On Mon, 2009-11-30 at 10:15 +1100, Benjamin Herrenschmidt wrote: > Yes, the asm should be changed. I suppose we could check if the result > of do_syscall_trace_enter is negative, and if it is, branch to the exit > path using r3 as the error code. Would that be ok ? > > Something like this:
Note however that there's a trace exit too and that's normally the right place to alter the result don't you think ? Cheers, Ben. > diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S > index 1175a85..7a88c88 100644 > --- a/arch/powerpc/kernel/entry_32.S > +++ b/arch/powerpc/kernel/entry_32.S > @@ -419,6 +419,9 @@ syscall_dotrace: > stw r0,_TRAP(r1) > addi r3,r1,STACK_FRAME_OVERHEAD > bl do_syscall_trace_enter > + cmpwi cr0,r3,0 > + blt ret_from_syscall > + > /* > * Restore argument registers possibly just changed. > * We use the return value of do_syscall_trace_enter > diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S > index 9763267..ec709a7 100644 > --- a/arch/powerpc/kernel/entry_64.S > +++ b/arch/powerpc/kernel/entry_64.S > @@ -240,6 +240,9 @@ syscall_dotrace: > bl .save_nvgprs > addi r3,r1,STACK_FRAME_OVERHEAD > bl .do_syscall_trace_enter > + cmpdi cr0,r3,0 > + blt syscall_exit > + > /* > * Restore argument registers possibly just changed. > * We use the return value of do_syscall_trace_enter > > > Cheers, > Ben.
