diff options
Diffstat (limited to 'arch/unicore32/kernel/head.S')
| -rw-r--r-- | arch/unicore32/kernel/head.S | 249 |
1 files changed, 0 insertions, 249 deletions
diff --git a/arch/unicore32/kernel/head.S b/arch/unicore32/kernel/head.S deleted file mode 100644 index 9bbb8668f9f7..000000000000 --- a/arch/unicore32/kernel/head.S +++ /dev/null @@ -1,249 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0-only */ -/* - * linux/arch/unicore32/kernel/head.S - * - * Code specific to PKUnity SoC and UniCore ISA - * - * Copyright (C) 2001-2010 GUAN Xue-tao - */ -#include <linux/linkage.h> -#include <linux/init.h> - -#include <asm/assembler.h> -#include <asm/ptrace.h> -#include <generated/asm-offsets.h> -#include <asm/memory.h> -#include <asm/thread_info.h> -#include <asm/hwdef-copro.h> -#include <asm/pgtable-hwdef.h> - -#if (PHYS_OFFSET & 0x003fffff) -#error "PHYS_OFFSET must be at an even 4MiB boundary!" -#endif - -#define KERNEL_RAM_VADDR (PAGE_OFFSET + KERNEL_IMAGE_START) -#define KERNEL_RAM_PADDR (PHYS_OFFSET + KERNEL_IMAGE_START) - -#define KERNEL_PGD_PADDR (KERNEL_RAM_PADDR - 0x1000) -#define KERNEL_PGD_VADDR (KERNEL_RAM_VADDR - 0x1000) - -#define KERNEL_START KERNEL_RAM_VADDR -#define KERNEL_END _end - -/* - * swapper_pg_dir is the virtual address of the initial page table. - * We place the page tables 4K below KERNEL_RAM_VADDR. Therefore, we must - * make sure that KERNEL_RAM_VADDR is correctly set. Currently, we expect - * the least significant 16 bits to be 0x8000, but we could probably - * relax this restriction to KERNEL_RAM_VADDR >= PAGE_OFFSET + 0x1000. - */ -#if (KERNEL_RAM_VADDR & 0xffff) != 0x8000 -#error KERNEL_RAM_VADDR must start at 0xXXXX8000 -#endif - - .globl swapper_pg_dir - .equ swapper_pg_dir, KERNEL_RAM_VADDR - 0x1000 - -/* - * Kernel startup entry point. - * --------------------------- - * - * This is normally called from the decompressor code. The requirements - * are: MMU = off, D-cache = off, I-cache = dont care - * - * This code is mostly position independent, so if you link the kernel at - * 0xc0008000, you call this at __pa(0xc0008000). - */ - __HEAD -ENTRY(stext) - @ set asr - mov r0, #PRIV_MODE @ ensure priv mode - or r0, #PSR_R_BIT | PSR_I_BIT @ disable irqs - mov.a asr, r0 - - @ process identify - movc r0, p0.c0, #0 @ cpuid - movl r1, 0xff00ffff @ mask - movl r2, 0x4d000863 @ value - and r0, r1, r0 - cxor.a r0, r2 - bne __error_p @ invalid processor id - - /* - * Clear the 4K level 1 swapper page table - */ - movl r0, #KERNEL_PGD_PADDR @ page table address - mov r1, #0 - add r2, r0, #0x1000 -101: stw.w r1, [r0]+, #4 - stw.w r1, [r0]+, #4 - stw.w r1, [r0]+, #4 - stw.w r1, [r0]+, #4 - cxor.a r0, r2 - bne 101b - - movl r4, #KERNEL_PGD_PADDR @ page table address - mov r7, #PMD_TYPE_SECT | PMD_PRESENT @ page size: section - or r7, r7, #PMD_SECT_CACHEABLE @ cacheable - or r7, r7, #PMD_SECT_READ | PMD_SECT_WRITE | PMD_SECT_EXEC - - /* - * Create identity mapping for first 4MB of kernel to - * cater for the MMU enable. This identity mapping - * will be removed by paging_init(). We use our current program - * counter to determine corresponding section base address. - */ - mov r6, pc - mov r6, r6 >> #22 @ start of kernel section - or r1, r7, r6 << #22 @ flags + kernel base - stw r1, [r4+], r6 << #2 @ identity mapping - - /* - * Now setup the