Currently, elf file must be loaded into a buffer and then passed to
elf_load_image. This requires to copy the whole elf file before booting
it. This commit allows to pass the filename directly and will allocate
data only for the elf header (elf header + program headers). This will
then be used to load the elf data from the file without copying it in an
intermediate buffer. Elf segments are first parsed into a list and are
then loaded from the file in a second time.
Signed-off-by: Clement Leger <cleger@xxxxxxxxx>
---
arch/mips/lib/bootm.c | 9 +-
common/elf.c | 220 +++++++++++++++++++++++++++++++++++-------
include/elf.h | 6 +-
3 files changed, 191 insertions(+), 44 deletions(-)
diff --git a/arch/mips/lib/bootm.c b/arch/mips/lib/bootm.c
index 5bb09cc2d..b07884ae0 100644
--- a/arch/mips/lib/bootm.c
+++ b/arch/mips/lib/bootm.c
@@ -47,14 +47,10 @@ static int do_bootm_elf(struct image_data *data)
{
void (*entry)(int, void *);
struct elf_image *elf;
- void *fdt, *buf;
+ void *fdt;
int ret = 0;
- buf = read_file(data->os_file, NULL);
- if (!buf)
- return -EINVAL;
-
- elf = elf_load_image(buf);
+ elf = elf_load_image(data->os_file);
if (IS_ERR(elf))
return PTR_ERR(elf);
@@ -82,7 +78,6 @@ static int do_bootm_elf(struct image_data *data)
bootm_elf_done:
elf_release_image(elf);
free(fdt);
- free(buf);
return ret;
}
diff --git a/common/elf.c b/common/elf.c
index bd97858c8..1bcaafea7 100644
--- a/common/elf.c
+++ b/common/elf.c
@@ -5,15 +5,22 @@
#include <common.h>
#include <elf.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <libfile.h>
#include <memory.h>
+#include <unistd.h>
+#include <linux/fs.h>
+#include <linux/list_sort.h>
struct elf_section {
struct list_head list;
struct resource *r;
+ void *phdr;
};
static int elf_request_region(struct elf_image *elf, resource_size_t start,
- resource_size_t size)
+ resource_size_t size, void *phdr)
{
struct list_head *list = &elf->list;
struct resource *r_new;
@@ -30,6 +37,7 @@ static int elf_request_region(struct elf_image *elf, resource_size_t start,
}
r->r = r_new;
+ r->phdr = phdr;
list_add_tail(&r->list, list);
return 0;
@@ -42,13 +50,12 @@ static void elf_release_regions(struct elf_image *elf)
list_for_each_entry_safe(r, r_tmp, list, list) {
release_sdram_region(r->r);
+ list_del(&r->list);
free(r);
}
}
-
-static int load_elf_phdr_segment(struct elf_image *elf, void *src,
- void *phdr)
+static int request_elf_segment(struct elf_image *elf, void *phdr)
{
void *dst = (void *) (phys_addr_t) elf_phdr_p_paddr(elf, phdr);
int ret;
@@ -67,59 +74,127 @@ static int load_elf_phdr_segment(struct elf_image *elf, void *src,
if (dst + p_memsz > elf->high_addr)
elf->high_addr = dst + p_memsz;
- pr_debug("Loading phdr to 0x%p (%llu bytes)\n", dst, p_filesz);
+ pr_debug("Requesting segment 0x%p (%llu bytes)\n", dst, p_filesz);
- ret = elf_request_region(elf, (resource_size_t)dst, p_filesz);
+ ret = elf_request_region(elf, (resource_size_t)dst, p_filesz, phdr);
if (ret)
return ret;
- memcpy(dst, src, p_filesz);
+ return 0;
+}
+
+static int elf_section_cmp(void *priv, struct list_head *a, struct list_head *b)
+{
+ struct elf_image *elf = priv;
+ struct elf_section *elf_a, *elf_b;
+
+ if (a == b)
+ return 0;
+
+ elf_a = list_entry(a, struct elf_section, list);
