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Re: [Qemu-devel] [PATCH v2 0/6] user-exec: cpu_resume_from_signal() clea
From: |
Peter Maydell |
Subject: |
Re: [Qemu-devel] [PATCH v2 0/6] user-exec: cpu_resume_from_signal() cleanups |
Date: |
Mon, 6 Jun 2016 15:55:12 +0100 |
Ping!
thanks
-- PMM
On 17 May 2016 at 15:18, Peter Maydell <address@hidden> wrote:
> I was trying to reason about user-mode's handling of signal masks,
> and I found our current code a bit confusing, so I cleaned it up.
>
> At the moment for user-only mode cpu_resume_from_signal() takes a
> usercontext pointer; if this is non-NULL then it has some awkward
> OS and CPU specific code to set the signal mask from something
> inside the usercontext before doing the same kind of siglongjmp()
> that the softmmu cpu_resume_from_signal() does.
>
> In fact the two use cases are completely separate:
> * almost all calls to cpu_resume_from_signal() pass a NULL puc
> argument (and most of those are softmmu-only anyway)
> * only the code path handle_cpu_signal -> page_unprotect ->
> tb_invalidate_phys_page -> cpu_resume_from_signal will pass
> a non-NULL puc.
>
> The cleanups are:
> * pull the call to cpu_resume_from_signal() up through the
> callstack so we do the signal mask manipulation in
> handle_cpu_signal()
> * drop the OS/CPU spceific code to get a signal mask out of
> a usercontext, because in the specific case of handle_cpu_signal()
> we already have the signal mask value and can just use it
> * rename cpu_resume_from_signal() to cpu_loop_exit_noexc(),
> since all the remaining callsites are not in fact signal handlers
> or even called from signal handlers
> * get rid of an ugly TARGET_I386 ifdef in user-exec.c by moving
> the i386-specific code into its handle_mmu_fault hook.
>
> Changes v1->v2:
> * patches 1-4 are the same and already reviewed
> * patch 5 is new, and just adds a clarifying comment to
> do_interrupt_user()
> * patch 6 is the old patch 5, and now sets env->exception_next_eip
> to -1 as a clear indication that the value is not going to be used
> (as noted in the comment in the new patch 5)
>
> thanks
> -- PMM
>
>
> Peter Maydell (6):
> translate-all.c: Don't pass puc, locked to tb_invalidate_phys_page()
> user-exec: Push resume-from-signal code out to handle_cpu_signal()
> cpu-exec: Rename cpu_resume_from_signal() to cpu_loop_exit_noexc()
> user-exec: Don't reextract sigmask from usercontext pointer
> target-i386: Add comment about do_interrupt_user() next_eip argument
> target-i386: Move user-mode exception actions out of user-exec.c
>
> cpu-exec-common.c | 8 ++---
> exec.c | 2 +-
> hw/i386/kvmvapic.c | 2 +-
> include/exec/exec-all.h | 2 +-
> target-i386/bpt_helper.c | 2 +-
> target-i386/helper.c | 2 ++
> target-i386/seg_helper.c | 6 +++-
> target-lm32/helper.c | 2 +-
> target-s390x/helper.c | 2 +-
> target-xtensa/helper.c | 2 +-
> translate-all.c | 40 ++++++++++++---------
> translate-all.h | 2 +-
> user-exec.c | 93
> +++++++++++++++++++++---------------------------
> 13 files changed, 82 insertions(+), 83 deletions(-)
>
> --
> 1.9.1
- Re: [Qemu-devel] [PATCH v2 0/6] user-exec: cpu_resume_from_signal() cleanups,
Peter Maydell <=