[1/3] spapr: Small fixes to rtas_ibm_get_system_parameter, remove rtas_st_buffer
diff mbox

Message ID 1452906886-806-2-git-send-email-david@gibson.dropbear.id.au
State New
Headers show

Commit Message

David Gibson Jan. 16, 2016, 1:14 a.m. UTC
rtas_st_buffer() appears in spapr.h as though it were a widely used helper,
but in fact it is only used for saving data in a format used by
rtas_ibm_get_system_parameter().  We can fold it into that caller just as
simply.

While we're there fix a couple of small defects in
rtas_ibm_get_system_parameter:
  - For the string value SPLPAR_CHARACTERISTICS, it wasn't including the
    terminating \0 in the length which it should according to LoPAPR
    7.3.16.1
  - It now checks that the supplied buffer has at least enough space for
    the length of the returned data, and returns an error if it does not.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 hw/ppc/spapr_rtas.c    | 28 ++++++++++++++++++++--------
 include/hw/ppc/spapr.h | 11 -----------
 2 files changed, 20 insertions(+), 19 deletions(-)

Comments

Alexey Kardashevskiy Jan. 19, 2016, 2 a.m. UTC | #1
On 01/16/2016 12:14 PM, David Gibson wrote:
> rtas_st_buffer() appears in spapr.h as though it were a widely used helper,
> but in fact it is only used for saving data in a format used by
> rtas_ibm_get_system_parameter().  We can fold it into that caller just as
> simply.
>
> While we're there fix a couple of small defects in
> rtas_ibm_get_system_parameter:
>    - For the string value SPLPAR_CHARACTERISTICS, it wasn't including the
>      terminating \0 in the length which it should according to LoPAPR
>      7.3.16.1
>    - It now checks that the supplied buffer has at least enough space for
>      the length of the returned data, and returns an error if it does not.
>
> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> ---
>   hw/ppc/spapr_rtas.c    | 28 ++++++++++++++++++++--------
>   include/hw/ppc/spapr.h | 11 -----------
>   2 files changed, 20 insertions(+), 19 deletions(-)
>
> diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
> index 34b12a3..f4fb9ba 100644
> --- a/hw/ppc/spapr_rtas.c
> +++ b/hw/ppc/spapr_rtas.c
> @@ -235,9 +235,15 @@ static void rtas_ibm_get_system_parameter(PowerPCCPU *cpu,
>                                             uint32_t nret, target_ulong rets)
>   {
>       target_ulong parameter = rtas_ld(args, 0);
> -    target_ulong buffer = rtas_ld(args, 1);
> +    target_ulong buffer = ppc64_phys_to_real(rtas_ld(args, 1));
>       target_ulong length = rtas_ld(args, 2);
> -    target_ulong ret = RTAS_OUT_SUCCESS;
> +    void *val;
> +    size_t vallen;

Having such temporary variables (val/vallen) tells me that a helper is a 
better solution as this assumes that one word and one buffer will be ever 
enough for all cases but there is already "7.3.16.17 Processor Module 
Information" coming (even though I have not heard from Sukadev for quite 
some time) which is more complicated that this.

May be rtas_st_buffer() is not the best name and it does not have to be 
global so I'd propose making it static and calling it syspar_st().


> +
> +    if (length < 2) {
> +        rtas_st(rets, 0, -9999); /* Parameter error */


#define RTAS_OUT_SYSPAR_PARAM_ERROR -9999
and then
rtas_st(rets, 0, RTAS_OUT_SYSPAR_PARAM_ERROR);

?

In all other places ("rtas_st(\S\+, 0") a macro is used (except just one 
case in spapr_pci.c which needs a fix).


> +        return;
> +    }
>
>       switch (parameter) {
>       case RTAS_SYSPARM_SPLPAR_CHARACTERISTICS: {
> @@ -249,24 +255,30 @@ static void rtas_ibm_get_system_parameter(PowerPCCPU *cpu,
>                                             current_machine->ram_size / M_BYTE,
>                                             smp_cpus,
>                                             max_cpus);
> -        rtas_st_buffer(buffer, length, (uint8_t *)param_val, strlen(param_val));
> +        val = param_val;
> +        vallen = strlen(param_val) + 1;
>           g_free(param_val);
>           break;
>       }
>       case RTAS_SYSPARM_DIAGNOSTICS_RUN_MODE: {
> -        uint8_t param_val = DIAGNOSTICS_RUN_MODE_DISABLED;
> +        uint8_t diagnostics_run_mode = DIAGNOSTICS_RUN_MODE_DISABLED;
>
> -        rtas_st_buffer(buffer, length, &param_val, sizeof(param_val));
> +        val = &diagnostics_run_mode;


I know that any reasonable compiler will keep @diagnostics_run_mode on 
stack till return but it is still not clean...



