This cleanup patch speeds up the null syscall path on ppc64 by about 3%,
and brings the ppc32 and ppc64 code slightly closer together.
The ppc64 code was checking current_thread_info()->flags twice in the
syscall exit path; once for TIF_SYSCALL_T_OR_A before disabling
interrupts, and then again for TIF_SIGPENDING|TIF_NEED_RESCHED etc after
disabling interrupts. Now we do the same as ppc32 -- check the flags
only once in the fast path, and re-enable interrupts if necessary in the
ptrace case.
The patch abolishes the 'syscall_noerror' member of struct thread_info
and replaces it with a TIF_NOERROR bit in the flags, which is handled in
the slow path. This shortens the syscall entry code, which no longer
needs to clear syscall_noerror.
The patch adds a TIF_SAVE_NVGPRS flag which causes the syscall exit slow
path to save the non-volatile GPRs into a signal frame. This removes the
need for the assembly wrappers around sys_sigsuspend(),
sys_rt_sigsuspend(), et al which existed solely to save those registers
in advance. It also means I don't have to add new wrappers for ppoll()
and pselect(), which is what I was supposed to be doing when I got
distracted into this...
Finally, it unifies the ppc64 and ppc32 methods of handling syscall exit
directly into a signal handler (as required by sigsuspend et al) by
introducing a TIF_RESTOREALL flag which causes _all_ the registers to be
reloaded from the pt_regs by taking the ret_from_exception path, instead
of the normal syscall exit path which stomps on the callee-saved GPRs.
It appears to pass an LTP test run on ppc64, and passes basic testing on
ppc32 too. Brief tests of ptrace functionality with strace and gdb also
appear OK. I wouldn't send it to Linus for 2.6.15 just yet though :)
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
- Add PTRACE_GET_DEBUGREG/PTRACE_SET_DEBUGREG. The definition is
as follows:
/*
* Get or set a debug register. The first 16 are DABR registers and the
* second 16 are IABR registers.
*/
#define PTRACE_GET_DEBUGREG 25
#define PTRACE_SET_DEBUGREG 26
DABR == data breakpoint and IABR = instruction breakpoint in IBM
speak. We could split out the IABR into 2 more ptrace calls but I
figured there was no need and 16 DABR registers should be more
than enough (POWER4/POWER5 have one).
- Add 2 new SIGTRAP si_codes: TRAP_HWBKPT and TRAP_BRANCH. I couldnt
find any standards on either of these so I copied what ia64 is
doing. Again this might be better placed in
include/asm-generic/siginfo.h
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
- Remove the PPC_REG* defines
- Wrap some more stuff with ifdef __KERNEL__
- Add missing PT_TRAP, PT_DAR, PT_DSISR defines
- Add PTRACE_GETEVRREGS/PTRACE_SETEVRREGS, even though we dont use it on
ppc64 we dont want to allocate them for something else.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
David Woodhouse