347 lines
9.0 KiB
ArmAsm
347 lines
9.0 KiB
ArmAsm
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/* SPDX-License-Identifier: GPL-2.0
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*
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* arch/sh/kernel/head_64.S
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*
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* Copyright (C) 2000, 2001 Paolo Alberelli
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* Copyright (C) 2003, 2004 Paul Mundt
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*/
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#include <linux/init.h>
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#include <asm/page.h>
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#include <asm/cache.h>
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#include <asm/tlb.h>
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#include <cpu/registers.h>
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#include <cpu/mmu_context.h>
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#include <asm/thread_info.h>
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/*
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* MMU defines: TLB boundaries.
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*/
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#define MMUIR_FIRST ITLB_FIXED
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#define MMUIR_END ITLB_LAST_VAR_UNRESTRICTED+TLB_STEP
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#define MMUIR_STEP TLB_STEP
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#define MMUDR_FIRST DTLB_FIXED
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#define MMUDR_END DTLB_LAST_VAR_UNRESTRICTED+TLB_STEP
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#define MMUDR_STEP TLB_STEP
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/* Safety check : CONFIG_PAGE_OFFSET has to be a multiple of 512Mb */
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#if (CONFIG_PAGE_OFFSET & ((1UL<<29)-1))
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#error "CONFIG_PAGE_OFFSET must be a multiple of 512Mb"
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#endif
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/*
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* MMU defines: Fixed TLBs.
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*/
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/* Deal safely with the case where the base of RAM is not 512Mb aligned */
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#define ALIGN_512M_MASK (0xffffffffe0000000)
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#define ALIGNED_EFFECTIVE ((CONFIG_PAGE_OFFSET + CONFIG_MEMORY_START) & ALIGN_512M_MASK)
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#define ALIGNED_PHYSICAL (CONFIG_MEMORY_START & ALIGN_512M_MASK)
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#define MMUIR_TEXT_H (0x0000000000000003 | ALIGNED_EFFECTIVE)
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/* Enabled, Shared, ASID 0, Eff. Add. 0xA0000000 */
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#define MMUIR_TEXT_L (0x000000000000009a | ALIGNED_PHYSICAL)
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/* 512 Mb, Cacheable, Write-back, execute, Not User, Ph. Add. */
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#define MMUDR_CACHED_H 0x0000000000000003 | ALIGNED_EFFECTIVE
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/* Enabled, Shared, ASID 0, Eff. Add. 0xA0000000 */
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#define MMUDR_CACHED_L 0x000000000000015a | ALIGNED_PHYSICAL
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/* 512 Mb, Cacheable, Write-back, read/write, Not User, Ph. Add. */
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#ifdef CONFIG_CACHE_OFF
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#define ICCR0_INIT_VAL ICCR0_OFF /* ICACHE off */
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#else
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#define ICCR0_INIT_VAL ICCR0_ON | ICCR0_ICI /* ICE + ICI */
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#endif
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#define ICCR1_INIT_VAL ICCR1_NOLOCK /* No locking */
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#if defined (CONFIG_CACHE_OFF)
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#define OCCR0_INIT_VAL OCCR0_OFF /* D-cache: off */
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#elif defined (CONFIG_CACHE_WRITETHROUGH)
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#define OCCR0_INIT_VAL OCCR0_ON | OCCR0_OCI | OCCR0_WT /* D-cache: on, */
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/* WT, invalidate */
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#elif defined (CONFIG_CACHE_WRITEBACK)
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#define OCCR0_INIT_VAL OCCR0_ON | OCCR0_OCI | OCCR0_WB /* D-cache: on, */
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/* WB, invalidate */
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#else
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#error preprocessor flag CONFIG_CACHE_... not recognized!
