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author | Russell King <rmk+kernel@arm.linux.org.uk> | 2011-01-04 19:04:00 +0000 |
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committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2011-02-17 23:27:30 +0000 |
commit | 72a20e22f49e2dad3180c23980a9df1c63faab0a (patch) | |
tree | 97edaa9db248ecc7e9a6a66c1ef5a054412af5c2 /arch/arm/kernel | |
parent | b75c178afaa975896e894bb2b6951dc4cd43c977 (diff) | |
download | op-kernel-dev-72a20e22f49e2dad3180c23980a9df1c63faab0a.zip op-kernel-dev-72a20e22f49e2dad3180c23980a9df1c63faab0a.tar.gz |
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')
-rw-r--r-- | arch/arm/kernel/head.S | 44 |
1 files changed, 22 insertions, 22 deletions
diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S index 8a154b9..03a588b 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 |