diff options
Diffstat (limited to 'arch/riscv/kernel/head.S')
| -rw-r--r-- | arch/riscv/kernel/head.S | 509 |
1 files changed, 407 insertions, 102 deletions
diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S index fe884cd69abd..bdf3352acf4c 100644 --- a/arch/riscv/kernel/head.S +++ b/arch/riscv/kernel/head.S @@ -1,140 +1,355 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ /* * Copyright (C) 2012 Regents of the University of California - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License - * as published by the Free Software Foundation, version 2. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. */ -#include <asm/thread_info.h> #include <asm/asm-offsets.h> #include <asm/asm.h> #include <linux/init.h> #include <linux/linkage.h> #include <asm/thread_info.h> #include <asm/page.h> +#include <asm/pgtable.h> #include <asm/csr.h> +#include <asm/hwcap.h> +#include <asm/image.h> +#include <asm/scs.h> +#include <asm/xip_fixup.h> +#include "efi-header.S" + +__HEAD +SYM_CODE_START(_start) + /* + * Image header expected by Linux boot-loaders. The image header data + * structure is described in asm/image.h. + * Do not modify it without modifying the structure and all bootloaders + * that expects this header format!! + */ +#ifdef CONFIG_EFI + /* + * This instruction decodes to "MZ" ASCII required by UEFI. + */ + c.li s4,-13 + j _start_kernel +#else + /* jump to start kernel */ + j _start_kernel + /* reserved */ + .word 0 +#endif + .balign 8 +#ifdef CONFIG_RISCV_M_MODE + /* Image load offset (0MB) from start of RAM for M-mode */ + .dword 0 +#else +#if __riscv_xlen == 64 + /* Image load offset(2MB) from start of RAM */ + .dword 0x200000 +#else + /* Image load offset(4MB) from start of RAM */ + .dword 0x400000 +#endif +#endif + /* Effective size of kernel image */ + .dword _end - _start + .dword __HEAD_FLAGS + .word RISCV_HEADER_VERSION + .word 0 + .dword 0 + .ascii RISCV_IMAGE_MAGIC + .balign 4 + .ascii RISCV_IMAGE_MAGIC2 +#ifdef CONFIG_EFI + .word pe_head_start - _start +pe_head_start: + + __EFI_PE_HEADER +#else + .word 0 +#endif + +.align 2 +#ifdef CONFIG_MMU + .global relocate_enable_mmu +relocate_enable_mmu: + /* Relocate return address */ + la a1, kernel_map + XIP_FIXUP_OFFSET a1 + REG_L a1, KERNEL_MAP_VIRT_ADDR(a1) + la a2, _start + sub a1, a1, a2 + add ra, ra, a1 + + /* Point stvec to virtual address of intruction after satp write */ + la a2, 1f + add a2, a2, a1 + csrw CSR_TVEC, a2 + + /* Compute satp for kernel page tables, but don't load it yet */ + srl a2, a0, PAGE_SHIFT + la a1, satp_mode + XIP_FIXUP_OFFSET a1 + REG_L a1, 0(a1) + or a2, a2, a1 + + /* + * Load trampoline page directory, which will cause us to trap to + * stvec if VA != PA, or simply fall through if VA == PA. We need a + * full fence here because setup_vm() just wrote these PTEs and we need + * to ensure the new translations are in use. + */ + la a0, trampoline_pg_dir + XIP_FIXUP_OFFSET a0 + srl a0, a0, PAGE_SHIFT + or a0, a0, a1 + sfence.vma + csrw CSR_SATP, a0 +.align 2 +1: + /* Set trap vector to spin forever to help debug */ + la a0, .Lsecondary_park + csrw CSR_TVEC, a0 + + /* Reload the