On Sun, Sep 19, 2021 at 4:55 AM Richard Henderson
<richard.hender...@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.hender...@linaro.org>
Acked-by: Alistair Francis <alistair.fran...@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
>
>
