diff options
author | Palmer Dabbelt <palmer@dabbelt.com> | 2017-07-10 18:04:30 -0700 |
---|---|---|
committer | Palmer Dabbelt <palmer@dabbelt.com> | 2017-09-26 15:26:46 -0700 |
commit | 7db91e57a0acde126a162ababfb1e0ab190130cb (patch) | |
tree | 1bbfd887d30e00b25318389256fdcb722b1b4785 /arch/riscv | |
parent | 2129a235c098960c57d4b6ef23be842a98d97ac9 (diff) |
RISC-V: Task implementation
This patch contains the implementation of tasks on RISC-V, most of which
is involved in task switching.
Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
Diffstat (limited to 'arch/riscv')
-rw-r--r-- | arch/riscv/include/asm/asm-offsets.h | 1 | ||||
-rw-r--r-- | arch/riscv/include/asm/current.h | 45 | ||||
-rw-r--r-- | arch/riscv/include/asm/kprobes.h | 22 | ||||
-rw-r--r-- | arch/riscv/include/asm/processor.h | 97 | ||||
-rw-r--r-- | arch/riscv/include/asm/switch_to.h | 69 | ||||
-rw-r--r-- | arch/riscv/include/asm/thread_info.h | 94 | ||||
-rw-r--r-- | arch/riscv/kernel/asm-offsets.c | 322 | ||||
-rw-r--r-- | arch/riscv/kernel/entry.S | 464 | ||||
-rw-r--r-- | arch/riscv/kernel/process.c | 129 |
9 files changed, 1243 insertions, 0 deletions
diff --git a/arch/riscv/include/asm/asm-offsets.h b/arch/riscv/include/asm/asm-offsets.h new file mode 100644 index 000000000000..d370ee36a182 --- /dev/null +++ b/arch/riscv/include/asm/asm-offsets.h @@ -0,0 +1 @@ +#include <generated/asm-offsets.h> diff --git a/arch/riscv/include/asm/current.h b/arch/riscv/include/asm/current.h new file mode 100644 index 000000000000..2cf6336ef600 --- /dev/null +++ b/arch/riscv/include/asm/current.h @@ -0,0 +1,45 @@ +/* + * Based on arm/arm64/include/asm/current.h + * + * Copyright (C) 2016 ARM + * Copyright (C) 2017 SiFive + * + * 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. + */ + + +#ifndef __ASM_CURRENT_H +#define __ASM_CURRENT_H + +#include <linux/bug.h> +#include <linux/compiler.h> + +#ifndef __ASSEMBLY__ + +struct task_struct; + +/* + * This only works because "struct thread_info" is at offset 0 from "struct + * task_struct". This constraint seems to be necessary on other architectures + * as well, but __switch_to enforces it. We can't check TASK_TI here because + * <asm/asm-offsets.h> includes this, and I can't get the definition of "struct + * task_struct" here due to some header ordering problems. + */ +static __always_inline struct task_struct *get_current(void) +{ + register struct task_struct *tp __asm__("tp"); + return tp; +} + +#define current get_current() + +#endif /* __ASSEMBLY__ */ + +#endif /* __ASM_CURRENT_H */ diff --git a/arch/riscv/include/asm/kprobes.h b/arch/riscv/include/asm/kprobes.h new file mode 100644 index 000000000000..c7eb010d1528 --- /dev/null +++ b/arch/riscv/include/asm/kprobes.h @@ -0,0 +1,22 @@ +/* + * Copied from arch/arm64/include/asm/kprobes.h + * + * Copyright (C) 2013 Linaro Limited + * Copyright (C) 2017 SiFive + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * 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. + */ + +#ifndef _RISCV_KPROBES_H +#define _RISCV_KPROBES_H + +#include <asm-generic/kprobes.h> + +#endif /* _RISCV_KPROBES_H */ diff --git a/arch/riscv/include/asm/processor.h b/arch/riscv/include/asm/processor.h new file mode 100644 index 000000000000..3fe4af8147d2 --- /dev/null +++ b/arch/riscv/include/asm/processor.h @@ -0,0 +1,97 @@ +/* + * 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. + */ + +#ifndef _ASM_RISCV_PROCESSOR_H +#define _ASM_RISCV_PROCESSOR_H + +#include <linux/const.h> + +#include <asm/ptrace.h> + +/* + * This decides where the kernel will search for a free chunk of vm + * space during mmap's. + */ +#define TASK_UNMAPPED_BASE PAGE_ALIGN(TASK_SIZE >> 1) + +#define STACK_TOP