1 files changed, 70 insertions, 18 deletions

diff --git a/drivers/firmware/efi/efi-init.c b/drivers/firmware/efi/efi-init.c
index 2fd770b499a3..a65c2d5b9e7b 100644
--- a/drivers/firmware/efi/efi-init.c
+++ b/drivers/firmware/efi/efi-init.c
@@ -12,6 +12,7 @@
 #include <linux/efi.h>
 #include <linux/fwnode.h>
 #include <linux/init.h>
+#include <linux/kexec_handover.h>
 #include <linux/memblock.h>
 #include <linux/mm_types.h>
 #include <linux/of.h>
@@ -22,6 +23,8 @@
 
 #include <asm/efi.h>
 
+unsigned long __initdata screen_info_table = EFI_INVALID_TABLE_ADDR;
+
 static int __init is_memory(efi_memory_desc_t *md)
 {
 	if (md->attribute & (EFI_MEMORY_WB|EFI_MEMORY_WT|EFI_MEMORY_WC))
@@ -53,11 +56,36 @@ static phys_addr_t __init efi_to_phys(unsigned long addr)
 
 extern __weak const efi_config_table_type_t efi_arch_tables[];
 
+/*
+ * x86 defines its own screen_info and uses it even without EFI,
+ * everything else can get it from here.
+ */
+#if !defined(CONFIG_X86) && (defined(CONFIG_SYSFB) || defined(CONFIG_EFI_EARLYCON))
+struct screen_info screen_info __section(".data");
+EXPORT_SYMBOL_GPL(screen_info);
+#endif
+
 static void __init init_screen_info(void)
 {
-	if (screen_info.orig_video_isVGA == VIDEO_TYPE_EFI &&
-	    memblock_is_map_memory(screen_info.lfb_base))
-		memblock_mark_nomap(screen_info.lfb_base, screen_info.lfb_size);
+	struct screen_info *si;
+
+	if (screen_info_table != EFI_INVALID_TABLE_ADDR) {
+		si = early_memremap(screen_info_table, sizeof(*si));
+		if (!si) {
+			pr_err("Could not map screen_info config table\n");
+			return;
+		}
+		screen_info = *si;
+		memset(si, 0, sizeof(*si));
+		early_memunmap(si, sizeof(*si));
+
+		if (memblock_is_map_memory(screen_info.lfb_base))
+			memblock_mark_nomap(screen_info.lfb_base,
+					    screen_info.lfb_size);
+
+		if (IS_ENABLED(CONFIG_EFI_EARLYCON))
+			efi_earlycon_reprobe();
+	}
 }
 
 static int __init uefi_init(u64 efi_system_table)
@@ -77,7 +105,7 @@ static int __init uefi_init(u64 efi_system_table)
 	if (IS_ENABLED(CONFIG_64BIT))
 		set_bit(EFI_64BIT, &efi.flags);
 
-	retval = efi_systab_check_header(&systab->hdr, 2);
+	retval = efi_systab_check_header(&systab->hdr);
 	if (retval)
 		goto out;
 
@@ -117,15 +145,6 @@ static __init int is_usable_memory(efi_memory_desc_t *md)
 	case EFI_CONVENTIONAL_MEMORY:
 	case EFI_PERSISTENT_MEMORY:
 		/*
-		 * Special purpose memory is 'soft reserved', which means it
-		 * is set aside initially, but can be hotplugged back in or
-		 * be assigned to the dax driver after boot.
-		 */
-		if (efi_soft_reserve_enabled() &&
-		    (md->attribute & EFI_MEMORY_SP))
-			return false;
-
-		/*
 		 * According to the spec, these regions are no longer reserved
 		 * after calling ExitBootServices(). However, we can only use
 		 * them as System RAM if they can be mapped writeback cacheable.
@@ -146,12 +165,32 @@ static __init void reserve_regions(void)
 		pr_info("Processing EFI memory map:\n");
 
 	/*
-	 * Discard memblocks discovered so far: if there are any at this
-	 * point, they originate from memory nodes in the DT, and UEFI
-	 * uses its own memory map instead.
+	 * Discard memblocks discovered so far except for KHO scratch
+	 * regions. Most memblocks at this point originate from memory nodes
+	 * in the DT and UEFI uses its own memory map instead. However, if
+	 * KHO is enabled, scratch regions, which are good known memory
+	 * must be preserved.
 	 */
 	memblock_dump_all();
-	memblock_remove(0, PHYS_ADDR_MAX);
+
+	if (is_kho_boot()) {
+		struct memblock_region *r;
+
+		/* Remove all non-KHO regions */
+		for_each_mem_region(r) {
+			if (!memblock_is_kho_scratch(r)) {
+				memblock_remove(r->base, r->size);
+				r--;
+			}
+		}
+	} else {
+		/*
+		 * KHO is disabled. Discard memblocks discovered so far:
+		 * if there are any at this point, they originate from memory
+		 * nodes in the DT, and UEFI uses its own memory map instead.
+		 */
+		memblock_remove(0, PHYS_ADDR_MAX);
+	}
 
 	for_each_efi_memory_desc(md) {
 		paddr = md->phys_addr;
@@ -169,6 +208,16 @@ static __init void reserve_regions(void)
 		size = npages << PAGE_SHIFT;
 
 		if (is_memory(md)) {
+			/*
+			 * Special purpose memory is 'soft reserved', which
+			 * means it is set aside initially. Don't add a memblock
+			 * for it now so that it can be hotplugged back in or
+			 * be assigned to the dax driver after boot.
+			 */
+			if (efi_soft_reserve_enabled() &&
+			    (md->attribute & EFI_MEMORY_SP))
+				continue;
+
 			early_init_dt_add_memory_arch(paddr, size);
 
 			if (!is_usable_memory(md))
@@ -222,5 +271,8 @@ void __init efi_init(void)
 	memblock_reserve(data.phys_map & PAGE_MASK,
 			 PAGE_ALIGN(data.size + (data.phys_map & ~PAGE_MASK)));
 
-	init_screen_info();
+	if (IS_ENABLED(CONFIG_X86) ||
+	    IS_ENABLED(CONFIG_SYSFB) ||
+	    IS_ENABLED(CONFIG_EFI_EARLYCON))
+		init_screen_info();
 }