Currently the only caller of syscall_set_return_value() is seccomp
filter, which is not enabled on powerpc.
This means we have not noticed that our implementation of
syscall_set_return_value() negates error, even though the value passed
in is already negative.
So remove the negation in syscall_set_return_value(), and expect the
caller to do it like all other implementations do.
Also add a comment about the ccr handling.
Signed-off-by: Michael Ellerman <m...@ellerman.id.au>
---
arch/powerpc/include/asm/syscall.h | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/syscall.h
b/arch/powerpc/include/asm/syscall.h
index c6239dabcfb1..cabe90133e69 100644
--- a/arch/powerpc/include/asm/syscall.h
+++ b/arch/powerpc/include/asm/syscall.h
@@ -44,9 +44,15 @@ static inline void syscall_set_return_value(struct
task_struct *task,
struct pt_regs *regs,
int error, long val)
{
+ /*
+ * In the general case it's not obvious that we must deal with CCR
+ * here, as the syscall exit path will also do that for us. However
+ * there are some places, eg. the signal code, which check ccr to
+ * decide if the value in r3 is actually an error.
+ */
if (error) {
regs->ccr |= 0x10000000L;
- regs->gpr[3] = -error;
+ regs->gpr[3] = error;
} else {
regs->ccr &= ~0x10000000L;
regs->gpr[3] = val;
--
2.1.0
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