| /* |
| * Copyright (c) 2017 Synopsys. |
| * |
| * SPDX-License-Identifier: Apache-2.0 |
| */ |
| |
| #include <offsets_short.h> |
| #include <toolchain.h> |
| #include <linker/sections.h> |
| #include <kernel_structs.h> |
| #include <arch/cpu.h> |
| #include <syscall.h> |
| |
| .macro clear_scratch_regs |
| mov r1, 0 |
| mov r2, 0 |
| mov r3, 0 |
| mov r4, 0 |
| mov r5, 0 |
| mov r6, 0 |
| mov r7, 0 |
| mov r8, 0 |
| mov r9, 0 |
| mov r10, 0 |
| mov r11, 0 |
| mov r12, 0 |
| |
| mov fp, 0 |
| mov r29, 0 |
| mov r30, 0 |
| mov blink, 0 |
| .endm |
| |
| .macro clear_callee_regs |
| mov r25, 0 |
| mov r24, 0 |
| mov r23, 0 |
| mov r22, 0 |
| mov r21, 0 |
| mov r20, 0 |
| mov r19, 0 |
| mov r18, 0 |
| mov r17, 0 |
| mov r16, 0 |
| |
| mov r15, 0 |
| mov r14, 0 |
| mov r13, 0 |
| .endm |
| |
| GTEXT(_arc_userspace_enter) |
| GTEXT(_arc_do_syscall) |
| GTEXT(_user_thread_entry_wrapper) |
| |
| |
| |
| /* |
| * @brief Wrapper for _thread_entry in the case of user thread |
| * |
| * @return N/A |
| */ |
| SECTION_FUNC(TEXT, _user_thread_entry_wrapper) |
| /* sp the user stack pointer, r0-r4 are in stack */ |
| mov r5, sp |
| /* start of privilege stack */ |
| add blink, r5, CONFIG_PRIVILEGED_STACK_SIZE+16 |
| |
| /* r4<- start of user stack region */ |
| mov r0, _kernel |
| ld_s r1, [r0, _kernel_offset_to_current] |
| ld r4, [r1, ___thread_stack_info_t_start_OFFSET] |
| |
| /* |
| * when CONFIG_INIT_STACK is enable, stack will be initialized |
| * in _new_thread_init. |
| */ |
| j _arc_go_to_user_space |
| |
| /** |
| * |
| * User space entry function |
| * |
| * This function is the entry point to user mode from privileged execution. |
| * The conversion is one way, and threads which transition to user mode do |
| * not transition back later, unless they are doing system calls. |
| * |
| */ |
| SECTION_FUNC(TEXT, _arc_userspace_enter) |
| /* |
| * In ARCv2, the U bit can only be set through exception return |
| */ |
| /* the end of user stack in r5 */ |
| add r5, r4, r5 |
| /* start of privilege stack */ |
| add blink, r5, CONFIG_PRIVILEGED_STACK_SIZE |
| mov sp, r5 |
| |
| push_s r0 |
| push_s r1 |
| push_s r2 |
| push_s r3 |
| |
| mov r5, sp /* skip r0, r1, r2, r3 */ |
| |
| #ifdef CONFIG_INIT_STACKS |
| mov r0, 0xaaaaaaaa |
| #else |
| mov r0, 0x0 |
| #endif |
| _clear_user_stack: |
| st.ab r0, [r4, 4] |
| cmp r4, r5 |
| jlt _clear_user_stack |
| |
| _arc_go_to_user_space: |
| lr r0, [_ARC_V2_STATUS32] |
| bset r0, r0, _ARC_V2_STATUS32_U_BIT |
| |
| mov r1, _thread_entry_wrapper |
| |
| /* fake exception return */ |
| kflag _ARC_V2_STATUS32_AE |
| |
| sr r0, [_ARC_V2_ERSTATUS] |
| sr r1, [_ARC_V2_ERET] |
| |
| #ifdef CONFIG_ARC_HAS_SECURE |
| lr r0, [_ARC_V2_SEC_STAT] |
| /* the mode returns from exception return is secure mode */ |
| bset r0, r0, 31 |
| sr r0, [_ARC_V2_ERSEC_STAT] |
| sr r5, [_ARC_V2_SEC_U_SP] |
| #else |
| /* when exception returns from kernel to user, sp and _ARC_V2_USER_SP |
| * will be switched |
| */ |
| sr r5, [_ARC_V2_USER_SP] |
| #endif |
| mov sp, blink |
| |
| mov r0, 0 |
| |
| clear_callee_regs |
| |
| clear_scratch_regs |
| |
| rtie |
| |
| /** |
| * |
| * Userspace system call function |
| * |
| * This function is used to do system calls from unprivileged code. This |
| * function is responsible for the following: |
| * 1) Dispatching the system call |
| * 2) Restoring stack and calling back to the caller of the system call |
| * |
| */ |
| SECTION_FUNC(TEXT, _arc_do_syscall) |
| /* r0-r5: arg1-arg6, r6 is call id */ |
| /* the call id is already checked in trap_s handler */ |
| push_s blink |
| |
| mov blink, _k_syscall_table |
| ld.as r6, [blink, r6] |
| |
| jl [r6] |
| |
| pop_s blink |
| |
| /* through fake exception return, go back to the caller */ |
| kflag _ARC_V2_STATUS32_AE |
| |
| #ifdef CONFIG_ARC_HAS_SECURE |
| lr r6, [_ARC_V2_SEC_STAT] |
| /* the mode returns from exception return is secure mode */ |
| bset r6, r6, 31 |
| sr r6, [_ARC_V2_ERSEC_STAT] |
| #endif |
| /* the status and return addesss are saved in trap_s handler */ |
| pop r6 |
| sr r6, [_ARC_V2_ERSTATUS] |
| pop r6 |
| sr r6, [_ARC_V2_ERET] |
| |
| /* no nned to clear callee regs */ |
| clear_scratch_regs |
| |
| rtie |