pagetables for our kernel direct - * mapped region. - */ - add r0, r4, #(KERNEL_START & 0xff000000) >> 20 - stw.w r1, [r0+], #(KERNEL_START & 0x00c00000) >> 20 - movl r6, #(KERNEL_END - 1) - add r0, r0, #4 - add r6, r4, r6 >> #20 -102: csub.a r0, r6 - add r1, r1, #1 << 22 - bua 103f - stw.w r1, [r0]+, #4 - b 102b -103: - /* - * Then map first 4MB of ram in case it contains our boot params. - */ - add r0, r4, #PAGE_OFFSET >> 20 - or r6, r7, #(PHYS_OFFSET & 0xffc00000) - stw r6, [r0] - - ldw r15, __switch_data @ address to jump to after - - /* - * Initialise TLB, Caches, and MMU state ready to switch the MMU - * on. - */ - mov r0, #0 - movc p0.c5, r0, #28 @ cache invalidate all - nop8 - movc p0.c6, r0, #6 @ TLB invalidate all - nop8 - - /* - * ..V. .... ..TB IDAM - * ..1. .... ..01 1111 - */ - movl r0, #0x201f @ control register setting - - /* - * Setup common bits before finally enabling the MMU. Essentially - * this is just loading the page table pointer and domain access - * registers. - */ - #ifndef CONFIG_ALIGNMENT_TRAP - andn r0, r0, #CR_A - #endif - #ifdef CONFIG_CPU_DCACHE_DISABLE - andn r0, r0, #CR_D - #endif - #ifdef CONFIG_CPU_DCACHE_WRITETHROUGH - andn r0, r0, #CR_B - #endif - #ifdef CONFIG_CPU_ICACHE_DISABLE - andn r0, r0, #CR_I - #endif - - movc p0.c2, r4, #0 @ set pgd - b __turn_mmu_on -ENDPROC(stext) - -/* - * Enable the MMU. This completely changes the structure of the visible - * memory space. You will not be able to trace execution through this. - * - * r0 = cp#0 control register - * r15 = *virtual* address to jump to upon completion - */ - .align 5 -__turn_mmu_on: - mov r0, r0 - movc p0.c1, r0, #0 @ write control reg - nop @ fetch inst by phys addr - mov pc, r15 - nop8 @ fetch inst by phys addr -ENDPROC(__turn_mmu_on) - -/* - * 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 - * - * Returns: - * r0, r3, r6, r7 corrupted - * r4 = physical page table address - */ - .ltorg - - .align 2 - .type __switch_data, %object -__switch_data: - .long __mmap_switched - .long __bss_start @ r6 - .long _end @ r7 - .long cr_alignment @ r8 - .long init_thread_union + THREAD_START_SP @ sp - -/* - * The following fragment of code is executed with the MMU on in MMU mode, - * and uses absolute addresses; this is not position independent. - * - * r0 = cp#0 control register - */ -__mmap_switched: - adr r3, __switch_data + 4 - - ldm.w (r6, r7, r8), [r3]+ - ldw sp, [r3] - - mov fp, #0 @ Clear BSS (and zero fp) -203: csub.a r6, r7 - bea 204f - stw.w fp, [r6]+,#4 - b 203b -204: - andn r1, r0, #CR_A @ Clear 'A' bit - stm (r0, r1), [r8]+ @ Save control register values - b start_kernel -ENDPROC(__mmap_switched) - -/* - * Exception handling. Something went wrong and we can't proceed. We - * ought to tell the user, but since we don't have any guarantee that - * we're even running on the right architecture, we do virtually nothing. - * - * If CONFIG_DEBUG_LL is set we try to print out something about the error - * and hope for the best (useful if bootloader fails to pass a proper - * machine ID for example). - */ -__error_p: -#ifdef CONFIG_DEBUG_LL - adr r0, str_p1 - b.l printascii - mov r0, r9 - b.l printhex8 - adr r0, str_p2 - b.l printascii -901: nop8 - b 901b -str_p1: .asciz "\nError: unrecognized processor variant (0x" -str_p2: .asciz ").\n" - .align -#endif -ENDPROC(__error_p) - |