[Skiboot] [PATCH] core/init: remove master_cpu parameter

[Oliver O'Halloran]

On Tue, Sep 6, 2016 at 12:50 PM, Oliver O'Halloran <oohall at gmail.com> wrote:
> master_cpu is used to determine the ChipTOD master if no ChipTOD
> information is available in the HDAT. However, it is set to zero at every
> skiboot entry point (fdt_entry, the 0x180 FSP entry and
> opal_boot_trampoline) and is otherwise unused. This patch removes this
> passing around and uses the boot CPU PIR to find the ChipTOD master rather
> than zero.
>
> Signed-off-by: Oliver O'Halloran <oohall at gmail.com>
> ---
>  asm/head.S        |  5 -----
>  core/init.c       |  8 ++++----
>  hdata/spira.c     | 15 ++++++---------
>  include/skiboot.h |  2 +-
>  4 files changed, 11 insertions(+), 19 deletions(-)
>
> diff --git a/asm/head.S b/asm/head.S
> index 60bdbe8bba86..a4105ca4812b 100644
> --- a/asm/head.S
> +++ b/asm/head.S
> @@ -57,7 +57,6 @@ __head:
>  .global fdt_entry
>  fdt_entry:
>         mr      %r27,%r3
> -       li      %r25,0
>         b       boot_entry
>
>         /* This is a pointer to a descriptor used by debugging tools
> @@ -109,7 +108,6 @@ hir_trigger:
>         /* Entry point set by the FSP */
>         .= 0x180
>         li      %r27,0
> -       li      %r25,0
>         b       boot_entry
>
>  #define EXCEPTION(nr)          \
> @@ -249,7 +247,6 @@ boot_offset:
>   *   r28 :  PVR
>   *   r27 :  DTB pointer (or NULL)
>   *   r26 :  PIR thread mask
> - *   r25 :  Selected master CPU (OPAL boot)
>   */
>  .global boot_entry
>  boot_entry:
> @@ -390,7 +387,6 @@ boot_entry:
>  #endif
>         /* Jump to C */
>         mr      %r3,%r27
> -       mr      %r4,%r25
>         bl      main_cpu_entry
>         b       .
>
> @@ -819,7 +815,6 @@ opal_naca:
>          * got to the same entry we use for pHyp and FDT HB.
>          */
>  opal_boot_trampoline:
> -       li      %r25,0
>         li      %r27,-1
>         ba      boot_entry - __head
>
> diff --git a/core/init.c b/core/init.c
> index 821094fed1c1..4e2f2e56a60b 100644
> --- a/core/init.c
> +++ b/core/init.c
> @@ -620,9 +620,9 @@ static void copy_exception_vectors(void)
>         sync_icache();
>  }
>  /* Called from head.S, thus no prototype. */
> -void main_cpu_entry(const void *fdt, u32 master_cpu);
> +void __noreturn main_cpu_entry(const void *fdt);
>
> -void __noreturn __nomcount main_cpu_entry(const void *fdt, u32 master_cpu)
> +void __noreturn main_cpu_entry(const void *fdt)

This shouldn't strip __nomcount. I'll post a respin later.

>  {
>         /*
>          * WARNING: At this point. the timebases have
> @@ -683,10 +683,10 @@ void __noreturn __nomcount main_cpu_entry(const void *fdt, u32 master_cpu)
>          * is set to -1, we record that and pass it to parse_hdat
>          */
>         if (fdt == (void *)-1ul) {
> -               if (parse_hdat(true, master_cpu) < 0)
> +               if (parse_hdat(true) < 0)
>                         abort();
>         } else if (fdt == NULL) {
> -               if (parse_hdat(false, master_cpu) < 0)
> +               if (parse_hdat(false) < 0)
>                         abort();
>         } else {
>                 dt_expand(fdt);
> diff --git a/hdata/spira.c b/hdata/spira.c
> index e4e6b2d5830c..330108b1e577 100644
> --- a/hdata/spira.c
> +++ b/hdata/spira.c
> @@ -624,10 +624,10 @@ static bool add_chiptod_old(void)
>         return found;
>  }
>
> -static bool add_chiptod_new(uint32_t master_cpu)
> +static bool add_chiptod_new(void)
>  {
>         const void *hdif;
> -       unsigned int i, master_chip;
> +       unsigned int i;
>         bool found = false;
>
>         /*
> @@ -636,8 +636,6 @@ static bool add_chiptod_new(uint32_t master_cpu)
>         if (!get_hdif(&spira.ntuples.proc_chip, SPPCRD_HDIF_SIG))
>                 return found;
>
> -       master_chip = pir_to_chip_id(master_cpu);
> -
>         for_each_ntuple_idx(&spira.ntuples.proc_chip, hdif, i,
>                             SPPCRD_HDIF_SIG) {
>                 const struct sppcrd_chip_info *cinfo;
> @@ -668,12 +666,11 @@ static bool add_chiptod_new(uint32_t master_cpu)
>                 /* The FSP may strip the chiptod info from HDAT; if we find
>                  * a zero-ed out entry, assume that the chiptod is
>                  * present, but we don't have any primary/secondary info. In
> -                * this case, pick the primary based on the CPU that was
> -                * assigned master.
> +                * this case, pick chip zero as the master.
>                  */
>                 if (!size) {
>                         flags = CHIPTOD_ID_FLAGS_STATUS_OK;
> -                       if (be32_to_cpu(cinfo->xscom_id) == master_chip)
> +                       if (be32_to_cpu(cinfo->xscom_id) == 0x0)
>                                 flags |= CHIPTOD_ID_FLAGS_PRIMARY;
>                 }
>
> @@ -1092,7 +1089,7 @@ static void fixup_spira(void)
>         spira.ntuples.hs_data = spiras->ntuples.hs_data;
>  }
>
> -int parse_hdat(bool is_opal, uint32_t master_cpu)
> +int parse_hdat(bool is_opal)
>  {
>         cpu_type = PVR_TYPE(mfspr(SPR_PVR));
>
> @@ -1133,7 +1130,7 @@ int parse_hdat(bool is_opal, uint32_t master_cpu)
>         fsp_parse();
>
>         /* Add ChipTOD's */
> -       if (!add_chiptod_old() && !add_chiptod_new(master_cpu))
> +       if (!add_chiptod_old() && !add_chiptod_new())
>                 prerror("CHIPTOD: No ChipTOD found !\n");
>
>         /* Add NX */
> diff --git a/include/skiboot.h b/include/skiboot.h
> index 4ccf46d9e565..52a235b57beb 100644
> --- a/include/skiboot.h
> +++ b/include/skiboot.h
> @@ -175,7 +175,7 @@ extern void start_kernel32(uint64_t entry, void* fdt,
>  extern void start_kernel_secondary(uint64_t entry) __noreturn;
>
>  /* Get description of machine from HDAT and create device-tree */
> -extern int parse_hdat(bool is_opal, uint32_t master_cpu);
> +extern int parse_hdat(bool is_opal);
>
>  /* Root of device tree. */
>  extern struct dt_node *dt_root;
> --
> 2.5.5
>