[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] [PATCH v2 2/6] user-exec: Push resume-from-signal code out
From: |
Peter Maydell |
Subject: |
[Qemu-devel] [PATCH v2 2/6] user-exec: Push resume-from-signal code out to handle_cpu_signal() |
Date: |
Tue, 17 May 2016 15:18:03 +0100 |
Since the only caller of page_unprotect() which might cause it to
need to call cpu_resume_from_signal() is handle_cpu_signal() in
the user-mode code, push the longjump handling out to that function.
Since this is the only caller of cpu_resume_from_signal() which
passes a non-NULL puc argument, split the non-NULL handling into
a new cpu_exit_tb_from_sighandler() function. This allows us
to merge the softmmu and usermode implementations of the
cpu_resume_from_signal() function, which are now identical.
Signed-off-by: Peter Maydell <address@hidden>
Reviewed-by: Sergey Fedorov <address@hidden>
---
cpu-exec-common.c | 2 +-
translate-all.c | 12 ++++++++----
translate-all.h | 2 +-
user-exec.c | 41 +++++++++++++++++++++++++++++------------
4 files changed, 39 insertions(+), 18 deletions(-)
diff --git a/cpu-exec-common.c b/cpu-exec-common.c
index 6bdda6b..62f5d6b 100644
--- a/cpu-exec-common.c
+++ b/cpu-exec-common.c
@@ -28,7 +28,6 @@ CPUState *tcg_current_cpu;
/* exit the current TB from a signal handler. The host registers are
restored in a state compatible with the CPU emulator
*/
-#if defined(CONFIG_SOFTMMU)
void cpu_resume_from_signal(CPUState *cpu, void *puc)
{
/* XXX: restore cpu registers saved in host registers */
@@ -37,6 +36,7 @@ void cpu_resume_from_signal(CPUState *cpu, void *puc)
siglongjmp(cpu->jmp_env, 1);
}
+#if defined(CONFIG_SOFTMMU)
void cpu_reloading_memory_map(void)
{
if (qemu_in_vcpu_thread()) {
diff --git a/translate-all.c b/translate-all.c
index 4820d2e..52a571e 100644
--- a/translate-all.c
+++ b/translate-all.c
@@ -1955,7 +1955,7 @@ int page_check_range(target_ulong start, target_ulong
len, int flags)
/* unprotect the page if it was put read-only because it
contains translated code */
if (!(p->flags & PAGE_WRITE)) {
- if (!page_unprotect(addr, 0, NULL)) {
+ if (!page_unprotect(addr, 0)) {
return -1;
}
}
@@ -1965,8 +1965,12 @@ int page_check_range(target_ulong start, target_ulong
len, int flags)
}
/* called from signal handler: invalidate the code and unprotect the
- page. Return TRUE if the fault was successfully handled. */
-int page_unprotect(target_ulong address, uintptr_t pc, void *puc)
+ * page. Return 0 if the fault was not handled, 1 if it was handled,
+ * and 2 if it was handled but the caller must cause the TB to be
+ * immediately exited. (We can only return 2 if the 'pc' argument is
+ * non-zero.)
+ */
+int page_unprotect(target_ulong address, uintptr_t pc)
{
unsigned int prot;
PageDesc *p;
@@ -1999,7 +2003,7 @@ int page_unprotect(target_ulong address, uintptr_t pc,
void *puc)
the corresponding translated code. */
if (tb_invalidate_phys_page(addr, pc)) {
mmap_unlock();
- cpu_resume_from_signal(current_cpu, puc);
+ return 2;
}
#ifdef DEBUG_TB_CHECK
tb_invalidate_check(addr);
diff --git a/translate-all.h b/translate-all.h
index 0384640..ce6071b 100644
--- a/translate-all.h
+++ b/translate-all.h
@@ -27,7 +27,7 @@ void tb_invalidate_phys_range(tb_page_addr_t start,
tb_page_addr_t end);
void tb_check_watchpoint(CPUState *cpu);
#ifdef CONFIG_USER_ONLY
-int page_unprotect(target_ulong address, uintptr_t pc, void *puc);
+int page_unprotect(target_ulong address, uintptr_t pc);
#endif
#endif /* TRANSLATE_ALL_H */
diff --git a/user-exec.c b/user-exec.c
index d8d597b..1d02e24 100644
--- a/user-exec.c
+++ b/user-exec.c
@@ -54,7 +54,7 @@ static void exception_action(CPUState *cpu)
/* exit the current TB from a signal handler. The host registers are
restored in a state compatible with the CPU emulator
*/
-void cpu_resume_from_signal(CPUState *cpu, void *puc)
+static void cpu_exit_tb_from_sighandler(CPUState *cpu, void *puc)
{
#ifdef __linux__
struct ucontext *uc = puc;
@@ -62,20 +62,18 @@ void cpu_resume_from_signal(CPUState *cpu, void *puc)
struct sigcontext *uc = puc;
#endif
- if (puc) {
- /* XXX: use siglongjmp ? */
+ /* XXX: use siglongjmp ? */
#ifdef __linux__
#ifdef __ia64
- sigprocmask(SIG_SETMASK, (sigset_t *)&uc->uc_sigmask, NULL);
+ sigprocmask(SIG_SETMASK, (sigset_t *)&uc->uc_sigmask, NULL);
#else
- sigprocmask(SIG_SETMASK, &uc->uc_sigmask, NULL);
+ sigprocmask(SIG_SETMASK, &uc->uc_sigmask, NULL);
#endif
#elif defined(__OpenBSD__)
- sigprocmask(SIG_SETMASK, &uc->sc_mask, NULL);
+ sigprocmask(SIG_SETMASK, &uc->sc_mask, NULL);
#endif
- }
- cpu->exception_index = -1;
- siglongjmp(cpu->jmp_env, 1);
+
+ cpu_resume_from_signal(cpu, NULL);
}
/* 'pc' is the host PC at which the exception was raised. 'address' is
@@ -95,9 +93,28 @@ static inline int handle_cpu_signal(uintptr_t pc, unsigned
long address,
pc, address, is_write, *(unsigned long *)old_set);
#endif
/* XXX: locking issue */
- if (is_write && h2g_valid(address)
- && page_unprotect(h2g(address), pc, puc)) {
- return 1;
+ if (is_write && h2g_valid(address)) {
+ switch (page_unprotect(h2g(address), pc)) {
+ case 0:
+ /* Fault not caused by a page marked unwritable to protect
+ * cached translations, must be the guest binary's problem
+ */
+ break;
+ case 1:
+ /* Fault caused by protection of cached translation; TBs
+ * invalidated, so resume execution
+ */
+ return 1;
+ case 2:
+ /* Fault caused by protection of cached translation, and the
+ * currently executing TB was modified and must be exited
+ * immediately.
+ */
+ cpu_exit_tb_from_sighandler(current_cpu, puc);
+ g_assert_not_reached();
+ default:
+ g_assert_not_reached();
+ }
}
/* Convert forcefully to guest address space, invalid addresses
--
1.9.1
- [Qemu-devel] [PATCH v2 0/6] user-exec: cpu_resume_from_signal() cleanups, Peter Maydell, 2016/05/17
- [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 <=
- [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