Revert "arm64: get rid of TEXT_OFFSET"

This reverts commit 120dc60.

arch/arm64/Makefile

@@ -11,6 +11,7 @@
 # Copyright (C) 1995-2001 by Russell King
 
 LDFLAGS_vmlinux	:=--no-undefined -X
+CPPFLAGS_vmlinux.lds = -DTEXT_OFFSET=$(TEXT_OFFSET)
 
 ifeq ($(CONFIG_RELOCATABLE), y)
 # Pass --no-apply-dynamic-relocs to restore pre-binutils-2.27 behaviour
@@ -138,6 +139,9 @@ endif
 # Default value
 head-y		:= arch/arm64/kernel/head.o
 
+# The byte offset of the kernel image in RAM from the start of RAM.
+TEXT_OFFSET := 0x0
+
 ifeq ($(CONFIG_KASAN_SW_TAGS), y)
 KASAN_SHADOW_SCALE_SHIFT := 4
 else
@@ -148,6 +152,8 @@ KBUILD_CFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT)
 KBUILD_CPPFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT)
 KBUILD_AFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT)
 
+export	TEXT_OFFSET
+
 core-y		+= arch/arm64/
 libs-y		:= arch/arm64/lib/ $(libs-y)
 libs-$(CONFIG_EFI_STUB) += $(objtree)/drivers/firmware/efi/libstub/lib.a

arch/arm64/include/asm/boot.h

@@ -13,7 +13,8 @@
 #define MAX_FDT_SIZE		SZ_2M
 
 /*
- * arm64 requires the kernel image to placed at a 2 MB aligned base address
+ * arm64 requires the kernel image to placed
+ * TEXT_OFFSET bytes beyond a 2 MB aligned base
  */
 #define MIN_KIMG_ALIGN		SZ_2M
 

arch/arm64/include/asm/kernel-pgtable.h

@@ -86,7 +86,7 @@
 			+ EARLY_PGDS((vstart), (vend)) 	/* each PGDIR needs a next level page table */	\
 			+ EARLY_PUDS((vstart), (vend))	/* each PUD needs a next level page table */	\
 			+ EARLY_PMDS((vstart), (vend)))	/* each PMD needs a next level page table */
-#define INIT_DIR_SIZE (PAGE_SIZE * EARLY_PAGES(KIMAGE_VADDR, _end))
+#define INIT_DIR_SIZE (PAGE_SIZE * EARLY_PAGES(KIMAGE_VADDR + TEXT_OFFSET, _end))
 #define IDMAP_DIR_SIZE		(IDMAP_PGTABLE_LEVELS * PAGE_SIZE)
 
 #ifdef CONFIG_ARM64_SW_TTBR0_PAN

arch/arm64/include/asm/memory.h

@@ -169,7 +169,7 @@ extern s64			memstart_addr;
 /* PHYS_OFFSET - the physical address of the start of memory. */
 #define PHYS_OFFSET		({ VM_BUG_ON(memstart_addr & 1); memstart_addr; })
 
-/* the virtual base of the kernel image */
+/* the virtual base of the kernel image (minus TEXT_OFFSET) */
 extern u64			kimage_vaddr;
 
 /* the offset between the kernel virtual and physical mappings */

arch/arm64/kernel/Makefile

@@ -3,6 +3,8 @@
 # Makefile for the linux kernel.
 #
 
+CPPFLAGS_vmlinux.lds	:= -DTEXT_OFFSET=$(TEXT_OFFSET)
+AFLAGS_head.o		:= -DTEXT_OFFSET=$(TEXT_OFFSET)
 CFLAGS_armv8_deprecated.o := -I$(src)
 
 CFLAGS_REMOVE_ftrace.o = $(CC_FLAGS_FTRACE)

arch/arm64/kernel/head.S

@@ -36,10 +36,14 @@
 
 #include "efi-header.S"
 
-#define __PHYS_OFFSET	KERNEL_START
+#define __PHYS_OFFSET	(KERNEL_START - TEXT_OFFSET)
 
-#if (PAGE_OFFSET & 0x1fffff) != 0
+#if (TEXT_OFFSET & 0xfff) != 0
+#error TEXT_OFFSET must be at least 4KB aligned
+#elif (PAGE_OFFSET & 0x1fffff) != 0
 #error PAGE_OFFSET must be at least 2MB aligned
+#elif TEXT_OFFSET > 0x1fffff
+#error TEXT_OFFSET must be less than 2MB
 #endif
 
