From 01573e231f18eb2d99162747186f59511f56b64d Mon Sep 17 00:00:00 2001 From: hc <hc@nodka.com> Date: Fri, 08 Dec 2023 10:40:48 +0000 Subject: [PATCH] 移去rt --- kernel/arch/riscv/kernel/entry.S | 493 +++++++++++++++++++++++++++--------------------------- 1 files changed, 249 insertions(+), 244 deletions(-) diff --git a/kernel/arch/riscv/kernel/entry.S b/kernel/arch/riscv/kernel/entry.S index d9de226..5214c57 100644 --- a/kernel/arch/riscv/kernel/entry.S +++ b/kernel/arch/riscv/kernel/entry.S @@ -1,15 +1,7 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ /* * 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> @@ -21,27 +13,21 @@ #include <asm/thread_info.h> #include <asm/asm-offsets.h> - .text - .altmacro +#if !IS_ENABLED(CONFIG_PREEMPTION) +.set resume_kernel, restore_all +#endif -/* - * 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 - +ENTRY(handle_exception) /* * 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. + * the kernel thread pointer. If we came from the kernel, the scratch + * register will contain 0, and we should continue on the current TP. */ - csrrw tp, sscratch, tp + csrrw tp, CSR_SCRATCH, tp bnez tp, _save_context _restore_kernel_tpsp: - csrr tp, sscratch + csrr tp, CSR_SCRATCH REG_S sp, TASK_TI_KERNEL_SP(tp) _save_context: REG_S sp, TASK_TI_USER_SP(tp) @@ -87,28 +73,220 @@ li t0, SR_SUM | 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 + csrrc s1, CSR_STATUS, t0 + csrr s2, CSR_EPC + csrr s3, CSR_TVAL + csrr s4, CSR_CAUSE + csrr s5, CSR_SCRATCH 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 s1, PT_STATUS(sp) + REG_S s2, PT_EPC(sp) + REG_S s3, PT_BADADDR(sp) + REG_S s4, PT_CAUSE(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 + /* + * Set the scratch register to 0, so that if a recursive exception + * occurs, the exception vector knows it came from the kernel + */ + csrw CSR_SCRATCH, x0 + + /* Load the global pointer */ +.option push +.option norelax + la gp, __global_pointer$ +.option pop + +#ifdef CONFIG_TRACE_IRQFLAGS + call __trace_hardirqs_off +#endif + +#ifdef CONFIG_CONTEXT_TRACKING + /* If previous state is in user mode, call context_tracking_user_exit. */ + li a0, SR_PP + and a0, s1, a0 + bnez a0, skip_context_tracking + call context_tracking_user_exit +skip_context_tracking: +#endif + + /* + * MSB of cause differentiates between + * interrupts and exceptions + */ + bge s4, zero, 1f + + la ra, ret_from_exception + + /* Handle interrupts */ + move a0, sp /* pt_regs */ + la a1, handle_arch_irq + REG_L a1, (a1) + jr a1 +1: + /* + * Exceptions run with interrupts enabled or disabled depending on the + * state of SR_PIE in m/sstatus. + */ + andi t0, s1, SR_PIE + beqz t0, 1f +#ifdef CONFIG_TRACE_IRQFLAGS + call __trace_hardirqs_on +#endif + csrs CSR_STATUS, SR_IE + +1: + la ra, ret_from_exception + /* 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: +#ifdef CONFIG_RISCV_M_MODE + /* + * When running is M-Mode (no MMU config), MPIE does not get set. + * As a result, we need to force enable interrupts here because + * handle_exception did not do set SR_IE as it always sees SR_PIE + * being cleared. + */ + csrs CSR_STATUS, SR_IE +#endif +#if defined(CONFIG_TRACE_IRQFLAGS) || defined(CONFIG_CONTEXT_TRACKING) + /* Recover a0 - a7 for system calls */ + 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) +#endif + /* 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_EPC(sp) + /* Trace syscalls, but only if requested by the user. */ + REG_L t0, TASK_TI_FLAGS(tp) + andi t0, t0, _TIF_SYSCALL_WORK + 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. + * If syscall number is above