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user-exec: Push resume-from-signal code out to handle_cpu_signal() 

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 <peter.maydell@linaro.org>
Reviewed-by: Sergey Fedorov <sergey.fedorov@linaro.org>
Acked-by: Eduardo Habkost <ehabkost@redhat.com>
Acked-by: Riku Voipio <riku.voipio@linaro.org>
Message-id: 1463494687-25947-3-git-send-email-peter.maydell@linaro.org
master
Peter Maydell 2016-05-17 15:18:03 +01:00
parent 75809229bb
commit f213e72f23
4 changed files with 39 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
cpu-exec-common.c
View File

@ -29,7 +29,6 @@ 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 */
@ -38,6 +37,7 @@ 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()) {

12
translate-all.c
View File

@ -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);

2
translate-all.h
View File

@ -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 */

41
user-exec.c
View File

@ -55,7 +55,7 @@ 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;
@ -63,20 +63,18 @@ 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
@ -96,9 +94,28 @@ 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