diff options
Diffstat (limited to 'arch/microblaze/kernel/head.S')
| -rw-r--r-- | arch/microblaze/kernel/head.S | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/arch/microblaze/kernel/head.S b/arch/microblaze/kernel/head.S index 319dc35fc92..e568d6ec621 100644 --- a/arch/microblaze/kernel/head.S +++ b/arch/microblaze/kernel/head.S @@ -3,6 +3,26 @@ * Copyright (C) 2007-2009 PetaLogix * Copyright (C) 2006 Atmark Techno, Inc. * + * MMU code derived from arch/ppc/kernel/head_4xx.S: + * Copyright (c) 1995-1996 Gary Thomas <gdt@linuxppc.org> + * Initial PowerPC version. + * Copyright (c) 1996 Cort Dougan <cort@cs.nmt.edu> + * Rewritten for PReP + * Copyright (c) 1996 Paul Mackerras <paulus@cs.anu.edu.au> + * Low-level exception handers, MMU support, and rewrite. + * Copyright (c) 1997 Dan Malek <dmalek@jlc.net> + * PowerPC 8xx modifications. + * Copyright (c) 1998-1999 TiVo, Inc. + * PowerPC 403GCX modifications. + * Copyright (c) 1999 Grant Erickson <grant@lcse.umn.edu> + * PowerPC 403GCX/405GP modifications. + * Copyright 2000 MontaVista Software Inc. + * PPC405 modifications + * PowerPC 403GCX/405GP modifications. + * Author: MontaVista Software, Inc. + * frank_rowand@mvista.com or source@mvista.com + * debbie_chu@mvista.com + * * This file is subject to the terms and conditions of the GNU General Public * License. See the file "COPYING" in the main directory of this archive * for more details. @@ -12,6 +32,22 @@ #include <asm/thread_info.h> #include <asm/page.h> +#ifdef CONFIG_MMU +#include <asm/setup.h> /* COMMAND_LINE_SIZE */ +#include <asm/mmu.h> +#include <asm/processor.h> + +.data +.global empty_zero_page +.align 12 +empty_zero_page: + .space 4096 +.global swapper_pg_dir +swapper_pg_dir: + .space 4096 + +#endif /* CONFIG_MMU */ + .text ENTRY(_start) mfs r1, rmsr @@ -32,6 +68,123 @@ _copy_fdt: addik r3, r3, -4 /* descrement loop */ no_fdt_arg: +#ifdef CONFIG_MMU + +#ifndef CONFIG_CMDLINE_BOOL +/* + * handling command line + * copy command line to __init_end. There is space for storing command line. + */ + or r6, r0, r0 /* incremment */ + ori r4, r0, __init_end /* load address of command line */ + tophys(r4,r4) /* convert to phys address */ + ori r3, r0, COMMAND_LINE_SIZE - 1 /* number of loops */ +_copy_command_line: + lbu r7, r5, r6 /* r7=r5+r6 - r5 contain pointer to command line */ + sb r7, r4, r6 /* addr[r4+r6]= r7*/ + addik r6, r6, 1 /* increment counting */ + bgtid r3, _copy_command_line /* loop for all entries */ + addik r3, r3, -1 /* descrement loop */ + addik r5, r4, 0 /* add new space for command line */ + tovirt(r5,r5) +#endif /* CONFIG_CMDLINE_BOOL */ + +#ifdef NOT_COMPILE +/* save bram context */ + or r6, r0, r0 /* incremment */ + ori r4, r0, TOPHYS(_bram_load_start) /* save bram context */ + ori r3, r0, (LMB_SIZE - 4) +_copy_bram: + lw r7, r0, r6 /* r7 = r0 + r6 */ + sw r7, r4, r6 /* addr[r4 + r6] = r7*/ + addik r6, r6, 4 /* increment counting */ + bgtid r3, _copy_bram /* loop for all entries */ + addik r3, r3, -4 /* descrement loop */ +#endif + /* We have to turn on the MMU right away. */ + + /* + * Set up the initial MMU state so we can do the first level of + * kernel initialization. This maps the first 