diff mbox series

[RFC,2/7] accel/tcg: Split out adjust_signal_pc

Message ID 20210913220552.604064-3-richard.henderson@linaro.org
State New
Headers show
Series linux-user: Streamline handling of SIGSEGV/SIGBUS | expand

Commit Message

Richard Henderson Sept. 13, 2021, 10:05 p.m. UTC 
Split out a function to adjust the raw signal pc into a
value that could be passed to cpu_restore_state.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

---
 include/exec/exec-all.h |  8 +++++++
 accel/tcg/user-exec.c   | 50 ++++++++++++++++++++++++++---------------
 2 files changed, 40 insertions(+), 18 deletions(-)

-- 
2.25.1

Comments

Philippe Mathieu-Daudé Sept. 14, 2021, 6:07 a.m. UTC | #1 
On 9/14/21 12:05 AM, Richard Henderson wrote:
> Split out a function to adjust the raw signal pc into a

> value that could be passed to cpu_restore_state.

> 

> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

> ---

>  include/exec/exec-all.h |  8 +++++++

>  accel/tcg/user-exec.c   | 50 ++++++++++++++++++++++++++---------------

>  2 files changed, 40 insertions(+), 18 deletions(-)


> -/* 'pc' is the host PC at which the exception was raised. 'address' is

> -   the effective address of the memory exception. 'is_write' is 1 if a

> -   write caused the exception and otherwise 0'. 'old_set' is the

> -   signal set which should be restored */

> -static inline int handle_cpu_signal(uintptr_t pc, siginfo_t *info,

> -                                    int is_write, sigset_t *old_set)


> +/* 'pc' is the host PC at which the exception was raised. 'address' is

> +   the effective address of the memory exception. 'is_write' is 1 if a

> +   write caused the exception and otherwise 0'. 'old_set' is the

> +   signal set which should be restored */

Pre-existing extra "'" in "otherwise 0."

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
diff mbox series

Patch

diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h
index 9d5987ba04..7207912306 100644
--- a/include/exec/exec-all.h
+++ b/include/exec/exec-all.h
@@ -663,6 +663,14 @@  static inline tb_page_addr_t get_page_addr_code_hostp(CPUArchState *env,
     return addr;
 }
 
+/**
+ * adjust_signal_pc:
+ * @pc: raw pc from the host signal ucontext_t.
+ *
+ * Return the pc to pass to cpu_restore_state.
+ */
+uintptr_t adjust_signal_pc(uintptr_t pc);
+
 /**
  * cpu_signal_handler
  * @signum: host signal number
diff --git a/accel/tcg/user-exec.c b/accel/tcg/user-exec.c
index 8fed542622..1f7b7a3692 100644
--- a/accel/tcg/user-exec.c
+++ b/accel/tcg/user-exec.c
@@ -57,18 +57,14 @@  static void QEMU_NORETURN cpu_exit_tb_from_sighandler(CPUState *cpu,
     cpu_loop_exit_noexc(cpu);
 }
 
-/* 'pc' is the host PC at which the exception was raised. 'address' is
-   the effective address of the memory exception. 'is_write' is 1 if a
-   write caused the exception and otherwise 0'. 'old_set' is the
-   signal set which should be restored */
-static inline int handle_cpu_signal(uintptr_t pc, siginfo_t *info,
-                                    int is_write, sigset_t *old_set)
+/**
+ * adjust_signal_pc:
+ * @pc: raw pc from the host signal ucontext_t.
+ *
+ * Return the pc to pass to cpu_restore_state.
+ */
+uintptr_t adjust_signal_pc(uintptr_t pc)
 {
-    CPUState *cpu = current_cpu;
-    CPUClass *cc;
-    unsigned long address = (unsigned long)info->si_addr;
-    MMUAccessType access_type = is_write ? MMU_DATA_STORE : MMU_DATA_LOAD;
-
     switch (helper_retaddr) {
     default:
         /*
@@ -77,8 +73,7 @@  static inline int handle_cpu_signal(uintptr_t pc, siginfo_t *info,
          * pointer into the generated code that will unwind to the
          * correct guest pc.
          */
-        pc = helper_retaddr;
-        break;
+        return helper_retaddr;
 
     case 0:
         /*
@@ -97,8 +92,7 @@  static inline int handle_cpu_signal(uintptr_t pc, siginfo_t *info,
          * Therefore, adjust to compensate for what will be done later
          * by cpu_restore_state_from_tb.
          */
-        pc += GETPC_ADJ;
-        break;
+        return pc + GETPC_ADJ;
 
     case 1:
         /*
@@ -113,11 +107,31 @@  static inline int handle_cpu_signal(uintptr_t pc, siginfo_t *info,
          *
          * Like tb_gen_code, release the memory lock before cpu_loop_exit.
          */
-        pc = 0;
-        access_type = MMU_INST_FETCH;
         mmap_unlock();
-        break;
+        return 0;
     }
+}
+
+/* 'pc' is the host PC at which the exception was raised. 'address' is
+   the effective address of the memory exception. 'is_write' is 1 if a
+   write caused the exception and otherwise 0'. 'old_set' is the
+   signal set which should be restored */
+static inline int handle_cpu_signal(uintptr_t pc, siginfo_t *info,
+                                    int is_write, sigset_t *old_set)
+{
+    CPUState *cpu = current_cpu;
+    CPUClass *cc;
+    unsigned long address = (unsigned long)info->si_addr;
+    MMUAccessType access_type;
+
+    if (is_write) {
+        access_type = MMU_DATA_STORE;
+    } else if (helper_retaddr == 1) {
+        access_type = MMU_INST_FETCH;
+    } else {
+        access_type = MMU_DATA_LOAD;
+    }
+    pc = adjust_signal_pc(pc);
 
     /* For synchronous signals we expect to be coming from the vCPU
      * thread (so current_cpu should be valid) and either from running