global pointer */ + load_global_pointer + + /* + * Switch to kernel page tables. A full fence is necessary in order to + * avoid using the trampoline translations, which are only correct for + * the first superpage. Fetching the fence is guaranteed to work + * because that first superpage is translated the same way. + */ + csrw CSR_SATP, a2 + sfence.vma + + ret +#endif /* CONFIG_MMU */ +#ifdef CONFIG_SMP + .global secondary_start_sbi +secondary_start_sbi: + /* Mask all interrupts */ + csrw CSR_IE, zero + csrw CSR_IP, zero + +#ifndef CONFIG_RISCV_M_MODE + /* Enable time CSR */ + li t0, 0x2 + csrw CSR_SCOUNTEREN, t0 +#endif + + /* Load the global pointer */ + load_global_pointer + + /* + * Disable FPU & VECTOR to detect illegal usage of + * floating point or vector in kernel space + */ + li t0, SR_FS_VS + csrc CSR_STATUS, t0 + + /* Set trap vector to spin forever to help debug */ + la a3, .Lsecondary_park + csrw CSR_TVEC, a3 + + /* a0 contains the hartid & a1 contains boot data */ + li a2, SBI_HART_BOOT_TASK_PTR_OFFSET + XIP_FIXUP_OFFSET a2 + add a2, a2, a1 + REG_L tp, (a2) + li a3, SBI_HART_BOOT_STACK_PTR_OFFSET + XIP_FIXUP_OFFSET a3 + add a3, a3, a1 + REG_L sp, (a3) + +.Lsecondary_start_common: + +#ifdef CONFIG_MMU + /* Enable virtual memory and relocate to virtual address */ + la a0, swapper_pg_dir + XIP_FIXUP_OFFSET a0 + call relocate_enable_mmu +#endif + call .Lsetup_trap_vector + scs_load_current + call smp_callin +#endif /* CONFIG_SMP */ + +.align 2 +.Lsecondary_park: + /* + * Park this hart if we: + * - have too many harts on CONFIG_RISCV_BOOT_SPINWAIT + * - receive an early trap, before setup_trap_vector finished + * - fail in smp_callin(), as a successful one wouldn't return + */ + wfi + j .Lsecondary_park + +.align 2 +.Lsetup_trap_vector: + /* Set trap vector to exception handler */ + la a0, handle_exception + csrw CSR_TVEC, a0 + + /* + * Set sup0 scratch register to 0, indicating to exception vector that + * we are presently executing in kernel. + */ + csrw CSR_SCRATCH, zero + ret + +SYM_CODE_END(_start) -__INIT -ENTRY(_start) +SYM_CODE_START(_start_kernel) /* Mask all interrupts */ - csrw sie, zero + csrw CSR_IE, zero + csrw CSR_IP, zero + +#ifdef CONFIG_RISCV_M_MODE + /* flush the instruction cache */ + fence.i + + /* Reset all registers except ra, a0, a1 */ + call reset_regs + + /* + * Setup a PMP to permit access to all of memory. Some machines may + * not implement PMPs, so we set up a quick trap handler to just skip + * touching the PMPs on any trap. + */ + la a0, .Lpmp_done + csrw CSR_TVEC, a0 + + li a0, -1 + csrw CSR_PMPADDR0, a0 + li a0, (PMP_A_NAPOT | PMP_R | PMP_W | PMP_X) + csrw CSR_PMPCFG0, a0 +.align 2 +.Lpmp_done: + + /* + * The hartid in a0 is expected later on, and we have no firmware + * to hand it to us. + */ + csrr a0, CSR_MHARTID +#else + /* Enable time CSR */ + li t0, 0x2 + csrw CSR_SCOUNTEREN, t0 +#endif /* CONFIG_RISCV_M_MODE */ /* Load the global pointer */ -.option push -.option norelax - la gp, __global_pointer$ -.option pop + load_global_pointer /* - * Disable FPU to detect illegal usage of - * floating point in kernel space + * Disable