> +        vallen = sizeof(diagnostics_run_mode);
>           break;
>       }
>       case RTAS_SYSPARM_UUID:
> -        rtas_st_buffer(buffer, length, qemu_uuid, (qemu_uuid_set ? 16 : 0));
> +        val = qemu_uuid;
> +        vallen = qemu_uuid_set ? 16 : 0;
>           break;
>       default:
> -        ret = RTAS_OUT_NOT_SUPPORTED;
> +        rtas_st(rets, 0, RTAS_OUT_NOT_SUPPORTED);
> +        return;
>       }
>
> -    rtas_st(rets, 0, ret);
> +    stw_be_phys(&address_space_memory, buffer, vallen);
> +    cpu_physical_memory_write(buffer + 2, val, MIN(vallen, length - 2));
> +    rtas_st(rets, 0, 0); /* Success */


rtas_st(rets, 0, RTAS_OUT_SUCCESS);



>   }
>
>   static void rtas_ibm_set_system_parameter(PowerPCCPU *cpu,
> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> index 53af76a..ec9e7ea 100644
> --- a/include/hw/ppc/spapr.h
> +++ b/include/hw/ppc/spapr.h
> @@ -513,17 +513,6 @@ static inline void rtas_st_buffer_direct(target_ulong phys,
>                                 MIN(buffer_len, phys_len));
>   }
>
> -static inline void rtas_st_buffer(target_ulong phys, target_ulong phys_len,
> -                                  uint8_t *buffer, uint16_t buffer_len)
> -{
> -    if (phys_len < 2) {
> -        return;
> -    }
> -    stw_be_phys(&address_space_memory,
> -                ppc64_phys_to_real(phys), buffer_len);
> -    rtas_st_buffer_direct(phys + 2, phys_len - 2, buffer, buffer_len);
> -}
> -
>   typedef void (*spapr_rtas_fn)(PowerPCCPU *cpu, sPAPRMachineState *sm,
>                                 uint32_t token,
>                                 uint32_t nargs, target_ulong args,
>
David Gibson Jan. 19, 2016, 3:56 a.m. UTC | #2
On Tue, Jan 19, 2016 at 01:00:50PM +1100, Alexey Kardashevskiy wrote:
> On 01/16/2016 12:14 PM, David Gibson wrote:
> >rtas_st_buffer() appears in spapr.h as though it were a widely used helper,
> >but in fact it is only used for saving data in a format used by
> >rtas_ibm_get_system_parameter().  We can fold it into that caller just as
> >simply.
> >
> >While we're there fix a couple of small defects in
> >rtas_ibm_get_system_parameter:
> >   - For the string value SPLPAR_CHARACTERISTICS, it wasn't including the
> >     terminating \0 in the length which it should according to LoPAPR
> >     7.3.16.1
> >   - It now checks that the supplied buffer has at least enough space for
> >     the length of the returned data, and returns an error if it does not.
> >
> >Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> >---
> >  hw/ppc/spapr_rtas.c    | 28 ++++++++++++++++++++--------
> >  include/hw/ppc/spapr.h | 11 -----------
> >  2 files changed, 20 insertions(+), 19 deletions(-)
> >
> >diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
> >index 34b12a3..f4fb9ba 100644
> >--- a/hw/ppc/spapr_rtas.c
> >+++ b/hw/ppc/spapr_rtas.c
> >@@ -235,9 +235,15 @@ static void rtas_ibm_get_system_parameter(PowerPCCPU *cpu,
> >                                            uint32_t nret, target_ulong rets)
> >  {
> >      target_ulong parameter = rtas_ld(args, 0);
> >-    target_ulong buffer = rtas_ld(args, 1);
> >+    target_ulong buffer = ppc64_phys_to_real(rtas_ld(args, 1));
> >      target_ulong length = rtas_ld(args, 2);
> >-    target_ulong ret = RTAS_OUT_SUCCESS;
> >+    void *val;
> >+    size_t vallen;
> 
> Having such temporary variables (val/vallen) tells me that a helper is a
> better solution as this assumes that one word and one buffer will be ever
> enough for all cases but there is already "7.3.16.17 Processor Module
> Information" coming (even though I have not heard from Sukadev for quite
> some time) which is more complicated that this.