TASK_SIZE +#define STACK_TOP_MAX STACK_TOP +#define STACK_ALIGN 16 + +#ifndef __ASSEMBLY__ + +struct task_struct; +struct pt_regs; + +/* + * Default implementation of macro that returns current + * instruction pointer ("program counter"). + */ +#define current_text_addr() ({ __label__ _l; _l: &&_l; }) + +/* CPU-specific state of a task */ +struct thread_struct { + /* Callee-saved registers */ + unsigned long ra; + unsigned long sp; /* Kernel mode stack */ + unsigned long s[12]; /* s[0]: frame pointer */ + struct __riscv_d_ext_state fstate; +}; + +#define INIT_THREAD { \ + .sp = sizeof(init_stack) + (long)&init_stack, \ +} + +#define task_pt_regs(tsk) \ + ((struct pt_regs *)(task_stack_page(tsk) + THREAD_SIZE \ + - ALIGN(sizeof(struct pt_regs), STACK_ALIGN))) + +#define KSTK_EIP(tsk) (task_pt_regs(tsk)->sepc) +#define KSTK_ESP(tsk) (task_pt_regs(tsk)->sp) + + +/* Do necessary setup to start up a newly executed thread. */ +extern void start_thread(struct pt_regs *regs, + unsigned long pc, unsigned long sp); + +/* Free all resources held by a thread. */ +static inline void release_thread(struct task_struct *dead_task) +{ +} + +extern unsigned long get_wchan(struct task_struct *p); + + +static inline void cpu_relax(void) +{ +#ifdef __riscv_muldiv + int dummy; + /* In lieu of a halt instruction, induce a long-latency stall. */ + __asm__ __volatile__ ("div %0, %0, zero" : "=r" (dummy)); +#endif + barrier(); +} + +static inline void wait_for_interrupt(void) +{ + __asm__ __volatile__ ("wfi"); +} + +struct device_node; +extern int riscv_of_processor_hart(struct device_node *node); + +extern void riscv_fill_hwcap(void); + +#endif /* __ASSEMBLY__ */ + +#endif /* _ASM_RISCV_PROCESSOR_H */ diff --git a/arch/riscv/include/asm/switch_to.h b/arch/riscv/include/asm/switch_to.h new file mode 100644 index 000000000000..dd6b05bff75b --- /dev/null +++ b/arch/riscv/include/asm/switch_to.h @@ -0,0 +1,69 @@ +/* + * 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. + */ + +#ifndef _ASM_RISCV_SWITCH_TO_H +#define _ASM_RISCV_SWITCH_TO_H + +#include <asm/processor.h> +#include <asm/ptrace.h> +#include <asm/csr.h> + +extern void __fstate_save(struct task_struct *save_to); +extern void __fstate_restore(struct task_struct *restore_from); + +static inline void __fstate_clean(struct pt_regs *regs) +{ + regs->sstatus |= (regs->sstatus & ~(SR_FS)) | SR_FS_CLEAN; +} + +static inline void fstate_save(struct task_struct *task, + struct pt_regs *regs) +{ + if ((regs->sstatus & SR_FS) == SR_FS_DIRTY) { + __fstate_save(task); + __fstate_clean(regs); + } +} + +static inline void fstate_restore(struct task_struct *task, + struct pt_regs *regs) +{ + if ((regs->sstatus & SR_FS) != SR_FS_OFF) { + __fstate_restore(task); + __fstate_clean(regs); + } +} + +static inline void __switch_to_aux(struct task_struct *prev, + struct task_struct *next) +{ + struct pt_regs *regs; + + regs = task_pt_regs(prev); + if (unlikely(regs->sstatus & SR_SD)) + fstate_save(prev, regs); + fstate_restore(next, task_pt_regs(next)); +} + +extern struct task_struct *__switch_to(struct task_struct *, + struct task_struct *); + +#define switch_to(prev, next, last) \ +do { \ + struct task_struct *__prev = (prev); \ + struct task_struct *__next = (next); \ + __switch_to_aux(__prev, __next); \ + ((last) = __switch_to(__prev, __next)); \ +} while (0) + +#endif /* _ASM_RISCV_SWITCH_TO_H */ diff --git a/arch/riscv/include/asm/thread_info.h b/arch/riscv/include/asm/thread_info.h new file mode 100644 index 000000000000..22c3536ed281 --- /dev/null +++ b/arch/riscv/include/asm/thread_info.h @@ -0,0 +1,94 @@ +/* + * Copyright (C) 2009 Chen Liqin <liqin.chen@sunplusct.com> + * Copyright (C) 2012 Regents