Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 134 insertions, 0 deletions

diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
new file mode 100644
index 000000000..4f9acb5fb
--- /dev/null
+++ b/arch/arm64/kernel/efi.c
@@ -0,0 +1,134 @@
+/*
+ * Extensible Firmware Interface
+ *
+ * Based on Extensible Firmware Interface Specification version 2.4
+ *
+ * Copyright (C) 2013, 2014 Linaro Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/efi.h>
+#include <linux/init.h>
+
+#include <asm/efi.h>
+
+/*
+ * Only regions of type EFI_RUNTIME_SERVICES_CODE need to be
+ * executable, everything else can be mapped with the XN bits
+ * set. Also take the new (optional) RO/XP bits into account.
+ */
+static __init pteval_t create_mapping_protection(efi_memory_desc_t *md)
+{
+	u64 attr = md->attribute;
+	u32 type = md->type;
+
+	if (type == EFI_MEMORY_MAPPED_IO)
+		return PROT_DEVICE_nGnRE;
+
+	if (WARN_ONCE(!PAGE_ALIGNED(md->phys_addr),
+		      "UEFI Runtime regions are not aligned to 64 KB -- buggy firmware?"))
+		/*
+		 * If the region is not aligned to the page size of the OS, we
+		 * can not use strict permissions, since that would also affect
+		 * the mapping attributes of the adjacent regions.
+		 */
+		return pgprot_val(PAGE_KERNEL_EXEC);
+
+	/* R-- */
+	if ((attr & (EFI_MEMORY_XP | EFI_MEMORY_RO)) ==
+	    (EFI_MEMORY_XP | EFI_MEMORY_RO))
+		return pgprot_val(PAGE_KERNEL_RO);
+
+	/* R-X */
+	if (attr & EFI_MEMORY_RO)
+		return pgprot_val(PAGE_KERNEL_ROX);
+
+	/* RW- */
+	if (((attr & (EFI_MEMORY_RP | EFI_MEMORY_WP | EFI_MEMORY_XP)) ==
+	     EFI_MEMORY_XP) ||
+	    type != EFI_RUNTIME_SERVICES_CODE)
+		return pgprot_val(PAGE_KERNEL);
+
+	/* RWX */
+	return pgprot_val(PAGE_KERNEL_EXEC);
+}
+
+/* we will fill this structure from the stub, so don't put it in .bss */
+struct screen_info screen_info __section(.data);
+
+int __init efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md)
+{
+	pteval_t prot_val = create_mapping_protection(md);
+	bool page_mappings_only = (md->type == EFI_RUNTIME_SERVICES_CODE ||
+				   md->type == EFI_RUNTIME_SERVICES_DATA);
+
+	if (!PAGE_ALIGNED(md->phys_addr) ||
+	    !PAGE_ALIGNED(md->num_pages << EFI_PAGE_SHIFT)) {
+		/*
+		 * If the end address of this region is not aligned to page
+		 * size, the mapping is rounded up, and may end up sharing a
+		 * page frame with the next UEFI memory region. If we create
+		 * a block entry now, we may need to split it again when mapping
+		 * the next region, and support for that is going to be removed
+		 * from the MMU routines. So avoid block mappings altogether in
+		 * that case.
+		 */
+		page_mappings_only = true;
+	}
+
+	create_pgd_mapping(mm, md->phys_addr, md->virt_addr,
+			   md->num_pages << EFI_PAGE_SHIFT,
+			   __pgprot(prot_val | PTE_NG), page_mappings_only);
+	return 0;
+}
+
+static int __init set_permissions(pte_t *ptep, pgtable_t token,
+				  unsigned long addr, void *data)
+{
+	efi_memory_desc_t *md = data;
+	pte_t pte = READ_ONCE(*ptep);
+
+	if (md->attribute & EFI_MEMORY_RO)
+		pte = set_pte_bit(pte, __pgprot(PTE_RDONLY));
+	if (md->attribute & EFI_MEMORY_XP)
+		pte = set_pte_bit(pte, __pgprot(PTE_PXN));
+	set_pte(ptep, pte);
+	return 0;
+}
+
+int __init efi_set_mapping_permissions(struct mm_struct *mm,
+				       efi_memory_desc_t *md)
+{
+	BUG_ON(md->type != EFI_RUNTIME_SERVICES_CODE &&
+	       md->type != EFI_RUNTIME_SERVICES_DATA);
+
+	/*
+	 * Calling apply_to_page_range() is only safe on regions that are
+	 * guaranteed to be mapped down to pages. Since we are only called
+	 * for regions that have been mapped using efi_create_mapping() above
+	 * (and this is checked by the generic Memory Attributes table parsing
+	 * routines), there is no need to check that again here.
+	 */
+	return apply_to_page_range(mm, md->virt_addr,
+				   md->num_pages << EFI_PAGE_SHIFT,
+				   set_permissions, md);
+}
+
+/*
+ * UpdateCapsule() depends on the system being shutdown via
+ * ResetSystem().
+ */
+bool efi_poweroff_required(void)
+{
+	return efi_enabled(EFI_RUNTIME_SERVICES);
+}
+
+asmlinkage efi_status_t efi_handle_corrupted_x18(efi_status_t s, const char *f)
+{
+	pr_err_ratelimited(FW_BUG "register x18 corrupted by EFI %s\n", f);
+	return s;
+}