Actually latest discussions with Sukadev and the RH licensing people
suggest we won't need that after all.  But still, point taken.

> May be rtas_st_buffer() is not the best name and it does not have to be
> global so I'd propose making it static and calling it syspar_st().

Ok, that works for me.

> 
> 
> >+
> >+    if (length < 2) {
> >+        rtas_st(rets, 0, -9999); /* Parameter error */
> 
> 
> #define RTAS_OUT_SYSPAR_PARAM_ERROR -9999
> and then
> rtas_st(rets, 0, RTAS_OUT_SYSPAR_PARAM_ERROR);
> 
> ?

Hm, ok.  I'm not entirely sold on the need, since most RTAS return
values are specific to individual RTAS calls, and they're not given
symbolic names by PAPR.  Still, why not.

> 
> In all other places ("rtas_st(\S\+, 0") a macro is used (except just one
> case in spapr_pci.c which needs a fix).
> 
> 
> >+        return;
> >+    }
> >
> >      switch (parameter) {
> >      case RTAS_SYSPARM_SPLPAR_CHARACTERISTICS: {
> >@@ -249,24 +255,30 @@ static void rtas_ibm_get_system_parameter(PowerPCCPU *cpu,
> >                                            current_machine->ram_size / M_BYTE,
> >                                            smp_cpus,
> >                                            max_cpus);
> >-        rtas_st_buffer(buffer, length, (uint8_t *)param_val, strlen(param_val));
> >+        val = param_val;
> >+        vallen = strlen(param_val) + 1;
> >          g_free(param_val);
> >          break;
> >      }
> >      case RTAS_SYSPARM_DIAGNOSTICS_RUN_MODE: {
> >-        uint8_t param_val = DIAGNOSTICS_RUN_MODE_DISABLED;
> >+        uint8_t diagnostics_run_mode = DIAGNOSTICS_RUN_MODE_DISABLED;
> >
> >-        rtas_st_buffer(buffer, length, &param_val, sizeof(param_val));
> >+        val = &diagnostics_run_mode;
> 
> 
> I know that any reasonable compiler will keep @diagnostics_run_mode on stack
> till return but it is still not clean...

For a minute I didn't see what you were getting at, then realized that
diagnostics_run_mode is in a different scope from the final store.

Yeah, that's not ok.

> 
> 
> 
> >+        vallen = sizeof(diagnostics_run_mode);
> >          break;
> >      }
> >      case RTAS_SYSPARM_UUID:
> >-        rtas_st_buffer(buffer, length, qemu_uuid, (qemu_uuid_set ? 16 : 0));
> >+        val = qemu_uuid;
> >+        vallen = qemu_uuid_set ? 16 : 0;
> >          break;
> >      default:
> >-        ret = RTAS_OUT_NOT_SUPPORTED;
> >+        rtas_st(rets, 0, RTAS_OUT_NOT_SUPPORTED);
> >+        return;
> >      }
> >
> >-    rtas_st(rets, 0, ret);
> >+    stw_be_phys(&address_space_memory, buffer, vallen);
> >+    cpu_physical_memory_write(buffer + 2, val, MIN(vallen, length - 2));
> >+    rtas_st(rets, 0, 0); /* Success */
> 
> 
> rtas_st(rets, 0, RTAS_OUT_SUCCESS);
> 
> 
> 
> >  }
> >
> >  static void rtas_ibm_set_system_parameter(PowerPCCPU *cpu,
> >diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> >index 53af76a..ec9e7ea 100644
> >--- a/include/hw/ppc/spapr.h
> >+++ b/include/hw/ppc/spapr.h
> >@@ -513,17 +513,6 @@ static inline void rtas_st_buffer_direct(target_ulong phys,
> >                                MIN(buffer_len, phys_len));
> >  }
> >
> >-static inline void rtas_st_buffer(target_ulong phys, target_ulong phys_len,
> >-                                  uint8_t *buffer, uint16_t buffer_len)
> >-{
> >-    if (phys_len < 2) {
> >-        return;
> >-    }
> >-    stw_be_phys(&address_space_memory,
> >-                ppc64_phys_to_real(phys), buffer_len);
> >-    rtas_st_buffer_direct(phys + 2, phys_len - 2, buffer, buffer_len);
> >-}
> >-
> >  typedef void (*spapr_rtas_fn)(PowerPCCPU *cpu, sPAPRMachineState *sm,
> >                                uint32_t token,
> >                                uint32_t nargs, target_ulong args,
> >
> 
>

