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[Qemu-devel] [PATCH v2 0/6] user-exec: cpu_resume_from_signal() cleanups
From: |
Peter Maydell |
Subject: |
[Qemu-devel] [PATCH v2 0/6] user-exec: cpu_resume_from_signal() cleanups |
Date: |
Tue, 17 May 2016 15:18:01 +0100 |
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
- [Qemu-devel] [PATCH v2 0/6] user-exec: cpu_resume_from_signal() cleanups,
Peter Maydell <=
- [Qemu-devel] [PATCH v2 5/6] target-i386: Add comment about do_interrupt_user() next_eip argument, Peter Maydell, 2016/05/17
- [Qemu-devel] [PATCH v2 4/6] user-exec: Don't reextract sigmask from usercontext pointer, Peter Maydell, 2016/05/17
- [Qemu-devel] [PATCH v2 2/6] user-exec: Push resume-from-signal code out to handle_cpu_signal(), Peter Maydell, 2016/05/17
- [Qemu-devel] [PATCH v2 1/6] translate-all.c: Don't pass puc, locked to tb_invalidate_phys_page(), Peter Maydell, 2016/05/17
- [Qemu-devel] [PATCH v2 3/6] cpu-exec: Rename cpu_resume_from_signal() to cpu_loop_exit_noexc(), Peter Maydell, 2016/05/17
- [Qemu-devel] [PATCH v2 6/6] target-i386: Move user-mode exception actions out of user-exec.c, Peter Maydell, 2016/05/17