 /*
@@ -51,7 +55,7 @@
  *   x0 = physical address to the FDT blob.
  *
  * This code is mostly position independent so you call this at
- * __pa(PAGE_OFFSET).
+ * __pa(PAGE_OFFSET + TEXT_OFFSET).
  *
  * Note that the callee-saved registers are used for storing variables
  * that are useful before the MMU is enabled. The allocations are described
@@ -73,7 +77,7 @@ _head:
 	b	primary_entry			// branch to kernel start, magic
 	.long	0				// reserved
 #endif
-	.quad	0				// Image load offset from start of RAM, little-endian
+	le64sym	_kernel_offset_le		// Image load offset from start of RAM, little-endian
 	le64sym	_kernel_size_le			// Effective size of kernel image, little-endian
 	le64sym	_kernel_flags_le		// Informative flags, little-endian
 	.quad	0				// reserved
@@ -378,7 +382,7 @@ SYM_FUNC_START_LOCAL(__create_page_tables)
 	 * Map the kernel image (starting with PHYS_OFFSET).
 	 */
 	adrp	x0, init_pg_dir
-	mov_q	x5, KIMAGE_VADDR		// compile time __va(_text)
+	mov_q	x5, KIMAGE_VADDR + TEXT_OFFSET	// compile time __va(_text)
 	add	x5, x5, x23			// add KASLR displacement
 	mov	x4, PTRS_PER_PGD
 	adrp	x6, _end			// runtime __pa(_end)
@@ -470,7 +474,7 @@ SYM_FUNC_END(__primary_switched)
 
 	.pushsection ".rodata", "a"
 SYM_DATA_START(kimage_vaddr)
-	.quad		_text
+	.quad		_text - TEXT_OFFSET
 SYM_DATA_END(kimage_vaddr)
 EXPORT_SYMBOL(kimage_vaddr)
 	.popsection

arch/arm64/kernel/image.h

@@ -62,6 +62,7 @@
  */
 #define HEAD_SYMBOLS						\
 	DEFINE_IMAGE_LE64(_kernel_size_le, _end - _text);	\
+	DEFINE_IMAGE_LE64(_kernel_offset_le, TEXT_OFFSET);	\
 	DEFINE_IMAGE_LE64(_kernel_flags_le, __HEAD_FLAGS);
 
 #endif /* __ARM64_KERNEL_IMAGE_H */

arch/arm64/kernel/vmlinux.lds.S

@@ -103,7 +103,7 @@ SECTIONS
 		*(.dynsym .dynstr .hash .gnu.hash)
 	}
 
-	. = KIMAGE_VADDR;
+	. = KIMAGE_VADDR + TEXT_OFFSET;
 
 	.head.text : {
 		_text = .;
@@ -294,4 +294,4 @@ ASSERT((__entry_tramp_text_end - __entry_tramp_text_start) == PAGE_SIZE,
 /*
  * If padding is applied before .head.text, virt<->phys conversions will fail.
  */
-ASSERT(_text == KIMAGE_VADDR, "HEAD is misaligned")
+ASSERT(_text == (KIMAGE_VADDR + TEXT_OFFSET), "HEAD is misaligned")

drivers/firmware/efi/libstub/Makefile

@@ -68,6 +68,7 @@ lib-$(CONFIG_ARM64)		+= arm64-stub.o
 lib-$(CONFIG_X86)		+= x86-stub.o
 lib-$(CONFIG_RISCV)		+= riscv-stub.o
 CFLAGS_arm32-stub.o		:= -DTEXT_OFFSET=$(TEXT_OFFSET)
+CFLAGS_arm64-stub.o		:= -DTEXT_OFFSET=$(TEXT_OFFSET)
 
 # Even when -mbranch-protection=none is set, Clang will generate a
 # .note.gnu.property for code-less object files (like lib/ctype.c),

drivers/firmware/efi/libstub/arm64-stub.c

@@ -77,7 +77,7 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
 
 	kernel_size = _edata - _text;
 	kernel_memsize = kernel_size + (_end - _edata);
-	*reserve_size = kernel_memsize;
+	*reserve_size = kernel_memsize + TEXT_OFFSET % min_kimg_align();
 
 	if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && phys_seed != 0) {
 		/*
@@ -91,7 +91,7 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
 	}
 
 	if (status != EFI_SUCCESS) {
-		if (IS_ALIGNED((u64)_text, min_kimg_align())) {
+		if (IS_ALIGNED((u64)_text - TEXT_OFFSET, min_kimg_align())) {
 			/*
 			 * Just execute from wherever we were loaded by the
 			 * UEFI PE/COFF loader if the alignment is suitable.
@@ -111,7 +111,7 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
 		}
 	}
 
-	*image_addr = *reserve_addr;
+	*image_addr = *reserve_addr + TEXT_OFFSET % min_kimg_align();
 	memcpy((void *)*image_addr, _text, kernel_size);
 
 	return EFI_SUCCESS;