In allocate_e820(), call the EFI get_memory_map() service directly
instead of indirectly via efi_get_memory_map(). This avoids allocation
of a buffer and return of the full EFI memory map, which is not needed
here and would otherwise need to be freed.
Routine allocate_e820() only needs to know how many EFI memory
descriptors there are in the map to allocate an adequately sized
e820ext buffer, if it's needed. Note that since efi_get_memory_map()
returns a memory map buffer sized with extra headroom, allocate_e820()
now needs to explicitly factor that into the e820ext size calculation.
Signed-off-by: Lenny Szubowicz <[email protected]>
Suggested-by: Ard Biesheuvel <[email protected]>
--
v2:
- Instead of freeing the EFI memory map buffer allocated by
efi_get_memory_map(), avoid the allocation in the first place.
- Changed the title of the patch because the v1 title no longer
applies. v1 ref:
https://lore.kernel.org/lkml/[email protected]/
--
---
drivers/firmware/efi/libstub/efistub.h | 2 ++
drivers/firmware/efi/libstub/mem.c | 5 +++++
drivers/firmware/efi/libstub/x86-stub.c | 22 ++++++++--------------
3 files changed, 15 insertions(+), 14 deletions(-)
diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h
index 67d26949fd26..191468b771b6 100644
--- a/drivers/firmware/efi/libstub/efistub.h
+++ b/drivers/firmware/efi/libstub/efistub.h
@@ -616,6 +616,8 @@ void efi_printk(char *str);
void efi_free(unsigned long size, unsigned long addr);
+unsigned int efi_get_mmap_nr_slack_slots(void);
+
char *efi_convert_cmdline(efi_loaded_image_t *image, int *cmd_line_len,
unsigned long max_addr);
diff --git a/drivers/firmware/efi/libstub/mem.c b/drivers/firmware/efi/libstub/mem.c
index 869a79c8946f..fc8b4fb08505 100644
--- a/drivers/firmware/efi/libstub/mem.c
+++ b/drivers/firmware/efi/libstub/mem.c
@@ -7,6 +7,11 @@
#define EFI_MMAP_NR_SLACK_SLOTS 8
+unsigned int efi_get_mmap_nr_slack_slots(void)
+{
+ return EFI_MMAP_NR_SLACK_SLOTS;
+}
+
static inline bool mmap_has_headroom(unsigned long buff_size,
unsigned long map_size,
unsigned long desc_size)
diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c
index 05ccb229fb45..9a5ee0678434 100644
--- a/drivers/firmware/efi/libstub/x86-stub.c
+++ b/drivers/firmware/efi/libstub/x86-stub.c
@@ -606,24 +606,18 @@ static efi_status_t allocate_e820(struct boot_params *params,
struct setup_data **e820ext,
u32 *e820ext_size)
{
- unsigned long map_size, desc_size, buff_size;
- struct efi_boot_memmap boot_map;
- efi_memory_desc_t *map;
+ unsigned long map_size, desc_size;
efi_status_t status;
__u32 nr_desc;
- boot_map.map = ↦
- boot_map.map_size = &map_size;
- boot_map.desc_size = &desc_size;
- boot_map.desc_ver = NULL;
- boot_map.key_ptr = NULL;
- boot_map.buff_size = &buff_size;
+ /* Only need the size of the mem map and size of each mem descriptor */
+ map_size = 0;
+ status = efi_bs_call(get_memory_map, &map_size, NULL, NULL,
+ &desc_size, NULL);
+ if (status != EFI_BUFFER_TOO_SMALL)
+ return (status != EFI_SUCCESS) ? status : EFI_UNSUPPORTED;
- status = efi_get_memory_map(&boot_map);
- if (status != EFI_SUCCESS)
- return status;
-
- nr_desc = buff_size / desc_size;
+ nr_desc = map_size / desc_size + efi_get_mmap_nr_slack_slots();
if (nr_desc > ARRAY_SIZE(params->e820_table)) {
u32 nr_e820ext = nr_desc - ARRAY_SIZE(params->e820_table);
--
2.18.4
On Thu, 7 May 2020 at 15:37, Lenny Szubowicz <[email protected]> wrote:
>
> In allocate_e820(), call the EFI get_memory_map() service directly
> instead of indirectly via efi_get_memory_map(). This avoids allocation
> of a buffer and return of the full EFI memory map, which is not needed
> here and would otherwise need to be freed.
