When allocating memory for the kernel image, try the AllocatePages()
boot service to obtain memory at the preferred offset of
'dram_base + TEXT_OFFSET', and only revert to efi_low_alloc() if that
fails. This is the only way to allocate at the base of DRAM if DRAM
starts at 0x0, since efi_low_alloc() refuses to allocate at 0x0.
Tested-by: Haojian Zhuang <haojian.zhuang@xxxxxxxxxx>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
---
v2:
- reshuffle code flow to make it more logical, and have only a single
memcpy() invocation at the end of the function
---
arch/arm64/kernel/efi-stub.c | 41 ++++++++++++++++++++++++++++++++---------
1 file changed, 32 insertions(+), 9 deletions(-)
diff --git a/arch/arm64/kernel/efi-stub.c b/arch/arm64/kernel/efi-stub.c
index f5374065ad53..816120ece6bc 100644
--- a/arch/arm64/kernel/efi-stub.c
+++ b/arch/arm64/kernel/efi-stub.c
@@ -13,7 +13,7 @@
#include <asm/efi.h>
#include <asm/sections.h>
-efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table,
+efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table_arg,
unsigned long *image_addr,
unsigned long *image_size,
unsigned long *reserve_addr,
@@ -23,21 +23,44 @@ efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table,
{
efi_status_t status;
unsigned long kernel_size, kernel_memsize = 0;
+ unsigned long nr_pages;
+ void *old_image_addr = (void *)*image_addr;
/* Relocate the image, if required. */
kernel_size = _edata - _text;
if (*image_addr != (dram_base + TEXT_OFFSET)) {
kernel_memsize = kernel_size + (_end - _edata);
- status = efi_low_alloc(sys_table, kernel_memsize + TEXT_OFFSET,
- SZ_2M, reserve_addr);
+
+ /*
+ * First, try a straight allocation at the preferred offset.
+ * This will work around the issue where, if dram_base == 0x0,
+ * efi_low_alloc() refuses to allocate at 0x0 (to prevent the
+ * address of the allocation to be mistaken for a FAIL return
+ * value or a NULL pointer). It will also ensure that, on
+ * platforms where the [dram_base, dram_base + TEXT_OFFSET)
+ * interval is partially occupied by the firmware (like on APM
+ * Mustang), we can still place the kernel at the address
+ * 'dram_base + TEXT_OFFSET'.
+ */
+ *image_addr = *reserve_addr = dram_base + TEXT_OFFSET;
+ nr_pages = round_up(kernel_memsize, EFI_ALLOC_ALIGN) /
+ EFI_PAGE_SIZE;
+ status = efi_call_early(allocate_pages, EFI_ALLOCATE_ADDRESS,
+ EFI_LOADER_DATA, nr_pages,
+ (efi_physical_addr_t *)reserve_addr);
if (status != EFI_SUCCESS) {
- pr_efi_err(sys_table, "Failed to relocate kernel\n");
- return status;
+ kernel_memsize += TEXT_OFFSET;
+ status = efi_low_alloc(sys_table_arg, kernel_memsize,
+ SZ_2M, reserve_addr);
+
+ if (status != EFI_SUCCESS) {
+ pr_efi_err(sys_table_arg, "Failed to relocate kernel\n");
+ return status;
+ }
+ *image_addr = *reserve_addr + TEXT_OFFSET;
}
- memcpy((void *)*reserve_addr + TEXT_OFFSET, (void *)*image_addr,
- kernel_size);
- *image_addr = *reserve_addr + TEXT_OFFSET;
- *reserve_size = kernel_memsize + TEXT_OFFSET;
+ memcpy((void *)*image_addr, old_image_addr, kernel_size);
+ *reserve_size = kernel_memsize;
}
--
1.9.1
--
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