Now that the create_mapping() code in mm/mmu.c is able to support
setting up kernel page tables at initcall time, we can move the whole
virtmap creation to arm64_enable_runtime_services() instead of having
a distinct stage during early boot. This also allows us to drop the
arm64-specific EFI_VIRTMAP flag.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
---
This applies on top of Laura's "arm64: add better page protections to arm64":
the refactoring of mmu.c she did there allows us to greatly simplify the UEFI
virtmap code, and drop the explicit 'efi_virtmap_init()' call from setup_arch().
arch/arm64/include/asm/efi.h | 18 ++-----
arch/arm64/kernel/efi.c | 111 +++++++++++++++++++++----------------------
arch/arm64/kernel/setup.c | 1 -
arch/arm64/mm/mmu.c | 2 +-
4 files changed, 59 insertions(+), 73 deletions(-)
diff --git a/arch/arm64/include/asm/efi.h b/arch/arm64/include/asm/efi.h
index 7baf2cc04e1e..ef572206f1c3 100644
--- a/arch/arm64/include/asm/efi.h
+++ b/arch/arm64/include/asm/efi.h
@@ -6,10 +6,8 @@
#ifdef CONFIG_EFI
extern void efi_init(void);
-extern void efi_virtmap_init(void);
#else
#define efi_init()
-#define efi_virtmap_init()
#endif
#define efi_call_virt(f, ...) \
@@ -53,23 +51,17 @@ extern void efi_virtmap_init(void);
#define EFI_ALLOC_ALIGN SZ_64K
/*
- * On ARM systems, virtually remapped UEFI runtime services are set up in three
+ * On ARM systems, virtually remapped UEFI runtime services are set up in two
* distinct stages:
* - The stub retrieves the final version of the memory map from UEFI, populates
* the virt_addr fields and calls the SetVirtualAddressMap() [SVAM] runtime
* service to communicate the new mapping to the firmware (Note that the new
* mapping is not live at this time)
- * - During early boot, the page tables are allocated and populated based on the
- * virt_addr fields in the memory map, but only if all descriptors with the
- * EFI_MEMORY_RUNTIME attribute have a non-zero value for virt_addr. If this
- * succeeds, the EFI_VIRTMAP flag is set to indicate that the virtual mappings
- * have been installed successfully.
- * - During an early initcall(), the UEFI Runtime Services are enabled and the
- * EFI_RUNTIME_SERVICES bit set if some conditions are met, i.e., we need a
- * non-early mapping of the UEFI system table, and we need to have the virtmap
- * installed.
+ * - During an early initcall(), the EFI system table is permanently remapped
+ * and the virtual remapping of the UEFI Runtime Services regions is loaded
+ * into a private set of page tables. If this all succeeds, the Runtime
+ * Services are enabled and the EFI_RUNTIME_SERVICES bit set.
*/
-#define EFI_VIRTMAP EFI_ARCH_1
void efi_virtmap_load(void);
void efi_virtmap_unload(void);
diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
index c9cb0fbe7aa4..b42c7b480e1e 100644
--- a/arch/arm64/kernel/efi.c
+++ b/arch/arm64/kernel/efi.c
@@ -38,6 +38,19 @@ struct efi_memory_map memmap;
static u64 efi_system_table;
+static pgd_t efi_pgd[PTRS_PER_PGD] __page_aligned_bss;
+
+static struct mm_struct efi_mm = {
+ .mm_rb = RB_ROOT,
+ .pgd = efi_pgd,
+ .mm_users = ATOMIC_INIT(2),
+ .mm_count = ATOMIC_INIT(1),
+ .mmap_sem = __RWSEM_INITIALIZER(efi_mm.mmap_sem),
+ .page_table_lock = __SPIN_LOCK_UNLOCKED(efi_mm.page_table_lock),
+ .mmlist = LIST_HEAD_INIT(efi_mm.mmlist),
+ INIT_MM_CONTEXT(efi_mm)
+};
+
static int uefi_debug __initdata;
static int __init uefi_debug_setup(char *str)
{
@@ -213,6 +226,45 @@ void __init efi_init(void)
return;
reserve_regions();
+ early_memunmap(memmap.map, params.mmap_size);
+}
+
+static bool __init efi_virtmap_init(void)
+{
+ efi_memory_desc_t *md;
+
+ for_each_efi_memory_desc(&memmap, md) {
+ u64 paddr, npages, size;
+ pgprot_t prot;
+
+ if (!(md->attribute & EFI_MEMORY_RUNTIME))
+ continue;
+ if (md->virt_addr == 0)
+ return false;
+
+ paddr = md->phys_addr;
+ npages = md->num_pages;
+ memrange_efi_to_native(&paddr, &npages);
+ size = npages << PAGE_SHIFT;
+
+ pr_info(" EFI remap 0x%016llx => %p\n",
+ md->phys_addr, (void *)md->virt_addr);
+
+ /*
+ * Only regions of type EFI_RUNTIME_SERVICES_CODE need to be
+ * executable, everything else can be mapped with the XN bits
+ * set.