+ elf_b = list_entry(b, struct elf_section, list);
+
+ return elf_phdr_p_offset(elf, elf_a->phdr) >
+ elf_phdr_p_offset(elf, elf_b->phdr);
+}
+
+static int load_elf_to_memory(struct elf_image *elf)
+{
+ void *dst;
+ int ret, fd;
+ u64 p_filesz, p_memsz, p_offset;
+ struct elf_section *r;
+ struct list_head *list = &elf->list;
+
+ fd = open(elf->filename, O_RDONLY);
+ if (fd < 0) {
+ pr_err("could not open: %s\n", errno_str());
+ return -errno;
+ }
- if (p_filesz < p_memsz)
- memset(dst + p_filesz, 0x00,
- p_memsz - p_filesz);
+ list_for_each_entry(r, list, list) {
+ p_offset = elf_phdr_p_offset(elf, r->phdr);
+ p_filesz = elf_phdr_p_filesz(elf, r->phdr);
+ p_memsz = elf_phdr_p_memsz(elf, r->phdr);
+ dst = (void *) (phys_addr_t) elf_phdr_p_paddr(elf, r->phdr);
+
+ ret = lseek(fd, p_offset, SEEK_SET);
+ if (ret == -1) {
+ pr_err("lseek at offset 0x%llx failed\n", p_offset);
+ close(fd);
+ return ret;
+ }
+
+ pr_debug("Loading phdr offset 0x%llx to 0x%p (%llu bytes)\n",
+ p_offset, dst, p_filesz);
+
+ if (read_full(fd, dst, p_filesz) < 0) {
+ pr_err("could not read elf segment: %s\n",
+ errno_str());
+ close(fd);
+ return -errno;
+ }
+
+ if (p_filesz < p_memsz)
+ memset(dst + p_filesz, 0x00, p_memsz - p_filesz);
+ }
+
+ close(fd);
return 0;
}
-static int load_elf_image_phdr(struct elf_image *elf)
+static int load_elf_image_segments(struct elf_image *elf)
{
- void *buf = elf->buf;
+ void *buf = elf->hdr_buf;
void *phdr = (void *) (buf + elf_hdr_e_phoff(elf, buf));
int i, ret;
- elf->entry = elf_hdr_e_entry(elf, buf);
+ /* File as already been loaded */
+ if (!list_empty(&elf->list))
+ return -EINVAL;
for (i = 0; i < elf_hdr_e_phnum(elf, buf) ; ++i) {
- void *src = buf + elf_phdr_p_offset(elf, phdr);
-
- ret = load_elf_phdr_segment(elf, src, phdr);
- /* in case of error elf_load_image() caller should clean up and
- * call elf_release_image() */
+ ret = request_elf_segment(elf, phdr);
if (ret)
- return ret;
+ goto elf_release_regions;
phdr += elf_size_of_phdr(elf);
}
+ /*
+ * Sort the list to avoid doing backward lseek while loading the elf
+ * segments from file to memory(some filesystems don't support it)
+ */
+ list_sort(elf, &elf->list, elf_section_cmp);
+
+ ret = load_elf_to_memory(elf);
+ if (ret)
+ goto elf_release_regions;
+
return 0;
+
+elf_release_regions:
+ elf_release_regions(elf);
+
+ return ret;
}
-static int elf_check_image(struct elf_image *elf)
+static int elf_check_image(struct elf_image *elf, void *buf)
{
- if (strncmp(elf->buf, ELFMAG, SELFMAG)) {
+ if (strncmp(buf, ELFMAG, SELFMAG)) {
pr_err("ELF magic not found.\n");
return -EINVAL;
}
- elf->class = ((char *) elf->buf)[EI_CLASS];
+ elf->class = ((char *) buf)[EI_CLASS];
- if (elf_hdr_e_type(elf, elf->buf) != ET_EXEC) {
+ if (elf_hdr_e_type(elf, buf) != ET_EXEC) {
pr_err("Non EXEC ELF image.\n");
return -ENOEXEC;
}
- if (!elf_hdr_e_phnum(elf, elf->buf)) {
+ if (!elf_hdr_e_phnum(elf, buf)) {
pr_err("No phdr found.\n");
return -ENOEXEC;
}
@@ -127,29 +202,102 @@ static int elf_check_image(struct elf_image *elf)
return 0;
}
-struct elf_image *elf_load_image(void *buf)
+static struct elf_image *elf_check_init(const char *filename)
{
+ int ret, fd;
+ int hdr_size;
+ struct elf64_hdr hdr;
struct elf_image *elf;
