arm64 fixes:

- Fix HugeTLB leak due to CoW and PTE_RDONLY mismatch
 - Avoid accessing unmapped FDT fields when checking validity
 - Correctly account for vDSO AUX entry in ARCH_DLINFO
 - Fix kallsyms with absolute expressions in linker script
 - Kill unnecessary symbol-based relocs in vmlinux
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Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 fixes from Will Deacon:

 - fix HugeTLB leak due to CoW and PTE_RDONLY mismatch

 - avoid accessing unmapped FDT fields when checking validity

 - correctly account for vDSO AUX entry in ARCH_DLINFO

 - fix kallsyms with absolute expressions in linker script

 - kill unnecessary symbol-based relocs in vmlinux

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: Fix copy-on-write referencing in HugeTLB
  arm64: mm: avoid fdt_check_header() before the FDT is fully mapped
  arm64: Define AT_VECTOR_SIZE_ARCH for ARCH_DLINFO
  arm64: relocatable: suppress R_AARCH64_ABS64 relocations in vmlinux
  arm64: vmlinux.lds: make __rela_offset and __dynsym_offset ABSOLUTE

arch/arm64/Makefile

@@ -15,7 +15,7 @@ CPPFLAGS_vmlinux.lds = -DTEXT_OFFSET=$(TEXT_OFFSET)
 GZFLAGS		:=-9
 
 ifneq ($(CONFIG_RELOCATABLE),)
-LDFLAGS_vmlinux		+= -pie
+LDFLAGS_vmlinux		+= -pie -Bsymbolic
 endif
 
 KBUILD_DEFCONFIG := defconfig

arch/arm64/include/asm/elf.h

@@ -140,6 +140,7 @@ typedef struct user_fpsimd_state elf_fpregset_t;
 
 #define SET_PERSONALITY(ex)		clear_thread_flag(TIF_32BIT);
 
+/* update AT_VECTOR_SIZE_ARCH if the number of NEW_AUX_ENT entries changes */
 #define ARCH_DLINFO							\
 do {									\
 	NEW_AUX_ENT(AT_SYSINFO_EHDR,					\

arch/arm64/include/asm/pgtable.h

@@ -224,6 +224,23 @@ static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
 	set_pte(ptep, pte);
 }
 
+#define __HAVE_ARCH_PTE_SAME
+static inline int pte_same(pte_t pte_a, pte_t pte_b)
+{
+	pteval_t lhs, rhs;
+
+	lhs = pte_val(pte_a);
+	rhs = pte_val(pte_b);
+
+	if (pte_present(pte_a))
+		lhs &= ~PTE_RDONLY;
+
+	if (pte_present(pte_b))
+		rhs &= ~PTE_RDONLY;
+
+	return (lhs == rhs);
+}
+
 /*
  * Huge pte definitions.
  */

arch/arm64/include/uapi/asm/auxvec.h

@@ -19,4 +19,6 @@
 /* vDSO location */
 #define AT_SYSINFO_EHDR	33
 
+#define AT_VECTOR_SIZE_ARCH 1 /* entries in ARCH_DLINFO */
+
 #endif

arch/arm64/kernel/head.S

@@ -781,40 +781,25 @@ __primary_switch:
 	 * Iterate over each entry in the relocation table, and apply the
 	 * relocations in place.
 	 */
-	ldr	w8, =__dynsym_offset		// offset to symbol table
 	ldr	w9, =__rela_offset		// offset to reloc table
 	ldr	w10, =__rela_size		// size of reloc table
 
 	mov_q	x11, KIMAGE_VADDR		// default virtual offset
 	add	x11, x11, x23			// actual virtual offset
-	add	x8, x8, x11			// __va(.dynsym)
 	add	x9, x9, x11			// __va(.rela)
 	add	x10, x9, x10			// __va(.rela) + sizeof(.rela)
 
 0:	cmp	x9, x10
-	b.hs	2f
+	b.hs	1f
 	ldp	x11, x12, [x9], #24
 	ldr	x13, [x9, #-8]
 	cmp	w12, #R_AARCH64_RELATIVE
-	b.ne	1f
+	b.ne	0b
 	add	x13, x13, x23			// relocate
 	str	x13, [x11, x23]
 	b	0b
 
-1:	cmp	w12, #R_AARCH64_ABS64
+1:
-	b.ne	0b
-	add	x12, x12, x12, lsl #1		// symtab offset: 24x top word
-	add	x12, x8, x12, lsr #(32 - 3)	// ... shifted into bottom word
-	ldrsh	w14, [x12, #6]			// Elf64_Sym::st_shndx
-	ldr	x15, [x12, #8]			// Elf64_Sym::st_value
-	cmp	w14, #-0xf			// SHN_ABS (0xfff1) ?
-	add	x14, x15, x23			// relocate
-	csel	x15, x14, x15, ne
-	add	x15, x13, x15
-	str	x15, [x11, x23]
-	b	0b
-
-2:
 #endif
 	ldr	x8, =__primary_switched
 	br	x8

arch/arm64/kernel/vmlinux.lds.S

@@ -103,6 +103,7 @@ SECTIONS
 		*(.discard)
 		*(.discard.*)
 		*(.interp .dynamic)
+		*(.dynsym .dynstr .hash)
 	}
 
 	. = KIMAGE_VADDR + TEXT_OFFSET;
@@ -174,19 +175,9 @@ SECTIONS
 	.rela : ALIGN(8) {
 		*(.rela .rela*)
 	}
-	.dynsym : ALIGN(8) {
-		*(.dynsym)
-	}
-	.dynstr : {
-		*(.dynstr)
-	}
-	.hash : {
-		*(.hash)
-	}
 
-	__rela_offset	= ADDR(.rela) - KIMAGE_VADDR;
+	__rela_offset	= ABSOLUTE(ADDR(.rela) - KIMAGE_VADDR);
 	__rela_size	= SIZEOF(.rela);
-	__dynsym_offset	= ADDR(.dynsym) - KIMAGE_VADDR;
 
 	. = ALIGN(SEGMENT_ALIGN);
 	__init_end = .;

arch/arm64/mm/mmu.c

@@ -686,9 +686,9 @@ void *__init __fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot)
 	/*
 	 * Check whether the physical FDT address is set and meets the minimum
 	 * alignment requirement. Since we are relying on MIN_FDT_ALIGN to be
-	 * at least 8 bytes so that we can always access the size field of the
+	 * at least 8 bytes so that we can always access the magic and size
-	 * FDT header after mapping the first chunk, double check here if that
+	 * fields of the FDT header after mapping the first chunk, double check
-	 * is indeed the case.
+	 * here if that is indeed the case.
 	 */
 	BUILD_BUG_ON(MIN_FDT_ALIGN < 8);
 	if (!dt_phys || dt_phys % MIN_FDT_ALIGN)
@@ -716,7 +716,7 @@ void *__init __fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot)
 	create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE),
 			dt_virt_base, SWAPPER_BLOCK_SIZE, prot);
 
-	if (fdt_check_header(dt_virt) != 0)
+	if (fdt_magic(dt_virt) != FDT_MAGIC)
 		return NULL;
 
 	*size = fdt_totalsize(dt_virt);