diff options
Diffstat (limited to 'arch/riscv64/kernel/entry.S')
| -rw-r--r-- | arch/riscv64/kernel/entry.S | 106 |
1 files changed, 72 insertions, 34 deletions
diff --git a/arch/riscv64/kernel/entry.S b/arch/riscv64/kernel/entry.S index 6096844..abf3cba 100644 --- a/arch/riscv64/kernel/entry.S +++ b/arch/riscv64/kernel/entry.S @@ -20,27 +20,31 @@ /* we can go back to relaxed mode if we want */ .option pop -.macro save_args +.macro save_caller sr a0, offsetof_a0(sp) sr a1, offsetof_a1(sp) sr a2, offsetof_a2(sp) sr a3, offsetof_a3(sp) sr a4, offsetof_a4(sp) sr a5, offsetof_a5(sp) + sr a6, offsetof_a6(sp) + sr a7, offsetof_a7(sp) + sr t0, offsetof_t0(sp) + sr t1, offsetof_t1(sp) + sr t2, offsetof_t2(sp) + sr t3, offsetof_t3(sp) + sr t4, offsetof_t4(sp) + sr t5, offsetof_t5(sp) + sr t6, offsetof_t6(sp) .endm -.macro save_regs +.macro save_callee /* save registers */ sr ra, offsetof_ra(sp) sr gp, offsetof_gp(sp) sr tp, offsetof_tp(sp) - sr t0, offsetof_t0(sp) - sr t1, offsetof_t1(sp) - sr t2, offsetof_t2(sp) sr s0, offsetof_s0(sp) sr s1, offsetof_s1(sp) - sr a6, offsetof_a6(sp) - sr a7, offsetof_a7(sp) sr s2, offsetof_s2(sp) sr s3, offsetof_s3(sp) sr s4, offsetof_s4(sp) @@ -49,10 +53,7 @@ sr s7, offsetof_s7(sp) sr s8, offsetof_s8(sp) sr s9, offsetof_s9(sp) - sr s10,offsetof_s10(sp) - sr s11,offsetof_s11(sp) - sr t3, offsetof_t3(sp) - sr t4, offsetof_t4(sp) + /* s10 and s11 always saved */ .endm .global handle_trap @@ -72,37 +73,37 @@ continue_trap: addi sp, sp, -sizeof_registers csrrw tp, CSR_SSCRATCH, tp - sr t5, offsetof_t5(sp) - sr t6, offsetof_t6(sp) + sr s10, offsetof_s10(sp) + sr s11, offsetof_s11(sp) /* get current tcb into tp and set scratch to 0 so we can figure out if * exception occured in kernel or userspace */ csrrw tp, CSR_SSCRATCH, x0 - lr t5, offsetof_arch(tp) - sr t5, offsetof_sp(sp) + lr s10, offsetof_arch(tp) + sr s10, offsetof_sp(sp) /* load supervisor cause */ - csrr t5, CSR_SCAUSE + csrr s10, CSR_SCAUSE /* interrupts fall through, exceptions jump */ /* (leading 1 means the value is interpreted as negative) */ - bge t5, zero, handle_exception + bge s10, zero, handle_exception - save_regs - save_args + save_callee + save_caller - mv a0, t5 + mv a0, s10 call riscv_handle_interrupt j _load_context handle_exception: - li t6, EXC_SYSCALL + li s11, EXC_SYSCALL /* system exceptions fall through, syscalls and ipis jump */ /* temp, at some point we want to handle system exceptions as well */ - beq t5, t6, handle_dispatch + beq s10, s11, handle_dispatch - save_regs - save_args + save_callee + save_caller csrr a0, CSR_SEPC csrr a1, CSR_STVAL @@ -114,21 +115,21 @@ handle_exception: j _load_context handle_dispatch: - li t5, SYS_IPC_RESP - bne a0, t5, slow_dispatch + li s10, SYS_IPC_RESP + bne a0, s10, slow_dispatch /* we're a sys_ipc_resp */ - lw t5, offsetof_rid(tp) - lw t6, offsetof_pid(tp) + lw s10, offsetof_rid(tp) + lw s11, offsetof_pid(tp) /* we're in an rpc, so we can skip saving the rest of the registers */ - beq t5, t6, fast_dispatch + beq s10, s11, fast_dispatch slow_dispatch: - save_regs + save_callee fast_dispatch: /* store execution continuation point */ - csrr t5, CSR_SEPC - sr t5, offsetof_exec(tp) + csrr s10, CSR_SEPC + sr s10, offsetof_exec(tp) /* jump to C */ call dispatch /* if we had a thread switch, load kernel stack of current thread and @@ -137,8 +138,8 @@ fast_dispatch: lr sp, offsetof_regs(tp) addi sp, sp, -sizeof_registers /* set execution continuation */ - lr t5, offsetof_exec(tp) - csrw CSR_SEPC, t5 + lr s10, offsetof_exec(tp) + csrw CSR_SEPC, s10 _load_context: /* restore registers besides possible return value, assume instruction @@ -182,6 +183,43 @@ _load_context: /* assume supervisor for now */ sret +.global ret_userspace_partial +ret_userspace_partial: + lr sp, offsetof_regs(tp) + addi sp, sp, -sizeof_registers + + lr s10, offsetof_exec(tp) + csrw CSR_SEPC, s10 + + csrw CSR_SSCRATCH, tp + + lr s0, offsetof_s0(sp) + lr a0, offsetof_a0(sp) + lr a1, offsetof_a1(sp) + lr a2, offsetof_a2(sp) + lr a3, offsetof_a3(sp) + lr a4, offsetof_a4(sp) + lr a5, offsetof_a5(sp) + lr s0, offsetof_s0(sp) + lr s1, offsetof_s1(sp) + lr s2, offsetof_s2(sp) + lr s3, offsetof_s3(sp) + lr s4, offsetof_s4(sp) + lr s5, offsetof_s5(sp) + lr s6, offsetof_s6(sp) + lr s7, offsetof_s7(sp) + lr s8, offsetof_s8(sp) + lr s9, offsetof_s9(sp) + lr s10, offsetof_s10(sp) + lr s11, offsetof_s11(sp) + lr ra, offsetof_ra(sp) + lr gp, offsetof_gp(sp) + lr tp, offsetof_tp(sp) + + lr sp, offsetof_sp(sp) + + sret + .global ret_userspace_fast ret_userspace_fast: lr sp, offsetof_regs(tp) |