4 files changed, 98 insertions, 1 deletions

diff --git a/arch/arm/kernel/armksyms.c b/arch/arm/kernel/armksyms.c
index e5e1e53..9615423 100644
--- a/arch/arm/kernel/armksyms.c
+++ b/arch/arm/kernel/armksyms.c
@@ -170,3 +170,7 @@ EXPORT_SYMBOL(mcount);
 #endif
 EXPORT_SYMBOL(__gnu_mcount_nc);
 #endif
+
+#ifdef CONFIG_ARM_PATCH_PHYS_VIRT
+EXPORT_SYMBOL(__pv_phys_offset);
+#endif
diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 03a588b..1db8ead 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -98,6 +98,9 @@ ENTRY(stext)
 #ifdef CONFIG_SMP_ON_UP
 	bl	__fixup_smp
 #endif
+#ifdef CONFIG_ARM_PATCH_PHYS_VIRT
+	bl	__fixup_pv_table
+#endif
 	bl	__create_page_tables
 
 	/*
@@ -438,4 +441,69 @@ smp_on_up:
 
 #endif
 
+#ifdef CONFIG_ARM_PATCH_PHYS_VIRT
+
+/* __fixup_pv_table - patch the stub instructions with the delta between
+ * PHYS_OFFSET and PAGE_OFFSET, which is assumed to be 16MiB aligned and
+ * can be expressed by an immediate shifter operand. The stub instruction
+ * has a form of '(add|sub) rd, rn, #imm'.
+ */
+	__HEAD
+__fixup_pv_table:
+	adr	r0, 1f
+	ldmia	r0, {r3-r5, r7}
+	sub	r3, r0, r3	@ PHYS_OFFSET - PAGE_OFFSET
+	add	r4, r4, r3	@ adjust table start address
+	add	r5, r5, r3	@ adjust table end address
+	str	r8, [r7, r3]!	@ save computed PHYS_OFFSET to __pv_phys_offset
+	mov	r6, r3, lsr #24	@ constant for add/sub instructions
+	teq	r3, r6, lsl #24 @ must be 16MiB aligned
+	bne	__error
+	str	r6, [r7, #4]	@ save to __pv_offset
+	b	__fixup_a_pv_table
+ENDPROC(__fixup_pv_table)
+
+	.align
+1:	.long	.
+	.long	__pv_table_begin
+	.long	__pv_table_end
+2:	.long	__pv_phys_offset
+
+	.text
+__fixup_a_pv_table:
+	b	3f
+2:	ldr	ip, [r7, r3]
+	bic	ip, ip, #0x000000ff
+	orr	ip, ip, r6
+	str	ip, [r7, r3]
+3:	cmp	r4, r5
+	ldrcc	r7, [r4], #4	@ use branch for delay slot
+	bcc	2b
+	mov	pc, lr
+ENDPROC(__fixup_a_pv_table)
+
+ENTRY(fixup_pv_table)
+	stmfd	sp!, {r4 - r7, lr}
+	ldr	r2, 2f			@ get address of __pv_phys_offset
+	mov	r3, #0			@ no offset
+	mov	r4, r0			@ r0 = table start
+	add	r5, r0, r1		@ r1 = table size
+	ldr	r6, [r2, #4]		@ get __pv_offset
+	bl	__fixup_a_pv_table
+	ldmfd	sp!, {r4 - r7, pc}
+ENDPROC(fixup_pv_table)
+
+	.align
+2:	.long	__pv_phys_offset
+
+	.data
+	.globl	__pv_phys_offset
+	.type	__pv_phys_offset, %object
+__pv_phys_offset:
+	.long	0
+	.size	__pv_phys_offset, . - __pv_phys_offset
+__pv_offset:
+	.long	0
+#endif
+
 #include "head-common.S"
diff --git a/arch/arm/kernel/module.c b/arch/arm/kernel/module.c
index 2cfe816..c5679f6 100644
--- a/arch/arm/kernel/module.c
+++ b/arch/arm/kernel/module.c
@@ -268,12 +268,28 @@ struct mod_unwind_map {
 	const Elf_Shdr *txt_sec;
 };
 
+static const Elf_Shdr *find_mod_section(const Elf32_Ehdr *hdr,
+	const Elf_Shdr *sechdrs, const char *name)
+{
+	const Elf_Shdr *s, *se;
+	const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
+
+	for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++)
+		if (strcmp(name, secstrs + s->sh_name) == 0)
+			return s;
+
+	return NULL;
+}
+
+extern void fixup_pv_table(const void *, unsigned long);
+
 int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
 		    struct module *mod)
 {
+	const Elf_Shdr *s = NULL;
 #ifdef CONFIG_ARM_UNWIND
 	const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
-	const Elf_Shdr *s, *sechdrs_end = sechdrs + hdr->e_shnum;
+	const Elf_Shdr *sechdrs_end = sechdrs + hdr->e_shnum;
 	struct mod_unwind_map maps[ARM_SEC_MAX];
 	int i;
 
@@ -315,6 +331,11 @@ int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
 					         maps[i].txt_sec->sh_addr,
 					         maps[i].txt_sec->sh_size);
 #endif
+#ifdef CONFIG_ARM_PATCH_PHYS_VIRT
+	s = find_mod_section(hdr, sechdrs, ".pv_table");
+	if (s)
+		fixup_pv_table((void *)s->sh_addr, s->sh_size);
+#endif
 	return 0;
 }
 
diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S
index 86b66f3..45b5651 100644
--- a/arch/arm/kernel/vmlinux.lds.S
+++ b/arch/arm/kernel/vmlinux.lds.S
@@ -57,6 +57,10 @@ SECTIONS
 		__smpalt_end = .;
 #endif
 
+		__pv_table_begin = .;
+			*(.pv_table)
+		__pv_table_end = .;
+
 		INIT_SETUP(16)
 
 		INIT_CALLS