- int ret;
- elf = xzalloc(sizeof(*elf));
+ elf = calloc(1, sizeof(*elf));
+ if (!elf)
+ return ERR_PTR(-ENOMEM);
INIT_LIST_HEAD(&elf->list);
-
- elf->buf = buf;
elf->low_addr = (void *) (unsigned long) -1;
elf->high_addr = 0;
- ret = elf_check_image(elf);
+ /* First pass is to read elf header only */
+ fd = open(filename, O_RDONLY);
+ if (fd < 0) {
+ pr_err("could not open: %s\n", errno_str());
+ ret = -errno;
+ goto err_free_elf;
+ }
+
+ if (read_full(fd, &hdr, sizeof(hdr)) < 0) {
+ pr_err("could not read elf header: %s\n", errno_str());
+ close(fd);
+ ret = -errno;
+ goto err_free_elf;
+ }
+ close(fd);
+
+ ret = elf_check_image(elf, &hdr);
if (ret)
- return ERR_PTR(ret);
+ goto err_free_elf;
- ret = load_elf_image_phdr(elf);
- if (ret) {
- elf_release_image(elf);
- return ERR_PTR(ret);
+ hdr_size = elf_hdr_e_phoff(elf, &hdr) +
+ elf_hdr_e_phnum(elf, &hdr) *
+ elf_hdr_e_phentsize(elf, &hdr);
+
+ /* Second pass is to read the whole elf header and program headers */
+ elf->hdr_buf = malloc(hdr_size);
+ if (!elf->hdr_buf) {
+ ret = -ENOMEM;
+ goto err_free_elf;
+ }
+
+ /*
+ * We must open the file again since some fs (tftp) do not support
+ * backward lseek operations
+ */
+ fd = open(filename, O_RDONLY);
+ if (fd < 0) {
+ pr_err("could not open: %s\n", errno_str());
+ ret = -errno;
+ goto err_free_hdr_buf;
+ }
+
+ if (read_full(fd, elf->hdr_buf, hdr_size) < 0) {
+ pr_err("could not read elf program headers: %s\n", errno_str());
+ ret = -errno;
+ close(fd);
+ goto err_free_hdr_buf;
+ }
+ close(fd);
+
+ elf->filename = strdup(filename);
+ if (!elf->filename) {
+ ret = -ENOMEM;
+ goto err_free_hdr_buf;
}
+ elf->entry = elf_hdr_e_entry(elf, elf->hdr_buf);
+
+ return elf;
+
+err_free_hdr_buf:
+ free(elf->hdr_buf);
+err_free_elf:
+ free(elf);
+
+ return ERR_PTR(ret);
+}
+
+struct elf_image *elf_load_image(const char *filename)
+{
+ int ret;
+ struct elf_image *elf;
+
+ elf = elf_check_init(filename);
+ if (IS_ERR(elf))
+ return elf;
+
+ ret = load_elf_image_segments(elf);
+ if (ret)
+ return ERR_PTR(ret);
+
return elf;
}
@@ -157,5 +305,7 @@ void elf_release_image(struct elf_image *elf)
{
elf_release_regions(elf);
+ free(elf->hdr_buf);
+ free(elf->filename);
free(elf);
}
diff --git a/include/elf.h b/include/elf.h
index 403412f3f..f1a80a20a 100644
--- a/include/elf.h
+++ b/include/elf.h
@@ -405,7 +405,8 @@ struct elf_image {
u64 entry;
void *low_addr;
void *high_addr;
- void *buf;
+ void *hdr_buf;
+ char *filename;
};
static inline size_t elf_get_mem_size(struct elf_image *elf)
@@ -413,7 +414,7 @@ static inline size_t elf_get_mem_size(struct elf_image *elf)
return elf->high_addr - elf->low_addr;
}
-struct elf_image *elf_load_image(void *buf);
+struct elf_image *elf_load_image(const char *filename);
void elf_release_image(struct elf_image *elf);
#define ELF_GET_FIELD(__s, __field, __type) \
@@ -427,6 +428,7 @@ static inline __type elf_##__s##_##__field(struct elf_image *elf, void *arg) { \
ELF_GET_FIELD(hdr, e_entry, u64)
ELF_GET_FIELD(hdr, e_phnum, u16)
ELF_GET_FIELD(hdr, e_phoff, u64)
+ELF_GET_FIELD(hdr, e_phentsize, u16)
ELF_GET_FIELD(hdr, e_type, u16)
ELF_GET_FIELD(phdr, p_paddr, u64)
ELF_GET_FIELD(phdr, p_filesz, u64)
--
2.17.1
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