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x86: EFI stub support for large memory maps
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This patch fixes a problem with EFI memory maps larger than 128 entries
when booting using the EFI stub, which results in overflowing e820_map
in boot_params and an eventual halt when checking the map size in
sanitize_e820_map().

If the number of map entries is greater than what can fit in e820_map,
add the extra entries to the setup_data list using type SETUP_E820_EXT.
These extra entries are then picked up when the setup_data list is
parsed in parse_e820_ext().

Signed-off-by: Linn Crosetto <linn@hp.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
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Linn Crosetto authored and Matt Fleming committed Sep 30, 2013
1 parent 3203209 commit d2078d5
Showing 1 changed file with 161 additions and 61 deletions.
222 changes: 161 additions & 61 deletions arch/x86/boot/compressed/eboot.c
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Original file line number Diff line number Diff line change
Expand Up @@ -519,71 +519,47 @@ struct boot_params *make_boot_params(void *handle, efi_system_table_t *_table)
return NULL;
}

static efi_status_t exit_boot(struct boot_params *boot_params,
void *handle)
static void add_e820ext(struct boot_params *params,
struct setup_data *e820ext, u32 nr_entries)
{
struct efi_info *efi = &boot_params->efi_info;
struct e820entry *e820_map = &boot_params->e820_map[0];
struct e820entry *prev = NULL;
unsigned long size, key, desc_size, _size;
efi_memory_desc_t *mem_map;
struct setup_data *data;
efi_status_t status;
__u32 desc_version;
bool called_exit = false;
u8 nr_entries;
int i;

get_map:
status = efi_get_memory_map(sys_table, &mem_map, &size, &desc_size,
&desc_version, &key);

if (status != EFI_SUCCESS)
return status;
unsigned long size;

memcpy(&efi->efi_loader_signature, EFI_LOADER_SIGNATURE, sizeof(__u32));
efi->efi_systab = (unsigned long)sys_table;
efi->efi_memdesc_size = desc_size;
efi->efi_memdesc_version = desc_version;
efi->efi_memmap = (unsigned long)mem_map;
efi->efi_memmap_size = size;
e820ext->type = SETUP_E820_EXT;
e820ext->len = nr_entries * sizeof(struct e820entry);
e820ext->next = 0;

#ifdef CONFIG_X86_64
efi->efi_systab_hi = (unsigned long)sys_table >> 32;
efi->efi_memmap_hi = (unsigned long)mem_map >> 32;
#endif
data = (struct setup_data *)(unsigned long)params->hdr.setup_data;

/* Might as well exit boot services now */
status = efi_call_phys2(sys_table->boottime->exit_boot_services,
handle, key);
if (status != EFI_SUCCESS) {
/*
* ExitBootServices() will fail if any of the event
* handlers change the memory map. In which case, we
* must be prepared to retry, but only once so that
* we're guaranteed to exit on repeated failures instead
* of spinning forever.
*/
if (called_exit)
goto free_mem_map;
while (data && data->next)
data = (struct setup_data *)(unsigned long)data->next;

called_exit = true;
efi_call_phys1(sys_table->boottime->free_pool, mem_map);
goto get_map;
}
if (data)
data->next = (unsigned long)e820ext;
else
params->hdr.setup_data = (unsigned long)e820ext;
}

/* Historic? */
boot_params->alt_mem_k = 32 * 1024;
static efi_status_t setup_e820(struct boot_params *params,
struct setup_data *e820ext, u32 e820ext_size)
{
struct e820entry *e820_map = &params->e820_map[0];
struct efi_info *efi = &params->efi_info;
struct e820entry *prev = NULL;
u32 nr_entries;
u32 nr_desc;
int i;

/*
* Convert the EFI memory map to E820.
*/
nr_entries = 0;
for (i = 0; i < size / desc_size; i++) {
nr_desc = efi->efi_memmap_size / efi->efi_memdesc_size;

for (i = 0; i < nr_desc; i++) {
efi_memory_desc_t *d;
unsigned int e820_type = 0;
unsigned long m = (unsigned long)mem_map;
unsigned long m = efi->efi_memmap;

d = (efi_memory_desc_t *)(m + (i * desc_size));
d = (efi_memory_desc_t *)(m + (i * efi->efi_memdesc_size));
switch (d->type) {
case EFI_RESERVED_TYPE:
case EFI_RUNTIME_SERVICES_CODE:
Expand Down Expand Up @@ -620,18 +596,142 @@ static efi_status_t exit_boot(struct boot_params *boot_params,

