diff options
| -rw-r--r-- | discover/Makefile.am | 4 | ||||
| -rw-r--r-- | discover/elf.c | 86 | ||||
| -rw-r--r-- | discover/elf.h | 29 |
3 files changed, 118 insertions, 1 deletions
diff --git a/discover/Makefile.am b/discover/Makefile.am index e2d0e93..2339203 100644 --- a/discover/Makefile.am +++ b/discover/Makefile.am @@ -80,7 +80,9 @@ discover_platform_ro_SOURCES = \ discover/ipmi.h \ discover/dt.c \ discover/dt.h \ - discover/hostboot.h + discover/hostboot.h \ + discover/elf.c \ + discover/elf.h if PLATFORM_ARM64 discover_platform_ro_SOURCES += discover/platform-arm64.c diff --git a/discover/elf.c b/discover/elf.c new file mode 100644 index 0000000..8c2711e --- /dev/null +++ b/discover/elf.c @@ -0,0 +1,86 @@ +#include <stdlib.h> +#include <string.h> +#include <fcntl.h> + +#include <log/log.h> +#include "elf.h" + +Elf *elf_open_image(const char *image) +{ + int fd; + Elf *elf = NULL; + int err; + + if (!image) { + pb_log_fn("kernel image path is null\n"); + return NULL; + } + + if ((elf_version(EV_CURRENT) == EV_NONE) || + ((fd = open(image, O_RDONLY, 0)) == -1) || + (!(elf = elf_begin(fd, ELF_C_READ, NULL)))) { + err = elf_errno(); + if (err) + pb_log_fn("failed to read %s elf: %s\n", + image, elf_errmsg(err)); + } + + return elf; +} + +static bool elf_getnote_offset(Elf_Data * const edata, + const char *namespace, + const uint32_t type, GElf_Nhdr *nhdr, + size_t *n_off, size_t *d_off) +{ + size_t off = 0; + size_t next; + + /* Iterate through notes */ + while ((next = gelf_getnote(edata, off, nhdr, n_off, d_off)) > 0) { + char *note_ns = (char *) edata->d_buf + (*n_off); + if ((strcmp(note_ns, namespace) == 0) && (nhdr->n_type == type)) + return true; + + off = next; + } + return false; +} + +void *elf_getnote_desc(Elf *elf, + const char *namespace, + uint32_t type) +{ + Elf_Scn *scn = NULL; + Elf_Data *edata = NULL; + GElf_Shdr shdr; + GElf_Nhdr nhdr; + + size_t n_off; + size_t d_off; + void *desc = NULL; + + if (!elf || !namespace) + return NULL; + + /* Iterate through sections */ + while ((scn = elf_nextscn(elf, scn))) { + gelf_getshdr(scn, &shdr); + + /* ELF might have more than one SHT_NOTE section but + only one has the 'namespace' note */ + if (shdr.sh_type == SHT_NOTE) { + edata = elf_getdata(scn, NULL); + if (elf_getnote_offset(edata, namespace, type, + &nhdr, &n_off, &d_off)) { + desc = calloc(nhdr.n_descsz, sizeof(char)); + memcpy(desc, edata->d_buf + d_off, + nhdr.n_descsz); + break; + } + } + } + + return desc; +} + diff --git a/discover/elf.h b/discover/elf.h new file mode 100644 index 0000000..742b791 --- /dev/null +++ b/discover/elf.h @@ -0,0 +1,29 @@ +#ifndef _PB_ELF_H +#define _PB_ELF_H + +#include <elfutils/libdw.h> +#include <libelf.h> + +/* + * The PowerPC namespace in an ELF Note of the kernel binary is used to store + * capabilities and information which can be used by a bootloader or userland + * + * docs: Documentation/powerpc/elfnote.rst + */ +#define POWERPC_ELFNOTE_NAMESPACE "PowerPC" + +/* + * The capabilities supported/required by the kernel + * This type uses a bitmap as "desc" field. + */ +#define PPC_ELFNOTE_CAPABILITIES 0x1 + +/* bitmap fields: */ +#define PPCCAP_ULTRAVISOR_BIT 0x1 + +Elf *elf_open_image(const char *image); +void *elf_getnote_desc(Elf *elf, + const char *namespace, + uint32_t type); + +#endif /* _PB_ELF_H */ |
