1. Patchew
  2. QEMU
  3. [PATCH v3 00/49] semihosting cleanup
  4. View patch

[PATCH v3 08/49] semihosting: Inline set_swi_errno into common_semi_cb

Richard Henderson posted 49 patches 3 years, 1 month ago
There is a newer version of this series
[PATCH v3 08/49] semihosting: Inline set_swi_errno into common_semi_cb
Posted by Richard Henderson 3 years, 1 month ago 
Do not store 'err' into errno only to read it back immediately.
Use 'ret' for the return value, not 'reg0'.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 semihosting/arm-compat-semi.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/semihosting/arm-compat-semi.c b/semihosting/arm-compat-semi.c
index c6bfd4d1ba..b00ed2c6d1 100644
--- a/semihosting/arm-compat-semi.c
+++ b/semihosting/arm-compat-semi.c
@@ -290,28 +290,29 @@ static target_ulong common_semi_syscall_len;
 
 static void common_semi_cb(CPUState *cs, target_ulong ret, target_ulong err)
 {
-    target_ulong reg0 = common_semi_arg(cs, 0);
-
     if (ret == (target_ulong)-1) {
-        errno = err;
-        set_swi_errno(cs, -1);
-        reg0 = ret;
+#ifdef CONFIG_USER_ONLY
+        TaskState *ts = cs->opaque;
+        ts->swi_errno = err;
+#else
+        syscall_err = err;
+#endif
     } else {
         /* Fixup syscalls that use nonstardard return conventions.  */
+        target_ulong reg0 = common_semi_arg(cs, 0);
         switch (reg0) {
         case TARGET_SYS_WRITE:
         case TARGET_SYS_READ:
-            reg0 = common_semi_syscall_len - ret;
+            ret = common_semi_syscall_len - ret;
             break;
         case TARGET_SYS_SEEK:
-            reg0 = 0;
+            ret = 0;
             break;
         default:
-            reg0 = ret;
             break;
         }
     }
-    common_semi_set_ret(cs, reg0);
+    common_semi_set_ret(cs, ret);
 }
 
 static target_ulong common_semi_flen_buf(CPUState *cs)
-- 
2.34.1
Re: [PATCH v3 08/49] semihosting: Inline set_swi_errno into common_semi_cb
Posted by Peter Maydell 3 years, 1 month ago 
On Sat, 21 May 2022 at 01:04, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> Do not store 'err' into errno only to read it back immediately.
> Use 'ret' for the return value, not 'reg0'.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  semihosting/arm-compat-semi.c | 19 ++++++++++---------
>  1 file changed, 10 insertions(+), 9 deletions(-)
>
> diff --git a/semihosting/arm-compat-semi.c b/semihosting/arm-compat-semi.c
> index c6bfd4d1ba..b00ed2c6d1 100644
> --- a/semihosting/arm-compat-semi.c
> +++ b/semihosting/arm-compat-semi.c
> @@ -290,28 +290,29 @@ static target_ulong common_semi_syscall_len;
>
>  static void common_semi_cb(CPUState *cs, target_ulong ret, target_ulong err)
>  {
> -    target_ulong reg0 = common_semi_arg(cs, 0);
> -
>      if (ret == (target_ulong)-1) {
> -        errno = err;
> -        set_swi_errno(cs, -1);
> -        reg0 = ret;
> +#ifdef CONFIG_USER_ONLY
> +        TaskState *ts = cs->opaque;
> +        ts->swi_errno = err;
> +#else
> +        syscall_err = err;
> +#endif
>      } else {
>          /* Fixup syscalls that use nonstardard return conventions.  */
> +        target_ulong reg0 = common_semi_arg(cs, 0);

This should be "ret = ", right? (Otherwise I think this fails to
compile. I assume that some later patch has this fix in it.)