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#endif
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#define OCCR1_INIT_VAL OCCR1_NOLOCK /* No locking */
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.section .empty_zero_page, "aw"
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.global empty_zero_page
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empty_zero_page:
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.long 1 /* MOUNT_ROOT_RDONLY */
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.long 0 /* RAMDISK_FLAGS */
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.long 0x0200 /* ORIG_ROOT_DEV */
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.long 1 /* LOADER_TYPE */
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.long 0x00800000 /* INITRD_START */
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.long 0x00800000 /* INITRD_SIZE */
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.long 0
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.text
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.balign 4096,0,4096
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.section .data, "aw"
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.balign PAGE_SIZE
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.section .data, "aw"
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.balign PAGE_SIZE
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.global mmu_pdtp_cache
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mmu_pdtp_cache:
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.space PAGE_SIZE, 0
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.global fpu_in_use
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fpu_in_use: .quad 0
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__HEAD
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.balign L1_CACHE_BYTES
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/*
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* Condition at the entry of __stext:
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* . Reset state:
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* . SR.FD = 1 (FPU disabled)
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* . SR.BL = 1 (Exceptions disabled)
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* . SR.MD = 1 (Privileged Mode)
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* . SR.MMU = 0 (MMU Disabled)
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* . SR.CD = 0 (CTC User Visible)
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* . SR.IMASK = Undefined (Interrupt Mask)
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*
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* Operations supposed to be performed by __stext:
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* . prevent speculative fetch onto device memory while MMU is off
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* . reflect as much as possible SH5 ABI (r15, r26, r27, r18)
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* . first, save CPU state and set it to something harmless
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* . any CPU detection and/or endianness settings (?)
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* . initialize EMI/LMI (but not TMU/RTC/INTC/SCIF): TBD
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* . set initial TLB entries for cached and uncached regions
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* (no fine granularity paging)
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* . set initial cache state
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* . enable MMU and caches
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* . set CPU to a consistent state
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* . registers (including stack pointer and current/KCR0)
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* . NOT expecting to set Exception handling nor VBR/RESVEC/DCR
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* at this stage. This is all to later Linux initialization steps.
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* . initialize FPU
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* . clear BSS
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* . jump into start_kernel()
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* . be prepared to hopeless start_kernel() returns.
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*
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*/
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.global _stext
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_stext:
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/*
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* Prevent speculative fetch on device memory due to
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* uninitialized target registers.
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*/
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ptabs/u ZERO, tr0
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ptabs/u ZERO, tr1
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ptabs/u ZERO, tr2
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ptabs/u ZERO, tr3
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ptabs/u ZERO, tr4
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ptabs/u ZERO, tr5
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ptabs/u ZERO, tr6
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ptabs/u ZERO, tr7
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synci
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/*
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* Read/Set CPU state. After this block:
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* r29 = Initial SR
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*/
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getcon SR, r29
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movi SR_HARMLESS, r20
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putcon r20, SR
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/*
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* Initialize EMI/LMI. To Be Done.
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*/
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/*
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* CPU detection and/or endianness settings (?). To Be Done.
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* Pure PIC code here, please ! Just save state into r30.
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* After this block:
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* r30 = CPU type/Platform Endianness
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*/
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/*
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* Set initial TLB entries for cached and uncached regions.
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* Note: PTA/BLINK is PIC code, PTABS/BLINK isn't !
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*/
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/* Clear ITLBs */
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pta clear_ITLB, tr1
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movi MMUIR_FIRST, r21
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movi MMUIR_END, r22
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clear_ITLB:
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putcfg r21, 0, ZERO /* Clear MMUIR[n].PTEH.V */
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addi r21, MMUIR_STEP, r21
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bne r21, r22, tr1
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/* Clear DTLBs */
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pta clear_DTLB, tr1
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movi MMUDR_FIRST, r21
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movi MMUDR_END, r22
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clear_DTLB:
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putcfg r21, 0, ZERO /* Clear MMUDR[n].PTEH.V */
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addi r21, MMUDR_STEP, r21
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bne r21, r22, tr1
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/* Map one big (512Mb) page for ITLB */
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movi MMUIR_FIRST, r21
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movi MMUIR_TEXT_L, r22 /* PTEL first */
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add.l r22, r63, r22 /* Sign extend */
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putcfg r21, 1, r22 /* Set MMUIR[0].PTEL */
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movi MMUIR_TEXT_H, r22 /* PTEH last */
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add.l r22, r63, r22 /* Sign extend */
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putcfg r21, 0, r22 /* Set MMUIR[0].PTEH */
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/* Map one big CACHED (512Mb) page for DTLB */
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movi MMUDR_FIRST, r21
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movi MMUDR_CACHED_L, r22 /* PTEL first */
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add.l r22, r63, r22 /* Sign extend */
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putcfg r21, 1, r22 /* Set MMUDR[0].PTEL */
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movi MMUDR_CACHED_H, r22 /* PTEH last */
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add.l r22, r63, r22 /* Sign extend */
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putcfg r21, 0, r22 /* Set MMUDR[0].PTEH */
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/*
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* Setup a DTLB translation for SCIF phys.
