Le 06/09/2019 à 18:57, Max Filippov a écrit :
> Xtensa binaries built for call0 ABI don't rotate register window on
> function calls and returns. Invocation of signal handlers from the
> kernel is therefore different in windowed and call0 ABIs.
> There's currently no way to determine xtensa ELF binary ABI from the
> binary itself. Add handler for the -xtensa-abi-call0 command line
> parameter/QEMU_XTENSA_ABI_CALL0 envitonment variable to the qemu-user
> and record ABI choice. Use it to initialize PS.WOE in xtensa_cpu_reset.
> Check PS.WOE in setup_rt_frame to determine how a signal should be
> delivered.
>
> Reviewed-by: Laurent Vivier <laur...@vivier.eu>
> Signed-off-by: Max Filippov <jcmvb...@gmail.com>
> ---
> linux-user/main.c | 11 +++++++++++
> linux-user/xtensa/signal.c | 25 +++++++++++++++++--------
> target/xtensa/cpu.c | 24 ++++++++++++++++++++----
> target/xtensa/cpu.h | 3 +++
> 4 files changed, 51 insertions(+), 12 deletions(-)
>
> diff --git a/linux-user/main.c b/linux-user/main.c
> index 47917bbb20fc..c9d97d2b1fc6 100644
> --- a/linux-user/main.c
> +++ b/linux-user/main.c
> @@ -393,6 +393,13 @@ static void handle_arg_trace(const char *arg)
> trace_file = trace_opt_parse(arg);
> }
>
> +#if defined(TARGET_XTENSA)
> +static void handle_arg_abi_call0(const char *arg)
> +{
> + xtensa_set_abi_call0();
> +}
> +#endif
> +
> struct qemu_argument {
> const char *argv;
> const char *env;
> @@ -446,6 +453,10 @@ static const struct qemu_argument arg_table[] = {
> "", "[[enable=]<pattern>][,events=<file>][,file=<file>]"},
> {"version", "QEMU_VERSION", false, handle_arg_version,
> "", "display version information and exit"},
> +#if defined(TARGET_XTENSA)
> + {"xtensa-abi-call0", "QEMU_XTENSA_ABI_CALL0", false,
> handle_arg_abi_call0,
> + "", "assume CALL0 Xtensa ABI"},
> +#endif
> {NULL, NULL, false, NULL, NULL, NULL}
> };
>
> diff --git a/linux-user/xtensa/signal.c b/linux-user/xtensa/signal.c
> index 8d54ef3ae34b..590f0313ffe9 100644
> --- a/linux-user/xtensa/signal.c
> +++ b/linux-user/xtensa/signal.c
> @@ -134,6 +134,8 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
> abi_ulong frame_addr;
> struct target_rt_sigframe *frame;
> uint32_t ra;
> + bool abi_call0;
> + unsigned base;
> int i;
>
> frame_addr = get_sigframe(ka, env, sizeof(*frame));
> @@ -182,20 +184,27 @@ void setup_rt_frame(int sig, struct target_sigaction
> *ka,
> __put_user(0x00, &frame->retcode[5]);
> #endif
> }
> - env->sregs[PS] = PS_UM | (3 << PS_RING_SHIFT);
> - if (xtensa_option_enabled(env->config, XTENSA_OPTION_WINDOWED_REGISTER))
> {
> - env->sregs[PS] |= PS_WOE | (1 << PS_CALLINC_SHIFT);
> - }
> memset(env->regs, 0, sizeof(env->regs));
> env->pc = ka->_sa_handler;
> env->regs[1] = frame_addr;
> env->sregs[WINDOW_BASE] = 0;
> env->sregs[WINDOW_START] = 1;
>
> - env->regs[4] = (ra & 0x3fffffff) | 0x40000000;
> - env->regs[6] = sig;
> - env->regs[7] = frame_addr + offsetof(struct target_rt_sigframe, info);
> - env->regs[8] = frame_addr + offsetof(struct target_rt_sigframe, uc);
> + abi_call0 = (env->sregs[PS] & PS_WOE) == 0;
> + env->sregs[PS] = PS_UM | (3 << PS_RING_SHIFT);
> +
> + if (abi_call0) {
> + base = 0;
> + env->regs[base] = ra;
> + } else {
> + env->sregs[PS] |= PS_WOE | (1 << PS_CALLINC_SHIFT);
> + base = 4;
> + env->regs[base] = (ra & 0x3fffffff) | 0x40000000;
> + }
> + env->regs[base + 2] = sig;
> + env->regs[base + 3] = frame_addr + offsetof(struct target_rt_sigframe,
> + info);
> + env->regs[base + 4] = frame_addr + offsetof(struct target_rt_sigframe,
> uc);
> unlock_user_struct(frame, frame_addr, 1);
> return;
>
> diff --git a/target/xtensa/cpu.c b/target/xtensa/cpu.c
> index 76db1741a796..c65dcf9dd782 100644
> --- a/target/xtensa/cpu.c
> +++ b/target/xtensa/cpu.c
> @@ -53,6 +53,20 @@ static bool xtensa_cpu_has_work(CPUState *cs)
> #endif
> }
>
> +#ifdef CONFIG_USER_ONLY
> +static bool abi_call0;
> +
> +void xtensa_set_abi_call0(void)
> +{
> + abi_call0 = true;
> +}
> +
> +bool xtensa_abi_call0(void)
> +{
> + return abi_call0;
> +}
> +#endif
> +
> /* CPUClass::reset() */
> static void xtensa_cpu_reset(CPUState *s)
> {
> @@ -70,10 +84,12 @@ static void xtensa_cpu_reset(CPUState *s)
> XTENSA_OPTION_INTERRUPT) ? 0x1f : 0x10;
> env->pending_irq_level = 0;
> #else
> - env->sregs[PS] =
> - (xtensa_option_enabled(env->config,
> - XTENSA_OPTION_WINDOWED_REGISTER) ? PS_WOE :
> 0) |
> - PS_UM | (3 << PS_RING_SHIFT);
> + env->sregs[PS] = PS_UM | (3 << PS_RING_SHIFT);
> + if (xtensa_option_enabled(env->config,
> + XTENSA_OPTION_WINDOWED_REGISTER) &&
> + !xtensa_abi_call0()) {
> + env->sregs[PS] |= PS_WOE;
> + }
> #endif
> env->sregs[VECBASE] = env->config->vecbase;
> env->sregs[IBREAKENABLE] = 0;
> diff --git a/target/xtensa/cpu.h b/target/xtensa/cpu.h
> index 0459243e6bb1..b363ffcf1066 100644
> --- a/target/xtensa/cpu.h
> +++ b/target/xtensa/cpu.h
> @@ -673,6 +673,9 @@ static inline MemoryRegion
> *xtensa_get_er_region(CPUXtensaState *env)
> {
> return env->system_er;
> }
> +#else
> +void xtensa_set_abi_call0(void);
> +bool xtensa_abi_call0(void);
> #endif
>
> static inline uint32_t xtensa_replicate_windowstart(CPUXtensaState *env)
>
Applied to my linux-user branch.
Thanks,
Laurent
