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authorMichael Ellerman <mpe@ellerman.id.au>2015-07-23 20:21:04 +1000
committerMichael Ellerman <mpe@ellerman.id.au>2015-07-29 11:56:12 +1000
commit1b1a3702a65c1a6511e4c95ecb3770dfdf235bcf (patch)
treee5f34faf6e7ee84bdea7d4d4aca7cf49d6605941
parent2923e6d503465e97a378d37a588e4e6987009bc7 (diff)
powerpc: Don't negate error in syscall_set_return_value()
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 <mpe@ellerman.id.au> Reviewed-by: Kees Cook <keescook@chromium.org>
-rw-r--r--arch/powerpc/include/asm/syscall.h8
1 files changed, 7 insertions, 1 deletions
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;