of the University of California + * Copyright (C) 2017 SiFive + * + * 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. + */ + +#ifndef _ASM_RISCV_THREAD_INFO_H +#define _ASM_RISCV_THREAD_INFO_H + +#include <asm/page.h> +#include <linux/const.h> + +/* thread information allocation */ +#define THREAD_SIZE_ORDER (1) +#define THREAD_SIZE (PAGE_SIZE << THREAD_SIZE_ORDER) + +#ifndef __ASSEMBLY__ + +#include <asm/processor.h> +#include <asm/csr.h> + +typedef unsigned long mm_segment_t; + +/* + * low level task data that entry.S needs immediate access to + * - this struct should fit entirely inside of one cache line + * - if the members of this struct changes, the assembly constants + * in asm-offsets.c must be updated accordingly + * - thread_info is included in task_struct at an offset of 0. This means that + * tp points to both thread_info and task_struct. + */ +struct thread_info { + unsigned long flags; /* low level flags */ + int preempt_count; /* 0=>preemptible, <0=>BUG */ + mm_segment_t addr_limit; + /* + * These stack pointers are overwritten on every system call or + * exception. SP is also saved to the stack it can be recovered when + * overwritten. + */ + long kernel_sp; /* Kernel stack pointer */ + long user_sp; /* User stack pointer */ + int cpu; +}; + +/* + * macros/functions for gaining access to the thread information structure + * + * preempt_count needs to be 1 initially, until the scheduler is functional. + */ +#define INIT_THREAD_INFO(tsk) \ +{ \ + .flags = 0, \ + .preempt_count = INIT_PREEMPT_COUNT, \ + .addr_limit = KERNEL_DS, \ +} + +#define init_stack (init_thread_union.stack) + +#endif /* !__ASSEMBLY__ */ + +/* + * thread information flags + * - these are process state flags that various assembly files may need to + * access + * - pending work-to-be-done flags are in lowest half-word + * - other flags in upper half-word(s) + */ +#define TIF_SYSCALL_TRACE 0 /* syscall trace active */ +#define TIF_NOTIFY_RESUME 1 /* callback before returning to user */ +#define TIF_SIGPENDING 2 /* signal pending */ +#define TIF_NEED_RESCHED 3 /* rescheduling necessary */ +#define TIF_RESTORE_SIGMASK 4 /* restore signal mask in do_signal() */ +#define TIF_MEMDIE 5 /* is terminating due to OOM killer */ +#define TIF_SYSCALL_TRACEPOINT 6 /* syscall tracepoint instrumentation */ + +#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE) +#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME) +#define _TIF_SIGPENDING (1 << TIF_SIGPENDING) +#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED) + +#define _TIF_WORK_MASK \ + (_TIF_NOTIFY_RESUME | _TIF_SIGPENDING | _TIF_NEED_RESCHED) + +#endif /* _ASM_RISCV_THREAD_INFO_H */ diff --git a/arch/riscv/kernel/asm-offsets.c b/arch/riscv/kernel/asm-offsets.c new file mode 100644 index 000000000000..6a92a2fe198e --- /dev/null +++ b/arch/riscv/kernel/asm-offsets.c @@ -0,0 +1,322 @@ +/* + * Copyright (C) 2012 Regents of the University of California + * Copyright (C) 2017 SiFive + * + * 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. + */ + +#define GENERATING_ASM_OFFSETS + +#include <linux/kbuild.h> +#include <linux/sched.h> +#include <asm/thread_info.h> +#include <asm/ptrace.h> + +void asm_offsets(void) +{ + OFFSET(TASK_THREAD_RA, task_struct, thread.ra); + OFFSET(TASK_THREAD_SP, task_struct, thread.sp); + OFFSET(TASK_THREAD_S0, task_struct, thread.s[0]); + OFFSET(TASK_THREAD_S1, task_struct, thread.s[1]); + OFFSET(TASK_THREAD_S2, task_struct, thread.s[2]); + OFFSET(TASK_THREAD_S3, task_struct, thread.s[3]); + OFFSET(TASK_THREAD_S4, task_struct, thread.s[4]); + OFFSET(TASK_THREAD_S5, task_struct, thread.s[5]); + OFFSET(TASK_THREAD_S6, task_struct, thread.s[6]); + OFFSET(TASK_THREAD_S7, task_struct, thread.s[7]); + OFFSET(TASK_THREAD_S8, task_struct, thread.s[8]); + OFFSET(TASK_THREAD_S9, task_struct, thread.s[9]); + OFFSET(TASK_THREAD_S10, task_struct, thread.s[10]); + OFFSET(TASK_THREAD_S11, task_struct, thread.s[11]); + OFFSET(TASK_THREAD_SP, task_struct, thread.sp); + OFFSET(TASK_STACK, task_struct, stack); + OFFSET(TASK_TI, task_struct, thread_info); + OFFSET(TASK_TI_FLAGS, task_struct, thread_info.flags); + OFFSET(TASK_TI_KERNEL_SP, task_struct, thread_info.kernel_sp); + OFFSET(TASK_TI_USER_SP, task_struct, thread_info.user_sp); + OFFSET(TASK_TI_CPU, task_struct, thread_info.cpu); + + OFFSET(TASK_THREAD_F0, task_struct, thread.fstate.f[0]); + OFFSET(TASK_THREAD_F1, task_struct, thread.fstate.f[1]); + OFFSET(TASK_THREAD_F2, task_struct, thread.fstate.f[2]); + OFFSET(TASK_THREAD_F3, task_struct, thread.fstate.f[3]); + OFFSET(TASK_THREAD_F4, task_struct, thread.fstate.f[4]); + OFFSET(TASK_THREAD_F5, task_struct, thread.fstate.f[5]); + OFFSET(TASK_THREAD_F6, task_struct, thread.fstate.f[6]); + OFFSET(TASK_THREAD_F7, task_struct, thread.fstate.f[7]); + OFFSET(TASK_THREAD_F8, task_struct, thread.fstate.f[8]); + OFFSET(TASK_THREAD_F9, task_struct, thread.fstate.f[9]); + OFFSET(TASK_THREAD_F10, task_struct, thread.fstate.f[10]); + OFFSET(TASK_THREAD_F11, task_struct, thread.fstate.f[11]); + OFFSET(TASK_THREAD_F12, task_struct, thread.fstate.f[12]); + OFFSET(TASK_THREAD_F13, task_struct, thread.fstate.f[13]); + OFFSET(TASK_THREAD_F14, task_struct, thread.fstate.f[14]); + OFFSET(TASK_THREAD_F15, task_struct, thread.fstate.f[15]); + OFFSET(TASK_THREAD_F16, task_struct, thread.fstate.f[16]); + OFFSET(TASK_THREAD_F17, task_struct, thread.fstate.f[17]); + OFFSET(TASK_THREAD_F18, task_struct, thread.fstate.f[18]); + OFFSET(TASK_THREAD_F19, task_struct, thread.fstate.f[19]); + OFFSET(TASK_THREAD_F20, task_struct, thread.fstate.f[20]); + OFFSET(TASK_THREAD_F21, task_struct, thread.fstate.f[21]); + OFFSET(TASK_THREAD_F22, task_struct, thread.fstate.f[22]); + OFFSET(TASK_THREAD_F23, task_struct, thread.fstate.f[23]); + OFFSET(TASK_THREAD_F24, task_struct, thread.fstate.f[24]); + OFFSET(TASK_THREAD_F25, task_struct, thread.fstate.f[25]); + OFFSET(TASK_THREAD_F26, task_struct, thread.fstate.f[26]); + OFFSET(TASK_THREAD_F27, task_struct, thread.fstate.f[27]); + OFFSET(TASK_THREAD_F28, task_struct, thread.fstate.f[28]); + OFFSET(TASK_THREAD_F29, task_struct, thread.fstate.f[29]); + OFFSET(TASK_THREAD_F30, task_struct, thread.fstate.f[30]); + OFFSET(TASK_THREAD_F31, task_struct, thread.fstate.f[31]); + OFFSET(TASK_THREAD_FCSR, task_struct, thread.fstate.fcsr); + + DEFINE(PT_SIZE, sizeof(struct pt_regs)); + OFFSET(PT_SEPC, pt_regs, sepc); + OFFSET(PT_RA, pt_regs, ra); + OFFSET(PT_FP, pt_regs, s0); + OFFSET(PT_S0, pt_regs, s0); + OFFSET(PT_S1, pt_regs, s1); + OFFSET(PT_S2, pt_regs, s2); + OFFSET(PT_S3, pt_regs, s3); + OFFSET(PT_S4, pt_regs, s4); + OFFSET(PT_S5, pt_regs, s5); + OFFSET(PT_S6, pt_regs, s6); + OFFSET(PT_S7, pt_regs, s7); + OFFSET(PT_S8, pt_regs, s8); + OFFSET(PT_S9, pt_regs, s9); + OFFSET(PT_S10, pt_regs, s10); + OFFSET(PT_S11, pt_regs, s11); + OFFSET(PT_SP, pt_regs, sp); + OFFSET(PT_TP, pt_regs, tp); + OFFSET(PT_A0, pt_regs, a0); + OFFSET(PT_A1, pt_regs, a1); + OFFSET(PT_A2, pt_regs, a2); + OFFSET(PT_A3, pt_regs, a3); + OFFSET(PT_A4, pt_regs, a4); + OFFSET(PT_A5, pt_regs, a5); + OFFSET(PT_A6, pt_regs, a6); + OFFSET(PT_A7, pt_regs, a7); + OFFSET(PT_T0, pt_regs, t0); + OFFSET(PT_T1, pt_regs, t1); + OFFSET(PT_T2, pt_regs, t2); + OFFSET(PT_T3, pt_regs, t3); + OFFSET(PT_T4, pt_regs, t4); + OFFSET(PT_T5, pt_regs, t5); + OFFSET(PT_T6, pt_regs, t6); + OFFSET(PT_GP, pt_regs, gp); + OFFSET(PT_ORIG_A0, pt_regs, orig_a0); + OFFSET(PT_SSTATUS, pt_regs, sstatus); + OFFSET(PT_SBADADDR, pt_regs, sbadaddr); + OFFSET(PT_SCAUSE, pt_regs, scause); + + /* + * THREAD_{F,X}* might