>
> Routine allocate_e820() only needs to know how many EFI memory
> descriptors there are in the map to allocate an adequately sized
> e820ext buffer, if it's needed. Note that since efi_get_memory_map()
> returns a memory map buffer sized with extra headroom, allocate_e820()
> now needs to explicitly factor that into the e820ext size calculation.
>
> Signed-off-by: Lenny Szubowicz <[email protected]>
> Suggested-by: Ard Biesheuvel <[email protected]>
> --
> v2:
> - Instead of freeing the EFI memory map buffer allocated by
> efi_get_memory_map(), avoid the allocation in the first place.
>
> - Changed the title of the patch because the v1 title no longer
> applies. v1 ref:
> https://lore.kernel.org/lkml/[email protected]/
> --
> ---
> drivers/firmware/efi/libstub/efistub.h | 2 ++
> drivers/firmware/efi/libstub/mem.c | 5 +++++
> drivers/firmware/efi/libstub/x86-stub.c | 22 ++++++++--------------
> 3 files changed, 15 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h
> index 67d26949fd26..191468b771b6 100644
> --- a/drivers/firmware/efi/libstub/efistub.h
> +++ b/drivers/firmware/efi/libstub/efistub.h
> @@ -616,6 +616,8 @@ void efi_printk(char *str);
>
> void efi_free(unsigned long size, unsigned long addr);
>
> +unsigned int efi_get_mmap_nr_slack_slots(void);
> +
> char *efi_convert_cmdline(efi_loaded_image_t *image, int *cmd_line_len,
> unsigned long max_addr);
>
> diff --git a/drivers/firmware/efi/libstub/mem.c b/drivers/firmware/efi/libstub/mem.c
> index 869a79c8946f..fc8b4fb08505 100644
> --- a/drivers/firmware/efi/libstub/mem.c
> +++ b/drivers/firmware/efi/libstub/mem.c
> @@ -7,6 +7,11 @@
>
> #define EFI_MMAP_NR_SLACK_SLOTS 8
>
> +unsigned int efi_get_mmap_nr_slack_slots(void)
> +{
> + return EFI_MMAP_NR_SLACK_SLOTS;
> +}
> +
Can we just move this #define to efistub.h and use it directly?
> static inline bool mmap_has_headroom(unsigned long buff_size,
> unsigned long map_size,
> unsigned long desc_size)
> diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c
> index 05ccb229fb45..9a5ee0678434 100644
> --- a/drivers/firmware/efi/libstub/x86-stub.c
> +++ b/drivers/firmware/efi/libstub/x86-stub.c
> @@ -606,24 +606,18 @@ static efi_status_t allocate_e820(struct boot_params *params,
> struct setup_data **e820ext,
> u32 *e820ext_size)
> {
> - unsigned long map_size, desc_size, buff_size;
> - struct efi_boot_memmap boot_map;
> - efi_memory_desc_t *map;
> + unsigned long map_size, desc_size;
> efi_status_t status;
> __u32 nr_desc;
>
> - boot_map.map = ↦
> - boot_map.map_size = &map_size;
> - boot_map.desc_size = &desc_size;
> - boot_map.desc_ver = NULL;
> - boot_map.key_ptr = NULL;
> - boot_map.buff_size = &buff_size;
> + /* Only need the size of the mem map and size of each mem descriptor */
> + map_size = 0;
> + status = efi_bs_call(get_memory_map, &map_size, NULL, NULL,
> + &desc_size, NULL);
> + if (status != EFI_BUFFER_TOO_SMALL)
> + return (status != EFI_SUCCESS) ? status : EFI_UNSUPPORTED;
>
> - status = efi_get_memory_map(&boot_map);
> - if (status != EFI_SUCCESS)
> - return status;
> -
> - nr_desc = buff_size / desc_size;
> + nr_desc = map_size / desc_size + efi_get_mmap_nr_slack_slots();
>
> if (nr_desc > ARRAY_SIZE(params->e820_table)) {
> u32 nr_e820ext = nr_desc - ARRAY_SIZE(params->e820_table);
> --
> 2.18.4
>