 insertions(+), 3 deletions(-)
>
> Acked-by: Max Filippov <jcmvbkbc@gmail.com>

Thanks! And apologies, my cross-compiler tricked me into thinking this
patch compiled without problems. It did, however. I've change the patch
slightly to deal with the needed casts:

diff --git a/arch/xtensa/include/asm/stacktrace.h b/arch/xtensa/include/asm/stacktrace.h
index fe06e8ed162b..a85e785a6288 100644
--- a/arch/xtensa/include/asm/stacktrace.h
+++ b/arch/xtensa/include/asm/stacktrace.h
@@ -19,14 +19,14 @@ struct stackframe {

static __always_inline unsigned long *stack_pointer(struct task_struct *task)
{
- unsigned long *sp;
+ unsigned long sp;

if (!task || task == current)
- __asm__ __volatile__ ("mov %0, a1\n" : "=a"(sp));
+ sp = current_stack_pointer;
else
- sp = (unsigned long *)task->thread.sp;
+ sp = task->thread.sp;

- return sp;
+ return (unsigned long *)sp;
}

void walk_stackframe(unsigned long *sp,
Shall I send a v2, or just carry this fix in my tree?

Sorry for the glitch!

-Kees

--
Kees Cook

\
 
 \ /
  Last update: 2022-02-24 07:44    [W:0.105 / U:2.736 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site