[PATCH AUTOSEL 5.10 19/27] m68k: Check syscall_trace_enter() return code

From: Sasha Levin
Date: Sun Feb 26 2023 - 09:58:31 EST


From: Michael Schmitz <schmitzmic@xxxxxxxxx>

[ Upstream commit 2ca8a1de4437f21562e57f9ac123914747a8e7a1 ]

Check return code of syscall_trace_enter(), and skip syscall
if -1. Return code will be left at what had been set by
ptrace or seccomp (in regs->d0).

No regression seen in testing with strace on ARAnyM.

Signed-off-by: Michael Schmitz <schmitzmic@xxxxxxxxx>
Reviewed-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20230112035529.13521-2-schmitzmic@xxxxxxxxx
Signed-off-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
arch/m68k/68000/entry.S | 2 ++
arch/m68k/coldfire/entry.S | 2 ++
arch/m68k/kernel/entry.S | 3 +++
3 files changed, 7 insertions(+)

diff --git a/arch/m68k/68000/entry.S b/arch/m68k/68000/entry.S
index 259b3661b6141..94abf3d8afc52 100644
--- a/arch/m68k/68000/entry.S
+++ b/arch/m68k/68000/entry.S
@@ -47,6 +47,8 @@ do_trace:
jbsr syscall_trace_enter
RESTORE_SWITCH_STACK
addql #4,%sp
+ addql #1,%d0
+ jeq ret_from_exception
movel %sp@(PT_OFF_ORIG_D0),%d1
movel #-ENOSYS,%d0
cmpl #NR_syscalls,%d1
diff --git a/arch/m68k/coldfire/entry.S b/arch/m68k/coldfire/entry.S
index d43a02795a4a4..f1d41a9328a27 100644
--- a/arch/m68k/coldfire/entry.S
+++ b/arch/m68k/coldfire/entry.S
@@ -92,6 +92,8 @@ ENTRY(system_call)
jbsr syscall_trace_enter
RESTORE_SWITCH_STACK
addql #4,%sp
+ addql #1,%d0
+ jeq ret_from_exception
movel %d3,%a0
jbsr %a0@
movel %d0,%sp@(PT_OFF_D0) /* save the return value */
diff --git a/arch/m68k/kernel/entry.S b/arch/m68k/kernel/entry.S
index 9dd76fbb7c6b2..546bab6bfc273 100644
--- a/arch/m68k/kernel/entry.S
+++ b/arch/m68k/kernel/entry.S
@@ -167,9 +167,12 @@ do_trace_entry:
jbsr syscall_trace
RESTORE_SWITCH_STACK
addql #4,%sp
+ addql #1,%d0 | optimization for cmpil #-1,%d0
+ jeq ret_from_syscall
movel %sp@(PT_OFF_ORIG_D0),%d0
cmpl #NR_syscalls,%d0
jcs syscall
+ jra ret_from_syscall
badsys:
movel #-ENOSYS,%sp@(PT_OFF_D0)
jra ret_from_syscall
--
2.39.0