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*/
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addi r21, MMUDR_STEP, r21
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movi 0x0a03, r22 /* SCIF phys */
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shori 0x0148, r22
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putcfg r21, 1, r22 /* PTEL first */
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movi 0xfa03, r22 /* 0xfa030000, fixed SCIF virt */
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shori 0x0003, r22
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putcfg r21, 0, r22 /* PTEH last */
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/*
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* Set cache behaviours.
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*/
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/* ICache */
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movi ICCR_BASE, r21
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movi ICCR0_INIT_VAL, r22
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movi ICCR1_INIT_VAL, r23
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putcfg r21, ICCR_REG0, r22
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putcfg r21, ICCR_REG1, r23
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/* OCache */
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movi OCCR_BASE, r21
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movi OCCR0_INIT_VAL, r22
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movi OCCR1_INIT_VAL, r23
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putcfg r21, OCCR_REG0, r22
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putcfg r21, OCCR_REG1, r23
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/*
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* Enable Caches and MMU. Do the first non-PIC jump.
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* Now head.S global variables, constants and externs
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* can be used.
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*/
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getcon SR, r21
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movi SR_ENABLE_MMU, r22
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or r21, r22, r21
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putcon r21, SSR
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movi hyperspace, r22
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ori r22, 1, r22 /* Make it SHmedia, not required but..*/
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putcon r22, SPC
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synco
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rte /* And now go into the hyperspace ... */
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hyperspace: /* ... that's the next instruction ! */
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/*
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* Set CPU to a consistent state.
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* r31 = FPU support flag
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* tr0/tr7 in use. Others give a chance to loop somewhere safe
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*/
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movi start_kernel, r32
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ori r32, 1, r32
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ptabs r32, tr0 /* r32 = _start_kernel address */
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pta/u hopeless, tr1
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pta/u hopeless, tr2
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pta/u hopeless, tr3
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pta/u hopeless, tr4
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pta/u hopeless, tr5
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pta/u hopeless, tr6
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pta/u hopeless, tr7
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gettr tr1, r28 /* r28 = hopeless address */
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/* Set initial stack pointer */
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movi init_thread_union, SP
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putcon SP, KCR0 /* Set current to init_task */
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movi THREAD_SIZE, r22 /* Point to the end */
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add SP, r22, SP
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/*
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* Initialize FPU.
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* Keep FPU flag in r31. After this block:
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* r31 = FPU flag
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*/
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movi fpu_in_use, r31 /* Temporary */
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#ifdef CONFIG_SH_FPU
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getcon SR, r21
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movi SR_ENABLE_FPU, r22
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and r21, r22, r22
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putcon r22, SR /* Try to enable */
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getcon SR, r22
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xor r21, r22, r21
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shlri r21, 15, r21 /* Supposedly 0/1 */
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st.q r31, 0 , r21 /* Set fpu_in_use */
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#else
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movi 0, r21
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st.q r31, 0 , r21 /* Set fpu_in_use */
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#endif
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or r21, ZERO, r31 /* Set FPU flag at last */
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#ifndef CONFIG_SH_NO_BSS_INIT
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/* Don't clear BSS if running on slow platforms such as an RTL simulation,
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remote memory via SHdebug link, etc. For these the memory can be guaranteed
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to be all zero on boot anyway. */
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/*
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* Clear bss
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*/
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pta clear_quad, tr1
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movi __bss_start, r22
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movi _end, r23
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clear_quad:
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st.q r22, 0, ZERO
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addi r22, 8, r22
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bne r22, r23, tr1 /* Both quad aligned, see vmlinux.lds.S */
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#endif
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pta/u hopeless, tr1
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/* Say bye to head.S but be prepared to wrongly get back ... */
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blink tr0, LINK
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/* If we ever get back here through LINK/tr1-tr7 */
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pta/u hopeless, tr7
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hopeless:
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/*
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* Something's badly wrong here. Loop endlessly,
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* there's nothing more we can do about it.
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*
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* Note on hopeless: it can be jumped into invariably
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* before or after jumping into hyperspace. The only
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* requirement is to be PIC called (PTA) before and
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* any way (PTA/PTABS) after. According to Virtual
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* to Physical mapping a simulator/emulator can easily
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* tell where we came here from just looking at hopeless
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* (PC) address.
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*
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* For debugging purposes:
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* (r28) hopeless/loop address
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* (r29) Original SR
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* (r30) CPU type/Platform endianness
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* (r31) FPU Support
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* (r32) _start_kernel address
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*/
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blink tr7, ZERO
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