efi/x86: Move the EFI BGRT init code to early init code

Before invoking the arch specific handler, efi_mem_reserve() reserves
the given memory region through memblock.

efi_bgrt_init() will call efi_mem_reserve() after mm_init(), at which
time memblock is dead and should not be used anymore.

The EFI BGRT code depends on ACPI initialization to get the BGRT ACPI
table, so move parsing of the BGRT table to ACPI early boot code to
ensure that efi_mem_reserve() in EFI BGRT code still use memblock safely.

Tested-by: Bhupesh Sharma <bhsharma@redhat.com>
Signed-off-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Len Brown <lenb@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-acpi@vger.kernel.org
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1485868902-20401-9-git-send-email-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/platform/efi/efi-bgrt.c

@@ -19,8 +19,7 @@
 #include <linux/efi.h>
 #include <linux/efi-bgrt.h>
 
-struct acpi_table_bgrt *bgrt_tab;
-void *__initdata bgrt_image;
+struct acpi_table_bgrt bgrt_tab;
 size_t __initdata bgrt_image_size;
 
 struct bmp_header {
@@ -28,66 +27,58 @@ struct bmp_header {
 	u32 size;
 } __packed;
 
-void __init efi_bgrt_init(void)
+void __init efi_bgrt_init(struct acpi_table_header *table)
 {
-	acpi_status status;
 	void *image;
 	struct bmp_header bmp_header;
+	struct acpi_table_bgrt *bgrt = &bgrt_tab;
 
 	if (acpi_disabled)
 		return;
 
-	status = acpi_get_table("BGRT", 0,
-	                        (struct acpi_table_header **)&bgrt_tab);
-	if (ACPI_FAILURE(status))
-		return;
-
-	if (bgrt_tab->header.length < sizeof(*bgrt_tab)) {
+	if (table->length < sizeof(bgrt_tab)) {
 		pr_notice("Ignoring BGRT: invalid length %u (expected %zu)\n",
-		       bgrt_tab->header.length, sizeof(*bgrt_tab));
+		       table->length, sizeof(bgrt_tab));
 		return;
 	}
-	if (bgrt_tab->version != 1) {
+	*bgrt = *(struct acpi_table_bgrt *)table;
+	if (bgrt->version != 1) {
 		pr_notice("Ignoring BGRT: invalid version %u (expected 1)\n",
-		       bgrt_tab->version);
-		return;
+		       bgrt->version);
+		goto out;
 	}
-	if (bgrt_tab->status & 0xfe) {
+	if (bgrt->status & 0xfe) {
 		pr_notice("Ignoring BGRT: reserved status bits are non-zero %u\n",
-		       bgrt_tab->status);
-		return;
+		       bgrt->status);
+		goto out;
 	}
-	if (bgrt_tab->image_type != 0) {
+	if (bgrt->image_type != 0) {
 		pr_notice("Ignoring BGRT: invalid image type %u (expected 0)\n",
-		       bgrt_tab->image_type);
-		return;
+		       bgrt->image_type);
+		goto out;
 	}
-	if (!bgrt_tab->image_address) {
+	if (!bgrt->image_address) {
 		pr_notice("Ignoring BGRT: null image address\n");
-		return;
+		goto out;
 	}
 
-	image = memremap(bgrt_tab->image_address, sizeof(bmp_header), MEMREMAP_WB);
+	image = early_memremap(bgrt->image_address, sizeof(bmp_header));
 	if (!image) {
 		pr_notice("Ignoring BGRT: failed to map image header memory\n");
-		return;
+		goto out;
 	}
 
 	memcpy(&bmp_header, image, sizeof(bmp_header));
-	memunmap(image);
+	early_memunmap(image, sizeof(bmp_header));
 	if (bmp_header.id != 0x4d42) {
 		pr_notice("Ignoring BGRT: Incorrect BMP magic number 0x%x (expected 0x4d42)\n",
 			bmp_header.id);
-		return;
+		goto out;
 	}
 	bgrt_image_size = bmp_header.size;
+	efi_mem_reserve(bgrt->image_address, bgrt_image_size);
 
-	bgrt_image = memremap(bgrt_tab->image_address, bmp_header.size, MEMREMAP_WB);
-	if (!bgrt_image) {
-		pr_notice("Ignoring BGRT: failed to map image memory\n");
-		bgrt_image = NULL;
-		return;
-	}
-
-	efi_mem_reserve(bgrt_tab->image_address, bgrt_image_size);
+	return;
+out:
+	memset(bgrt, 0, sizeof(bgrt_tab));
 }

arch/x86/platform/efi/efi.c

@@ -542,11 +542,6 @@ void __init efi_init(void)
 		efi_print_memmap();
 }
 
-void __init efi_late_init(void)
-{
-	efi_bgrt_init();
-}
-
 void __init efi_set_executable(efi_memory_desc_t *md, bool executable)
 {
 	u64 addr, npages;