The current elf loader uses too much memory. For example, I have a
executable with a bss section of 400 MB and I set the ram size to 512
MB. Qemu uses about 780MB of RAM (which is fine), but there's a peak at
1.6 GB during initialization (this is not fine).
This patch fixes two things:
1) do not allocate each elf program twice.
2) do not allocate memory for areas that are only zeros.
For this we need a new field in Rom: "datasize" which is the size of the
allocated data. If datasize is less than romsize, it means that the area
from datasize to romsize is filled with zeros.
Signed-off-by: Fabien Chouteau <chout...@adacore.com>
---
hw/elf_ops.h | 18 ++++++++------
hw/loader.c | 74 +++++++++++++++++++++++++++++++++++++++++++++++-----------
hw/loader.h | 2 +
3 files changed, 72 insertions(+), 22 deletions(-)
diff --git a/hw/elf_ops.h b/hw/elf_ops.h
index 6af357f..3bfc575 100644
--- a/hw/elf_ops.h
+++ b/hw/elf_ops.h
@@ -199,7 +199,7 @@ static int glue(load_elf, SZ)(const char *name, int fd,
struct elfhdr ehdr;
struct elf_phdr *phdr = NULL, *ph;
int size, i, total_size;
- elf_word mem_size;
+ elf_word mem_size, file_size;
uint64_t addr, low = (uint64_t)-1, high = 0;
uint8_t *data = NULL;
char label[128];
@@ -254,14 +254,16 @@ static int glue(load_elf, SZ)(const char *name, int fd,
for(i = 0; i < ehdr.e_phnum; i++) {
ph = &phdr[i];
if (ph->p_type == PT_LOAD) {
- mem_size = ph->p_memsz;
- /* XXX: avoid allocating */
- data = g_malloc0(mem_size);
+ mem_size = ph->p_memsz; /* Size of the ROM */
+ file_size = ph->p_filesz; /* Size of the allocated data */
+ data = g_malloc0(file_size);
if (ph->p_filesz > 0) {
- if (lseek(fd, ph->p_offset, SEEK_SET) < 0)
+ if (lseek(fd, ph->p_offset, SEEK_SET) < 0) {
goto fail;
- if (read(fd, data, ph->p_filesz) != ph->p_filesz)
+ }
+ if (read(fd, data, file_size) != file_size) {
goto fail;
+ }
}
/* address_offset is hack for kernel images that are
linked at the wrong physical address. */
@@ -272,7 +274,8 @@ static int glue(load_elf, SZ)(const char *name, int fd,
}
snprintf(label, sizeof(label), "phdr #%d: %s", i, name);
- rom_add_blob_fixed(label, data, mem_size, addr);
+
+ rom_add_elf_program(label, data, file_size, mem_size, addr);
total_size += mem_size;
if (addr < low)
@@ -280,7 +283,6 @@ static int glue(load_elf, SZ)(const char *name, int fd,
if ((addr + mem_size) > high)
high = addr + mem_size;
- g_free(data);
data = NULL;
}
}
diff --git a/hw/loader.c b/hw/loader.c
index 9bbcddd..224666d 100644
--- a/hw/loader.c
+++ b/hw/loader.c
@@ -527,7 +527,14 @@ typedef struct Rom Rom;
struct Rom {
char *name;
char *path;
+
+ /* datasize is the amount of memory allocated in "data". If datasize is
less
+ * than romsize, it means that the area from datasize to romsize is filled
+ * with zeros.