Otherwise
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

thanks
-- PMM
Re: [PATCH v3 08/49] semihosting: Inline set_swi_errno into common_semi_cb
Posted by Richard Henderson 3 years, 1 month ago 
On 5/23/22 03:58, Peter Maydell wrote:
> On Sat, 21 May 2022 at 01:04, Richard Henderson
> <richard.henderson@linaro.org> wrote:
>>
>> Do not store 'err' into errno only to read it back immediately.
>> Use 'ret' for the return value, not 'reg0'.
>>
>> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
>> ---
>>   semihosting/arm-compat-semi.c | 19 ++++++++++---------
>>   1 file changed, 10 insertions(+), 9 deletions(-)
>>
>> diff --git a/semihosting/arm-compat-semi.c b/semihosting/arm-compat-semi.c
>> index c6bfd4d1ba..b00ed2c6d1 100644
>> --- a/semihosting/arm-compat-semi.c
>> +++ b/semihosting/arm-compat-semi.c
>> @@ -290,28 +290,29 @@ static target_ulong common_semi_syscall_len;
>>
>>   static void common_semi_cb(CPUState *cs, target_ulong ret, target_ulong err)
>>   {
>> -    target_ulong reg0 = common_semi_arg(cs, 0);
>> -
>>       if (ret == (target_ulong)-1) {
>> -        errno = err;
>> -        set_swi_errno(cs, -1);
>> -        reg0 = ret;
>> +#ifdef CONFIG_USER_ONLY
>> +        TaskState *ts = cs->opaque;
>> +        ts->swi_errno = err;
>> +#else
>> +        syscall_err = err;
>> +#endif
>>       } else {
>>           /* Fixup syscalls that use nonstardard return conventions.  */
>> +        target_ulong reg0 = common_semi_arg(cs, 0);
> 
> This should be "ret = ", right? (Otherwise I think this fails to
> compile. I assume that some later patch has this fix in it.)

Eh?  No, we're extracting argument reg 0, and then switching on it.
Why would it not compile -- I've moved the whole declaration down.


r~


> 
> Otherwise
> Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
> 
> thanks
> -- PMM
Re: [PATCH v3 08/49] semihosting: Inline set_swi_errno into common_semi_cb
Posted by Peter Maydell 3 years, 1 month ago 
On Mon, 23 May 2022 at 15:58, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> On 5/23/22 03:58, Peter Maydell wrote:
> > On Sat, 21 May 2022 at 01:04, Richard Henderson
> > <richard.henderson@linaro.org> wrote:
> >>
> >> Do not store 'err' into errno only to read it back immediately.
> >> Use 'ret' for the return value, not 'reg0'.
> >>
> >> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> >> ---
> >>   semihosting/arm-compat-semi.c | 19 ++++++++++---------
> >>   1 file changed, 10 insertions(+), 9 deletions(-)
> >>
> >> diff --git a/semihosting/arm-compat-semi.c b/semihosting/arm-compat-semi.c
> >> index c6bfd4d1ba..b00ed2c6d1 100644
> >> --- a/semihosting/arm-compat-semi.c
> >> +++ b/semihosting/arm-compat-semi.c
> >> @@ -290,28 +290,29 @@ static target_ulong common_semi_syscall_len;
> >>
> >>   static void common_semi_cb(CPUState *cs, target_ulong ret, target_ulong err)
> >>   {
> >> -    target_ulong reg0 = common_semi_arg(cs, 0);
> >> -
> >>       if (ret == (target_ulong)-1) {
> >> -        errno = err;
> >> -        set_swi_errno(cs, -1);
> >> -        reg0 = ret;
> >> +#ifdef CONFIG_USER_ONLY
> >> +        TaskState *ts = cs->opaque;
> >> +        ts->swi_errno = err;
> >> +#else
> >> +        syscall_err = err;
> >> +#endif
> >>       } else {
> >>           /* Fixup syscalls that use nonstardard return conventions.  */
> >> +        target_ulong reg0 = common_semi_arg(cs, 0);
> >
> > This should be "ret = ", right? (Otherwise I think this fails to
> > compile. I assume that some later patch has this fix in it.)
>
> Eh?  No, we're extracting argument reg 0, and then switching on it.
> Why would it not compile -- I've moved the whole declaration down.

Yes, you're right -- I misread the diff as doing a rename of
'reg0' to 'ret', but these are different variables and both
present both before and after the change.

-- PMM

Patchew 2.1-devel-8c64711

© 2016 - 2025 Red Hat, Inc.