FPU & VECTOR to detect illegal usage of + * floating point or vector in kernel space */ - li t0, SR_FS - csrc sstatus, t0 + li t0, SR_FS_VS + csrc CSR_STATUS, t0 + +#ifdef CONFIG_RISCV_BOOT_SPINWAIT + li t0, CONFIG_NR_CPUS + blt a0, t0, .Lgood_cores + tail .Lsecondary_park +.Lgood_cores: + /* The lottery system is only required for spinwait booting method */ +#ifndef CONFIG_XIP_KERNEL /* Pick one hart to run the main boot sequence */ la a3, hart_lottery li a2, 1 amoadd.w a3, a2, (a3) bnez a3, .Lsecondary_start +#else + /* hart_lottery in flash contains a magic number */ + la a3, hart_lottery + mv a2, a3 + XIP_FIXUP_OFFSET a2 + XIP_FIXUP_FLASH_OFFSET a3 + lw t1, (a3) + amoswap.w t0, t1, (a2) + /* first time here if hart_lottery in RAM is not set */ + beq t0, t1, .Lsecondary_start + +#endif /* CONFIG_XIP */ +#endif /* CONFIG_RISCV_BOOT_SPINWAIT */ + +#ifdef CONFIG_XIP_KERNEL + la sp, _end + THREAD_SIZE + XIP_FIXUP_OFFSET sp + mv s0, a0 + mv s1, a1 + call __copy_data + + /* Restore a0 & a1 copy */ + mv a0, s0 + mv a1, s1 +#endif + +#ifndef CONFIG_XIP_KERNEL /* Clear BSS for flat non-ELF images */ la a3, __bss_start la a4, __bss_stop - ble a4, a3, clear_bss_done -clear_bss: + ble a4, a3, .Lclear_bss_done +.Lclear_bss: REG_S zero, (a3) add a3, a3, RISCV_SZPTR - blt a3, a4, clear_bss -clear_bss_done: - - /* Save hart ID and DTB physical address */ - mv s0, a0 - mv s1, a1 + blt a3, a4, .Lclear_bss +.Lclear_bss_done: +#endif la a2, boot_cpu_hartid + XIP_FIXUP_OFFSET a2 REG_S a0, (a2) /* Initialize page tables and relocate to virtual addresses */ + la tp, init_task la sp, init_thread_union + THREAD_SIZE + XIP_FIXUP_OFFSET sp + addi sp, sp, -PT_SIZE_ON_STACK + scs_load_init_stack +#ifdef CONFIG_BUILTIN_DTB + la a0, __dtb_start + XIP_FIXUP_OFFSET a0 +#else + mv a0, a1 +#endif /* CONFIG_BUILTIN_DTB */ + /* Set trap vector to spin forever to help debug */ + la a3, .Lsecondary_park + csrw CSR_TVEC, a3 call setup_vm - call relocate +#ifdef CONFIG_MMU + la a0, early_pg_dir + XIP_FIXUP_OFFSET a0 + call relocate_enable_mmu +#endif /* CONFIG_MMU */ + call .Lsetup_trap_vector /* Restore C environment */ la tp, init_task - sw zero, TASK_TI_CPU(tp) - - la sp, init_thread_union - li a0, ASM_THREAD_SIZE - add sp, sp, a0 + la sp, init_thread_union + THREAD_SIZE + addi sp, sp, -PT_SIZE_ON_STACK + scs_load_current +#ifdef CONFIG_KASAN + call kasan_early_init +#endif /* Start the kernel */ - mv a0, s0 - mv a1, s1 - call parse_dtb + call soc_early_init tail start_kernel -relocate: - /* Relocate return address */ - li a1, PAGE_OFFSET - la a0, _start - sub a1, a1, a0 - add ra, ra, a1 - - /* Point stvec to virtual address of intruction after satp write */ - la a0, 1f - add a0, a0, a1 - csrw stvec, a0 - - /* Compute satp for kernel page tables, but don't load it yet */ - la a2, swapper_pg_dir - srl a2, a2, PAGE_SHIFT - li a1, SATP_MODE - or a2, a2, a1 - - /* - * Load trampoline page directory, which will cause us to trap to - * stvec if VA != PA, or simply fall through if VA == PA - */ - la a0, trampoline_pg_dir - srl a0, a0, PAGE_SHIFT - or a0, a0, a1 - sfence.vma - csrw sptbr, a0 -.align 2 -1: - /* Set trap