| Message ID | 20210918184527.408540-7-richard.henderson@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | linux-user: Streamline handling of SIGSEGV | expand |
On 9/18/21 20:44, Richard Henderson wrote: > Add stub host-signal.h for all linux-user hosts. > Add new code replacing cpu_signal_handler. > Full migration will happen one host at a time. > > Signed-off-by: Richard Henderson <richard.henderson@linaro.org> > --- > diff --git a/linux-user/signal.c b/linux-user/signal.c > index 5ea8e4584a..6f953f10d4 100644 > --- a/linux-user/signal.c > +++ b/linux-user/signal.c > @@ -18,12 +18,15 @@ > */ > #include "qemu/osdep.h" > #include "qemu/bitops.h" > +#include "hw/core/tcg-cpu-ops.h" > + > #include <sys/ucontext.h> > #include <sys/resource.h> > > #include "qemu.h" > #include "trace.h" > #include "signal-common.h" > +#include "host-signal.h" > > static struct target_sigaction sigact_table[TARGET_NSIG]; > > @@ -761,41 +764,115 @@ static inline void rewind_if_in_safe_syscall(void *puc) > } > #endif > > -static void host_signal_handler(int host_signum, siginfo_t *info, > - void *puc) > +static void host_signal_handler(int host_sig, siginfo_t *info, void *puc) > { > CPUArchState *env = thread_cpu->env_ptr; > CPUState *cpu = env_cpu(env); > TaskState *ts = cpu->opaque; > - > - int sig; > target_siginfo_t tinfo; > ucontext_t *uc = puc; > struct emulated_sigtable *k; > + int guest_sig; > > +#ifdef HOST_SIGNAL_PLACEHOLDER > /* the CPU emulator uses some host signals to detect exceptions, > we forward to it some signals */ > - if ((host_signum == SIGSEGV || host_signum == SIGBUS) > + if ((host_sig == SIGSEGV || host_sig == SIGBUS) > && info->si_code > 0) { > - if (cpu_signal_handler(host_signum, info, puc)) > + if (cpu_signal_handler(host_sig, info, puc)) > return; > } > +#else > + uintptr_t pc = 0; > + bool sync_sig = false; > + > + /* > + * Non-spoofed SIGSEGV and SIGBUS are synchronous, and need special > + * handling wrt signal blocking and unwinding. > + */ > + if ((host_sig == SIGSEGV || host_sig == SIGBUS) && info->si_code > 0) { > + MMUAccessType access_type; > + uintptr_t host_addr; > + abi_ptr guest_addr; > + bool is_write; > + > + host_addr = (uintptr_t)info->si_addr; > + > + /* > + * Convert forcefully to guest address space: addresses outside > + * reserved_va are still valid to report via SEGV_MAPERR. > + */ > + guest_addr = h2g_nocheck(host_addr); > + > + pc = host_signal_pc(uc); > + is_write = host_signal_write(info, uc); > + access_type = adjust_signal_pc(&pc, is_write); > + > + if (host_sig == SIGSEGV) { > + const struct TCGCPUOps *tcg_ops; > + > + if (info->si_code == SEGV_ACCERR && h2g_valid(host_addr)) { > + /* If this was a write to a TB protected page, restart. */ > + if (is_write && > + handle_sigsegv_accerr_write(cpu, &uc->uc_sigmask, > + pc, guest_addr)) { > + return; > + } > + > + /* > + * With reserved_va, the whole address space is PROT_NONE, > + * which means that we may get ACCERR when we want MAPERR. > + */ > + if (page_get_flags(guest_addr) & PAGE_VALID) { > + /* maperr = false; */ > + } else { > + info->si_code = SEGV_MAPERR; > + } > + } > + > + sigprocmask(SIG_SETMASK, &uc->uc_sigmask, NULL); > + > + tcg_ops = CPU_GET_CLASS(cpu)->tcg_ops; > + tcg_ops->tlb_fill(cpu, guest_addr, 0, access_type, > + MMU_USER_IDX, false, pc); > + g_assert_not_reached(); > + } else { > + sigprocmask(SIG_SETMASK, &uc->uc_sigmask, NULL); > + } > + > + sync_sig = true; > + } > +#endif > > /* get target signal number */ > - sig = host_to_target_signal(host_signum); > - if (sig < 1 || sig > TARGET_NSIG) > + guest_sig = host_to_target_signal(host_sig); > + if (guest_sig < 1 || guest_sig > TARGET_NSIG) { > return; > - trace_user_host_signal(env, host_signum, sig); > + } > + trace_user_host_signal(env, host_sig, guest_sig); > + > + host_to_target_siginfo_noswap(&tinfo, info); > + k = &ts->sigtab[guest_sig - 1]; > + k->info = tinfo; > + k->pending = guest_sig; > + ts->signal_pending = 1; > + > +#ifndef HOST_SIGNAL_PLACEHOLDER > + /* > + * For synchronous signals, unwind the cpu state to the faulting > + * insn and then