On 20.12.2015 20:39, John David Anglin wrote: > On 2015-12-18, at 6:30 PM, Helge Deller wrote: > >> + /* Usually we don't have to restore %r20 (the system call number) >> + * because it gets loaded in the delay slot of the branch external >> + * instruction via the ldi instruction. >> + * In some cases a register-to-register copy instruction might have >> + * been used instead, in which case we need to copy the syscall >> + * number into the source register before returning to userspace. >> + */ > > I'm thinking it might be better to fix syscall() in glibc. The copy could be > moved before ble and a nop placed delay slot. Yes, I think it should be fixed in glibc which makes it cleaner. I looked at dietlibc. There a "nop" is being used. Nevertheless, it may happen anytime if people forget, that we will see a "copy" there again, so IMHO it's probably safer to include the workaround in kernel too. Helge -- To unsubscribe from this list: send the line "unsubscribe linux-parisc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
