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Diffstat (limited to 'arch/sh64/kernel/head.S')
| -rw-r--r-- | arch/sh64/kernel/head.S | 373 |
1 files changed, 373 insertions, 0 deletions
diff --git a/arch/sh64/kernel/head.S b/arch/sh64/kernel/head.S new file mode 100644 index 000000000000..cc0b628a9ea7 --- /dev/null +++ b/arch/sh64/kernel/head.S @@ -0,0 +1,373 @@ +/* + * 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. + * + * arch/sh64/kernel/head.S + * + * Copyright (C) 2000, 2001 Paolo Alberelli + * Copyright (C) 2003, 2004 Paul Mundt + * + * + * benedict.gaster@superh.com: 2nd May 2002 + * Moved definition of empty_zero_page to its own section allowing + * it to be placed at an absolute address known at load time. + * + * lethal@linux-sh.org: 9th May 2003 + * Kill off GLOBAL_NAME() usage. + * + * lethal@linux-sh.org: 8th May 2004 + * Add early SCIF console DTLB mapping. + */ + +#include <linux/config.h> + +#include <asm/page.h> +#include <asm/mmu_context.h> +#include <asm/cache.h> +#include <asm/tlb.h> +#include <asm/processor.h> +#include <asm/registers.h> +#include <asm/thread_info.h> + +/* + * MMU defines: TLB boundaries. + */ + +#define MMUIR_FIRST ITLB_FIXED +#define MMUIR_END ITLB_LAST_VAR_UNRESTRICTED+TLB_STEP +#define MMUIR_STEP TLB_STEP + +#define MMUDR_FIRST DTLB_FIXED +#define MMUDR_END DTLB_LAST_VAR_UNRESTRICTED+TLB_STEP +#define MMUDR_STEP TLB_STEP + +/* Safety check : CONFIG_CACHED_MEMORY_OFFSET has to be a multiple of 512Mb */ +#if (CONFIG_CACHED_MEMORY_OFFSET & ((1UL<<29)-1)) +#error "CONFIG_CACHED_MEMORY_OFFSET must be a multiple of 512Mb" +#endif + +/* + * MMU defines: Fixed TLBs. + */ +/* Deal safely with the case where the base of RAM is not 512Mb aligned */ + +#define ALIGN_512M_MASK (0xffffffffe0000000) +#define ALIGNED_EFFECTIVE ((CONFIG_CACHED_MEMORY_OFFSET + CONFIG_MEMORY_START) & ALIGN_512M_MASK) +#define ALIGNED_PHYSICAL (CONFIG_MEMORY_START & ALIGN_512M_MASK) + +#define MMUIR_TEXT_H (0x0000000000000003 | ALIGNED_EFFECTIVE) + /* Enabled, Shared, ASID 0, Eff. Add. 0xA0000000 */ + +#define MMUIR_TEXT_L (0x000000000000009a | ALIGNED_PHYSICAL) + /* 512 Mb, Cacheable, Write-back, execute, Not User, Ph. Add. */ + +#define MMUDR_CACHED_H 0x0000000000000003 | ALIGNED_EFFECTIVE + /* Enabled, Shared, ASID 0, Eff. Add. 0xA0000000 */ +#define MMUDR_CACHED_L 0x000000000000015a | ALIGNED_PHYSICAL + /* 512 Mb, Cacheable, Write-back, read/write, Not User, Ph. Add. */ + +#ifdef CONFIG_ICACHE_DISABLED +#define ICCR0_INIT_VAL ICCR0_OFF /* ICACHE off */ +#else +#define ICCR0_INIT_VAL ICCR0_ON | ICCR0_ICI /* ICE + ICI */ +#endif +#define ICCR1_INIT_VAL ICCR1_NOLOCK /* No locking */ + +#if defined (CONFIG_DCACHE_DISABLED) +#define OCCR0_INIT_VAL OCCR0_OFF /* D-cache: off */ +#elif defined (CONFIG_DCACHE_WRITE_THROUGH) +#define OCCR0_INIT_VAL OCCR0_ON | OCCR0_OCI | OCCR0_WT /* D-cache: on, */ + /* WT, invalidate */ +#elif defined (CONFIG_DCACHE_WRITE_BACK) +#define OCCR0_INIT_VAL OCCR0_ON | OCCR0_OCI | OCCR0_WB /* D-cache: on, */ + /* WB, invalidate */ +#else +#error preprocessor flag CONFIG_DCACHE_... not recognized! +#endif + +#define OCCR1_INIT_VAL OCCR1_NOLOCK /* No locking */ + + .section .empty_zero_page, "aw" + .global empty_zero_page + +empty_zero_page: + .long 1 /* MOUNT_ROOT_RDONLY */ + .long 0 /* RAMDISK_FLAGS */ + .long 0x0200 /* ORIG_ROOT_DEV */ + .long 1 /* LOADER_TYPE */ + .long 0x00800000 /* INITRD_START */ + .long 0x00800000 /* INITRD_SIZE */ + .long 0 + + .text + .balign 4096,0,4096 + + .section .data, "aw" + .balign PAGE_SIZE + + .section .data, "aw" + .balign PAGE_SIZE + + .global swapper_pg_dir +swapper_pg_dir: + .space PAGE_SIZE, 0 + + .global empty_bad_page +empty_bad_page: + .space PAGE_SIZE, 0 + + .global empty_bad_pte_table +empty_bad_pte_table: + .space PAGE_SIZE, 0 + + .global fpu_in_use +fpu_in_use: .quad 0 + + + .section .text, "ax" + .balign L1_CACHE_BYTES +/* + * Condition at the entry of __stext: + * . Reset state: + * . SR.FD = 1 (FPU disabled) + * . SR.BL = 1 (Exceptions disabled) + * . SR.MD = 1 (Privileged Mode) + * . SR.MMU = 0 (MMU Disabled) + * . SR.CD = 0 (CTC User Visible) + * . SR.IMASK = Undefined (Interrupt Mask) + * + * Operations supposed to be performed by __stext: + * . prevent speculative fetch onto device memory while MMU is off + * . reflect as much as possible SH5 ABI (r15, r26, r27, r18) + * . first, save CPU state and set it to something harmless + * . any CPU detection and/or endianness settings (?) + * . initialize EMI/LMI (but not TMU/RTC/INTC/SCIF): TBD + * . set initial TLB entries for cached and uncached regions + * (no fine granularity paging) + * . set initial cache state + * . enable MMU and caches + * . set CPU to a consistent state + * . registers (including stack pointer and current/KCR0) + * . NOT expecting to set Exception handling nor VBR/RESVEC/DCR + * at this stage. This is all to later Linux initialization steps. + * . initialize FPU + * . clear BSS + * . jump into start_kernel() + * . be prepared to hopeless start_kernel() returns. + * + */ + .global _stext +_stext: + /* + * Prevent speculative fetch on device memory due to + * uninitialized target registers. + */ + ptabs/u ZERO, tr0 + ptabs/u ZERO, tr1 + ptabs/u ZERO, tr2 + ptabs/u ZERO, tr3 + ptabs/u ZERO, tr4 + ptabs/u ZERO, tr5 + ptabs/u ZERO, tr6 + ptabs/u ZERO, tr7 + synci + + /* + * Read/Set CPU state. After this block: + * r29 = Initial SR + */ + getcon SR, r29 + movi SR_HARMLESS, r20 + putcon r20, SR + + /* + * Initialize EMI/LMI. To Be Done. + */ + + /* + * CPU detection and/or endianness settings (?). To Be Done. + * Pure PIC code here, please ! Just save state into r30. + * After this block: + * r30 = CPU type/Platform Endianness + */ + + /* + * Set initial TLB entries for cached and uncached regions. + * Note: PTA/BLINK is PIC code, PTABS/BLINK isn't ! + */ + /* Clear ITLBs */ + pta clear_ITLB, tr1 + movi MMUIR_FIRST, r21 + movi MMUIR_END, r22 +clear_ITLB: + putcfg r21, 0, ZERO /* Clear MMUIR[n].PTEH.V */ + addi r21, MMUIR_STEP, r21 + bne r21, r22, tr1 + + /* Clear DTLBs */ + pta clear_DTLB, tr1 + movi MMUDR_FIRST, r21 + movi MMUDR_END, r22 +clear_DTLB: + putcfg r21, 0, ZERO /* Clear MMUDR[n].PTEH.V */ + addi r21, MMUDR_STEP, r21 + bne r21, r22, tr1 + + /* Map one big (512Mb) page for ITLB */ + movi MMUIR_FIRST, r21 + movi MMUIR_TEXT_L, r22 /* PTEL first */ + add.l r22, r63, r22 /* Sign extend */ + putcfg r21, 1, r22 /* Set MMUIR[0].PTEL */ + movi MMUIR_TEXT_H, r22 /* PTEH last */ + add.l r22, r63, r22 /* Sign extend */ + putcfg r21, 0, r22 /* Set MMUIR[0].PTEH */ + + /* Map one big CACHED (512Mb) page for DTLB */ + movi MMUDR_FIRST, r21 + movi MMUDR_CACHED_L, r22 /* PTEL first */ + add.l r22, r63, r22 /* Sign extend */ + putcfg r21, 1, r22 /* Set MMUDR[0].PTEL */ + movi MMUDR_CACHED_H, r22 /* PTEH last */ + add.l r22, r63, r22 /* Sign extend */ + putcfg r21, 0, r22 /* Set MMUDR[0].PTEH */ + +#ifdef CONFIG_EARLY_PRINTK + /* + * Setup a DTLB translation for SCIF phys. + */ + addi r21, MMUDR_STEP, r21 + movi 0x0a03, r22 /* SCIF phys */ + shori 0x0148, r22 + putcfg r21, 1, r22 /* PTEL first */ + movi 0xfa03, r22 /* 0xfa030000, fixed SCIF virt */ + shori 0x0003, r22 + putcfg r21, 0, r22 /* PTEH last */ +#endif + + /* + * Set cache behaviours. + */ + /* ICache */ + movi ICCR_BASE, r21 + movi ICCR0_INIT_VAL, r22 + movi ICCR1_INIT_VAL, r23 + putcfg r21, ICCR_REG0, r22 + putcfg r21, ICCR_REG1, r23 + + /* OCache */ + movi OCCR_BASE, r21 + movi OCCR0_INIT_VAL, r22 + movi OCCR1_INIT_VAL, r23 + putcfg r21, OCCR_REG0, r22 + putcfg r21, OCCR_REG1, r23 + + + /* + * Enable Caches and MMU. Do the first non-PIC jump. + * Now head.S global variables, constants and externs + * can be used. + */ + getcon SR, r21 + movi SR_ENABLE_MMU, r22 + or r21, r22, r21 + putcon r21, SSR + movi hyperspace, r22 + ori r22, 1, r22 /* Make it SHmedia, not required but..*/ + putcon r22, SPC + synco + rte /* And now go into the hyperspace ... */ +hyperspace: /* ... that's the next instruction ! */ + + /* + * Set CPU to a consistent state. + * r31 = FPU support flag + * tr0/tr7 in use. Others give a chance to loop somewhere safe + */ + movi start_kernel, r32 + ori r32, 1, r32 + + ptabs r32, tr0 /* r32 = _start_kernel address */ + pta/u hopeless, tr1 + pta/u hopeless, tr2 + pta/u hopeless, tr3 + pta/u hopeless, tr4 + pta/u hopeless, tr5 + pta/u hopeless, tr6 + pta/u hopeless, tr7 + gettr tr1, r28 /* r28 = hopeless address */ + + /* Set initial stack pointer */ + movi init_thread_union, SP + putcon SP, KCR0 /* Set current to init_task */ + movi THREAD_SIZE, r22 /* Point to the end */ + add SP, r22, SP + + /* + * Initialize FPU. + * Keep FPU flag in r31. After this block: + * r31 = FPU flag + */ + movi fpu_in_use, r31 /* Temporary */ + +#ifdef CONFIG_SH_FPU + getcon SR, r21 + movi SR_ENABLE_FPU, r22 + and r21, r22, r22 + putcon r22, SR /* Try to enable */ + getcon SR, r22 + xor r21, r22, r21 + shlri r21, 15, r21 /* Supposedly 0/1 */ + st.q r31, 0 , r21 /* Set fpu_in_use */ +#else + movi 0, r21 + st.q r31, 0 , r21 /* Set fpu_in_use */ +#endif + or r21, ZERO, r31 /* Set FPU flag at last */ + +#ifndef CONFIG_SH_NO_BSS_INIT +/* Don't clear BSS if running on slow platforms such as an RTL simulation, + remote memory via SHdebug link, etc. For these the memory can be guaranteed + to be all zero on boot anyway. */ + /* + * Clear bss + */ + pta clear_quad, tr1 + movi __bss_start, r22 + movi _end, r23 +clear_quad: + st.q r22, 0, ZERO + addi r22, 8, r22 + bne r22, r23, tr1 /* Both quad aligned, see vmlinux.lds.S */ +#endif + pta/u hopeless, tr1 + + /* Say bye to head.S but be prepared to wrongly get back ... */ + blink tr0, LINK + + /* If we ever get back here through LINK/tr1-tr7 */ + pta/u hopeless, tr7 + +hopeless: + /* + * Something's badly wrong here. Loop endlessly, + * there's nothing more we can do about it. + * + * Note on hopeless: it can be jumped into invariably + * before or after jumping into hyperspace. The only + * requirement is to be PIC called (PTA) before and + * any way (PTA/PTABS) after. According to Virtual + * to Physical mapping a simulator/emulator can easily + * tell where we came here from just looking at hopeless + * (PC) address. + * + * For debugging purposes: + * (r28) hopeless/loop address + * (r29) Original SR + * (r30) CPU type/Platform endianness + * (r31) FPU Support + * (r32) _start_kernel address + */ + blink tr7, ZERO + + |