[PATCH v2 03/22] ARM: use late patch framework for phys-virt patching
From: Cyril Chemparathy
Date: Fri Aug 10 2012 - 21:29:17 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/Kconfig | 1 +
arch/arm/include/asm/memory.h | 26 +++--------
arch/arm/kernel/armksyms.c | 4 --
arch/arm/kernel/head.S | 95 +++++++----------------------------------
arch/arm/kernel/module.c | 5 ---
arch/arm/kernel/setup.c | 12 ++++++
arch/arm/kernel/vmlinux.lds.S | 5 ---
7 files changed, 36 insertions(+), 112 deletions(-)
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 7e552dc..9ac86ea 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -199,6 +199,7 @@ config ARM_PATCH_PHYS_VIRT
default y
depends on !XIP_KERNEL && MMU
depends on !ARCH_REALVIEW || !SPARSEMEM
+ select ARM_RUNTIME_PATCH
help
Patch phys-to-virt and virt-to-phys translation functions at
boot and module load time according to the position of the
diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h
index e965f1b..3d93779 100644
--- a/arch/arm/include/asm/memory.h
+++ b/arch/arm/include/asm/memory.h
@@ -18,6 +18,8 @@
#include <linux/types.h>
#include <linux/sizes.h>
+#include <asm/runtime-patch.h>
+
#ifdef CONFIG_NEED_MACH_MEMORY_H
#include <mach/memory.h>
#endif
@@ -151,35 +153,21 @@
#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;
+extern unsigned long __pv_phys_offset;
+#define PHYS_OFFSET __virt_to_phys(PAGE_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("add", t, x, __pv_offset, 0);
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("sub", t, x, __pv_offset, 0);
return t;
}
#else
diff --git a/arch/arm/kernel/armksyms.c b/arch/arm/kernel/armksyms.c
index 60d3b73..6b388f8 100644
--- a/arch/arm/kernel/armksyms.c
+++ b/arch/arm/kernel/armksyms.c
@@ -152,7 +152,3 @@ 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 3db960e..69a3c09 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -117,7 +117,7 @@ ENTRY(stext)
bl __fixup_smp
#endif
#ifdef CONFIG_ARM_PATCH_PHYS_VIRT
- bl __fixup_pv_table
+ bl __fixup_pv_offsets
#endif
bl __create_page_tables
@@ -511,92 +511,29 @@ 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'.
+/*
+ * __fixup_pv_offsets - update __pv_offset and __pv_phys_offset based on the
+ * runtime location of the kernel.
*/
__HEAD
-__fixup_pv_table:
+__fixup_pv_offsets:
adr r0, 1f
- ldmia r0, {r3-r5, r7}
+ ldmia r0, {r3-r6}
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)
+ add r4, r4, r3 @ virt_to_phys(__pv_phys_offset)
+ add r5, r5, r3 @ virt_to_phys(__pv_offset)
+ add r6, r6, r3 @ virt_to_phys(PAGE_OFFSET) = PHYS_OFFSET
+ str r6, [r4] @ save __pv_phys_offset
+ str r3, [r5] @ save __pv_offset
+ mov pc, lr
+ENDPROC(__fixup_pv_offsets)
.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
+ .long __pv_phys_offset
+ .long __pv_offset
+ .long PAGE_OFFSET
#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
-__pv_offset:
- .long 0
-#endif
#include "head-common.S"
diff --git a/arch/arm/kernel/module.c b/arch/arm/kernel/module.c
index dcebf80..ac13dd5 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, ".runtime.patch.table");
if (s)
runtime_patch((void *)s->sh_addr, s->sh_size);
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 669bbf0..59e0f57 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -152,6 +152,18 @@ static union { char c[4]; unsigned long l; } endian_test __initdata = { { 'l', '
DEFINE_PER_CPU(struct cpuinfo_arm, cpu_data);
+#ifdef CONFIG_ARM_PATCH_PHYS_VIRT
+
+/*
+ * These are initialized in head.S code prior to BSS getting cleared out.
+ * The initializers here prevent these from landing in the BSS section.
+ */
+unsigned long __pv_offset = 0xdeadbeef;
+unsigned long __pv_phys_offset = 0xdeadbeef;
+EXPORT_SYMBOL(__pv_phys_offset);
+
+#endif
+
/*
* Standard memory resources
*/
diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S
index ea35ca0..2080111 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.runtime_patch_table : {
__runtime_patch_table_begin = .;
*(.runtime.patch.table)
--
1.7.9.5
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