/* Merge adjacent mappings */
if (prev && prev->type == e820_type &&
(prev->addr + prev->size) == d->phys_addr)
(prev->addr + prev->size) == d->phys_addr) {
prev->size += d->num_pages << 12;
else {
e820_map->addr = d->phys_addr;
e820_map->size = d->num_pages << 12;
e820_map->type = e820_type;
prev = e820_map++;
nr_entries++;
continue;
}

if (nr_entries == ARRAY_SIZE(params->e820_map)) {
u32 need = (nr_desc - i) * sizeof(struct e820entry) +
sizeof(struct setup_data);

if (!e820ext || e820ext_size < need)
return EFI_BUFFER_TOO_SMALL;

/* boot_params map full, switch to e820 extended */
e820_map = (struct e820entry *)e820ext->data;
}

e820_map->addr = d->phys_addr;
e820_map->size = d->num_pages << PAGE_SHIFT;
e820_map->type = e820_type;
prev = e820_map++;
nr_entries++;
}

boot_params->e820_entries = nr_entries;
if (nr_entries > ARRAY_SIZE(params->e820_map)) {
u32 nr_e820ext = nr_entries - ARRAY_SIZE(params->e820_map);

add_e820ext(params, e820ext, nr_e820ext);
nr_entries -= nr_e820ext;
}

params->e820_entries = (u8)nr_entries;

return EFI_SUCCESS;
}

static efi_status_t alloc_e820ext(u32 nr_desc, struct setup_data **e820ext,
u32 *e820ext_size)
{
efi_status_t status;
unsigned long size;

size = sizeof(struct setup_data) +
sizeof(struct e820entry) * nr_desc;

if (*e820ext) {
efi_call_phys1(sys_table->boottime->free_pool, *e820ext);
*e820ext = NULL;
*e820ext_size = 0;
}

status = efi_call_phys3(sys_table->boottime->allocate_pool,
EFI_LOADER_DATA, size, e820ext);

if (status == EFI_SUCCESS)
*e820ext_size = size;

return status;
}

static efi_status_t exit_boot(struct boot_params *boot_params,
void *handle)
{
struct efi_info *efi = &boot_params->efi_info;
unsigned long map_sz, key, desc_size;
efi_memory_desc_t *mem_map;
struct setup_data *e820ext;
__u32 e820ext_size;
__u32 nr_desc, prev_nr_desc;
efi_status_t status;
__u32 desc_version;
bool called_exit = false;
u8 nr_entries;
int i;

nr_desc = 0;
e820ext = NULL;
e820ext_size = 0;

get_map:
status = efi_get_memory_map(sys_table, &mem_map, &map_sz, &desc_size,
&desc_version, &key);

if (status != EFI_SUCCESS)
return status;

prev_nr_desc = nr_desc;
nr_desc = map_sz / desc_size;
if (nr_desc > prev_nr_desc &&
nr_desc > ARRAY_SIZE(boot_params->e820_map)) {
u32 nr_e820ext = nr_desc - ARRAY_SIZE(boot_params->e820_map);

status = alloc_e820ext(nr_e820ext, &e820ext, &e820ext_size);
if (status != EFI_SUCCESS)
goto free_mem_map;

efi_call_phys1(sys_table->boottime->free_pool, mem_map);
goto get_map; /* Allocated memory, get map again */
}

memcpy(&efi->efi_loader_signature, EFI_LOADER_SIGNATURE, sizeof(__u32));
efi->efi_systab = (unsigned long)sys_table;
efi->efi_memdesc_size = desc_size;
efi->efi_memdesc_version = desc_version;
efi->efi_memmap = (unsigned long)mem_map;
efi->efi_memmap_size = map_sz;

#ifdef CONFIG_X86_64
efi->efi_systab_hi = (unsigned long)sys_table >> 32;
efi->efi_memmap_hi = (unsigned long)mem_map >> 32;
#endif

/* Might as well exit boot services now */
status = efi_call_phys2(sys_table->boottime->exit_boot_services,
handle, key);
if (status != EFI_SUCCESS) {
/*
* ExitBootServices() will fail if any of the event
* handlers change the memory map. In which case, we
* must be prepared to retry, but only once so that
* we're guaranteed to exit on repeated failures instead
* of spinning forever.
*/
if (called_exit)
goto free_mem_map;

called_exit = true;
efi_call_phys1(sys_table->boottime->free_pool, mem_map);
goto get_map;
}

/* Historic? */
boot_params->alt_mem_k = 32 * 1024;

status = setup_e820(boot_params, e820ext, e820ext_size);
if (status != EFI_SUCCESS)
return status;

return EFI_SUCCESS;

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