This changes the way memblocks are installed based on the contents of
the UEFI memory map. Formerly, all regions would be memblock_add()'ed,
after which unusable regions would be memblock_reserve()'d as well.
To simplify things, but also to allow access to the unusable regions
through mmap(/dev/mem), even with CONFIG_STRICT_DEVMEM set, change
this so that only usable regions are memblock_add()'ed in the first
place.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
---
arch/arm64/kernel/efi.c | 69 +++++++++++++++++++------------------------------
1 file changed, 26 insertions(+), 43 deletions(-)
diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
index 3009c22e2620..af2214c692d3 100644
--- a/arch/arm64/kernel/efi.c
+++ b/arch/arm64/kernel/efi.c
@@ -40,13 +40,6 @@ static int __init uefi_debug_setup(char *str)
}
early_param("uefi_debug", uefi_debug_setup);
-static int __init is_normal_ram(efi_memory_desc_t *md)
-{
- if (md->attribute & EFI_MEMORY_WB)
- return 1;
- return 0;
-}
-
static int __init uefi_init(void)
{
efi_char16_t *c16;
@@ -105,28 +98,11 @@ out:
return retval;
}
-/*
- * Return true for RAM regions we want to permanently reserve.
- */
-static __init int is_reserve_region(efi_memory_desc_t *md)
-{
- switch (md->type) {
- case EFI_LOADER_CODE:
- case EFI_LOADER_DATA:
- case EFI_BOOT_SERVICES_CODE:
- case EFI_BOOT_SERVICES_DATA:
- case EFI_CONVENTIONAL_MEMORY:
- return 0;
- default:
- break;
- }
- return is_normal_ram(md);
-}
-
-static __init void reserve_regions(void)
+static __init void process_memory_map(void)
{
efi_memory_desc_t *md;
u64 paddr, npages, size;
+ u32 lost = 0;
if (uefi_debug)
pr_info("Processing EFI memory map:\n");
@@ -134,31 +110,38 @@ static __init void reserve_regions(void)
for_each_efi_memory_desc(&memmap, md) {
paddr = md->phys_addr;
npages = md->num_pages;
+ size = npages << EFI_PAGE_SHIFT;
if (uefi_debug) {
char buf[64];
- pr_info(" 0x%012llx-0x%012llx %s",
- paddr, paddr + (npages << EFI_PAGE_SHIFT) - 1,
+ pr_info(" 0x%012llx-0x%012llx %s\n",
+ paddr, paddr + size - 1,
efi_md_typeattr_format(buf, sizeof(buf), md));
}
- memrange_efi_to_native(&paddr, &npages);
- size = npages << PAGE_SHIFT;
-
- if (is_normal_ram(md))
- early_init_dt_add_memory_arch(paddr, size);
-
- if (is_reserve_region(md)) {
- memblock_reserve(paddr, size);
- if (uefi_debug)
- pr_cont("*");
- }
-
- if (uefi_debug)
- pr_cont("\n");
+ if (!efi_mem_is_usable_region(md))
+ continue;
+
+ early_init_dt_add_memory_arch(paddr, size);
+
+ /*
+ * Keep a tally of how much memory we are losing due to
+ * rounding of regions that are not aligned to the page
+ * size. We cannot easily recover this memory without
+ * sorting the memory map and attempting to merge adjacent
+ * usable regions.
+ */
+ if (PAGE_SHIFT != EFI_PAGE_SHIFT)
+ lost += (npages << EFI_PAGE_SHIFT) -
+ round_down(max_t(s64, size - PAGE_ALIGN(paddr) +
+ md->phys_addr, 0),
+ PAGE_SIZE);
}
+ if (lost > SZ_1K)
+ pr_warn("efi: lost %u KB of RAM to rounding\n", lost / SZ_1K);
+
set_bit(EFI_MEMMAP, &efi.flags);
}
@@ -182,7 +165,7 @@ void __init efi_init(void)
WARN_ON(uefi_init() < 0);
- reserve_regions();
+ process_memory_map();
}
static int __init arm64_enter_virtual_mode(void)
--
1.8.3.2
--
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