exit back to the main loop so that the signal > + * is delivered immediately. > + */ > + if (sync_sig) { > + cpu->exception_index = EXCP_INTERRUPT; > + cpu_loop_exit_restore(cpu, pc); > + } > +#endif > > rewind_if_in_safe_syscall(puc); > > - host_to_target_siginfo_noswap(&tinfo, info); > - k = &ts->sigtab[sig - 1]; > - k->info = tinfo; > - k->pending = sig; > - ts->signal_pending = 1; > - > - /* Block host signals until target signal handler entered. We > + /* > + * Block host signals until target signal handler entered. We > * can't block SIGSEGV or SIGBUS while we're executing guest > * code in case the guest code provokes one in the window between > * now and it getting out to the main loop. Signals will be > So this is outside of my comfort zone; however after reviewing and to the best of my knowledge it looks OK, so: Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> And I'll review the next patches assuming this one is OK.
> On Sep 18, 2021, at 12:44 PM, Richard Henderson <richard.henderson@linaro.org> wrote: > > Add stub host-signal.h for all linux-user hosts. > Add new code replacing cpu_signal_handler. > Full migration will happen one host at a time. > > Signed-off-by: Richard Henderson <richard.henderson@linaro.org> > --- > linux-user/host/aarch64/host-signal.h | 1 + > linux-user/host/arm/host-signal.h | 1 + > linux-user/host/i386/host-signal.h | 1 + > linux-user/host/mips/host-signal.h | 1 + > linux-user/host/ppc/host-signal.h | 1 + > linux-user/host/ppc64/host-signal.h | 1 + > linux-user/host/riscv/host-signal.h | 1 + > linux-user/host/s390/host-signal.h | 1 + > linux-user/host/s390x/host-signal.h | 1 + > linux-user/host/sparc/host-signal.h | 1 + > linux-user/host/sparc64/host-signal.h | 1 + > linux-user/host/x32/host-signal.h | 1 + > linux-user/host/x86_64/host-signal.h | 1 + > linux-user/signal.c | 109 ++++++++++++++++++++++---- > 14 files changed, 106 insertions(+), 16 deletions(-) > create mode 100644 linux-user/host/aarch64/host-signal.h > create mode 100644 linux-user/host/arm/host-signal.h > create mode 100644 linux-user/host/i386/host-signal.h > create mode 100644 linux-user/host/mips/host-signal.h > create mode 100644 linux-user/host/ppc/host-signal.h > create mode 100644 linux-user/host/ppc64/host-signal.h > create mode 100644 linux-user/host/riscv/host-signal.h > create mode 100644 linux-user/host/s390/host-signal.h > create mode 100644 linux-user/host/s390x/host-signal.h > create mode 100644 linux-user/host/sparc/host-signal.h > create mode 100644 linux-user/host/sparc64/host-signal.h > create mode 100644 linux-user/host/x32/host-signal.h > create mode 100644 linux-user/host/x86_64/host-signal.h Seems sensible to me. Reviewed-by: Warner Losh <imp@bsdimp.com> > diff --git a/linux-user/host/aarch64/host-signal.h b/linux-user/host/aarch64/host-signal.h > new file mode 100644 > index 0000000000..f4b4d65031 > --- /dev/null > +++ b/linux-user/host/aarch64/host-signal.h > @@ -0,0 +1 @@ > +#define HOST_SIGNAL_PLACEHOLDER > diff --git a/linux-user/host/arm/host-signal.h b/linux-user/host/arm/host-signal.h > new file mode 100644 > index 0000000000..f4b4d65031 > --- /dev/null > +++ b/linux-user/host/arm/host-signal.h > @@ -0,0 +1 @@ > +#define HOST_SIGNAL_PLACEHOLDER > diff --git a/linux-user/host/i386/host-signal.h b/linux-user/host/i386/host-signal.h > new file mode 100644 > index 0000000000..f4b4d65031 > --- /dev/null > +++ b/linux-user/host/i386/host-signal.h > @@ -0,0 +1 @@ > +#define HOST_SIGNAL_PLACEHOLDER > diff --git a/linux-user/host/mips/host-signal.h b/linux-user/host/mips/host-signal.h > new file mode 100644 > index 0000000000..f4b4d65031 > --- /dev/null > +++ b/linux-user/host/mips/host-signal.h > @@ -0,0 +1 @@ > +#define HOST_SIGNAL_PLACEHOLDER > diff --git a/linux-user/host/ppc/host-signal.h b/linux-user/host/ppc/host-signal.h > new file mode 100644 > index 0000000000..f4b4d65031 > --- /dev/null > +++ b/linux-user/host/ppc/host-signal.h > @@ -0,0 +1 @@ > +#define HOST_SIGNAL_PLACEHOLDER > diff --git a/linux-user/host/ppc64/host-signal.h b/linux-user/host/ppc64/host-signal.h > new file mode 