be larger than a S-type offset can handle, but + * these are used in performance-sensitive assembly so we can't resort + * to loading the long immediate every time. + */ + DEFINE(TASK_THREAD_RA_RA, + offsetof(struct task_struct, thread.ra) + - offsetof(struct task_struct, thread.ra) + ); + DEFINE(TASK_THREAD_SP_RA, + offsetof(struct task_struct, thread.sp) + - offsetof(struct task_struct, thread.ra) + ); + DEFINE(TASK_THREAD_S0_RA, + offsetof(struct task_struct, thread.s[0]) + - offsetof(struct task_struct, thread.ra) + ); + DEFINE(TASK_THREAD_S1_RA, + offsetof(struct task_struct, thread.s[1]) + - offsetof(struct task_struct, thread.ra) + ); + DEFINE(TASK_THREAD_S2_RA, + offsetof(struct task_struct, thread.s[2]) + - offsetof(struct task_struct, thread.ra) + ); + DEFINE(TASK_THREAD_S3_RA, + offsetof(struct task_struct, thread.s[3]) + - offsetof(struct task_struct, thread.ra) + ); + DEFINE(TASK_THREAD_S4_RA, + offsetof(struct task_struct, thread.s[4]) + - offsetof(struct task_struct, thread.ra) + ); + DEFINE(TASK_THREAD_S5_RA, + offsetof(struct task_struct, thread.s[5]) + - offsetof(struct task_struct, thread.ra) + ); + DEFINE(TASK_THREAD_S6_RA, + offsetof(struct task_struct, thread.s[6]) + - offsetof(struct task_struct, thread.ra) + ); + DEFINE(TASK_THREAD_S7_RA, + offsetof(struct task_struct, thread.s[7]) + - offsetof(struct task_struct, thread.ra) + ); + DEFINE(TASK_THREAD_S8_RA, + offsetof(struct task_struct, thread.s[8]) + - offsetof(struct task_struct, thread.ra) + ); + DEFINE(TASK_THREAD_S9_RA, + offsetof(struct task_struct, thread.s[9]) + - offsetof(struct task_struct, thread.ra) + ); + DEFINE(TASK_THREAD_S10_RA, + offsetof(struct task_struct, thread.s[10]) + - offsetof(struct task_struct, thread.ra) + ); + DEFINE(TASK_THREAD_S11_RA, + offsetof(struct task_struct, thread.s[11]) + - offsetof(struct task_struct, thread.ra) + ); + + DEFINE(TASK_THREAD_F0_F0, + offsetof(struct task_struct, thread.fstate.f[0]) + - offsetof(struct task_struct, thread.fstate.f[0]) + ); + DEFINE(TASK_THREAD_F1_F0, + offsetof(struct task_struct, thread.fstate.f[1]) + - offsetof(struct task_struct, thread.fstate.f[0]) + ); + DEFINE(TASK_THREAD_F2_F0, + offsetof(struct task_struct, thread.fstate.f[2]) + - offsetof(struct task_struct, thread.fstate.f[0]) + ); + DEFINE(TASK_THREAD_F3_F0, + offsetof(struct task_struct, thread.fstate.f[3]) + - offsetof(struct task_struct, thread.fstate.f[0]) + ); + DEFINE(TASK_THREAD_F4_F0, + offsetof(struct task_struct, thread.fstate.f[4]) + - offsetof(struct task_struct, thread.fstate.f[0]) + ); + DEFINE(TASK_THREAD_F5_F0, + offsetof(struct task_struct, thread.fstate.f[5]) + - offsetof(struct task_struct, thread.fstate.f[0]) + ); + DEFINE(TASK_THREAD_F6_F0, + offsetof(struct task_struct, thread.fstate.f[6]) + - offsetof(struct task_struct, thread.fstate.f[0]) + ); + DEFINE(TASK_THREAD_F7_F0, + offsetof(struct task_struct, thread.fstate.f[7]) + - offsetof(struct task_struct, thread.fstate.f[0]) + ); + DEFINE(TASK_THREAD_F8_F0, + offsetof(struct task_struct, thread.fstate.f[8]) + - offsetof(struct task_struct, thread.fstate.f[0]) + ); + DEFINE(TASK_THREAD_F9_F0, + offsetof(struct task_struct, thread.fstate.f[9]) + - offsetof(struct task_struct, thread.fstate.f[0]) + ); + DEFINE(TASK_THREAD_F10_F0, + offsetof(struct task_struct, thread.fstate.f[10]) + - offsetof(struct task_struct, thread.fstate.f[0]) + ); + DEFINE(TASK_THREAD_F11_F0, + offsetof(struct task_struct, thread.fstate.f[11]) + - offsetof(struct task_struct, thread.fstate.f[0]) + ); + DEFINE(TASK_THREAD_F12_F0, + offsetof(struct