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 <da...@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, ¶m_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,
> >
>
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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