Re: [Qemu-devel] [PATCH v2 08/15] target/arm/arm-semi: Factor out implementation of SYS_WRITE

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 9/16/19 4:15 PM, Peter Maydell wrote:
> Factor out the implementation of SYS_WRITE via the
> new function tables.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

> ---
>   target/arm/arm-semi.c | 51 ++++++++++++++++++++++++++++---------------
>   1 file changed, 33 insertions(+), 18 deletions(-)
> 
> diff --git a/target/arm/arm-semi.c b/target/arm/arm-semi.c
> index e5f1e2aaaf2..c21cbb97bc1 100644
> --- a/target/arm/arm-semi.c
> +++ b/target/arm/arm-semi.c
> @@ -384,6 +384,8 @@ static target_ulong arm_gdb_syscall(ARMCPU *cpu, gdb_syscall_complete_cb cb,
>    * setting the guest errno if appropriate.
>    */
>   typedef uint32_t sys_closefn(ARMCPU *cpu, GuestFD *gf);
> +typedef uint32_t sys_writefn(ARMCPU *cpu, GuestFD *gf,
> +                             target_ulong buf, uint32_t len);
>   
>   static uint32_t host_closefn(ARMCPU *cpu, GuestFD *gf)
>   {
> @@ -392,21 +394,51 @@ static uint32_t host_closefn(ARMCPU *cpu, GuestFD *gf)
>       return set_swi_errno(env, close(gf->hostfd));
>   }
>   
> +static uint32_t host_writefn(ARMCPU *cpu, GuestFD *gf,
> +                             target_ulong buf, uint32_t len)
> +{
> +    uint32_t ret;
> +    CPUARMState *env = &cpu->env;
> +    char *s = lock_user(VERIFY_READ, buf, len, 1);
> +    if (!s) {
> +        /* Return bytes not written on error */
> +        return len;
> +    }
> +    ret = set_swi_errno(env, write(gf->hostfd, s, len));
> +    unlock_user(s, buf, 0);
> +    if (ret == (uint32_t)-1) {
> +        ret = 0;
> +    }
> +    /* Return bytes not written */
> +    return len - ret;
> +}
> +
>   static uint32_t gdb_closefn(ARMCPU *cpu, GuestFD *gf)
>   {
>       return arm_gdb_syscall(cpu, arm_semi_cb, "close,%x", gf->hostfd);
>   }
>   
> +static uint32_t gdb_writefn(ARMCPU *cpu, GuestFD *gf,
> +                            target_ulong buf, uint32_t len)
> +{
> +    arm_semi_syscall_len = len;
> +    return arm_gdb_syscall(cpu, arm_semi_cb, "write,%x,%x,%x",
> +                           gf->hostfd, buf, len);
> +}
> +
>   typedef struct GuestFDFunctions {
>       sys_closefn *closefn;
> +    sys_writefn *writefn;
>   } GuestFDFunctions;
>   
>   static const GuestFDFunctions guestfd_fns[] = {
>       [GuestFDHost] = {
>           .closefn = host_closefn,
> +        .writefn = host_writefn,
>       },
>       [GuestFDGDB] = {
>           .closefn = gdb_closefn,
> +        .writefn = gdb_writefn,
>       },
>   };
>   
> @@ -539,24 +571,7 @@ target_ulong do_arm_semihosting(CPUARMState *env)
>               return set_swi_errno(env, -1);
>           }
>   
> -        if (use_gdb_syscalls()) {
> -            arm_semi_syscall_len = len;
> -            return arm_gdb_syscall(cpu, arm_semi_cb, "write,%x,%x,%x",
> -                                   gf->hostfd, arg1, len);
> -        } else {
> -            s = lock_user(VERIFY_READ, arg1, len, 1);
> -            if (!s) {
> -                /* Return bytes not written on error */
> -                return len;
> -            }
> -            ret = set_swi_errno(env, write(gf->hostfd, s, len));
> -            unlock_user(s, arg1, 0);
> -            if (ret == (uint32_t)-1) {
> -                ret = 0;
> -            }
> -            /* Return bytes not written */
> -            return len - ret;
> -        }
> +        return guestfd_fns[gf->type].writefn(cpu, gf, arg1, len);
>       case TARGET_SYS_READ:
>           GET_ARG(0);
>           GET_ARG(1);
>