[Skiboot] [PATCH] Add OPAL_GET_SYMBOL / OPAL_LOOKUP_SYMBOL

Oliver O'Halloran oohall at gmail.com
Fri Mar 6 13:42:58 AEDT 2020


On Fri, Feb 28, 2020 at 2:09 PM Nicholas Piggin <npiggin at gmail.com> wrote:
>
> These calls can be used by Linux to annotate BUG addresses with symbols,
> look up symbol addresses in xmon, etc.
>
> This is preferable over having Linux parse the OPAL symbol map itself,
> because OPAL's parsing code already exists for its own symbol printing,
> and it can support other code regions than the skiboot symbols, e.g.,
> the wake-up code in the HOMER (where CPUs have been seen to get stuck).
>
> Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
> ---
>  core/opal.c                             |  2 +
>  core/utils.c                            | 92 +++++++++++++++++++++++--
>  doc/opal-api/opal-get-symbol-181.rst    | 42 +++++++++++
>  doc/opal-api/opal-lookup-symbol-182.rst | 35 ++++++++++
>  include/opal-api.h                      |  4 +-
>  5 files changed, 168 insertions(+), 7 deletions(-)
>  create mode 100644 doc/opal-api/opal-get-symbol-181.rst
>  create mode 100644 doc/opal-api/opal-lookup-symbol-182.rst
>
> diff --git a/core/opal.c b/core/opal.c
> index d6ff6027b..d9fc4fe05 100644
> --- a/core/opal.c
> +++ b/core/opal.c
> @@ -142,6 +142,8 @@ int64_t opal_entry_check(struct stack_frame *eframe)
>                 case OPAL_CEC_REBOOT:
>                 case OPAL_CEC_REBOOT2:
>                 case OPAL_SIGNAL_SYSTEM_RESET:
> +               case OPAL_GET_SYMBOL:
> +               case OPAL_LOOKUP_SYMBOL:

