From: Andreas Larsson <andreas@gaisler.com>
To: David Miller <davem@davemloft.net>, sparclinux@vger.kernel.org
Cc: Sam Ravnborg <sam@ravnborg.org>,
linux-kernel@vger.kernel.org, software@gaisler.com
Subject: [PATCH] sparc32: Preserve clone syscall flags argument for restarts due to signals
Date: Thu, 4 Feb 2021 17:23:41 +0100 [thread overview]
Message-ID: <20210204162341.4218-1-andreas@gaisler.com> (raw)
This fixes a bug where a clone syscall that is restarted due to a
pending signal is restarted with garbage in the register %o0 that holds
the clone flags.
This keep the original %i0 of a syscall (as seen from the trap handler)
in %l6 rather than %l5. This is done because for clone (and also qfork)
%l5 is used as a temporary variable in the same register window. Before
this, that temporary value would be the value that was then incorrectly
used as the orig_i0 argument to do_notify_resume.
In order to preserve %l6, the temporary usage of %l6 in ret_sys_call is
changed to use %l5 instead and the setting %l6 to 0 or 1 was removed.
The use of that 0 or 1 value in %l6 was removed in commit
28e6103665301ce60634e8a77f0b657c6cc099de.
Signed-off-by: Andreas Larsson <andreas@gaisler.com>
---
arch/sparc/kernel/entry.S | 8 +++-----
arch/sparc/kernel/rtrap_32.S | 2 +-
2 files changed, 4 insertions(+), 6 deletions(-)
diff --git a/arch/sparc/kernel/entry.S b/arch/sparc/kernel/entry.S
index d58940280f8d..a269ad2fe6df 100644
--- a/arch/sparc/kernel/entry.S
+++ b/arch/sparc/kernel/entry.S
@@ -994,7 +994,7 @@ do_syscall:
andcc %l5, _TIF_SYSCALL_TRACE, %g0
mov %i4, %o4
bne linux_syscall_trace
- mov %i0, %l5
+ mov %i0, %l6
2:
call %l7
mov %i5, %o5
@@ -1003,16 +1003,15 @@ do_syscall:
st %o0, [%sp + STACKFRAME_SZ + PT_I0]
ret_sys_call:
- ld [%curptr + TI_FLAGS], %l6
+ ld [%curptr + TI_FLAGS], %l5
cmp %o0, -ERESTART_RESTARTBLOCK
ld [%sp + STACKFRAME_SZ + PT_PSR], %g3
set PSR_C, %g2
bgeu 1f
- andcc %l6, _TIF_SYSCALL_TRACE, %g0
+ andcc %l5, _TIF_SYSCALL_TRACE, %g0
/* System call success, clear Carry condition code. */
andn %g3, %g2, %g3
- clr %l6
st %g3, [%sp + STACKFRAME_SZ + PT_PSR]
bne linux_syscall_trace2
ld [%sp + STACKFRAME_SZ + PT_NPC], %l1 /* pc = npc */
@@ -1027,7 +1026,6 @@ ret_sys_call:
sub %g0, %o0, %o0
or %g3, %g2, %g3
st %o0, [%sp + STACKFRAME_SZ + PT_I0]
- mov 1, %l6
st %g3, [%sp + STACKFRAME_SZ + PT_PSR]
bne linux_syscall_trace2
ld [%sp + STACKFRAME_SZ + PT_NPC], %l1 /* pc = npc */
diff --git a/arch/sparc/kernel/rtrap_32.S b/arch/sparc/kernel/rtrap_32.S
index dca8ed810046..8931fe266346 100644
--- a/arch/sparc/kernel/rtrap_32.S
+++ b/arch/sparc/kernel/rtrap_32.S
@@ -75,7 +75,7 @@ signal_p:
ld [%sp + STACKFRAME_SZ + PT_PSR], %t_psr
mov %g2, %o2
- mov %l5, %o1
+ mov %l6, %o1
call do_notify_resume
add %sp, STACKFRAME_SZ, %o0 ! pt_regs ptr
--
2.17.1
reply other threads:[~2021-02-04 16:25 UTC|newest]
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