diff options
Diffstat (limited to 'arch/nds32/kernel/ex-exit.S')
| -rw-r--r-- | arch/nds32/kernel/ex-exit.S | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/arch/nds32/kernel/ex-exit.S b/arch/nds32/kernel/ex-exit.S new file mode 100644 index 000000000000..03e4f7788a18 --- /dev/null +++ b/arch/nds32/kernel/ex-exit.S @@ -0,0 +1,184 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (C) 2005-2017 Andes Technology Corporation + +#include <linux/linkage.h> +#include <asm/unistd.h> +#include <asm/assembler.h> +#include <asm/nds32.h> +#include <asm/asm-offsets.h> +#include <asm/thread_info.h> +#include <asm/current.h> + + + +#ifdef CONFIG_HWZOL + .macro pop_zol + mtusr $r14, $LB + mtusr $r15, $LE + mtusr $r16, $LC + .endm +#endif + + .macro restore_user_regs_first + setgie.d + isb + + addi $sp, $sp, FUCOP_CTL_OFFSET + + lmw.adm $r12, [$sp], $r24, #0x0 + mtsr $r12, $SP_USR + mtsr $r13, $IPC +#ifdef CONFIG_HWZOL + pop_zol +#endif + mtsr $r19, $PSW + mtsr $r20, $IPSW + mtsr $r21, $P_IPSW + mtsr $r22, $P_IPC + mtsr $r23, $P_P0 + mtsr $r24, $P_P1 + lmw.adm $sp, [$sp], $sp, #0xe + .endm + + .macro restore_user_regs_last + pop $p0 + cmovn $sp, $p0, $p0 + + iret + nop + + .endm + + .macro restore_user_regs + restore_user_regs_first + lmw.adm $r0, [$sp], $r25, #0x0 + addi $sp, $sp, OSP_OFFSET + restore_user_regs_last + .endm + + .macro fast_restore_user_regs + restore_user_regs_first + lmw.adm $r1, [$sp], $r25, #0x0 + addi $sp, $sp, OSP_OFFSET-4 + restore_user_regs_last + .endm + +#ifdef CONFIG_PREEMPT + .macro preempt_stop + .endm +#else + .macro preempt_stop + setgie.d + isb + .endm +#define resume_kernel no_work_pending +#endif + +ENTRY(ret_from_exception) + preempt_stop +ENTRY(ret_from_intr) + +/* + * judge Kernel or user mode + * + */ + lwi $p0, [$sp+(#IPSW_OFFSET)] ! Check if in nested interrupt + andi $p0, $p0, #PSW_mskINTL + bnez $p0, resume_kernel ! done with iret + j resume_userspace + + +/* + * This is the fast syscall return path. We do as little as + * possible here, and this includes saving $r0 back into the SVC + * stack. + * fixed: tsk - $r25, syscall # - $r7, syscall table pointer - $r8 + */ +ENTRY(ret_fast_syscall) + gie_disable + lwi $r1, [tsk+#TSK_TI_FLAGS] + andi $p1, $r1, #_TIF_WORK_MASK + bnez $p1, fast_work_pending + fast_restore_user_regs ! iret + +/* + * Ok, we need to do extra processing, + * enter the slow path returning from syscall, while pending work. + */ +fast_work_pending: + swi $r0, [$sp+(#R0_OFFSET)] ! what is different from ret_from_exception +work_pending: + andi $p1, $r1, #_TIF_NEED_RESCHED + bnez $p1, work_resched + + andi $p1, $r1, #_TIF_SIGPENDING|#_TIF_NOTIFY_RESUME + beqz $p1, no_work_pending + + move $r0, $sp ! 'regs' + gie_enable + bal do_notify_resume + b ret_slow_syscall +work_resched: + bal schedule ! path, return to user mode + +/* + * "slow" syscall return path. + */ +ENTRY(resume_userspace) +ENTRY(ret_slow_syscall) + gie_disable + lwi $p0, [$sp+(#IPSW_OFFSET)] ! Check if in nested interrupt + andi $p0, $p0, #PSW_mskINTL + bnez $p0, no_work_pending ! done with iret + lwi $r1, [tsk+#TSK_TI_FLAGS] + andi $p1, $r1, #_TIF_WORK_MASK + bnez $p1, work_pending ! handle work_resched, sig_pend + +no_work_pending: +#ifdef CONFIG_TRACE_IRQFLAGS + lwi $p0, [$sp+(#IPSW_OFFSET)] + andi $p0, $p0, #0x1 + la $r10, trace_hardirqs_off + la $r9, trace_hardirqs_on + cmovz $r9, $p0, $r10 + jral $r9 +#endif + restore_user_regs ! return from iret + + +/* + * preemptive kernel + */ +#ifdef CONFIG_PREEMPT +resume_kernel: + gie_disable + lwi $t0, [tsk+#TSK_TI_PREEMPT] + bnez $t0, no_work_pending +need_resched: + lwi $t0, [tsk+#TSK_TI_FLAGS] + andi $p1, $t0, #_TIF_NEED_RESCHED + beqz $p1, no_work_pending + + lwi $t0, [$sp+(#IPSW_OFFSET)] ! Interrupts off? + andi $t0, $t0, #1 + beqz $t0, no_work_pending + + jal preempt_schedule_irq + b need_resched +#endif + +/* + * This is how we return from a fork. + */ +ENTRY(ret_from_fork) + bal schedule_tail + beqz $r6, 1f ! r6 stores fn for kernel thread + move $r0, $r7 ! prepare kernel thread arg + jral $r6 +1: + lwi $r1, [tsk+#TSK_TI_FLAGS] ! check for syscall tracing + andi $p1, $r1, #_TIF_WORK_SYSCALL_LEAVE ! are we tracing syscalls? + beqz $p1, ret_slow_syscall + move $r0, $sp + bal syscall_trace_leave + b ret_slow_syscall |