* [PATCH] nios2: fixed broken sys_clone syscall
@ 2021-02-05 8:23 Andreas Oetken
2021-02-05 8:38 ` Christian Brauner
0 siblings, 1 reply; 2+ messages in thread
From: Andreas Oetken @ 2021-02-05 8:23 UTC (permalink / raw)
To: Ley Foon Tan, Christian Brauner, linux-kernel
Cc: Andreas Oetken, Andreas Oetken
From: Andreas Oetken <andreas.oetken@siemens.com>
The tls pointer must be pushed on the stack prior to calling nios2_clone
as it is the 5th function argument. Prior handling of the tls pointer was
done inside former called function copy_thread_tls using the r8 register
from the current_pt_regs directly. This was a bad design and resulted in
the current bug introduced in 04bd52fb.
Fixes: 04bd52fb ("nios2: enable HAVE_COPY_THREAD_TLS, switch to kernel_clone_args")
Signed-off-by: Andreas Oetken <andreas.oetken@siemens.com>
---
arch/nios2/kernel/entry.S | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/nios2/kernel/entry.S b/arch/nios2/kernel/entry.S
index da8442450e46..0794cd7803df 100644
--- a/arch/nios2/kernel/entry.S
+++ b/arch/nios2/kernel/entry.S
@@ -389,7 +389,10 @@ ENTRY(ret_from_interrupt)
*/
ENTRY(sys_clone)
SAVE_SWITCH_STACK
+ subi sp, sp, 4 /* make space for tls pointer */
+ stw r8, 0(sp) /* pass tls pointer (r8) via stack (5th argument) */
call nios2_clone
+ addi sp, sp, 4
RESTORE_SWITCH_STACK
ret
--
2.30.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] nios2: fixed broken sys_clone syscall
2021-02-05 8:23 [PATCH] nios2: fixed broken sys_clone syscall Andreas Oetken
@ 2021-02-05 8:38 ` Christian Brauner
0 siblings, 0 replies; 2+ messages in thread
From: Christian Brauner @ 2021-02-05 8:38 UTC (permalink / raw)
To: Andreas Oetken; +Cc: Ley Foon Tan, linux-kernel, Andreas Oetken, Andreas Oetken
On Fri, Feb 05, 2021 at 09:23:38AM +0100, Andreas Oetken wrote:
> From: Andreas Oetken <andreas.oetken@siemens.com>
>
> The tls pointer must be pushed on the stack prior to calling nios2_clone
> as it is the 5th function argument. Prior handling of the tls pointer was
> done inside former called function copy_thread_tls using the r8 register
> from the current_pt_regs directly. This was a bad design and resulted in
> the current bug introduced in 04bd52fb.
>
> Fixes: 04bd52fb ("nios2: enable HAVE_COPY_THREAD_TLS, switch to kernel_clone_args")
> Signed-off-by: Andreas Oetken <andreas.oetken@siemens.com>
> ---
Thanks for catching this!
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
^ permalink raw reply [flat|nested] 2+ messages in thread
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