EFI supports allocating memory below a specified address; use that to
implement GRUB_MMAP_MALLOC_LOW by requesting memory below 1M.
---
ChangeLog entry:
2013-11-13 Josh Triplett <j...@joshtriplett.org>
* include/grub/efi/memory.h (GRUB_MMAP_MALLOC_LOW): Define.
* grub-core/mmap/efi/mmap.c (grub_mmap_malign_and_register): Add
support for GRUB_MMAP_MALLOC_LOW, to allocate memory below 1M via the
EFI firmware.
grub-core/mmap/efi/mmap.c | 15 ++++++++++-----
include/grub/efi/memory.h | 2 ++
2 files changed, 12 insertions(+), 5 deletions(-)
diff --git a/grub-core/mmap/efi/mmap.c b/grub-core/mmap/efi/mmap.c
index e6cd185..64ad05c 100644
--- a/grub-core/mmap/efi/mmap.c
+++ b/grub-core/mmap/efi/mmap.c
@@ -239,9 +239,9 @@ void *
grub_mmap_malign_and_register (grub_uint64_t align __attribute__ ((unused)),
grub_uint64_t size,
int *handle, int type,
- int flags __attribute__ ((unused)))
+ int flags)
{
- grub_efi_physical_address_t address;
+ grub_efi_physical_address_t address, max_address;
grub_efi_boot_services_t *b;
grub_efi_uintn_t pages;
grub_efi_status_t status;
@@ -254,13 +254,18 @@ grub_mmap_malign_and_register (grub_uint64_t align
__attribute__ ((unused)),
b = grub_efi_system_table->boot_services;
- address = 0xffffffff;
+ if (flags & GRUB_MMAP_MALLOC_LOW)
+ max_address = 0xfffff;
+ else
+ max_address = 0xffffffff;
+ address = max_address;
#if GRUB_TARGET_SIZEOF_VOID_P < 8
/* Limit the memory access to less than 4GB for 32-bit platforms. */
atype = GRUB_EFI_ALLOCATE_MAX_ADDRESS;
#else
- atype = GRUB_EFI_ALLOCATE_ANY_PAGES;
+ atype = (flags & GRUB_MMAP_MALLOC_LOW) ? GRUB_EFI_ALLOCATE_MAX_ADDRESS
+ : GRUB_EFI_ALLOCATE_ANY_PAGES;
#endif
pages = (size + 0xfff) >> 12;
@@ -276,7 +281,7 @@ grub_mmap_malign_and_register (grub_uint64_t align
__attribute__ ((unused)),
{
/* Uggh, the address 0 was allocated... This is too annoying,
so reallocate another one. */
- address = 0xffffffff;
+ address = max_address;
status = efi_call_4 (b->allocate_pages, atype,
make_efi_memtype (type), pages, &address);
grub_efi_free_pages (0, pages);
diff --git a/include/grub/efi/memory.h b/include/grub/efi/memory.h
index 20526b1..b4940af 100644
--- a/include/grub/efi/memory.h
+++ b/include/grub/efi/memory.h
@@ -24,6 +24,8 @@
#define GRUB_MMAP_REGISTER_BY_FIRMWARE 1
+#define GRUB_MMAP_MALLOC_LOW 1
+
grub_err_t grub_machine_mmap_register (grub_uint64_t start, grub_uint64_t size,
int type, int handle);
grub_err_t grub_machine_mmap_unregister (int handle);
--
1.8.4.3
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