allowed value, redirect to ni_syscall. + */ + bgeu a7, t0, 1f + /* Call syscall */ + 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) + /* + * We didn't execute the actual syscall. + * Seccomp already set return value for the current task pt_regs. + * (If it was configured with SECCOMP_RET_ERRNO/TRACE) + */ +ret_from_syscall_rejected: + /* Trace syscalls, but only if requested by the user. */ + REG_L t0, TASK_TI_FLAGS(tp) + andi t0, t0, _TIF_SYSCALL_WORK + bnez t0, handle_syscall_trace_exit + +ret_from_exception: + REG_L s0, PT_STATUS(sp) + csrc CSR_STATUS, SR_IE +#ifdef CONFIG_TRACE_IRQFLAGS + call __trace_hardirqs_off +#endif +#ifdef CONFIG_RISCV_M_MODE + /* the MPP value is too large to be used as an immediate arg for addi */ + li t0, SR_MPP + and s0, s0, t0 +#else + andi s0, s0, SR_SPP +#endif + bnez s0, resume_kernel + +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 + +#ifdef CONFIG_CONTEXT_TRACKING + call context_tracking_user_enter +#endif + + /* 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 the scratch register , so we can find the kernel data + * structures again. + */ + csrw CSR_SCRATCH, tp + +restore_all: +#ifdef CONFIG_TRACE_IRQFLAGS + REG_L s1, PT_STATUS(sp) + andi t0, s1, SR_PIE + beqz t0, 1f + call __trace_hardirqs_on + j 2f +1: + call __trace_hardirqs_off +2: +#endif + REG_L a0, PT_STATUS(sp) + /* + * The current load reservation is effectively part of the processor's + * state, in the sense that load reservations cannot be shared between + * different hart contexts. We can't actually save and restore a load + * reservation, so instead here we clear any existing reservation -- + * it's always legal for implementations to clear load reservations at + * any point (as long as the forward progress guarantee is kept, but + * we'll ignore that here). + * + * Dangling load reservations can be the result of taking a trap in the + * middle of an LR/SC sequence, but can also be the result of a taken + * forward branch around an SC -- which is how we implement CAS. As a + * result we need to clear reservations between the last CAS and the + * jump back to the new context. While it is unlikely the store + * completes, implementations are allowed to expand reservations to be + * arbitrarily large. + */ + REG_L a2, PT_EPC(sp) + REG_SC x0, a2, PT_EPC(sp) + + csrw CSR_STATUS, a0 + csrw CSR_EPC, a2 REG_L x1, PT_RA(sp) REG_L x3, PT_GP(sp) @@ -142,118 +320,23 @@ 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 */ - move a0, sp /* pt_regs */ - move a1, s4 /* scause */ - tail do_IRQ -1: - /* Exceptions run with interrupts enabled or disabled - depending on the state of sstatus.SR_SPIE */ - andi t0, s1, SR_SPIE - beqz t0, 1f - csrs sstatus, SR_SIE - -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) - /* 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_SIE - andi s0, s0, SR_SPP - 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 +#ifdef CONFIG_RISCV_M_MODE + mret +#else sret +#endif + +#if IS_ENABLED(CONFIG_PREEMPTION) +resume_kernel: + REG_L s0, TASK_TI_PREEMPT_COUNT(tp) + bnez s0, restore_all + REG_L s0, TASK_TI_FLAGS(tp) + andi s0, s0, _TIF_NEED_RESCHED + beqz s0, restore_all + call preempt_schedule_irq + j restore_all +#endif work_pending: /* Enter slow path for supplementary processing */ @@ -262,7 +345,7 @@ bnez s1, work_resched work_notifysig: /* Handle pending signals and notify-resume requests */ - csrs sstatus, SR_SIE /* Enable interrupts for do_notify_resume() */ + csrs CSR_STATUS, SR_IE /* Enable interrupts for do_notify_resume() */ move a0, sp /* pt_regs */ move a1, s0 /* current_thread_info->flags */ tail do_notify_resume @@ -273,6 +356,7 @@ handle_syscall_trace_enter: move a0, sp call do_syscall_trace_enter + move t0, a0 REG_L a0, PT_A0(sp) REG_L a1, PT_A1(sp) REG_L a2, PT_A2(sp) @@ -281,6 +365,7 @@ REG_L a5, PT_A5(sp) REG_L a6, PT_A6(sp) REG_L a7, PT_A7(sp) + bnez t0, ret_from_syscall_rejected j check_syscall_nr handle_syscall_trace_exit: move a0, sp @@ -352,101 +437,14 @@ lw a4, TASK_TI_CPU(a1) sw a3, TASK_TI_CPU(a1) sw a4, TASK_TI_CPU(a0) -#if TASK_TI != 0 -#error "TASK_TI != 0: tp will contain a 'struct thread_info', not a 'struct task_struct' so get_current() won't work." - addi tp, a1, TASK_TI -#else + /* The offset of thread_info in task_struct is zero. */ move tp, a1 -#endif ret ENDPROC(__switch_to) -ENTRY(__fstate_save) - li a2, TASK_THREAD_F0 - add a0, a0, a2 - li t1, SR_FS - csrs sstatus, t1 - frcsr t0 - fsd f0, TASK_THREAD_F0_F0(a0) - fsd f1, TASK_THREAD_F1_F0(a0) - fsd f2, TASK_THREAD_F2_F0(a0) - fsd f3, TASK_THREAD_F3_F0(a0) - fsd f4, TASK_THREAD_F4_F0(a0) - fsd f5, TASK_THREAD_F5_F0(a0) - fsd f6, TASK_THREAD_F6_F0(a0) - fsd f7, TASK_THREAD_F7_F0(a0) - fsd f8, TASK_THREAD_F8_F0(a0) - fsd f9, TASK_THREAD_F9_F0(a0) - fsd f10, TASK_THREAD_F10_F0(a0) - fsd f11, TASK_THREAD_F11_F0(a0) - fsd f12, TASK_THREAD_F12_F0(a0) - fsd f13, TASK_THREAD_F13_F0(a0) - fsd f14, TASK_THREAD_F14_F0(a0) - fsd f15, TASK_THREAD_F15_F0(a0) - fsd f16, TASK_THREAD_F16_F0(a0) - fsd f17, TASK_THREAD_F17_F0(a0) - fsd f18, TASK_THREAD_F18_F0(a0) - fsd f19, TASK_THREAD_F19_F0(a0) - fsd f20, TASK_THREAD_F20_F0(a0) - fsd f21, TASK_THREAD_F21_F0(a0) - fsd f22, TASK_THREAD_F22_F0(a0) - fsd f23, TASK_THREAD_F23_F0(a0) - fsd f24, TASK_THREAD_F24_F0(a0) - fsd f25, TASK_THREAD_F25_F0(a0) - fsd f26, TASK_THREAD_F26_F0(a0) - fsd f27, TASK_THREAD_F27_F0(a0) - fsd f28, TASK_THREAD_F28_F0(a0) - fsd f29, TASK_THREAD_F29_F0(a0) - fsd f30, TASK_THREAD_F30_F0(a0) - fsd f31, TASK_THREAD_F31_F0(a0) - sw t0, TASK_THREAD_FCSR_F0(a0) - csrc sstatus, t1 - ret -ENDPROC(__fstate_save) - -ENTRY(__fstate_restore) - li a2, TASK_THREAD_F0 - add a0, a0, a2 - li t1, SR_FS - lw t0, TASK_THREAD_FCSR_F0(a0) - csrs sstatus, t1 - fld f0, TASK_THREAD_F0_F0(a0) - fld f1, TASK_THREAD_F1_F0(a0) - fld f2, TASK_THREAD_F2_F0(a0) - fld f3, TASK_THREAD_F3_F0(a0) - fld f4, TASK_THREAD_F4_F0(a0) - fld f5, TASK_THREAD_F5_F0(a0) - fld f6, TASK_THREAD_F6_F0(a0) - fld f7, TASK_THREAD_F7_F0(a0) - fld f8, TASK_THREAD_F8_F0(a0) - fld f9, TASK_THREAD_F9_F0(a0) - fld f10, TASK_THREAD_F10_F0(a0) - fld f11, TASK_THREAD_F11_F0(a0) - fld f12, TASK_THREAD_F12_F0(a0) - fld f13, TASK_THREAD_F13_F0(a0) - fld f14, TASK_THREAD_F14_F0(a0) - fld f15, TASK_THREAD_F15_F0(a0) - fld f16, TASK_THREAD_F16_F0(a0) - fld f17, TASK_THREAD_F17_F0(a0) - fld f18, TASK_THREAD_F18_F0(a0) - fld f19, TASK_THREAD_F19_F0(a0) - fld f20, TASK_THREAD_F20_F0(a0) - fld f21, TASK_THREAD_F21_F0(a0) - fld f22, TASK_THREAD_F22_F0(a0) - fld f23, TASK_THREAD_F23_F0(a0) - fld f24, TASK_THREAD_F24_F0(a0) - fld f25, TASK_THREAD_F25_F0(a0) - fld f26, TASK_THREAD_F26_F0(a0) - fld f27, TASK_THREAD_F27_F0(a0) - fld f28, TASK_THREAD_F28_F0(a0) - fld f29, TASK_THREAD_F29_F0(a0) - fld f30, TASK_THREAD_F30_F0(a0) - fld f31, TASK_THREAD_F31_F0(a0) - fscsr t0 - csrc sstatus, t1 - ret -ENDPROC(__fstate_restore) - +#ifndef CONFIG_MMU +#define do_page_fault do_trap_unknown +#endif .section ".rodata" .align LGREG @@ -470,3 +468,10 @@ RISCV_PTR do_page_fault /* store page fault */ excp_vect_table_end: END(excp_vect_table) + +#ifndef CONFIG_MMU +ENTRY(__user_rt_sigreturn) + li a7, __NR_rt_sigreturn + scall +END(__user_rt_sigreturn) +#endif -- Gitblit v1.6.2