16 MBytes of memory 1:1 + * virtual to physical. + */ + nop + addik r3, r0, 63 /* Invalidate all TLB entries */ +_invalidate: + mts rtlbx, r3 + mts rtlbhi, r0 /* flush: ensure V is clear */ + bgtid r3, _invalidate /* loop for all entries */ + addik r3, r3, -1 + /* sync */ + + /* + * We should still be executing code at physical address area + * RAM_BASEADDR at this point. However, kernel code is at + * a virtual address. So, set up a TLB mapping to cover this once + * translation is enabled. + */ + + addik r3,r0, CONFIG_KERNEL_START /* Load the kernel virtual address */ + tophys(r4,r3) /* Load the kernel physical address */ + + mts rpid,r0 /* Load the kernel PID */ + nop + bri 4 + + /* + * Configure and load two entries into TLB slots 0 and 1. + * In case we are pinning TLBs, these are reserved in by the + * other TLB functions. If not reserving, then it doesn't + * matter where they are loaded. + */ + andi r4,r4,0xfffffc00 /* Mask off the real page number */ + ori r4,r4,(TLB_WR | TLB_EX) /* Set the write and execute bits */ + + andi r3,r3,0xfffffc00 /* Mask off the effective page number */ + ori r3,r3,(TLB_VALID | TLB_PAGESZ(PAGESZ_16M)) + + mts rtlbx,r0 /* TLB slow 0 */ + + mts rtlblo,r4 /* Load the data portion of the entry */ + mts rtlbhi,r3 /* Load the tag portion of the entry */ + + addik r4, r4, 0x01000000 /* Map next 16 M entries */ + addik r3, r3, 0x01000000 + + ori r6,r0,1 /* TLB slot 1 */ + mts rtlbx,r6 + + mts rtlblo,r4 /* Load the data portion of the entry */ + mts rtlbhi,r3 /* Load the tag portion of the entry */ + + /* + * Load a TLB entry for LMB, since we need access to + * the exception vectors, using a 4k real==virtual mapping. + */ + ori r6,r0,3 /* TLB slot 3 */ + mts rtlbx,r6 + + ori r4,r0,(TLB_WR | TLB_EX) + ori r3,r0,(TLB_VALID | TLB_PAGESZ(PAGESZ_4K)) + + mts rtlblo,r4 /* Load the data portion of the entry */ + mts rtlbhi,r3 /* Load the tag portion of the entry */ + + /* + * We now have the lower 16 Meg of RAM mapped into TLB entries, and the + * caches ready to work. + */ +turn_on_mmu: + ori r15,r0,start_here + ori r4,r0,MSR_KERNEL_VMS + mts rmsr,r4 + nop + rted r15,0 /* enables MMU */ + nop + +start_here: +#endif /* CONFIG_MMU */ + /* Initialize small data anchors */ la r13, r0, _KERNEL_SDA_BASE_ la r2, r0, _KERNEL_SDA2_BASE_ @@ -51,6 +204,43 @@ no_fdt_arg: brald r15, r8 nop +#ifndef CONFIG_MMU la r15, r0, machine_halt braid start_kernel nop +#else + /* + * Initialize the MMU. + */ + bralid r15, mmu_init + nop + + /* Go back to running unmapped so we can load up new values + * and change to using our exception vectors. + * On the MicroBlaze, all we invalidate the used TLB entries to clear + * the old 16M byte TLB mappings. + */ + ori r15,r0,TOPHYS(kernel_load_context) + ori r4,r0,MSR_KERNEL + mts rmsr,r4 + nop + bri 4 + rted r15,0 + nop + + /* Load up the kernel context */ +kernel_load_context: + # Keep entry 0 and 1 valid. Entry 3 mapped to LMB can go away. + ori r5,r0,3 + mts rtlbx,r5 + nop + mts rtlbhi,r0 + nop + addi r15, r0, machine_halt + ori r17, r0, start_kernel + ori r4, r0, MSR_KERNEL_VMS + mts rmsr, r4 + nop + rted r17, 0 /* enable MMU and jump to start_kernel */ + nop +#endif /* CONFIG_MMU */ |