diff options
Diffstat (limited to 'arch/riscv/kernel/process.c')
| -rw-r--r-- | arch/riscv/kernel/process.c | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c new file mode 100644 index 000000000..8955f2432 --- /dev/null +++ b/arch/riscv/kernel/process.c @@ -0,0 +1,191 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2009 Sunplus Core Technology Co., Ltd. + * Chen Liqin <liqin.chen@sunplusct.com> + * Lennox Wu <lennox.wu@sunplusct.com> + * Copyright (C) 2012 Regents of the University of California + * Copyright (C) 2017 SiFive + */ + +#include <linux/cpu.h> +#include <linux/kernel.h> +#include <linux/sched.h> +#include <linux/sched/debug.h> +#include <linux/sched/task_stack.h> +#include <linux/tick.h> +#include <linux/ptrace.h> +#include <linux/uaccess.h> + +#include <asm/unistd.h> +#include <asm/processor.h> +#include <asm/csr.h> +#include <asm/stacktrace.h> +#include <asm/string.h> +#include <asm/switch_to.h> +#include <asm/thread_info.h> +#include <asm/cpuidle.h> + +register unsigned long gp_in_global __asm__("gp"); + +#if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_STACKPROTECTOR_PER_TASK) +#include <linux/stackprotector.h> +unsigned long __stack_chk_guard __read_mostly; +EXPORT_SYMBOL(__stack_chk_guard); +#endif + +extern asmlinkage void ret_from_fork(void); +extern asmlinkage void ret_from_kernel_thread(void); + +void arch_cpu_idle(void) +{ + cpu_do_idle(); + raw_local_irq_enable(); +} + +void __show_regs(struct pt_regs *regs) +{ + show_regs_print_info(KERN_DEFAULT); + + if (!user_mode(regs)) { + pr_cont("epc : %pS\n", (void *)regs->epc); + pr_cont(" ra : %pS\n", (void *)regs->ra); + } + + pr_cont("epc : " REG_FMT " ra : " REG_FMT " sp : " REG_FMT "\n", + regs->epc, regs->ra, regs->sp); + pr_cont(" gp : " REG_FMT " tp : " REG_FMT " t0 : " REG_FMT "\n", + regs->gp, regs->tp, regs->t0); + pr_cont(" t1 : " REG_FMT " t2 : " REG_FMT " s0 : " REG_FMT "\n", + regs->t1, regs->t2, regs->s0); + pr_cont(" s1 : " REG_FMT " a0 : " REG_FMT " a1 : " REG_FMT "\n", + regs->s1, regs->a0, regs->a1); + pr_cont(" a2 : " REG_FMT " a3 : " REG_FMT " a4 : " REG_FMT "\n", + regs->a2, regs->a3, regs->a4); + pr_cont(" a5 : " REG_FMT " a6 : " REG_FMT " a7 : " REG_FMT "\n", + regs->a5, regs->a6, regs->a7); + pr_cont(" s2 : " REG_FMT " s3 : " REG_FMT " s4 : " REG_FMT "\n", + regs->s2, regs->s3, regs->s4); + pr_cont(" s5 : " REG_FMT " s6 : " REG_FMT " s7 : " REG_FMT "\n", + regs->s5, regs->s6, regs->s7); + pr_cont(" s8 : " REG_FMT " s9 : " REG_FMT " s10: " REG_FMT "\n", + regs->s8, regs->s9, regs->s10); + pr_cont(" s11: " REG_FMT " t3 : " REG_FMT " t4 : " REG_FMT "\n", + regs->s11, regs->t3, regs->t4); + pr_cont(" t5 : " REG_FMT " t6 : " REG_FMT "\n", + regs->t5, regs->t6); + + pr_cont("status: " REG_FMT " badaddr: " REG_FMT " cause: " REG_FMT "\n", + regs->status, regs->badaddr, regs->cause); +} +void show_regs(struct pt_regs *regs) +{ + __show_regs(regs); + if (!user_mode(regs)) + dump_backtrace(regs, NULL, KERN_DEFAULT); +} + +#ifdef CONFIG_COMPAT +static bool compat_mode_supported __read_mostly; + +bool compat_elf_check_arch(Elf32_Ehdr *hdr) +{ + return compat_mode_supported && + hdr->e_machine == EM_RISCV && + hdr->e_ident[EI_CLASS] == ELFCLASS32; +} + +static int __init compat_mode_detect(void) +{ + unsigned long tmp = csr_read(CSR_STATUS); + + csr_write(CSR_STATUS, (tmp & ~SR_UXL) | SR_UXL_32); + compat_mode_supported = + (csr_read(CSR_STATUS) & SR_UXL) == SR_UXL_32; + + csr_write(CSR_STATUS, tmp); + + pr_info("riscv: ELF compat mode %s", + compat_mode_supported ? "supported" : "unsupported"); + + return 0; +} +early_initcall(compat_mode_detect); +#endif + +void start_thread(struct pt_regs *regs, unsigned long pc, + unsigned long sp) +{ + regs->status = SR_PIE; + if (has_fpu()) { + regs->status |= SR_FS_INITIAL; + /* + * Restore the initial value to the FP register + * before starting the user program. + */ + fstate_restore(current, regs); + } + regs->epc = pc; + regs->sp = sp; + +#ifdef CONFIG_64BIT + regs->status &= ~SR_UXL; + + if (is_compat_task()) + regs->status |= SR_UXL_32; + else + regs->status |= SR_UXL_64; +#endif +} + +void flush_thread(void) +{ +#ifdef CONFIG_FPU + /* + * Reset FPU state and context + * frm: round to nearest, ties to even (IEEE default) + * fflags: accrued exceptions cleared + */ + fstate_off(current, task_pt_regs(current)); + memset(¤t->thread.fstate, 0, sizeof(current->thread.fstate)); +#endif +} + +int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) +{ + fstate_save(src, task_pt_regs(src)); + *dst = *src; + return 0; +} + +int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) +{ + unsigned long clone_flags = args->flags; + unsigned long usp = args->stack; + unsigned long tls = args->tls; + struct pt_regs *childregs = task_pt_regs(p); + + memset(&p->thread.s, 0, sizeof(p->thread.s)); + + /* p->thread holds context to be restored by __switch_to() */ + if (unlikely(args->fn)) { + /* Kernel thread */ + memset(childregs, 0, sizeof(struct pt_regs)); + childregs->gp = gp_in_global; + /* Supervisor/Machine, irqs on: */ + childregs->status = SR_PP | SR_PIE; + + p->thread.ra = (unsigned long)ret_from_kernel_thread; + p->thread.s[0] = (unsigned long)args->fn; + p->thread.s[1] = (unsigned long)args->fn_arg; + } else { + *childregs = *(current_pt_regs()); + if (usp) /* User fork */ + childregs->sp = usp; + if (clone_flags & CLONE_SETTLS) + childregs->tp = tls; + childregs->a0 = 0; /* Return value of fork() */ + p->thread.ra = (unsigned long)ret_from_fork; + } + p->thread.sp = (unsigned long)childregs; /* kernel sp */ + return 0; +} |