diff options
Diffstat (limited to 'elf/dl-hwcaps.c')
| -rw-r--r-- | elf/dl-hwcaps.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/elf/dl-hwcaps.c b/elf/dl-hwcaps.c index 8d49383d76..1b7fe52a6a 100644 --- a/elf/dl-hwcaps.c +++ b/elf/dl-hwcaps.c @@ -66,6 +66,11 @@ _dl_important_hwcaps (const char *platform, size_t platform_len, size_t *sz, { const ElfW(Addr) start = (phdr[i].p_vaddr + GLRO(dl_sysinfo_map)->l_addr); + /* The standard ELF note layout is exactly as the anonymous struct. + The next element is a variable length vendor name of length + VENDORLEN (with a real length rounded to ElfW(Addr)), followed + by the data of length DATALEN (with a real length rounded to + ElfW(Addr)). */ const struct { ElfW(Word) vendorlen; @@ -75,6 +80,11 @@ _dl_important_hwcaps (const char *platform, size_t platform_len, size_t *sz, while ((ElfW(Addr)) (note + 1) - start < phdr[i].p_memsz) { #define ROUND(len) (((len) + sizeof (ElfW(Word)) - 1) & -sizeof (ElfW(Word))) + /* The layout of the type 2, vendor "GNU" note is as follows: + .long <Number of capabilities enabled by this note> + .long <Capabilities mask> (as mask >> _DL_FIRST_EXTRA). + .byte <The bit number for the next capability> + .asciz <The name of the capability>. */ if (note->type == NT_GNU_HWCAP && note->vendorlen == sizeof "GNU" && !memcmp ((note + 1), "GNU", sizeof "GNU") @@ -84,7 +94,7 @@ _dl_important_hwcaps (const char *platform, size_t platform_len, size_t *sz, + ROUND (sizeof "GNU")); cnt += *p++; ++p; /* Skip mask word. */ - dsocaps = (const char *) p; + dsocaps = (const char *) p; /* Pseudo-string "<b>name" */ dsocapslen = note->datalen - sizeof *p * 2; break; } @@ -107,6 +117,8 @@ _dl_important_hwcaps (const char *platform, size_t platform_len, size_t *sz, #ifdef NEED_DL_SYSINFO_DSO if (dsocaps != NULL) { + /* dsocaps points to the .asciz string, and -1 points to the mask + .long just before the string. */ const ElfW(Word) mask = ((const ElfW(Word) *) dsocaps)[-1]; GLRO(dl_hwcap) |= (uint64_t) mask << _DL_FIRST_EXTRA; /* Note that we add the dsocaps to the set already chosen by the |