+ */
+ if (!is_normal_ram(md))
+ prot = __pgprot(PROT_DEVICE_nGnRE);
+ else if (md->type == EFI_RUNTIME_SERVICES_CODE)
+ prot = PAGE_KERNEL_EXEC;
+ else
+ prot = PAGE_KERNEL;
+
+ create_pgd_mapping(&efi_mm, paddr, md->virt_addr, size, prot);
+ }
+ return true;
}
/*
@@ -254,7 +306,7 @@ static int __init arm64_enable_runtime_services(void)
}
set_bit(EFI_SYSTEM_TABLES, &efi.flags);
- if (!efi_enabled(EFI_VIRTMAP)) {
+ if (!efi_virtmap_init()) {
pr_err("No UEFI virtual mapping was installed -- runtime services will not be available\n");
return -1;
}
@@ -283,19 +335,6 @@ static int __init arm64_dmi_init(void)
}
core_initcall(arm64_dmi_init);
-static pgd_t efi_pgd[PTRS_PER_PGD] __page_aligned_bss;
-
-static struct mm_struct efi_mm = {
- .mm_rb = RB_ROOT,
- .pgd = efi_pgd,
- .mm_users = ATOMIC_INIT(2),
- .mm_count = ATOMIC_INIT(1),
- .mmap_sem = __RWSEM_INITIALIZER(efi_mm.mmap_sem),
- .page_table_lock = __SPIN_LOCK_UNLOCKED(efi_mm.page_table_lock),
- .mmlist = LIST_HEAD_INIT(efi_mm.mmlist),
- INIT_MM_CONTEXT(efi_mm)
-};
-
static void efi_set_pgd(struct mm_struct *mm)
{
cpu_switch_mm(mm->pgd, mm);
@@ -315,47 +354,3 @@ void efi_virtmap_unload(void)
efi_set_pgd(current->active_mm);
preempt_enable();
}
-
-void __init efi_virtmap_init(void)
-{
- efi_memory_desc_t *md;
-
- if (!efi_enabled(EFI_BOOT))
- return;
-
- for_each_efi_memory_desc(&memmap, md) {
- u64 paddr, npages, size;
- pgprot_t prot;
-
- if (!(md->attribute & EFI_MEMORY_RUNTIME))
- continue;
- if (WARN(md->virt_addr == 0,
- "UEFI virtual mapping incomplete or missing -- no entry found for 0x%llx\n",
- md->phys_addr))
- return;
-
- paddr = md->phys_addr;
- npages = md->num_pages;
- memrange_efi_to_native(&paddr, &npages);
- size = npages << PAGE_SHIFT;
-
- pr_info(" EFI remap 0x%016llx => %p\n",
- md->phys_addr, (void *)md->virt_addr);
-
- /*
- * Only regions of type EFI_RUNTIME_SERVICES_CODE need to be
- * executable, everything else can be mapped with the XN bits
- * set.
- */
- if (!is_normal_ram(md))
- prot = __pgprot(PROT_DEVICE_nGnRE);
- else if (md->type == EFI_RUNTIME_SERVICES_CODE)
- prot = PAGE_KERNEL_EXEC;
- else
- prot = PAGE_KERNEL;
-
- create_pgd_mapping(&efi_mm, paddr, md->virt_addr, size, prot);
- }
- set_bit(EFI_VIRTMAP, &efi.flags);
- early_memunmap(memmap.map, memmap.map_end - memmap.map);
-}
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 207413fe08a0..bb10903887d4 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -382,7 +382,6 @@ void __init setup_arch(char **cmdline_p)
paging_init();
request_standard_resources();
- efi_virtmap_init();
early_ioremap_reset();
unflatten_device_tree();
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 91d55b6efd8a..155cbb0a74b6 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -269,7 +269,7 @@ void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
pgprot_t prot)
{
__create_mapping(mm, pgd_offset(mm, virt), phys, virt, size, prot,
- early_alloc);
+ late_alloc);
}
static void create_mapping_late(phys_addr_t phys, unsigned long virt,
--
1.8.3.2
--
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