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-rw-r--r--arch/arm/kernel/efi.c136
1 files changed, 136 insertions, 0 deletions
diff --git a/arch/arm/kernel/efi.c b/arch/arm/kernel/efi.c
new file mode 100644
index 0000000000..e94655ef16
--- /dev/null
+++ b/arch/arm/kernel/efi.c
@@ -0,0 +1,136 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2015 Linaro Ltd <ard.biesheuvel@linaro.org>
+ */
+
+#include <linux/efi.h>
+#include <linux/memblock.h>
+#include <linux/screen_info.h>
+
+#include <asm/efi.h>
+#include <asm/mach/map.h>
+#include <asm/mmu_context.h>
+
+static int __init set_permissions(pte_t *ptep, unsigned long addr, void *data)
+{
+ efi_memory_desc_t *md = data;
+ pte_t pte = *ptep;
+
+ if (md->attribute & EFI_MEMORY_RO)
+ pte = set_pte_bit(pte, __pgprot(L_PTE_RDONLY));
+ if (md->attribute & EFI_MEMORY_XP)
+ pte = set_pte_bit(pte, __pgprot(L_PTE_XN));
+ set_pte_ext(ptep, pte, PTE_EXT_NG);
+ return 0;
+}
+
+int __init efi_set_mapping_permissions(struct mm_struct *mm,
+ efi_memory_desc_t *md,
+ bool ignored)
+{
+ unsigned long base, size;
+
+ base = md->virt_addr;
+ size = md->num_pages << EFI_PAGE_SHIFT;
+
+ /*
+ * We can only use apply_to_page_range() if we can guarantee that the
+ * entire region was mapped using pages. This should be the case if the
+ * region does not cover any naturally aligned SECTION_SIZE sized
+ * blocks.
+ */
+ if (round_down(base + size, SECTION_SIZE) <
+ round_up(base, SECTION_SIZE) + SECTION_SIZE)
+ return apply_to_page_range(mm, base, size, set_permissions, md);
+
+ return 0;
+}
+
+int __init efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md)
+{
+ struct map_desc desc = {
+ .virtual = md->virt_addr,
+ .pfn = __phys_to_pfn(md->phys_addr),
+ .length = md->num_pages * EFI_PAGE_SIZE,
+ };
+
+ /*
+ * Order is important here: memory regions may have all of the
+ * bits below set (and usually do), so we check them in order of
+ * preference.
+ */
+ if (md->attribute & EFI_MEMORY_WB)
+ desc.type = MT_MEMORY_RWX;
+ else if (md->attribute & EFI_MEMORY_WT)
+ desc.type = MT_MEMORY_RWX_NONCACHED;
+ else if (md->attribute & EFI_MEMORY_WC)
+ desc.type = MT_DEVICE_WC;
+ else
+ desc.type = MT_DEVICE;
+
+ create_mapping_late(mm, &desc, true);
+
+ /*
+ * If stricter permissions were specified, apply them now.
+ */
+ if (md->attribute & (EFI_MEMORY_RO | EFI_MEMORY_XP))
+ return efi_set_mapping_permissions(mm, md, false);
+ return 0;
+}
+
+static unsigned long __initdata cpu_state_table = EFI_INVALID_TABLE_ADDR;
+
+const efi_config_table_type_t efi_arch_tables[] __initconst = {
+ {LINUX_EFI_ARM_CPU_STATE_TABLE_GUID, &cpu_state_table},
+ {}
+};
+
+static void __init load_cpu_state_table(void)
+{
+ if (cpu_state_table != EFI_INVALID_TABLE_ADDR) {
+ struct efi_arm_entry_state *state;
+ bool dump_state = true;
+
+ state = early_memremap_ro(cpu_state_table,
+ sizeof(struct efi_arm_entry_state));
+ if (state == NULL) {
+ pr_warn("Unable to map CPU entry state table.\n");
+ return;
+ }
+
+ if ((state->sctlr_before_ebs & 1) == 0)
+ pr_warn(FW_BUG "EFI stub was entered with MMU and Dcache disabled, please fix your firmware!\n");
+ else if ((state->sctlr_after_ebs & 1) == 0)
+ pr_warn(FW_BUG "ExitBootServices() returned with MMU and Dcache disabled, please fix your firmware!\n");
+ else
+ dump_state = false;
+
+ if (dump_state || efi_enabled(EFI_DBG)) {
+ pr_info("CPSR at EFI stub entry : 0x%08x\n",
+ state->cpsr_before_ebs);
+ pr_info("SCTLR at EFI stub entry : 0x%08x\n",
+ state->sctlr_before_ebs);
+ pr_info("CPSR after ExitBootServices() : 0x%08x\n",
+ state->cpsr_after_ebs);
+ pr_info("SCTLR after ExitBootServices(): 0x%08x\n",
+ state->sctlr_after_ebs);
+ }
+ early_memunmap(state, sizeof(struct efi_arm_entry_state));
+ }
+}
+
+void __init arm_efi_init(void)
+{
+ efi_init();
+
+ if (screen_info.orig_video_isVGA == VIDEO_TYPE_EFI) {
+ /* dummycon on ARM needs non-zero values for columns/lines */
+ screen_info.orig_video_cols = 80;
+ screen_info.orig_video_lines = 25;
+ }
+
+ /* ARM does not permit early mappings to persist across paging_init() */
+ efi_memmap_unmap();
+
+ load_cpu_state_table();
+}