100644 > index 0000000000..f4b4d65031 > --- /dev/null > +++ b/linux-user/host/ppc64/host-signal.h > @@ -0,0 +1 @@ > +#define HOST_SIGNAL_PLACEHOLDER > diff --git a/linux-user/host/riscv/host-signal.h b/linux-user/host/riscv/host-signal.h > new file mode 100644 > index 0000000000..f4b4d65031 > --- /dev/null > +++ b/linux-user/host/riscv/host-signal.h > @@ -0,0 +1 @@ > +#define HOST_SIGNAL_PLACEHOLDER > diff --git a/linux-user/host/s390/host-signal.h b/linux-user/host/s390/host-signal.h > new file mode 100644 > index 0000000000..f4b4d65031 > --- /dev/null > +++ b/linux-user/host/s390/host-signal.h > @@ -0,0 +1 @@ > +#define HOST_SIGNAL_PLACEHOLDER > diff --git a/linux-user/host/s390x/host-signal.h b/linux-user/host/s390x/host-signal.h > new file mode 100644 > index 0000000000..f4b4d65031 > --- /dev/null > +++ b/linux-user/host/s390x/host-signal.h > @@ -0,0 +1 @@ > +#define HOST_SIGNAL_PLACEHOLDER > diff --git a/linux-user/host/sparc/host-signal.h b/linux-user/host/sparc/host-signal.h > new file mode 100644 > index 0000000000..f4b4d65031 > --- /dev/null > +++ b/linux-user/host/sparc/host-signal.h > @@ -0,0 +1 @@ > +#define HOST_SIGNAL_PLACEHOLDER > diff --git a/linux-user/host/sparc64/host-signal.h b/linux-user/host/sparc64/host-signal.h > new file mode 100644 > index 0000000000..f4b4d65031 > --- /dev/null > +++ b/linux-user/host/sparc64/host-signal.h > @@ -0,0 +1 @@ > +#define HOST_SIGNAL_PLACEHOLDER > diff --git a/linux-user/host/x32/host-signal.h b/linux-user/host/x32/host-signal.h > new file mode 100644 > index 0000000000..f4b4d65031 > --- /dev/null > +++ b/linux-user/host/x32/host-signal.h > @@ -0,0 +1 @@ > +#define HOST_SIGNAL_PLACEHOLDER > diff --git a/linux-user/host/x86_64/host-signal.h b/linux-user/host/x86_64/host-signal.h > new file mode 100644 > index 0000000000..f4b4d65031 > --- /dev/null > +++ b/linux-user/host/x86_64/host-signal.h > @@ -0,0 +1 @@ > +#define HOST_SIGNAL_PLACEHOLDER > diff --git a/linux-user/signal.c b/linux-user/signal.c > index 5ea8e4584a..6f953f10d4 100644 > --- a/linux-user/signal.c > +++ b/linux-user/signal.c > @@ -18,12 +18,15 @@ > */ > #include "qemu/osdep.h" > #include "qemu/bitops.h" > +#include "hw/core/tcg-cpu-ops.h" > + > #include <sys/ucontext.h> > #include <sys/resource.h> > > #include "qemu.h" > #include "trace.h" > #include "signal-common.h" > +#include "host-signal.h" > > static struct target_sigaction sigact_table[TARGET_NSIG]; > > @@ -761,41 +764,115 @@ static inline void rewind_if_in_safe_syscall(void *puc) > } > #endif > > -static void host_signal_handler(int host_signum, siginfo_t *info, > - void *puc) > +static void host_signal_handler(int host_sig, siginfo_t *info, void *puc) > { > CPUArchState *env = thread_cpu->env_ptr; > CPUState *cpu = env_cpu(env); > TaskState *ts = cpu->opaque; > - > - int sig; > target_siginfo_t tinfo; > ucontext_t *uc = puc; > struct emulated_sigtable *k; > + int guest_sig; > > +#ifdef HOST_SIGNAL_PLACEHOLDER > /* the CPU emulator uses some host signals to detect exceptions, > we forward to it some signals */ > - if ((host_signum == SIGSEGV || host_signum == SIGBUS) > + if ((host_sig == SIGSEGV || host_sig == SIGBUS) > && info->si_code > 0) { > - if (cpu_signal_handler(host_signum, info, puc)) > + if (cpu_signal_handler(host_sig, info, puc)) > return; > } > +#else > + uintptr_t pc = 0; > + bool sync_sig = false; > + > + /* > + * Non-spoofed SIGSEGV and SIGBUS are synchronous, and need special > + * handling wrt signal blocking and unwinding. > + */ > + if ((host_sig == SIGSEGV || host_sig == SIGBUS) && info->si_code > 0) { > + MMUAccessType access_type; > + uintptr_t host_addr; > + abi_ptr guest_addr; > + bool is_write; > + > + host_addr = (uintptr_t)info->si_addr; > + > + /* > + * Convert forcefully to guest address space: addresses outside > + * reserved_va are still valid to report via SEGV_MAPERR. > + */ > + guest_addr = h2g_nocheck(host_addr); > + > + pc = host_signal_pc(uc); > + is_write = host_signal_write(info, uc); > + access_type = adjust_signal_pc(&pc, is_write); > + > + if (host_sig == SIGSEGV) { > + const struct TCGCPUOps *tcg_ops; > + > + if (info->si_code == SEGV_ACCERR && h2g_valid(host_addr)) { > + /* If this was a write to a TB protected page, restart. */ > + if (is_write && > + handle_sigsegv_accerr_write(cpu, &uc->uc_sigmask, > + pc, guest_addr)) { > + return; > + } > + > + /* > + * With reserved_va, the whole address space is PROT_NONE, > + * which means that we may get ACCERR when we want MAPERR. > + */ > + if (page_get_flags(guest_addr) & PAGE_VALID) { > + /* maperr = false; */ > + } else { > + info->si_code = SEGV_MAPERR; > + } > + } > + > + sigprocmask(SIG_SETMASK, &uc->uc_sigmask, NULL); > + > + tcg_ops = CPU_GET_CLASS(cpu)->tcg_ops; > + tcg_ops->tlb_fill(cpu, guest_addr, 0, access_type, > + MMU_USER_IDX, false, pc); > + g_assert_not_reached(); > + } else { > + sigprocmask(SIG_SETMASK, &uc->uc_sigmask, NULL); > + } > + > + sync_sig = true; > + } > +#endif > > /* get target signal number */ > - sig = host_to_target_signal(host_signum); > - if (sig < 1 || sig > TARGET_NSIG) > + guest_sig = host_to_target_signal(host_sig); > + if (guest_sig < 1 || guest_sig > TARGET_NSIG) { > return; > - trace_user_host_signal(env, host_signum, sig); > + } > + trace_user_host_signal(env, host_sig, guest_sig); > + > + host_to_target_siginfo_noswap(&tinfo, info); > + k = &ts->sigtab[guest_sig - 1]; > + k->info = tinfo; > + k->pending = guest_sig; > + ts->signal_pending = 1; > + > +#ifndef HOST_SIGNAL_PLACEHOLDER > + /* > + * For synchronous signals, unwind the cpu state to the faulting > + * insn and then exit back to the main loop so that the signal > + * is delivered immediately. > + */ > + if (sync_sig) { > + cpu->exception_index = EXCP_INTERRUPT; > + cpu_loop_exit_restore(cpu, pc); > + } > +#endif > > rewind_if_in_safe_syscall(puc); > > - host_to_target_siginfo_noswap(&tinfo, info); > - k = &ts->sigtab[sig - 1]; > - k->info = tinfo; > - k->pending = sig; > - ts->signal_pending = 1; > - > - /* Block host signals until target signal handler entered. We > + /* > + * Block host signals until target signal handler entered. We > * can't block SIGSEGV or SIGBUS while we're executing guest > * code in case the guest code provokes one in the window between > * now and it getting out to the main loop. Signals will be > -- > 2.25.1 > >
On Sun, Sep 19, 2021 at 4:55 AM Richard Henderson <richard.henderson@linaro.org> wrote: > > Add stub host-signal.h for all linux-user hosts. > Add new code replacing cpu_signal_handler. > Full migration will happen one host at a time. > > Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Acked-by: Alistair Francis <alistair.francis@wdc.com> Alistair > --- > linux-user/host/aarch64/host-signal.h | 1 + > linux-user/host/arm/host-signal.h | 1 + > linux-user/host/i386/host-signal.h | 1 + > linux-user/host/mips/host-signal.h | 1 + > linux-user/host/ppc/host-signal.h | 1 + > linux-user/host/ppc64/host-signal.h | 1 + > linux-user/host/riscv/host-signal.h | 1 + > linux-user/host/s390/host-signal.h | 1 + > linux-user/host/s390x/host-signal.h | 1 + > linux-user/host/sparc/host-signal.h | 1 + > linux-user/host/sparc64/host-signal.h | 1 + > linux-user/host/x32/host-signal.h | 1 + > linux-user/host/x86_64/host-signal.h | 1 + > linux-user/signal.c | 109 ++++++++++++++++++++++---- > 14 files changed, 106 insertions(+), 16 deletions(-) > create mode 100644 linux-user/host/aarch64/host-signal.h > create mode 100644 linux-user/host/arm/host-signal.h > create mode 100644 linux-user/host/i386/host-signal.h > create mode 100644 linux-user/host/mips/host-signal.h > create mode 100644 linux-user/host/ppc/host-signal.h > create mode 100644 linux-user/host/ppc64/host-signal.h > create mode 100644 linux-user/host/riscv/host-signal.h > create mode 100644 linux-user/host/s390/host-signal.h > create mode 100644 linux-user/host/s390x/host-signal.h > create mode 100644 linux-user/host/sparc/host-signal.h > create mode 100644 linux-user/host/sparc64/host-signal.h > create mode 100644 linux-user/host/x32/host-signal.h > create mode 100644 linux-user/host/x86_64/host-signal.h > > diff --git a/linux-user/host/aarch64/host-signal.h b/linux-user/host/aarch64/host-signal.h > new file mode 100644 > index 0000000000..f4b4d65031 > --- /dev/null > +++ b/linux-user/host/aarch64/host-signal.h > @@ -0,0 +1 @@ > +#define HOST_SIGNAL_PLACEHOLDER > diff --git a/linux-user/host/arm/host-signal.h b/linux-user/host/arm/host-signal.h > new file mode 100644 > index 0000000000..f4b4d65031 > --- /dev/null > +++ b/linux-user/host/arm/host-signal.h > @@ -0,0 +1 @@ > +#define HOST_SIGNAL_PLACEHOLDER > diff --git a/linux-user/host/i386/host-signal.h b/linux-user/host/i386/host-signal.h > new file mode 100644 > index 0000000000..f4b4d65031 > --- /dev/null > +++ b/linux-user/host/i386/host-signal.h > @@ -0,0 +1 @@ > +#define HOST_SIGNAL_PLACEHOLDER > diff --git a/linux-user/host/mips/host-signal.h b/linux-user/host/mips/host-signal.h > new file mode 100644 > index 0000000000..f4b4d65031 > --- /dev/null > +++ b/linux-user/host/mips/host-signal.h > @@ -0,0 +1 @@ > +#define HOST_SIGNAL_PLACEHOLDER > diff --git a/linux-user/host/ppc/host-signal.h b/linux-user/host/ppc/host-signal.h > new file mode 100644 > index 0000000000..f4b4d65031 > --- /dev/null > +++ b/linux-user/host/ppc/host-signal.h > @@ -0,0 +1 @@ > +#define HOST_SIGNAL_PLACEHOLDER > diff --git a/linux-user/host/ppc64/host-signal.h b/linux-user/host/ppc64/host-signal.h > new file mode 100644 > index 0000000000..f4b4d65031 > --- /dev/null > +++ b/linux-user/host/ppc64/host-signal.h > @@ -0,0 +1 @@ > +#define HOST_SIGNAL_PLACEHOLDER > diff --git a/linux-user/host/riscv/host-signal.h b/linux-user/host/riscv/host-signal.h > new file mode 100644 > index 0000000000..f4b4d65031 > --- /dev/null > +++ b/linux-user/host/riscv/host-signal.h > @@ -0,0 +1 @@ > +#define HOST_SIGNAL_PLACEHOLDER > diff --git a/linux-user/host/s390/host-signal.h b/linux-user/host/s390/host-signal.h > new file mode 100644 > index 0000000000..f4b4d65031 > --- /dev/null > +++ b/linux-user/host/s390/host-signal.h > @@ -0,0 +1 @@ > +#define HOST_SIGNAL_PLACEHOLDER > diff --git a/linux-user/host/s390x/host-signal.h b/linux-user/host/s390x/host-signal.h > new file mode 100644 > index 0000000000..f4b4d65031 > --- /dev/null > +++ b/linux-user/host/s390x/host-signal.h > @@ -0,0 +1 @@ > +#define HOST_SIGNAL_PLACEHOLDER > diff --git a/linux-user/host/sparc/host-signal.h b/linux-user/host/sparc/host-signal.h > new file mode 100644 > index 0000000000..f4b4d65031 > --- /dev/null > +++ b/linux-user/host/sparc/host-signal.h > @@ -0,0 +1 @@ > +#define HOST_SIGNAL_PLACEHOLDER > diff --git a/linux-user/host/sparc64/host-signal.h b/linux-user/host/sparc64/host-signal.h > new file mode 100644 > index 0000000000..f4b4d65031 > --- /dev/null > +++ b/linux-user/host/sparc64/host-signal.h > @@ -0,0 +1 @@ > +#define HOST_SIGNAL_PLACEHOLDER > diff --git a/linux-user/host/x32/host-signal.h b/linux-user/host/x32/host-signal.h > new file mode 100644 > index 0000000000..f4b4d65031 > --- /dev/null > +++ b/linux-user/host/x32/host-signal.h > @@ -0,0 +1 @@ > +#define HOST_SIGNAL_PLACEHOLDER > diff --git a/linux-user/host/x86_64/host-signal.h b/linux-user/host/x86_64/host-signal.h > new file mode 100644 > index 0000000000..f4b4d65031 > --- /dev/null > +++ b/linux-user/host/x86_64/host-signal.h > @@ -0,0 +1 @@ > +#define HOST_SIGNAL_PLACEHOLDER > diff --git a/linux-user/signal.c b/linux-user/signal.c > index 5ea8e4584a..6f953f10d4 100644 > --- a/linux-user/signal.c > +++ b/linux-user/signal.c > @@ -18,12 +18,15 @@ > */ > #include "qemu/osdep.h" > #include "qemu/bitops.h" > +#include "hw/core/tcg-cpu-ops.h" > + > #include <sys/ucontext.h> > #include <sys/resource.h> > > #include "qemu.h" > #include "trace.h" > #include "signal-common.h" > +#include "host-signal.h" > > static struct target_sigaction sigact_table[TARGET_NSIG]; > > @@ -761,41 +764,115 @@ static inline void rewind_if_in_safe_syscall(void *puc) > } > #endif > > -static void host_signal_handler(int host_signum, siginfo_t *info, > - void *puc) > +static void host_signal_handler(int host_sig, siginfo_t *info, void *puc) > { > CPUArchState *env = thread_cpu->env_ptr; > CPUState *cpu = env_cpu(env); > TaskState *ts = cpu->opaque; > - > - int sig; > target_siginfo_t