[PATCH 02/22] ARM: use late patch framework for phys-virt patching
From: Cyril Chemparathy
Date: Tue Jul 31 2012 - 19:08:37 EST
This patch replaces the original physical offset patching implementation
with one that uses the newly added patching framework. In the process, we now
unconditionally initialize the __pv_phys_offset and __pv_offset globals in the
head.S code.
Signed-off-by: Cyril Chemparathy <cyril@xxxxxx>
---
arch/arm/include/asm/memory.h | 20 ++-------
arch/arm/kernel/head.S | 96 +++++------------------------------------
arch/arm/kernel/module.c | 5 ---
arch/arm/kernel/vmlinux.lds.S | 5 ---
4 files changed, 15 insertions(+), 111 deletions(-)
diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h
index fcb5757..01c710d 100644
--- a/arch/arm/include/asm/memory.h
+++ b/arch/arm/include/asm/memory.h
@@ -17,6 +17,7 @@
#include <linux/const.h>
#include <linux/types.h>
#include <asm/sizes.h>
+#include <asm/patch.h>
#ifdef CONFIG_NEED_MACH_MEMORY_H
#include <mach/memory.h>
@@ -151,35 +152,22 @@
#ifndef __virt_to_phys
#ifdef CONFIG_ARM_PATCH_PHYS_VIRT
-/*
- * Constants used to force the right instruction encodings and shifts
- * so that all we need to do is modify the 8-bit constant field.
- */
-#define __PV_BITS_31_24 0x81000000
-
extern unsigned long __pv_phys_offset;
#define PHYS_OFFSET __pv_phys_offset
-#define __pv_stub(from,to,instr,type) \
- __asm__("@ __pv_stub\n" \
- "1: " instr " %0, %1, %2\n" \
- " .pushsection .pv_table,\"a\"\n" \
- " .long 1b\n" \
- " .popsection\n" \
- : "=r" (to) \
- : "r" (from), "I" (type))
+extern unsigned long __pv_offset;
static inline unsigned long __virt_to_phys(unsigned long x)
{
unsigned long t;
- __pv_stub(x, t, "add", __PV_BITS_31_24);
+ early_patch_imm8(x, t, "add", __pv_offset);
return t;
}
static inline unsigned long __phys_to_virt(unsigned long x)
{
unsigned long t;
- __pv_stub(x, t, "sub", __PV_BITS_31_24);
+ early_patch_imm8(x, t, "sub", __pv_offset);
return t;
}
#else
diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 835898e..d165896 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -109,9 +109,13 @@ ENTRY(stext)
#ifndef CONFIG_XIP_KERNEL
adr r3, 2f
- ldmia r3, {r4, r8}
+ ldmia r3, {r4, r5, r6, r8}
sub r4, r3, r4 @ (PHYS_OFFSET - PAGE_OFFSET)
add r8, r8, r4 @ PHYS_OFFSET
+ add r5, r5, r4
+ str r8, [r5] @ set __pv_phys_offset
+ add r6, r6, r4
+ str r4, [r6] @ set __pv_offset
#else
ldr r8, =PHYS_OFFSET @ always constant in this case
#endif
@@ -124,9 +128,6 @@ 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
/*
@@ -148,6 +149,8 @@ ENDPROC(stext)
.ltorg
#ifndef CONFIG_XIP_KERNEL
2: .long .
+ .long __pv_phys_offset
+ .long __pv_offset
.long PAGE_OFFSET
#endif
@@ -522,94 +525,17 @@ ENTRY(fixup_smp)
ldmfd sp!, {r4 - r6, pc}
ENDPROC(fixup_smp)
-#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
- add r7, r7, r3 @ adjust __pv_phys_offset address
- str r8, [r7] @ 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
-THUMB( it ne @ cross section branch )
- 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:
-#ifdef CONFIG_THUMB2_KERNEL
- lsls r6, #24
- beq 2f
- clz r7, r6
- lsr r6, #24
- lsl r6, r7
- bic r6, #0x0080
- lsrs r7, #1
- orrcs r6, #0x0080
- orr r6, r6, r7, lsl #12
- orr r6, #0x4000
- b 2f
-1: add r7, r3
- ldrh ip, [r7, #2]
- and ip, 0x8f00
- orr ip, r6 @ mask in offset bits 31-24
- strh ip, [r7, #2]
-2: cmp r4, r5
- ldrcc r7, [r4], #4 @ use branch for delay slot
- bcc 1b
- bx lr
-#else
- b 2f
-1: ldr ip, [r7, r3]
- bic ip, ip, #0x000000ff
- orr ip, ip, r6 @ mask in offset bits 31-24
- str ip, [r7, r3]
-2: cmp r4, r5
- ldrcc r7, [r4], #4 @ use branch for delay slot
- bcc 1b
- mov pc, lr
-#endif
-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
+
+ .globl __pv_offset
+ .type __pv_offset, %object
__pv_offset:
.long 0
-#endif
+ .size __pv_offset, . - __pv_offset
#include "head-common.S"
diff --git a/arch/arm/kernel/module.c b/arch/arm/kernel/module.c
index df5e897..39f8fce 100644
--- a/arch/arm/kernel/module.c
+++ b/arch/arm/kernel/module.c
@@ -317,11 +317,6 @@ 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
s = find_mod_section(hdr, sechdrs, ".patch.table");
if (s)
patch_kernel((void *)s->sh_addr, s->sh_size);
diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S
index bacb275..13731e3 100644
--- a/arch/arm/kernel/vmlinux.lds.S
+++ b/arch/arm/kernel/vmlinux.lds.S
@@ -162,11 +162,6 @@ SECTIONS
__smpalt_end = .;
}
#endif
- .init.pv_table : {
- __pv_table_begin = .;
- *(.pv_table)
- __pv_table_end = .;
- }
.init.patch_table : {
__patch_table_begin = .;
*(.patch.table)
--
1.7.9.5
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