Patch
diff mbox

diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
index 34b12a3..f4fb9ba 100644
--- a/hw/ppc/spapr_rtas.c
+++ b/hw/ppc/spapr_rtas.c
@@ -235,9 +235,15 @@  static void rtas_ibm_get_system_parameter(PowerPCCPU *cpu,
                                           uint32_t nret, target_ulong rets)
 {
     target_ulong parameter = rtas_ld(args, 0);
-    target_ulong buffer = rtas_ld(args, 1);
+    target_ulong buffer = ppc64_phys_to_real(rtas_ld(args, 1));
     target_ulong length = rtas_ld(args, 2);
-    target_ulong ret = RTAS_OUT_SUCCESS;
+    void *val;
+    size_t vallen;
+
+    if (length < 2) {
+        rtas_st(rets, 0, -9999); /* Parameter error */
+        return;
+    }
 
     switch (parameter) {
     case RTAS_SYSPARM_SPLPAR_CHARACTERISTICS: {
@@ -249,24 +255,30 @@  static void rtas_ibm_get_system_parameter(PowerPCCPU *cpu,
                                           current_machine->ram_size / M_BYTE,
                                           smp_cpus,
                                           max_cpus);
-        rtas_st_buffer(buffer, length, (uint8_t *)param_val, strlen(param_val));
+        val = param_val;
+        vallen = strlen(param_val) + 1;
         g_free(param_val);
         break;
     }
     case RTAS_SYSPARM_DIAGNOSTICS_RUN_MODE: {
-        uint8_t param_val = DIAGNOSTICS_RUN_MODE_DISABLED;
+        uint8_t diagnostics_run_mode = DIAGNOSTICS_RUN_MODE_DISABLED;
 
-        rtas_st_buffer(buffer, length, &param_val, sizeof(param_val));
+        val = &diagnostics_run_mode;
+        vallen = sizeof(diagnostics_run_mode);
         break;
     }
     case RTAS_SYSPARM_UUID:
-        rtas_st_buffer(buffer, length, qemu_uuid, (qemu_uuid_set ? 16 : 0));
+        val = qemu_uuid;
+        vallen = qemu_uuid_set ? 16 : 0;
         break;
     default:
-        ret = RTAS_OUT_NOT_SUPPORTED;
+        rtas_st(rets, 0, RTAS_OUT_NOT_SUPPORTED);
+        return;
     }
 
-    rtas_st(rets, 0, ret);
+    stw_be_phys(&address_space_memory, buffer, vallen);
+    cpu_physical_memory_write(buffer + 2, val, MIN(vallen, length - 2));
+    rtas_st(rets, 0, 0); /* Success */
 }
 
 static void rtas_ibm_set_system_parameter(PowerPCCPU *cpu,
diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index 53af76a..ec9e7ea 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -513,17 +513,6 @@  static inline void rtas_st_buffer_direct(target_ulong phys,
                               MIN(buffer_len, phys_len));
 }
 
-static inline void rtas_st_buffer(target_ulong phys, target_ulong phys_len,
-                                  uint8_t *buffer, uint16_t buffer_len)
-{
-    if (phys_len < 2) {
-        return;
-    }
-    stw_be_phys(&address_space_memory,
-                ppc64_phys_to_real(phys), buffer_len);
-    rtas_st_buffer_direct(phys + 2, phys_len - 2, buffer, buffer_len);
-}
-
 typedef void (*spapr_rtas_fn)(PowerPCCPU *cpu, sPAPRMachineState *sm,
                               uint32_t token,
                               uint32_t nargs, target_ulong args,