These names are still awful :|

>                         break;
>                 default:
>                         printf("CPU ATTEMPT TO RE-ENTER FIRMWARE! PIR=%04lx cpu @%p -> pir=%04x token=%llu\n",
> diff --git a/core/utils.c b/core/utils.c
> index 8fd63fcb7..5f0d5130b 100644
> --- a/core/utils.c
> +++ b/core/utils.c
> @@ -48,40 +48,120 @@ char __attrconst tohex(uint8_t nibble)
>         return __tohex[nibble];
>  }
>
> -static unsigned long get_symbol(unsigned long addr, char **sym, char **sym_end)
> +static unsigned long get_symbol(unsigned long addr, char **sym, char **sym_end, unsigned long *size)
>  {
>         unsigned long prev = 0, next;
>         char *psym = NULL, *p = __sym_map_start;
>
>         *sym = *sym_end = NULL;
> -       while(p < __sym_map_end) {
> +       while (p < __sym_map_end) {
>                 next = strtoul(p, &p, 16) | SKIBOOT_BASE;
>                 if (next > addr && prev <= addr) {
> -                       p = psym + 3;;
> +                       p = psym + 3;
>                         if (p >= __sym_map_end)
>                                 return 0;
>                         *sym = p;
> -                       while(p < __sym_map_end && *p != 10)
> +                       while (p < __sym_map_end && *p != '\n')
>                                 p++;
>                         *sym_end = p;
> +                       *size = next - prev;
>                         return prev;
>                 }
>                 prev = next;
>                 psym = p;
> -               while(p < __sym_map_end && *p != 10)
> +               while (p < __sym_map_end && *p != '\n')
>                         p++;
>                 p++;
>         }
>         return 0;
>  }
>
> +static unsigned long lookup_symbol(const char *name, unsigned long *size)
> +{
> +       size_t len = strlen(name);
> +       unsigned long addr = 0;
> +       char *sym;
> +       char *p = __sym_map_start;
> +
> +       while (p < __sym_map_end) {
> +               addr = strtoul(p, &p, 16) | SKIBOOT_BASE;
> +               p += 3;
> +               if (p >= __sym_map_end)
> +                       return 0;
> +
> +               if (*(p + len) == '\n' && !strncmp(name, p, len)) {
> +                       char *sym_end;
> +
> +                       if (get_symbol(addr, &sym, &sym_end, size) == 0) {
> +                               assert(!strcmp(name, "_end"));
> +                               *size = 0;
> +                       }
> +
> +                       /*
> +                        * May be more than one symbol at this address but
> +                        * symbol length calculation should still work in
> +                        * that case.
> +                        */
> +
> +                       return addr;
> +               }
> +
> +               while(p < __sym_map_end && *p != '\n')
> +                       p++;
> +               p++;
> +       }
> +       return 0;
> +}
> +
> +static int64_t opal_get_symbol(uint64_t addr, __be64 *symaddr, __be64 *symsize, char *namebuf, uint64_t buflen)
> +{
> +       unsigned long saddr;
> +       unsigned long ssize;
> +       char *sym, *sym_end;
> +       size_t l;
> +
> +       saddr = get_symbol(addr, &sym, &sym_end, &ssize);
> +       if (!saddr)
> +               return OPAL_RESOURCE;
> +
> +       if (buflen > sym_end - sym)
> +               l = sym_end - sym;
> +       else
> +               l = buflen - 1;
> +       memcpy(namebuf, sym, l);
> +       namebuf[l] = '\0';
> +
> +       *symaddr = cpu_to_be64(saddr);
> +       *symsize = cpu_to_be64(ssize);
> +
> +       return OPAL_SUCCESS;
> +}
> +opal_call(OPAL_GET_SYMBOL, opal_get_symbol, 5);
> +
> +static int64_t opal_lookup_symbol(const char *name, __be64 *symaddr, __be64 *symsize)
> +{
> +       unsigned long saddr;
> +       unsigned long ssize;
> +
> +       saddr = lookup_symbol(name, &ssize);
> +       if (!saddr)
> +               return OPAL_RESOURCE;
> +
> +       *symaddr = cpu_to_be64(saddr);
> +       *symsize = cpu_to_be64(ssize);
> +
> +       return OPAL_SUCCESS;
> +}
> +opal_call(OPAL_LOOKUP_SYMBOL, opal_lookup_symbol, 3);
> +
>  size_t snprintf_symbol(char *buf, size_t len, uint64_t addr)
>  {
>         unsigned long saddr;
> +       unsigned long ssize;
>         char *sym, *sym_end;
>         size_t l;
>
> -       saddr = get_symbol(addr, &sym, &sym_end);
> +       saddr = get_symbol(addr, &sym, &sym_end, &ssize);
>         if (!saddr)
>                 return 0;
>
> diff --git a/doc/opal-api/opal-get-symbol-181.rst b/doc/opal-api/opal-get-symbol-181.rst
> new file mode 100644
> index 000000000..a57de6c1c
> --- /dev/null
> +++ b/doc/opal-api/opal-get-symbol-181.rst
> @@ -0,0 +1,42 @@
> +.. _OPAL_GET_SYMBOL:
> +
> +OPAL_GET_SYMBOL
> +================
> +
> +.. code-block:: c
> +
> +   #define OPAL_GET_SYMBOL                     181
> +
> +   static int64_t opal_get_symbol(uint64_t addr, __be64 *symaddr, __be64 *symsize, char *namebuf, uint64_t buflen);
> +
> +This OPAL call looks up a firmware code address for symbol information.
> +
> +Arguments
> +---------
> +
> +  ``addr``
> +    Contains address to be looked up.
> +
> +  ``symaddr``
> +    Returns the start address of the symbol for the object which
> +    contains addr or immediately precedes addr.
> +
> +  ``symsize``
> +    Returns the size of the object, or the number of bytes until the
> +    next symbol.
> +
> +  ``namebuf``
> +    Contains a buffer for the symbol name to be copied into, as a NUL
> +    terminated string.
> +
> +  ``buflen``
> +    Contains the length of the bufer that may be used.
> +
> +
> +Returns
> +-------
> +
> +:ref:`OPAL_SUCCESS`
> +  Found a symbol.
> +:ref:`OPAL_RESOURCE`
> +  Did not find a symbol.
> diff --git a/doc/opal-api/opal-lookup-symbol-182.rst b/doc/opal-api/opal-lookup-symbol-182.rst
> new file mode 100644
> index 000000000..e9f6eba33
> --- /dev/null
> +++ b/doc/opal-api/opal-lookup-symbol-182.rst
> @@ -0,0 +1,35 @@
> +.. _OPAL_LOOKUP_SYMBOL:
> +
> +OPAL_LOOKUP_SYMBOL
> +================
> +
> +.. code-block:: c
> +
> +   #define OPAL_LOOKUP_SYMBOL                  182
> +
> +   static int64_t opal_lookup_symbol(const char *name, __be64 *symaddr, __be64 *symsize);
> +
> +This OPAL call looks up a firmware symbol name for its address.
> +
> +Arguments
> +---------
> +
> +  ``name``
> +    Contains a pointer to NUL terminated symbol name to be looked up.
> +
> +  ``symaddr``
> +    Returns the start address of the symbol for the object which
> +    contains addr or immediately precedes addr.
> +
> +  ``symsize``
> +    Returns the size of the object, or the number of bytes until the
> +    next symbol.
> +
> +
> +Returns
> +-------
> +
> +:ref:`OPAL_SUCCESS`
> +  Found a symbol.
> +:ref:`OPAL_RESOURCE`
> +  Did not find a symbol.
> diff --git a/include/opal-api.h b/include/opal-api.h
> index 5b07dea13..4474631a6 100644
> --- a/include/opal-api.h
> +++ b/include/opal-api.h
> @@ -227,7 +227,9 @@
>  #define OPAL_SECVAR_ENQUEUE_UPDATE             178
>  #define OPAL_PHB_SET_OPTION                    179
>  #define OPAL_PHB_GET_OPTION                    180
> -#define OPAL_LAST                              180
> +#define OPAL_GET_SYMBOL                                181
> +#define OPAL_LOOKUP_SYMBOL                     182
> +#define OPAL_LAST                              182
>
>  #define QUIESCE_HOLD                   1 /* Spin all calls at entry */
>  #define QUIESCE_REJECT                 2 /* Fail all calls with OPAL_BUSY */
> --
> 2.23.0
>


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