tinfo; > ucontext_t *uc = puc; > struct emulated_sigtable *k; > + int guest_sig; > > +#ifdef HOST_SIGNAL_PLACEHOLDER > /* the CPU emulator uses some host signals to detect exceptions, > we forward to it some signals */ > - if ((host_signum == SIGSEGV || host_signum == SIGBUS) > + if ((host_sig == SIGSEGV || host_sig == SIGBUS) > && info->si_code > 0) { > - if (cpu_signal_handler(host_signum, info, puc)) > + if (cpu_signal_handler(host_sig, info, puc)) > return; > } > +#else > + uintptr_t pc = 0; > + bool sync_sig = false; > + > + /* > + * Non-spoofed SIGSEGV and SIGBUS are synchronous, and need special > + * handling wrt signal blocking and unwinding. > + */ > + if ((host_sig == SIGSEGV || host_sig == SIGBUS) && info->si_code > 0) { > + MMUAccessType access_type; > + uintptr_t host_addr; > + abi_ptr guest_addr; > + bool is_write; > + > + host_addr = (uintptr_t)info->si_addr; > + > + /* > + * Convert forcefully to guest address space: addresses outside > + * reserved_va are still valid to report via SEGV_MAPERR. > + */ > + guest_addr = h2g_nocheck(host_addr); > + > + pc = host_signal_pc(uc); > + is_write = host_signal_write(info, uc); > + access_type = adjust_signal_pc(&pc, is_write); > + > + if (host_sig == SIGSEGV) { > + const struct TCGCPUOps *tcg_ops; > + > + if (info->si_code == SEGV_ACCERR && h2g_valid(host_addr)) { > + /* If this was a write to a TB protected page, restart. */ > + if (is_write && > + handle_sigsegv_accerr_write(cpu, &uc->uc_sigmask, > + pc, guest_addr)) { > + return; > + } > + > + /* > + * With reserved_va, the whole address space is PROT_NONE, > + * which means that we may get ACCERR when we want MAPERR. > + */ > + if (page_get_flags(guest_addr) & PAGE_VALID) { > + /* maperr = false; */ > + } else { > + info->si_code = SEGV_MAPERR; > + } > + } > + > + sigprocmask(SIG_SETMASK, &uc->uc_sigmask, NULL); > + > + tcg_ops = CPU_GET_CLASS(cpu)->tcg_ops; > + tcg_ops->tlb_fill(cpu, guest_addr, 0, access_type, > + MMU_USER_IDX, false, pc); > + g_assert_not_reached(); > + } else { > + sigprocmask(SIG_SETMASK, &uc->uc_sigmask, NULL); > + } > + > + sync_sig = true; > + } > +#endif > > /* get target signal number */ > - sig = host_to_target_signal(host_signum); > - if (sig < 1 || sig > TARGET_NSIG) > + guest_sig = host_to_target_signal(host_sig); > + if (guest_sig < 1 || guest_sig > TARGET_NSIG) { > return; > - trace_user_host_signal(env, host_signum, sig); > + } > + trace_user_host_signal(env, host_sig, guest_sig); > + > + host_to_target_siginfo_noswap(&tinfo, info); > + k = &ts->sigtab[guest_sig - 1]; > + k->info = tinfo; > + k->pending = guest_sig; > + ts->signal_pending = 1; > + > +#ifndef HOST_SIGNAL_PLACEHOLDER > + /* > + * For synchronous signals, unwind the cpu state to the faulting > + * insn and then exit back to the main loop so that the signal > + * is delivered immediately. > + */ > + if (sync_sig) { > + cpu->exception_index = EXCP_INTERRUPT; > + cpu_loop_exit_restore(cpu, pc); > + } > +#endif > > rewind_if_in_safe_syscall(puc); > > - host_to_target_siginfo_noswap(&tinfo, info); > - k = &ts->sigtab[sig - 1]; > - k->info = tinfo; > - k->pending = sig; > - ts->signal_pending = 1; > - > - /* Block host signals until target signal handler entered. We > + /* > + * Block host signals until target signal handler entered. We > * can't block SIGSEGV or SIGBUS while we're executing guest > * code in case the guest code provokes one in the window between > * now and it getting out to the main loop. Signals will be > -- > 2.25.1 > >
