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authorRussell King <rmk+kernel@arm.linux.org.uk>2011-01-04 22:04:00 +0300
committerRussell King <rmk+kernel@arm.linux.org.uk>2011-02-18 02:27:30 +0300
commit72a20e22f49e2dad3180c23980a9df1c63faab0a (patch)
tree97edaa9db248ecc7e9a6a66c1ef5a054412af5c2 /arch/arm/kernel/head.S
parentb75c178afaa975896e894bb2b6951dc4cd43c977 (diff)
downloadlinux-72a20e22f49e2dad3180c23980a9df1c63faab0a.tar.xz
ARM: P2V: eliminate head.S use of PHYS_OFFSET for !XIP_KERNEL
head.S makes use of PHYS_OFFSET. When it becomes a variable, the assembler won't understand this. Compute PHYS_OFFSET by the following method. This code is linked at its virtual address, but run at before the MMU is enabled, so at his physical address. 1: .long . .long PAGE_OFFSET adr r0, 1b @ r0 = physical ',' ldmia r0, {r1, r2} @ r1 = virtual '.', r2 = PAGE_OFFSET sub r1, r0, r1 @ r1 = physical-virtual add r2, r2, r1 @ r2 = PAGE_OFFSET + physical-virtual @ := PHYS_OFFSET. Switch XIP users of PHYS_OFFSET to use PLAT_PHYS_OFFSET - we can't use this method for XIP kernels as the code doesn't execute in RAM. Tested-by: Tony Lindgren <tony@atomide.com> Reviewed-by: Nicolas Pitre <nicolas.pitre@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/kernel/head.S')
-rw-r--r--arch/arm/kernel/head.S44
1 files changed, 22 insertions, 22 deletions
diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 8a154b940fef..03a588b6e15c 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -26,14 +26,6 @@
#include <mach/debug-macro.S>
#endif
-#if (PHYS_OFFSET & 0x001fffff)
-#error "PHYS_OFFSET must be at an even 2MiB boundary!"
-#endif
-
-#define KERNEL_RAM_VADDR (PAGE_OFFSET + TEXT_OFFSET)
-#define KERNEL_RAM_PADDR (PHYS_OFFSET + TEXT_OFFSET)
-
-
/*
* swapper_pg_dir is the virtual address of the initial page table.
* We place the page tables 16K below KERNEL_RAM_VADDR. Therefore, we must
@@ -41,6 +33,7 @@
* the least significant 16 bits to be 0x8000, but we could probably
* relax this restriction to KERNEL_RAM_VADDR >= PAGE_OFFSET + 0x4000.
*/
+#define KERNEL_RAM_VADDR (PAGE_OFFSET + TEXT_OFFSET)
#if (KERNEL_RAM_VADDR & 0xffff) != 0x8000
#error KERNEL_RAM_VADDR must start at 0xXXXX8000
#endif
@@ -48,8 +41,8 @@
.globl swapper_pg_dir
.equ swapper_pg_dir, KERNEL_RAM_VADDR - 0x4000
- .macro pgtbl, rd
- ldr \rd, =(KERNEL_RAM_PADDR - 0x4000)
+ .macro pgtbl, rd, phys
+ add \rd, \phys, #TEXT_OFFSET - 0x4000
.endm
#ifdef CONFIG_XIP_KERNEL
@@ -88,9 +81,18 @@ ENTRY(stext)
THUMB( it eq ) @ force fixup-able long branch encoding
beq __error_p @ yes, error 'p'
+#ifndef CONFIG_XIP_KERNEL
+ adr r3, 2f
+ ldmia r3, {r4, r8}
+ sub r4, r3, r4 @ (PHYS_OFFSET - PAGE_OFFSET)
+ add r8, r8, r4 @ PHYS_OFFSET
+#else
+ ldr r8, =PLAT_PHYS_OFFSET
+#endif
+
/*
* r1 = machine no, r2 = atags,
- * r9 = cpuid, r10 = procinfo
+ * r8 = phys_offset, r9 = cpuid, r10 = procinfo
*/
bl __vet_atags
#ifdef CONFIG_SMP_ON_UP
@@ -114,21 +116,24 @@ ENTRY(stext)
1: b __enable_mmu
ENDPROC(stext)
.ltorg
+#ifndef CONFIG_XIP_KERNEL
+2: .long .
+ .long PAGE_OFFSET
+#endif
/*
* Setup the initial page tables. We only setup the barest
* amount which are required to get the kernel running, which
* generally means mapping in the kernel code.
*
- * r9 = cpuid
- * r10 = procinfo
+ * r8 = phys_offset, r9 = cpuid, r10 = procinfo
*
* Returns:
* r0, r3, r5-r7 corrupted
* r4 = physical page table address
*/
__create_page_tables:
- pgtbl r4 @ page table address
+ pgtbl r4, r8 @ page table address
/*
* Clear the 16K level 1 swapper page table
@@ -184,10 +189,8 @@ __create_page_tables:
/*
* Map some ram to cover our .data and .bss areas.
*/
- orr r3, r7, #(KERNEL_RAM_PADDR & 0xff000000)
- .if (KERNEL_RAM_PADDR & 0x00f00000)
- orr r3, r3, #(KERNEL_RAM_PADDR & 0x00f00000)
- .endif
+ add r3, r8, #TEXT_OFFSET
+ orr r3, r3, r7
add r0, r4, #(KERNEL_RAM_VADDR & 0xff000000) >> 18
str r3, [r0, #(KERNEL_RAM_VADDR & 0x00f00000) >> 18]!
ldr r6, =(_end - 1)
@@ -203,10 +206,7 @@ __create_page_tables:
* Then map first 1MB of ram in case it contains our boot params.
*/
add r0, r4, #PAGE_OFFSET >> 18
- orr r6, r7, #(PHYS_OFFSET & 0xff000000)
- .if (PHYS_OFFSET & 0x00f00000)
- orr r6, r6, #(PHYS_OFFSET & 0x00f00000)
- .endif
+ orr r6, r7, r8
str r6, [r0]
#ifdef CONFIG_DEBUG_LL