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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 17:57:35 +0100 |
On 6 June 2016 at 15:55, Peter Maydell <address@hidden> wrote:
> Ping!
Thanks for the review, Sergey. Unless anybody else wants to review
or wants to take it through their tree (Riku?), I propose to apply
this to master sometime later this week.
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