On Thu, Jan 26, 2012 at 9:23 AM, Pedro Alves <palves@xxxxxxxxxx> wrote: > On 01/26/2012 12:59 AM, Jamie Lokier wrote: >> Tracers mainly want to know if it's a 32-bit or 64-bit syscall, not >> whether it's compat as such. > > Another idea, avoiding new PTRACE_EVENTs per arch, would be to make > the abi32/abi64/compat/whatnot discriminator retrievable with PTRACE_GETEVENTMSG > instead. So you'd get PTRACE_EVENT_SYSCALL_ENTRY|EXIT, or the regular old > 0x80|SIGTRAP, you'd still fetch the syscall number from $orig_ax (or whatever means > for other archs), as usual, then have extra syscall info in PTRACE_GETEVENTMSG. > I don't know if it'd be simple to make it possible to do PTRACE_GETEVENTMSG > on a 0x80|SIGTRAP trap, but I imagine it so. > > -> wait > <- 0x80|SIGTRAP (or PTRACE_EVENT_SYSCALL_ENTRY) > -> read regs, find out syscall number > -> PTRACE_GETEVENTMSG, figure out which entry mode was used. This would require additional ptrace op per syscall entry. Linus' method and event method wouldn't. -- vda -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
