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sparc32: Preserve clone syscall flags argument for restarts due to signals

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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
28e6103665.

Signed-off-by: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Andreas Larsson 2021-02-04 17:23:41 +01:00 committed by David S. Miller
parent bda166930c
commit c599a7821b
2 changed files with 4 additions and 6 deletions
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8
arch/sparc/kernel/entry.S
View File

@ -1009,7 +1009,7 @@ 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
@ -1018,16 +1018,15 @@ 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 */
@ -1042,7 +1041,6 @@ 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 */

2
arch/sparc/kernel/rtrap_32.S
View File

@ -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