vector to spin forever to help debug */ - la a0, .Lsecondary_park - csrw stvec, a0 - - /* Reload the global pointer */ -.option push -.option norelax - la gp, __global_pointer$ -.option pop - - /* Switch to kernel page tables */ - csrw sptbr, a2 - - ret - +#ifdef CONFIG_RISCV_BOOT_SPINWAIT .Lsecondary_start: -#ifdef CONFIG_SMP - li a1, CONFIG_NR_CPUS - bgeu a0, a1, .Lsecondary_park - /* Set trap vector to spin forever to help debug */ la a3, .Lsecondary_park - csrw stvec, a3 + csrw CSR_TVEC, a3 slli a3, a0, LGREG - la a1, __cpu_up_stack_pointer - la a2, __cpu_up_task_pointer + la a1, __cpu_spinwait_stack_pointer + XIP_FIXUP_OFFSET a1 + la a2, __cpu_spinwait_task_pointer + XIP_FIXUP_OFFSET a2 add a1, a3, a1 add a2, a3, a2 @@ -150,19 +365,109 @@ relocate: beqz tp, .Lwait_for_cpu_up fence - /* Enable virtual memory and relocate to virtual address */ - call relocate + tail .Lsecondary_start_common +#endif /* CONFIG_RISCV_BOOT_SPINWAIT */ - tail smp_callin -#endif +SYM_CODE_END(_start_kernel) -.align 2 -.Lsecondary_park: - /* We lack SMP support or have too many harts, so park this hart */ - wfi - j .Lsecondary_park -END(_start) +#ifdef CONFIG_RISCV_M_MODE +SYM_CODE_START_LOCAL(reset_regs) + li sp, 0 + li gp, 0 + li tp, 0 + li t0, 0 + li t1, 0 + li t2, 0 + li s0, 0 + li s1, 0 + li a2, 0 + li a3, 0 + li a4, 0 + li a5, 0 + li a6, 0 + li a7, 0 + li s2, 0 + li s3, 0 + li s4, 0 + li s5, 0 + li s6, 0 + li s7, 0 + li s8, 0 + li s9, 0 + li s10, 0 + li s11, 0 + li t3, 0 + li t4, 0 + li t5, 0 + li t6, 0 + csrw CSR_SCRATCH, 0 + +#ifdef CONFIG_FPU + csrr t0, CSR_MISA + andi t0, t0, (COMPAT_HWCAP_ISA_F | COMPAT_HWCAP_ISA_D) + beqz t0, .Lreset_regs_done_fpu + + li t1, SR_FS + csrs CSR_STATUS, t1 + fmv.s.x f0, zero + fmv.s.x f1, zero + fmv.s.x f2, zero + fmv.s.x f3, zero + fmv.s.x f4, zero + fmv.s.x f5, zero + fmv.s.x f6, zero + fmv.s.x f7, zero + fmv.s.x f8, zero + fmv.s.x f9, zero + fmv.s.x f10, zero + fmv.s.x f11, zero + fmv.s.x f12, zero + fmv.s.x f13, zero + fmv.s.x f14, zero + fmv.s.x f15, zero + fmv.s.x f16, zero + fmv.s.x f17, zero + fmv.s.x f18, zero + fmv.s.x f19, zero + fmv.s.x f20, zero + fmv.s.x f21, zero + fmv.s.x f22, zero + fmv.s.x f23, zero + fmv.s.x f24, zero + fmv.s.x f25, zero + fmv.s.x f26, zero + fmv.s.x f27, zero + fmv.s.x f28, zero + fmv.s.x f29, zero + fmv.s.x f30, zero + fmv.s.x f31, zero + csrw fcsr, 0 + /* note that the caller must clear SR_FS */ +.Lreset_regs_done_fpu: +#endif /* CONFIG_FPU */ -__PAGE_ALIGNED_BSS - /* Empty zero page */ - .balign PAGE_SIZE +#ifdef CONFIG_RISCV_ISA_V + csrr t0, CSR_MISA + li t1, COMPAT_HWCAP_ISA_V + and t0, t0, t1 + beqz t0, .Lreset_regs_done_vector + + /* + * Clear vector registers and reset vcsr + * VLMAX has a defined value, VLEN is a constant, + * and this form of vsetvli is defined to set vl to VLMAX. + */ + li t1, SR_VS + csrs CSR_STATUS, t1 + csrs CSR_VCSR, x0 + vsetvli t1, x0, e8, m8, ta, ma + vmv.v.i v0, 0 + vmv.v.i v8, 0 + vmv.v.i v16, 0 + vmv.v.i v24, 0 + /* note that the caller must clear SR_VS */ +.Lreset_regs_done_vector: +#endif /* CONFIG_RISCV_ISA_V */ + ret +SYM_CODE_END(reset_regs) +#endif /* CONFIG_RISCV_M_MODE */ |