Re: [Qemu-devel] [PATCH 07/14] Avoid declaring the env variable at all if CONFIG_TCG_PASS_AREG0.

[Blue Swirl]

On Wed, Mar 28, 2012 at 00:32, Richard Henderson <address@hidden> wrote:
> At the same time, remove use of the global ENV from user-exec.c.
>
> Signed-off-by: Richard Henderson <address@hidden>
> ---
>  Makefile.target |    5 -----
>  dyngen-exec.h   |    5 +++++
>  user-exec.c     |   17 ++++++-----------
>  3 files changed, 11 insertions(+), 16 deletions(-)
>
> diff --git a/Makefile.target b/Makefile.target
> index aa53e28..81fdf9e 100644
> --- a/Makefile.target
> +++ b/Makefile.target
> @@ -110,11 +110,6 @@ $(libobj-y): $(GENERATED_HEADERS)
>  ifndef CONFIG_TCG_PASS_AREG0
>  op_helper.o: QEMU_CFLAGS += $(HELPER_CFLAGS)
>  endif
> -user-exec.o: QEMU_CFLAGS += $(HELPER_CFLAGS)
> -
> -# Note: this is a workaround. The real fix is to avoid compiling
> -# cpu_signal_handler() in user-exec.c.
> -signal.o: QEMU_CFLAGS += $(HELPER_CFLAGS)

The patch does not apply, please rebase.
Applying: Avoid declaring the env variable at all if CONFIG_TCG_PASS_AREG0.
error: patch failed: Makefile.target:110
error: Makefile.target: patch does not apply

>
>  #########################################################
>  # Linux user emulator target
> diff --git a/dyngen-exec.h b/dyngen-exec.h
> index cfeef99..65fcb43 100644
> --- a/dyngen-exec.h
> +++ b/dyngen-exec.h
> @@ -19,6 +19,10 @@
>  #if !defined(__DYNGEN_EXEC_H__)
>  #define __DYNGEN_EXEC_H__
>
> +/* If the target has indicated that it does not need an AREG0,
> +   don't declare the env variable at all, much less as a register.  */
> +#if !defined(CONFIG_TCG_PASS_AREG0)
> +
>  #if defined(CONFIG_TCG_INTERPRETER)
>  /* The TCG interpreter does not need a special register AREG0,
>  * but it is possible to use one by defining AREG0.
> @@ -65,4 +69,5 @@ register CPUArchState *env asm(AREG0);
>  extern CPUArchState *env;
>  #endif
>
> +#endif /* !CONFIG_TCG_PASS_AREG0 */
>  #endif /* !defined(__DYNGEN_EXEC_H__) */
> diff --git a/user-exec.c b/user-exec.c
> index cd905ff..9691f09 100644
> --- a/user-exec.c
> +++ b/user-exec.c
> @@ -18,7 +18,6 @@
>  */
>  #include "config.h"
>  #include "cpu.h"
> -#include "dyngen-exec.h"
>  #include "disas.h"
>  #include "tcg.h"
>
> @@ -58,8 +57,6 @@ void cpu_resume_from_signal(CPUArchState *env1, void *puc)
>     struct sigcontext *uc = puc;
>  #endif
>
> -    env = env1;
> -
>     /* XXX: restore cpu registers saved in host registers */
>
>     if (puc) {
> @@ -74,8 +71,8 @@ void cpu_resume_from_signal(CPUArchState *env1, void *puc)
>         sigprocmask(SIG_SETMASK, &uc->sc_mask, NULL);
>  #endif
>     }
> -    env->exception_index = -1;
> -    longjmp(env->jmp_env, 1);
> +    env1->exception_index = -1;
> +    longjmp(env1->jmp_env, 1);
>  }
>
>  /* 'pc' is the host PC at which the exception was raised. 'address' is
> @@ -86,12 +83,10 @@ static inline int handle_cpu_signal(unsigned long pc, 
> unsigned long address,
>                                     int is_write, sigset_t *old_set,
>                                     void *puc)
>  {
> +    CPUArchState *env1 = cpu_single_env;
>     TranslationBlock *tb;
>     int ret;
>
> -    if (cpu_single_env) {
> -        env = cpu_single_env; /* XXX: find a correct solution for 
> multithread */
> -    }
>  #if defined(DEBUG_SIGNAL)
>     qemu_printf("qemu: SIGSEGV pc=0x%08lx address=%08lx w=%d 
> oldset=0x%08lx\n",
>                 pc, address, is_write, *(unsigned long *)old_set);
> @@ -102,7 +97,7 @@ static inline int handle_cpu_signal(unsigned long pc, 
> unsigned long address,
>     }
>
>     /* see if it is an MMU fault */
> -    ret = cpu_handle_mmu_fault(env, address, is_write, MMU_USER_IDX);
> +    ret = cpu_handle_mmu_fault(env1, address, is_write, MMU_USER_IDX);
>     if (ret < 0) {
>         return 0; /* not an MMU fault */
>     }
> @@ -114,13 +109,13 @@ static inline int handle_cpu_signal(unsigned long pc, 
> unsigned long address,
>     if (tb) {
>         /* the PC is inside the translated code. It means that we have
>            a virtual CPU fault */
> -        cpu_restore_state(tb, env, pc);
> +        cpu_restore_state(tb, env1, pc);
>     }
>
>     /* we restore the process signal mask as the sigreturn should
>        do it (XXX: use sigsetjmp) */
>     sigprocmask(SIG_SETMASK, old_set, NULL);
> -    exception_action(env);
> +    exception_action(env1);
>
>     /* never comes here */
>     return 1;
> --
> 1.7.7.6
>