+ */
size_t romsize;
+ size_t datasize;
+
uint8_t *data;
int isrom;
char *fw_dir;
@@ -583,14 +590,15 @@ int rom_add_file(const char *file, const char *fw_dir,
rom->fw_dir = g_strdup(fw_dir);
rom->fw_file = g_strdup(file);
}
- rom->addr = addr;
- rom->romsize = lseek(fd, 0, SEEK_END);
- rom->data = g_malloc0(rom->romsize);
+ rom->addr = addr;
+ rom->romsize = lseek(fd, 0, SEEK_END);
+ rom->datasize = rom->romsize;
+ rom->data = g_malloc0(rom->datasize);
lseek(fd, 0, SEEK_SET);
- rc = read(fd, rom->data, rom->romsize);
- if (rc != rom->romsize) {
+ rc = read(fd, rom->data, rom->datasize);
+ if (rc != rom->datasize) {
fprintf(stderr, "rom: file %-20s: read error: rc=%d (expected %zd)\n",
- rom->name, rc, rom->romsize);
+ rom->name, rc, rom->datasize);
goto err;
}
close(fd);
@@ -631,16 +639,37 @@ int rom_add_blob(const char *name, const void *blob,
size_t len,
{
Rom *rom;
- rom = g_malloc0(sizeof(*rom));
- rom->name = g_strdup(name);
- rom->addr = addr;
- rom->romsize = len;
- rom->data = g_malloc0(rom->romsize);
+ rom = g_malloc0(sizeof(*rom));
+ rom->name = g_strdup(name);
+ rom->addr = addr;
+ rom->romsize = len;
+ rom->datasize = len;
+ rom->data = g_malloc0(rom->datasize);
memcpy(rom->data, blob, len);
rom_insert(rom);
return 0;
}
+/* This function is specific for elf program because we don't need to allocate
+ * all the rom. We just allocate the first part and the rest is just zeros.
That
+ * is why romsize and datasize are different. Also, this function seize the
+ * memory ownership of "data", so we don't have to allocate and copy the
buffer.
+ */
+int rom_add_elf_program(const char *name, void *data, size_t datasize,
+ size_t romsize, target_phys_addr_t addr)
+{
+ Rom *rom;
+
+ rom = g_malloc0(sizeof(*rom));
+ rom->name = g_strdup(name);
+ rom->addr = addr;
+ rom->datasize = datasize;
+ rom->romsize = romsize;
+ rom->data = data;
+ rom_insert(rom);
+ return 0;
+}
+
int rom_add_vga(const char *file)
{
return rom_add_file(file, "vgaroms", 0, -1);
@@ -662,7 +691,7 @@ static void rom_reset(void *unused)
if (rom->data == NULL) {
continue;
}
- cpu_physical_memory_write_rom(rom->addr, rom->data, rom->romsize);
+ cpu_physical_memory_write_rom(rom->addr, rom->data, rom->datasize);
if (rom->isrom) {
/* rom needs to be written only once */
g_free(rom->data);
@@ -751,13 +780,30 @@ int rom_copy(uint8_t *dest, target_phys_addr_t addr,
size_t size)
d = dest + (rom->addr - addr);
s = rom->data;
- l = rom->romsize;
+ l = rom->datasize;
if ((d + l) > (dest + size)) {
l = dest - d;
}
memcpy(d, s, l);
+
+ if (rom->romsize > rom->datasize) {
+ /* If datasize is less than romsize, it means that we didn't
+ * allocate all the ROM because the trailing data are only zeros.
+ */
+
+ d += l;
+ l = rom->romsize - rom->datasize;
+
+ if ((d + l) > (dest + size)) {
+ l = dest - d;
+ }
+
+ if (l > 0) {
+ memset(d, 0x0, l);
+ }
+ }
}
return (d + l) - dest;
@@ -786,7 +832,7 @@ void do_info_roms(Monitor *mon)
rom->name);
} else {
monitor_printf(mon, "fw=%s/%s"
- " size=0x%06zx name=\"%s\"\n",
+ " size=0x%06zx name=\"%s\"\n",
rom->fw_dir,
rom->fw_file,
rom->romsize,
diff --git a/hw/loader.h b/hw/loader.h
index fbcaba9..a941448 100644
--- a/hw/loader.h
+++ b/hw/loader.h
@@ -25,6 +25,8 @@ int rom_add_file(const char *file, const char *fw_dir,
target_phys_addr_t addr, int32_t bootindex);
int rom_add_blob(const char *name, const void *blob, size_t len,
target_phys_addr_t addr);
+int rom_add_elf_program(const char *name, void *data, size_t datasize,
+ size_t romsize, target_phys_addr_t addr);
int rom_load_all(void);
void rom_set_fw(void *f);
int rom_copy(uint8_t *dest, target_phys_addr_t addr, size_t size);
--
1.7.4.1
