Commit 1b1a3702 authored Jul 23, 2015 by Michael Ellerman

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>

parent 2923e6d5

arch/powerpc/include/asm/syscall.h

+7 −1

Original line number	Diff line number	Diff line
		@@ -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;