task_struct, thread.fstate.f[12]) + - offsetof(struct task_struct, thread.fstate.f[0]) + ); + DEFINE(TASK_THREAD_F13_F0, + offsetof(struct task_struct, thread.fstate.f[13]) + - offsetof(struct task_struct, thread.fstate.f[0]) + ); + DEFINE(TASK_THREAD_F14_F0, + offsetof(struct task_struct, thread.fstate.f[14]) + - offsetof(struct task_struct, thread.fstate.f[0]) + ); + DEFINE(TASK_THREAD_F15_F0, + offsetof(struct task_struct, thread.fstate.f[15]) + - offsetof(struct task_struct, thread.fstate.f[0]) + ); + DEFINE(TASK_THREAD_F16_F0, + offsetof(struct task_struct, thread.fstate.f[16]) + - offsetof(struct task_struct, thread.fstate.f[0]) + ); + DEFINE(TASK_THREAD_F17_F0, + offsetof(struct task_struct, thread.fstate.f[17]) + - offsetof(struct task_struct, thread.fstate.f[0]) + ); + DEFINE(TASK_THREAD_F18_F0, + offsetof(struct task_struct, thread.fstate.f[18]) + - offsetof(struct task_struct, thread.fstate.f[0]) + ); + DEFINE(TASK_THREAD_F19_F0, + offsetof(struct task_struct, thread.fstate.f[19]) + - offsetof(struct task_struct, thread.fstate.f[0]) + ); + DEFINE(TASK_THREAD_F20_F0, + offsetof(struct task_struct, thread.fstate.f[20]) + - offsetof(struct task_struct, thread.fstate.f[0]) + ); + DEFINE(TASK_THREAD_F21_F0, + offsetof(struct task_struct, thread.fstate.f[21]) + - offsetof(struct task_struct, thread.fstate.f[0]) + ); + DEFINE(TASK_THREAD_F22_F0, + offsetof(struct task_struct, thread.fstate.f[22]) + - offsetof(struct task_struct, thread.fstate.f[0]) + ); + DEFINE(TASK_THREAD_F23_F0, + offsetof(struct task_struct, thread.fstate.f[23]) + - offsetof(struct task_struct, thread.fstate.f[0]) + ); + DEFINE(TASK_THREAD_F24_F0, + offsetof(struct task_struct, thread.fstate.f[24]) + - offsetof(struct task_struct, thread.fstate.f[0]) + ); + DEFINE(TASK_THREAD_F25_F0, + offsetof(struct task_struct, thread.fstate.f[25]) + - offsetof(struct task_struct, thread.fstate.f[0]) + ); + DEFINE(TASK_THREAD_F26_F0, + offsetof(struct task_struct, thread.fstate.f[26]) + - offsetof(struct task_struct, thread.fstate.f[0]) + ); + DEFINE(TASK_THREAD_F27_F0, + offsetof(struct task_struct, thread.fstate.f[27]) + - offsetof(struct task_struct, thread.fstate.f[0]) + ); + DEFINE(TASK_THREAD_F28_F0, + offsetof(struct task_struct, thread.fstate.f[28]) + - offsetof(struct task_struct, thread.fstate.f[0]) + ); + DEFINE(TASK_THREAD_F29_F0, + offsetof(struct task_struct, thread.fstate.f[29]) + - offsetof(struct task_struct, thread.fstate.f[0]) + ); + DEFINE(TASK_THREAD_F30_F0, + offsetof(struct task_struct, thread.fstate.f[30]) + - offsetof(struct task_struct, thread.fstate.f[0]) + ); + DEFINE(TASK_THREAD_F31_F0, + offsetof(struct task_struct, thread.fstate.f[31]) + - offsetof(struct task_struct, thread.fstate.f[0]) + ); + DEFINE(TASK_THREAD_FCSR_F0, + offsetof(struct task_struct, thread.fstate.fcsr) + - offsetof(struct task_struct, thread.fstate.f[0]) + ); + + /* The assembler needs access to THREAD_SIZE as well. */ + DEFINE(ASM_THREAD_SIZE, THREAD_SIZE); + + /* + * We allocate a pt_regs on the stack when entering the kernel. This + * ensures the alignment is sane. + */ + DEFINE(PT_SIZE_ON_STACK, ALIGN(sizeof(struct pt_regs), STACK_ALIGN)); +} diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S new file mode 100644 index 000000000000..20ee86f782a9 --- /dev/null +++ b/arch/riscv/kernel/entry.S @@ -0,0 +1,464 @@ +/* + * Copyright (C) 2012 Regents of the University of California + * Copyright (C) 2017 SiFive + * + * 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 <linux/init.h> +#include <linux/linkage.h> + +#include <asm/asm.h> +#include <asm/csr.h> +#include <asm/unistd.h> +#include <asm/thread_info.h> +#include <asm/asm-offsets.h> + + .text + .altmacro + +/* + * Prepares to enter a system call or exception by saving all registers to the + * stack. + */ + .macro SAVE_ALL + LOCAL _restore_kernel_tpsp + LOCAL _save_context + + /* + * If coming from userspace, preserve the user thread pointer and load + * the kernel thread pointer. If we came from the kernel, sscratch + * will contain 0, and we should continue on the current TP. + */ + csrrw tp, sscratch, tp + bnez tp, _save_context + +_restore_kernel_tpsp: + csrr tp, sscratch + REG_S sp, TASK_TI_KERNEL_SP(tp) +_save_context: + REG_S sp, TASK_TI_USER_SP(tp) + REG_L sp, TASK_TI_KERNEL_SP(tp) + addi sp, sp, -(PT_SIZE_ON_STACK) + REG_S x1, PT_RA(sp) + REG_S x3, PT_GP(sp) + REG_S x5, PT_T0(sp) + REG_S x6, PT_T1(sp) + REG_S x7, PT_T2(sp) + REG_S x8, PT_S0(sp) + REG_S x9, PT_S1(sp) + REG_S x10, PT_A0(sp) + REG_S x11, PT_A1(sp) + REG_S x12, PT_A2(sp) + REG_S x13, PT_A3(sp) + REG_S x14, PT_A4(sp) + REG_S x15, PT_A5(sp) + REG_S x16, PT_A6(sp) + REG_S x17, PT_A7(sp) + REG_S x18, PT_S2(sp) + REG_S x19, PT_S3(sp) + REG_S x20, PT_S4(sp) + REG_S x21, PT_S5(sp) + REG_S x22, PT_S6(sp) + REG_S x23, PT_S7(sp) + REG_S x24, PT_S8(sp) + REG_S x25, PT_S9(sp) + REG_S x26, PT_S10(sp) + REG_S x27, PT_S11(sp) + REG_S x28, PT_T3(sp) + REG_S x29, PT_T4(sp) + REG_S x30, PT_T5(sp) + REG_S x31, PT_T6(sp) + + /* + * Disable FPU to detect illegal usage of + * floating point in kernel space + */ + li t0, SR_FS + + REG_L s0, TASK_TI_USER_SP(tp) + csrrc s1, sstatus, t0 + csrr s2, sepc + csrr s3, sbadaddr + csrr s4, scause + csrr s5, sscratch + REG_S s0, PT_SP(sp) + REG_S s1, PT_SSTATUS(sp) + REG_S s2, PT_SEPC(sp) + REG_S s3, PT_SBADADDR(sp) + REG_S s4, PT_SCAUSE(sp) + REG_S s5, PT_TP(sp) + .endm + +/* + * Prepares to return from a system call or exception by restoring all + * registers from the stack. + */ + .macro RESTORE_ALL + REG_L a0, PT_SSTATUS(sp) + REG_L a2, PT_SEPC(sp) + csrw sstatus, a0 + csrw sepc, a2 + + REG_L x1, PT_RA(sp) + REG_L x3, PT_GP(sp) + REG_L x4, PT_TP(sp) + REG_L x5, PT_T0(sp) + REG_L x6, PT_T1(sp) + REG_L x7, PT_T2(sp) + REG_L x8, PT_S0(sp) + REG_L x9, PT_S1(sp) + REG_L x10, PT_A0(sp) + REG_L x11, PT_A1(sp) + REG_L x12, PT_A2(sp) + REG_L x13, PT_A3(sp) + REG_L x14, PT_A4(sp) + REG_L x15, PT_A5(sp) + REG_L x16, PT_A6(sp) + REG_L x17, PT_A7(sp) + REG_L x18, PT_S2(sp) + REG_L x19, PT_S3(sp) + REG_L x20, PT_S4(sp) + REG_L x21, PT_S5(sp) + REG_L x22, PT_S6(sp) + REG_L x23, PT_S7(sp) + REG_L x24, PT_S8(sp) + REG_L x25, PT_S9(sp) + REG_L x26, PT_S10(sp) + REG_L x27, PT_S11(sp) + REG_L x28, PT_T3(sp) + REG_L x29, PT_T4(sp) + REG_L x30, PT_T5(sp) + REG_L x31, PT_T6(sp) + + REG_L x2, PT_SP(sp) + .endm + +ENTRY(handle_exception) + SAVE_ALL + + /* + * Set sscratch register to 0, so that if a recursive exception + * occurs, the exception vector knows it came from the kernel + */ + csrw sscratch, x0 + + /* Load the global pointer */ +.option push +.option norelax + la gp, __global_pointer$ +.option pop + + la ra, ret_from_exception + /* + * MSB of cause differentiates between + * interrupts and exceptions + */ + bge s4, zero, 1f + + /* Handle interrupts */ + slli a0, s4, 1 + srli a0, a0, 1 + move a1, sp /* pt_regs */ + tail do_IRQ +1: + /* Handle syscalls */ + li t0, EXC_SYSCALL + beq s4, t0, handle_syscall + + /* Handle other exceptions */ + slli t0, s4, RISCV_LGPTR + la t1, excp_vect_table + la t2, excp_vect_table_end + move a0, sp /* pt_regs */ + add t0, t1, t0 + /* Check if exception code lies within bounds */ + bgeu t0, t2, 1f + REG_L t0, 0(t0) + jr t0 +1: + tail do_trap_unknown + +handle_syscall: + /* save the initial A0 value (needed in signal handlers) */ + REG_S a0, PT_ORIG_A0(sp) + /* + * Advance SEPC to avoid executing