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[Qemu-devel] [PATCH v4] target/xtensa: linux-user: add call0 ABI support

Max Filippov posted 1 patch 4 years, 7 months ago
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git fetch https://github.com/patchew-project/qemu tags/patchew/20190906165713.5558-1-jcmvbkbc@gmail.com
Maintainers: Riku Voipio <riku.voipio@iki.fi>, Max Filippov <jcmvbkbc@gmail.com>, Laurent Vivier <laurent@vivier.eu>
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(-)
[Qemu-devel] [PATCH v4] target/xtensa: linux-user: add call0 ABI support
Posted by Max Filippov 4 years, 7 months ago 
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 <laurent@vivier.eu>
Signed-off-by: Max Filippov <jcmvbkbc@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)
-- 
2.11.0
Re: [Qemu-devel] [PATCH v4] target/xtensa: linux-user: add call0 ABI support
Posted by Laurent Vivier 4 years, 7 months ago 
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 <laurent@vivier.eu>
> Signed-off-by: Max Filippov <jcmvbkbc@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

Patchew 2.1-devel-0870f84

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