diff options
Diffstat (limited to 'drivers/firmware/efi/libstub/arm-stub.c')
-rw-r--r-- | drivers/firmware/efi/libstub/arm-stub.c | 70 |
1 files changed, 69 insertions, 1 deletions
diff --git a/drivers/firmware/efi/libstub/arm-stub.c b/drivers/firmware/efi/libstub/arm-stub.c index 75ee05964cbc..e2432b39b6df 100644 --- a/drivers/firmware/efi/libstub/arm-stub.c +++ b/drivers/firmware/efi/libstub/arm-stub.c @@ -247,9 +247,18 @@ unsigned long __init efi_entry(void *handle, efi_system_table_t *sys_table, goto fail_free_cmdline; } } - if (!fdt_addr) + + if (fdt_addr) { + pr_efi(sys_table, "Using DTB from command line\n"); + } else { /* Look for a device tree configuration table entry. */ fdt_addr = (uintptr_t)get_fdt(sys_table); + if (fdt_addr) + pr_efi(sys_table, "Using DTB from configuration table\n"); + } + + if (!fdt_addr) + pr_efi(sys_table, "Generating empty DTB\n"); status = handle_cmdline_files(sys_table, image, cmdline_ptr, "initrd=", dram_base + SZ_512M, @@ -286,3 +295,62 @@ fail_free_image: fail: return EFI_ERROR; } + +/* + * This is the base address at which to start allocating virtual memory ranges + * for UEFI Runtime Services. This is in the low TTBR0 range so that we can use + * any allocation we choose, and eliminate the risk of a conflict after kexec. + * The value chosen is the largest non-zero power of 2 suitable for this purpose + * both on 32-bit and 64-bit ARM CPUs, to maximize the likelihood that it can + * be mapped efficiently. + */ +#define EFI_RT_VIRTUAL_BASE 0x40000000 + +/* + * efi_get_virtmap() - create a virtual mapping for the EFI memory map + * + * This function populates the virt_addr fields of all memory region descriptors + * in @memory_map whose EFI_MEMORY_RUNTIME attribute is set. Those descriptors + * are also copied to @runtime_map, and their total count is returned in @count. + */ +void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size, + unsigned long desc_size, efi_memory_desc_t *runtime_map, + int *count) +{ + u64 efi_virt_base = EFI_RT_VIRTUAL_BASE; + efi_memory_desc_t *out = runtime_map; + int l; + + for (l = 0; l < map_size; l += desc_size) { + efi_memory_desc_t *in = (void *)memory_map + l; + u64 paddr, size; + + if (!(in->attribute & EFI_MEMORY_RUNTIME)) + continue; + + /* + * Make the mapping compatible with 64k pages: this allows + * a 4k page size kernel to kexec a 64k page size kernel and + * vice versa. + */ + paddr = round_down(in->phys_addr, SZ_64K); + size = round_up(in->num_pages * EFI_PAGE_SIZE + + in->phys_addr - paddr, SZ_64K); + + /* + * Avoid wasting memory on PTEs by choosing a virtual base that + * is compatible with section mappings if this region has the + * appropriate size and physical alignment. (Sections are 2 MB + * on 4k granule kernels) + */ + if (IS_ALIGNED(in->phys_addr, SZ_2M) && size >= SZ_2M) + efi_virt_base = round_up(efi_virt_base, SZ_2M); + + in->virt_addr = efi_virt_base + in->phys_addr - paddr; + efi_virt_base += size; + + memcpy(out, in, desc_size); + out = (void *)out + desc_size; + ++*count; + } +} |