diff --git a/linux-user/host/aarch64/host-signal.h b/linux-user/host/aarch64/host-signal.h new file mode 100644 index 0000000000..f4b4d65031 --- /dev/null +++ b/linux-user/host/aarch64/host-signal.h @@ -0,0 +1 @@ +#define HOST_SIGNAL_PLACEHOLDER diff --git a/linux-user/host/arm/host-signal.h b/linux-user/host/arm/host-signal.h new file mode 100644 index 0000000000..f4b4d65031 --- /dev/null +++ b/linux-user/host/arm/host-signal.h @@ -0,0 +1 @@ +#define HOST_SIGNAL_PLACEHOLDER diff --git a/linux-user/host/i386/host-signal.h b/linux-user/host/i386/host-signal.h new file mode 100644 index 0000000000..f4b4d65031 --- /dev/null +++ b/linux-user/host/i386/host-signal.h @@ -0,0 +1 @@ +#define HOST_SIGNAL_PLACEHOLDER diff --git a/linux-user/host/mips/host-signal.h b/linux-user/host/mips/host-signal.h new file mode 100644 index 0000000000..f4b4d65031 --- /dev/null +++ b/linux-user/host/mips/host-signal.h @@ -0,0 +1 @@ +#define HOST_SIGNAL_PLACEHOLDER diff --git a/linux-user/host/ppc/host-signal.h b/linux-user/host/ppc/host-signal.h new file mode 100644 index 0000000000..f4b4d65031 --- /dev/null +++ b/linux-user/host/ppc/host-signal.h @@ -0,0 +1 @@ +#define HOST_SIGNAL_PLACEHOLDER diff --git a/linux-user/host/ppc64/host-signal.h b/linux-user/host/ppc64/host-signal.h new file mode 100644 index 0000000000..f4b4d65031 --- /dev/null +++ b/linux-user/host/ppc64/host-signal.h @@ -0,0 +1 @@ +#define HOST_SIGNAL_PLACEHOLDER diff --git a/linux-user/host/riscv/host-signal.h b/linux-user/host/riscv/host-signal.h new file mode 100644 index 0000000000..f4b4d65031 --- /dev/null +++ b/linux-user/host/riscv/host-signal.h @@ -0,0 +1 @@ +#define HOST_SIGNAL_PLACEHOLDER diff --git a/linux-user/host/s390/host-signal.h b/linux-user/host/s390/host-signal.h new file mode 100644 index 0000000000..f4b4d65031 --- /dev/null +++ b/linux-user/host/s390/host-signal.h @@ -0,0 +1 @@ +#define HOST_SIGNAL_PLACEHOLDER diff --git a/linux-user/host/s390x/host-signal.h b/linux-user/host/s390x/host-signal.h new file mode 100644 index 0000000000..f4b4d65031 --- /dev/null +++ b/linux-user/host/s390x/host-signal.h @@ -0,0 +1 @@ +#define HOST_SIGNAL_PLACEHOLDER diff --git a/linux-user/host/sparc/host-signal.h b/linux-user/host/sparc/host-signal.h new file mode 100644 index 0000000000..f4b4d65031 --- /dev/null +++ b/linux-user/host/sparc/host-signal.h @@ -0,0 +1 @@ +#define HOST_SIGNAL_PLACEHOLDER diff --git a/linux-user/host/sparc64/host-signal.h b/linux-user/host/sparc64/host-signal.h new file mode 100644 index 0000000000..f4b4d65031 --- /dev/null +++ b/linux-user/host/sparc64/host-signal.h @@ -0,0 +1 @@ +#define HOST_SIGNAL_PLACEHOLDER diff --git a/linux-user/host/x32/host-signal.h b/linux-user/host/x32/host-signal.h new file mode 100644 index 0000000000..f4b4d65031 --- /dev/null +++ b/linux-user/host/x32/host-signal.h @@ -0,0 +1 @@ +#define HOST_SIGNAL_PLACEHOLDER diff --git a/linux-user/host/x86_64/host-signal.h b/linux-user/host/x86_64/host-signal.h new file mode 100644 index 0000000000..f4b4d65031 --- /dev/null +++ b/linux-user/host/x86_64/host-signal.h @@ -0,0 +1 @@ +#define HOST_SIGNAL_PLACEHOLDER diff --git a/linux-user/signal.c b/linux-user/signal.c index 5ea8e4584a..6f953f10d4 100644 --- a/linux-user/signal.c +++ b/linux-user/signal.c @@ -18,12 +18,15 @@ */ #include "qemu/osdep.h" #include "qemu/bitops.h" +#include "hw/core/tcg-cpu-ops.h" + #include <sys/ucontext.h> #include <sys/resource.h> #include "qemu.h" #include "trace.h" #include "signal-common.h" +#include "host-signal.h" static struct target_sigaction sigact_table[TARGET_NSIG]; @@ -761,41 +764,115 @@ static inline void rewind_if_in_safe_syscall(void *puc) } #endif -static void host_signal_handler(int host_signum, siginfo_t *info, - void *puc) +static void host_signal_handler(int host_sig, siginfo_t *info, void *puc) { CPUArchState *env = thread_cpu->env_ptr; CPUState *cpu = env_cpu(env); TaskState *ts = cpu->opaque; - - int sig; target_siginfo_t tinfo; ucontext_t *uc = puc; struct emulated_sigtable *k; + int guest_sig; +#ifdef HOST_SIGNAL_PLACEHOLDER /* the CPU emulator uses some host signals to detect exceptions, we forward to it some signals */ - if ((host_signum == SIGSEGV || host_signum == SIGBUS) + if ((host_sig == SIGSEGV || host_sig == SIGBUS) && info->si_code > 0) { - if (cpu_signal_handler(host_signum, info, puc)) + if (cpu_signal_handler(host_sig, info, puc)) return; } +#else + uintptr_t pc = 0; + bool sync_sig = false; + + /* + * Non-spoofed SIGSEGV and SIGBUS are synchronous, and need special + * handling wrt signal blocking and unwinding. + */ + if ((host_sig == SIGSEGV || host_sig == SIGBUS) && info->si_code > 0) { + MMUAccessType access_type; + uintptr_t