diff options
Diffstat (limited to 'arch/riscv/kernel/entry.S')
| -rw-r--r-- | arch/riscv/kernel/entry.S | 321 |
1 files changed, 33 insertions, 288 deletions
diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S index 99d38fdf8b18..3fbb100bc9e4 100644 --- a/arch/riscv/kernel/entry.S +++ b/arch/riscv/kernel/entry.S @@ -14,11 +14,7 @@ #include <asm/asm-offsets.h> #include <asm/errata_list.h> -#if !IS_ENABLED(CONFIG_PREEMPTION) -.set resume_kernel, restore_all -#endif - -ENTRY(handle_exception) +SYM_CODE_START(handle_exception) /* * If coming from userspace, preserve the user thread pointer and load * the kernel thread pointer. If we came from the kernel, the scratch @@ -46,32 +42,7 @@ _save_context: 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) + save_from_x6_to_x31 /* * Disable user-mode memory access as it should only be set in the @@ -106,19 +77,8 @@ _save_context: .option norelax la gp, __global_pointer$ .option pop - -#ifdef CONFIG_TRACE_IRQFLAGS - call __trace_hardirqs_off -#endif - -#ifdef CONFIG_CONTEXT_TRACKING_USER - /* If previous state is in user mode, call user_exit_callable(). */ - li a0, SR_PP - and a0, s1, a0 - bnez a0, skip_context_tracking - call user_exit_callable -skip_context_tracking: -#endif + move a0, sp /* pt_regs */ + la ra, ret_from_exception /* * MSB of cause differentiates between @@ -126,38 +86,13 @@ skip_context_tracking: */ bge s4, zero, 1f - la ra, ret_from_exception - /* Handle interrupts */ - move a0, sp /* pt_regs */ - la a1, generic_handle_arch_irq - 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 - /* kprobes, entered via ebreak, must have interrupts disabled. */ - li t0, EXC_BREAKPOINT - beq s4, t0, 1f -#ifdef CONFIG_TRACE_IRQFLAGS - call __trace_hardirqs_on -#endif - csrs CSR_STATUS, SR_IE - + tail do_irq 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 @@ -165,95 +100,16 @@ skip_context_tracking: jr t0 1: tail do_trap_unknown +SYM_CODE_END(handle_exception) -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_USER) - /* 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, 3f -#ifdef CONFIG_COMPAT - REG_L s0, PT_STATUS(sp) - srli s0, s0, SR_UXL_SHIFT - andi s0, s0, (SR_UXL >> SR_UXL_SHIFT) - li t0, (SR_UXL_32 >> SR_UXL_SHIFT) - sub t0, s0, t0 - bnez t0, 1f - - /* Call compat_syscall */ - la s0, compat_sys_call_table - j 2f -1: -#endif - /* Call syscall */ - la s0, sys_call_table -2: - slli t0, a7, RISCV_LGPTR - add s0, s0, t0 - REG_L s0, 0(s0) -3: - 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: -#ifdef CONFIG_DEBUG_RSEQ - move a0, sp - call rseq_syscall -#endif - /* 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 - +/* + * The ret_from_exception must be called with interrupt disabled. Here is the + * caller list: + * - handle_exception + * - ret_from_fork + */ SYM_CODE_START_NOALIGN(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 @@ -261,17 +117,7 @@ SYM_CODE_START_NOALIGN(ret_from_exception) #else andi s0, s0, SR_SPP #endif - bnez s0, resume_kernel -SYM_CODE_END(ret_from_exception) - - /* 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, resume_userspace_slow -resume_userspace: -#ifdef CONFIG_CONTEXT_TRACKING_USER - call user_enter_callable -#endif + bnez s0, 1f /* Save unwound kernel stack pointer in thread_info */ addi s0, sp, PT_SIZE_ON_STACK @@ -282,18 +128,7 @@ resume_userspace: * 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 @@ -322,32 +157,7 @@ restore_all: 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) + restore_from_x6_to_x31 REG_L x2, PT_SP(sp) @@ -356,47 +166,10 @@ restore_all: #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 - -resume_userspace_slow: - /* Enter slow path for supplementary processing */ - move a0, sp /* pt_regs */ - move a1, s0 /* current_thread_info->flags */ - call do_work_pending - j resume_userspace - -/* Slow paths for ptrace. */ -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) - 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) - bnez t0, ret_from_syscall_rejected - j check_syscall_nr -handle_syscall_trace_exit: - move a0, sp - call do_syscall_trace_exit - j ret_from_exception +SYM_CODE_END(ret_from_exception) #ifdef CONFIG_VMAP_STACK -handle_kernel_stack_overflow: +SYM_CODE_START_LOCAL(handle_kernel_stack_overflow) /* * Takes the psuedo-spinlock for the shadow stack, in case multiple * harts are concurrently overflowing their kernel stacks. We could @@ -464,32 +237,7 @@ restore_caller_reg: 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) + save_from_x6_to_x31 REG_L s0, TASK_TI_KERNEL_SP(tp) csrr s1, CSR_STATUS @@ -505,23 +253,20 @@ restore_caller_reg: REG_S s5, PT_TP(sp) move a0, sp tail handle_bad_stack +SYM_CODE_END(handle_kernel_stack_overflow) #endif -END(handle_exception) - -ENTRY(ret_from_fork) - la ra, ret_from_exception - tail schedule_tail -ENDPROC(ret_from_fork) - -ENTRY(ret_from_kernel_thread) +SYM_CODE_START(ret_from_fork) call schedule_tail + beqz s0, 1f /* not from kernel thread */ /* Call fn(arg) */ - la ra, ret_from_exception move a0, s1 - jr s0 -ENDPROC(ret_from_kernel_thread) - + jalr s0 +1: + move a0, sp /* pt_regs */ + la ra, ret_from_exception + tail syscall_exit_to_user_mode +SYM_CODE_END(ret_from_fork) /* * Integer register context switch @@ -533,7 +278,7 @@ ENDPROC(ret_from_kernel_thread) * 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) +SYM_FUNC_START(__switch_to) /* Save context into prev->thread */ li a4, TASK_THREAD_RA add a3, a0, a4 @@ -570,7 +315,7 @@ ENTRY(__switch_to) /* The offset of thread_info in task_struct is zero. */ move tp, a1 ret -ENDPROC(__switch_to) +SYM_FUNC_END(__switch_to) #ifndef CONFIG_MMU #define do_page_fault do_trap_unknown @@ -579,7 +324,7 @@ ENDPROC(__switch_to) .section ".rodata" .align LGREG /* Exception vector table */ -ENTRY(excp_vect_table) +SYM_CODE_START(excp_vect_table) RISCV_PTR do_trap_insn_misaligned ALT_INSN_FAULT(RISCV_PTR do_trap_insn_fault) RISCV_PTR do_trap_insn_illegal @@ -588,7 +333,7 @@ ENTRY(excp_vect_table) RISCV_PTR do_trap_load_fault RISCV_PTR do_trap_store_misaligned RISCV_PTR do_trap_store_fault - RISCV_PTR do_trap_ecall_u /* system call, gets intercepted */ + RISCV_PTR do_trap_ecall_u /* system call */ RISCV_PTR do_trap_ecall_s RISCV_PTR do_trap_unknown RISCV_PTR do_trap_ecall_m @@ -598,11 +343,11 @@ ENTRY(excp_vect_table) RISCV_PTR do_trap_unknown RISCV_PTR do_page_fault /* store page fault */ excp_vect_table_end: -END(excp_vect_table) +SYM_CODE_END(excp_vect_table) #ifndef CONFIG_MMU -ENTRY(__user_rt_sigreturn) +SYM_CODE_START(__user_rt_sigreturn) li a7, __NR_rt_sigreturn scall -END(__user_rt_sigreturn) +SYM_CODE_END(__user_rt_sigreturn) #endif |