/*
- * linux/arch/arm/kernel/head-armv.S
+ * linux/arch/arm/kernel/head.S
*
* Copyright (C) 1994-2002 Russell King
*
#include <asm/ptrace.h>
#include <asm/constants.h>
+#ifndef CONFIG_XIP_KERNEL
/*
* We place the page tables 16K below TEXTADDR. Therefore, we must make sure
* that TEXTADDR is correctly set. Currently, we expect the least significant
* 16 bits to be 0x8000, but we could probably relax this restriction to
- * TEXTADDR > PAGE_OFFSET + 0x4000
+ * TEXTADDR >= PAGE_OFFSET + 0x4000
*
* Note that swapper_pg_dir is the virtual address of the page tables, and
* pgtbl gives us a position-independent reference to these tables. We can
* do this because stext == TEXTADDR
- *
- * swapper_pg_dir, pgtbl and krnladr are all closely related.
*/
#if (TEXTADDR & 0xffff) != 0x8000
#error TEXTADDR must start at 0xXXXX8000
.globl swapper_pg_dir
.equ swapper_pg_dir, TEXTADDR - 0x4000
- .macro pgtbl, reg
- adr \reg, stext
- sub \reg, \reg, #0x4000
+ .macro pgtbl, rd, phys
+ adr \rd, stext
+ sub \rd, \rd, #0x4000
.endm
-
+#else
/*
- * Since the page table is closely related to the kernel start address, we
- * can convert the page table base address to the base address of the section
- * containing both.
+ * XIP Kernel:
+ *
+ * We place the page tables 16K below DATAADDR. Therefore, we must make sure
+ * that DATAADDR is correctly set. Currently, we expect the least significant
+ * 16 bits to be 0x8000, but we could probably relax this restriction to
+ * DATAADDR >= PAGE_OFFSET + 0x4000
+ *
+ * Note that pgtbl is meant to return the physical address of swapper_pg_dir.
+ * We can't make it relative to the kernel position in this case since
+ * the kernel can physically be anywhere.
*/
- .macro krnladr, rd, pgtable
- bic \rd, \pgtable, #0x000ff000
+#if (DATAADDR & 0xffff) != 0x8000
+#error DATAADDR must start at 0xXXXX8000
+#endif
+
+ .globl swapper_pg_dir
+ .equ swapper_pg_dir, DATAADDR - 0x4000
+
+ .macro pgtbl, rd, phys
+ ldr \rd, =((DATAADDR - 0x4000) - VIRT_OFFSET)
+ add \rd, \rd, \phys
.endm
+#endif
/*
* Kernel startup entry point.
.type __switch_data, %object
__switch_data:
.long __mmap_switched
+ .long __data_loc @ r2
+ .long __data_start @ r3
.long __bss_start @ r4
.long _end @ r5
.long processor_id @ r6
*/
.align 5
__mmap_switched:
- adr r3, __switch_data + 4
- ldmia r3, {r4, r5, r6, r7, r8, sp}
+ adr r2, __switch_data + 4
+ ldmia r2, {r2, r3, r4, r5, r6, r7, r8, sp}
+
+ cmp r2, r3 @ Copy data segment if needed
+1: cmpne r3, r4
+ ldrne fp, [r2], #4
+ strne fp, [r3], #4
+ bne 1b
+
mov fp, #0 @ Clear BSS (and zero fp)
1: cmp r4, r5
strcc fp, [r4],#4
bcc 1b
+
str r9, [r6] @ Save processor ID
str r1, [r7] @ Save machine type
bic r2, r0, #2 @ Clear 'A' bit
* amount which are required to get the kernel running, which
* generally means mapping in the kernel code.
*
- * We only map in 4MB of RAM, which should be sufficient in
- * all cases.
- *
* r5 = physical address of start of RAM
* r6 = physical IO address
* r7 = byte offset into page tables for IO
* r8 = page table flags
*/
__create_page_tables:
- pgtbl r4 @ page table address
+ pgtbl r4, r5 @ page table address
/*
* Clear the 16K level 1 swapper page table
/*
* Create identity mapping for first MB of kernel to
* cater for the MMU enable. This identity mapping
- * will be removed by paging_init()
+ * will be removed by paging_init(). We use our current program
+ * counter to determine corresponding section base address.
*/
- krnladr r2, r4 @ start of kernel
- add r3, r8, r2 @ flags + kernel base
- str r3, [r4, r2, lsr #18] @ identity mapping
+ mov r2, pc, lsr #20 @ start of kernel section
+ add r3, r8, r2, lsl #20 @ flags + kernel base
+ str r3, [r4, r2, lsl #2] @ identity mapping
/*
* Now setup the pagetables for our kernel direct
* mapped region. We round TEXTADDR down to the
- * nearest megabyte boundary.
+ * nearest megabyte boundary. It is assumed that
+ * the kernel fits within 4 contigous 1MB sections.
*/
- add r0, r4, #(TEXTADDR & 0xff000000) >> 18 @ start of kernel
- bic r2, r3, #0x00f00000
- str r2, [r0] @ PAGE_OFFSET + 0MB
- add r0, r0, #(TEXTADDR & 0x00f00000) >> 18
- str r3, [r0], #4 @ KERNEL + 0MB
+ add r0, r4, #(TEXTADDR & 0xff000000) >> 18 @ start of kernel
+ str r3, [r0, #(TEXTADDR & 0x00f00000) >> 18]!
add r3, r3, #1 << 20
- str r3, [r0], #4 @ KERNEL + 1MB
+ str r3, [r0, #4]! @ KERNEL + 1MB
add r3, r3, #1 << 20
- str r3, [r0], #4 @ KERNEL + 2MB
+ str r3, [r0, #4]! @ KERNEL + 2MB
add r3, r3, #1 << 20
- str r3, [r0], #4 @ KERNEL + 3MB
+ str r3, [r0, #4] @ KERNEL + 3MB
+
+ /*
+ * Then map first 1MB of ram in case it contains our boot params.
+ */
+ add r0, r4, #VIRT_OFFSET >> 18
+ add r2, r5, r8
+ str r2, [r0]
+
+#ifdef CONFIG_XIP_KERNEL
+ /*
+ * Map some ram to cover our .data and .bss areas.
+ * Mapping 3MB should be plenty.
+ */
+ sub r3, r4, r5
+ mov r3, r3, lsr #20
+ add r0, r0, r3, lsl #2
+ add r2, r2, r3, lsl #20
+ str r2, [r0], #4
+ add r2, r2, #(1 << 20)
+ str r2, [r0], #4
+ add r2, r2, #(1 << 20)
+ str r2, [r0]
+#endif
bic r8, r8, #0x0c @ turn off cacheable
@ and bufferable bits
str r3, [r0]
#endif
mov pc, lr
+ .ltorg
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