host_addr; + abi_ptr guest_addr; + bool is_write; + + host_addr = (uintptr_t)info->si_addr; + + /* + * Convert forcefully to guest address space: addresses outside + * reserved_va are still valid to report via SEGV_MAPERR. + */ + guest_addr = h2g_nocheck(host_addr); + + pc = host_signal_pc(uc); + is_write = host_signal_write(info, uc); + access_type = adjust_signal_pc(&pc, is_write); + + if (host_sig == SIGSEGV) { + const struct TCGCPUOps *tcg_ops; + + if (info->si_code == SEGV_ACCERR && h2g_valid(host_addr)) { + /* If this was a write to a TB protected page, restart. */ + if (is_write && + handle_sigsegv_accerr_write(cpu, &uc->uc_sigmask, + pc, guest_addr)) { + return; + } + + /* + * With reserved_va, the whole address space is PROT_NONE, + * which means that we may get ACCERR when we want MAPERR. + */ + if (page_get_flags(guest_addr) & PAGE_VALID) { + /* maperr = false; */ + } else { + info->si_code = SEGV_MAPERR; + } + } + + sigprocmask(SIG_SETMASK, &uc->uc_sigmask, NULL); + + tcg_ops = CPU_GET_CLASS(cpu)->tcg_ops; + tcg_ops->tlb_fill(cpu, guest_addr, 0, access_type, + MMU_USER_IDX, false, pc); + g_assert_not_reached(); + } else { + sigprocmask(SIG_SETMASK, &uc->uc_sigmask, NULL); + } + + sync_sig = true; + } +#endif /* get target signal number */ - sig = host_to_target_signal(host_signum); - if (sig < 1 || sig > TARGET_NSIG) + guest_sig = host_to_target_signal(host_sig); + if (guest_sig < 1 || guest_sig > TARGET_NSIG) { return; - trace_user_host_signal(env, host_signum, sig); + } + trace_user_host_signal(env, host_sig, guest_sig); + + host_to_target_siginfo_noswap(&tinfo, info); + k = &ts->sigtab[guest_sig - 1]; + k->info = tinfo; + k->pending = guest_sig; + ts->signal_pending = 1; + +#ifndef HOST_SIGNAL_PLACEHOLDER + /* + * For synchronous signals, unwind the cpu state to the faulting + * insn and then exit back to the main loop so that the signal + * is delivered immediately. + */ + if (sync_sig) { + cpu->exception_index = EXCP_INTERRUPT; + cpu_loop_exit_restore(cpu, pc); + } +#endif rewind_if_in_safe_syscall(puc); - host_to_target_siginfo_noswap(&tinfo, info); - k = &ts->sigtab[sig - 1]; - k->info = tinfo; - k->pending = sig; - ts->signal_pending = 1; - - /* Block host signals until target signal handler entered. We + /* + * Block host signals until target signal handler entered. We * can't block SIGSEGV or SIGBUS while we're executing guest * code in case the guest code provokes one in the window between * now and it getting out to the main loop. Signals will be
Add stub host-signal.h for all linux-user hosts. Add new code replacing cpu_signal_handler. Full migration will happen one host at a time. Signed-off-by: Richard Henderson <richard.henderson@linaro.org> --- linux-user/host/aarch64/host-signal.h | 1 + linux-user/host/arm/host-signal.h | 1 + linux-user/host/i386/host-signal.h | 1 + linux-user/host/mips/host-signal.h | 1 + linux-user/host/ppc/host-signal.h | 1 + linux-user/host/ppc64/host-signal.h | 1 + linux-user/host/riscv/host-signal.h | 1 + linux-user/host/s390/host-signal.h | 1 + linux-user/host/s390x/host-signal.h | 1 + linux-user/host/sparc/host-signal.h | 1 + linux-user/host/sparc64/host-signal.h | 1 + linux-user/host/x32/host-signal.h | 1 + linux-user/host/x86_64/host-signal.h | 1 + linux-user/signal.c | 109 ++++++++++++++++++++++---- 14 files changed, 106 insertions(+), 16 deletions(-) create mode 100644 linux-user/host/aarch64/host-signal.h create mode 100644 linux-user/host/arm/host-signal.h create mode 100644 linux-user/host/i386/host-signal.h create mode 100644 linux-user/host/mips/host-signal.h create mode 100644 linux-user/host/ppc/host-signal.h create mode 100644 linux-user/host/ppc64/host-signal.h create mode 100644 linux-user/host/riscv/host-signal.h create mode 100644 linux-user/host/s390/host-signal.h create mode 100644 linux-user/host/s390x/host-signal.h create mode 100644 linux-user/host/sparc/host-signal.h create mode 100644 linux-user/host/sparc64/host-signal.h create mode 100644 linux-user/host/x32/host-signal.h create mode 100644 linux-user/host/x86_64/host-signal.h -- 2.25.1