diff options
Diffstat (limited to 'arch/riscv/kernel/head.S')
| -rw-r--r-- | arch/riscv/kernel/head.S | 43 |
1 files changed, 20 insertions, 23 deletions
diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S index fe884cd69abd..4e46f31072da 100644 --- a/arch/riscv/kernel/head.S +++ b/arch/riscv/kernel/head.S @@ -1,14 +1,6 @@ +/* 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> @@ -23,7 +15,8 @@ __INIT ENTRY(_start) /* Mask all interrupts */ - csrw sie, zero + csrw CSR_SIE, zero + csrw CSR_SIP, zero /* Load the global pointer */ .option push @@ -68,14 +61,10 @@ clear_bss_done: /* 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 /* Start the kernel */ - mv a0, s0 - mv a1, s1 + mv a0, s1 call parse_dtb tail start_kernel @@ -89,7 +78,7 @@ relocate: /* Point stvec to virtual address of intruction after satp write */ la a0, 1f add a0, a0, a1 - csrw stvec, a0 + csrw CSR_STVEC, a0 /* Compute satp for kernel page tables, but don't load it yet */ la a2, swapper_pg_dir @@ -99,18 +88,20 @@ relocate: /* * Load trampoline page directory, which will cause us to trap to - * stvec if VA != PA, or simply fall through if VA == PA + * 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 srl a0, a0, PAGE_SHIFT or a0, a0, a1 sfence.vma - csrw sptbr, a0 + csrw CSR_SATP, a0 .align 2 1: /* Set trap vector to spin forever to help debug */ la a0, .Lsecondary_park - csrw stvec, a0 + csrw CSR_STVEC, a0 /* Reload the global pointer */ .option push @@ -118,8 +109,14 @@ relocate: la gp, __global_pointer$ .option pop - /* Switch to kernel page tables */ - csrw sptbr, a2 + /* + * 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 guarnteed to work + * because that first superpage is translated the same way. + */ + csrw CSR_SATP, a2 + sfence.vma ret @@ -130,7 +127,7 @@ relocate: /* Set trap vector to spin forever to help debug */ la a3, .Lsecondary_park - csrw stvec, a3 + csrw CSR_STVEC, a3 slli a3, a0, LGREG la a1, __cpu_up_stack_pointer |