the original + * scall instruction on sret + */ + addi s2, s2, 0x4 + REG_S s2, PT_SEPC(sp) + /* System calls run with interrupts enabled */ + csrs sstatus, SR_IE + /* Trace syscalls, but only if requested by the user. */ + REG_L t0, TASK_TI_FLAGS(tp) + andi t0, t0, _TIF_SYSCALL_TRACE + bnez t0, handle_syscall_trace_enter +check_syscall_nr: + /* Check to make sure we don't jump to a bogus syscall number. */ + li t0, __NR_syscalls + la s0, sys_ni_syscall + /* Syscall number held in a7 */ + bgeu a7, t0, 1f + la s0, sys_call_table + slli t0, a7, RISCV_LGPTR + add s0, s0, t0 + REG_L s0, 0(s0) +1: + jalr s0 + +ret_from_syscall: + /* Set user a0 to kernel a0 */ + REG_S a0, PT_A0(sp) + /* Trace syscalls, but only if requested by the user. */ + REG_L t0, TASK_TI_FLAGS(tp) + andi t0, t0, _TIF_SYSCALL_TRACE + bnez t0, handle_syscall_trace_exit + +ret_from_exception: + REG_L s0, PT_SSTATUS(sp) + csrc sstatus, SR_IE + andi s0, s0, SR_PS + bnez s0, restore_all + +resume_userspace: + /* Interrupts must be disabled here so flags are checked atomically */ + REG_L s0, TASK_TI_FLAGS(tp) /* current_thread_info->flags */ + andi s1, s0, _TIF_WORK_MASK + bnez s1, work_pending + + /* Save unwound kernel stack pointer in thread_info */ + addi s0, sp, PT_SIZE_ON_STACK + REG_S s0, TASK_TI_KERNEL_SP(tp) + + /* + * Save TP into sscratch, so we can find the kernel data structures + * again. + */ + csrw sscratch, tp + +restore_all: + RESTORE_ALL + sret + +work_pending: + /* Enter slow path for supplementary processing */ + la ra, ret_from_exception + andi s1, s0, _TIF_NEED_RESCHED + bnez s1, work_resched +work_notifysig: + /* Handle pending signals and notify-resume requests */ + csrs sstatus, SR_IE /* Enable interrupts for do_notify_resume() */ + move a0, sp /* pt_regs */ + move a1, s0 /* current_thread_info->flags */ + tail do_notify_resume +work_resched: + tail schedule + +/* Slow paths for ptrace. */ +handle_syscall_trace_enter: + move a0, sp + call do_syscall_trace_enter + REG_L a0, PT_A0(sp) + REG_L a1, PT_A1(sp) + REG_L a2, PT_A2(sp) + REG_L a3, PT_A3(sp) + REG_L a4, PT_A4(sp) + REG_L a5, PT_A5(sp) + REG_L a6, PT_A6(sp) + REG_L a7, PT_A7(sp) + j check_syscall_nr +handle_syscall_trace_exit: + move a0, sp + call do_syscall_trace_exit + j ret_from_exception + +END(handle_exception) + +ENTRY(ret_from_fork) + la ra, ret_from_exception + tail schedule_tail +ENDPROC(ret_from_fork) + +ENTRY(ret_from_kernel_thread) + call schedule_tail + /* Call fn(arg) */ + la ra, ret_from_exception + move a0, s1 + jr s0 +ENDPROC(ret_from_kernel_thread) + + +/* + * Integer register context switch + * The callee-saved registers must be saved and restored. + * + * a0: previous task_struct (must be preserved across the switch) + * a1: next task_struct + * + * The value of a0 and a1 must be preserved by this function, as that's how + * arguments are passed to schedule_tail. + */ +ENTRY(__switch_to) + /* Save context into prev->thread */ + li a4, TASK_THREAD_RA + add a3, a0, a4 + add a4, a1, a4 + REG_S ra, TASK_THREAD_RA_RA(a3) + REG_S sp, TASK_THREAD_SP_RA(a3) + REG_S s0, TASK_THREAD_S0_RA(a3) + REG_S s1, TASK_THREAD_S1_RA(a3) + REG_S s2, TASK_THREAD_S2_RA(a3) + REG_S s3, TASK_THREAD_S3_RA(a3) + REG_S s4, TASK_THREAD_S4_RA(a3) + REG_S s5, TASK_THREAD_S5_RA(a3) + REG_S s6, TASK_THREAD_S6_RA(a3) + REG_S s7, TASK_THREAD_S7_RA(a3) + REG_S s8, TASK_THREAD_S8_RA(a3) + REG_S s9, TASK_THREAD_S9_RA(a3) + REG_S s10, TASK_THREAD_S10_RA(a3) + REG_S s11, TASK_THREAD_S11_RA(a3) + /* Restore context from next->thread */ + REG_L ra, TASK_THREAD_RA_RA(a4) + REG_L sp, TASK_THREAD_SP_RA(a4) + REG_L s0, TASK_THREAD_S0_RA(a4) + REG_L s1, TASK_THREAD_S1_RA(a4) + REG_L s2, TASK_THREAD_S2_RA(a4) + |