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Diffstat (limited to '')
| -rw-r--r-- | arch/nds32/kernel/ex-scall.S | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/arch/nds32/kernel/ex-scall.S b/arch/nds32/kernel/ex-scall.S new file mode 100644 index 000000000..36aa87ecd --- /dev/null +++ b/arch/nds32/kernel/ex-scall.S @@ -0,0 +1,98 @@ +// 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> + +/* + * $r0 = previous task_struct, + * $r1 = next task_struct, + * previous and next are guaranteed not to be the same. + */ + +ENTRY(__switch_to) + + la $p0, __entry_task + sw $r1, [$p0] + move $p1, $r0 + addi $p1, $p1, #THREAD_CPU_CONTEXT + smw.bi $r6, [$p1], $r14, #0xb ! push r6~r14, fp, lp, sp + move $r25, $r1 + addi $r1, $r1, #THREAD_CPU_CONTEXT + lmw.bi $r6, [$r1], $r14, #0xb ! pop r6~r14, fp, lp, sp + ret + + +#define tbl $r8 + +/* + * $r7 will be writen as syscall nr + */ + .macro get_scno + lwi $r7, [$sp + R15_OFFSET] + swi $r7, [$sp + SYSCALLNO_OFFSET] + .endm + + .macro updateipc + addi $r17, $r13, #4 ! $r13 is $IPC + swi $r17, [$sp + IPC_OFFSET] + .endm + +ENTRY(eh_syscall) + updateipc + + get_scno + gie_enable + + lwi $p0, [tsk+#TSK_TI_FLAGS] ! check for syscall tracing + + andi $p1, $p0, #_TIF_WORK_SYSCALL_ENTRY ! are we tracing syscalls? + bnez $p1, __sys_trace + + la $lp, ret_fast_syscall ! return address +jmp_systbl: + addi $p1, $r7, #-__NR_syscalls ! syscall number of syscall instruction is guarded by addembler + bgez $p1, _SCNO_EXCEED ! call sys_* routine + la tbl, sys_call_table ! load syscall table pointer + slli $p1, $r7, #2 + add $p1, tbl, $p1 + lwi $p1, [$p1] + jr $p1 ! no return + +_SCNO_EXCEED: + ori $r0, $r7, #0 + ori $r1, $sp, #0 + b bad_syscall + +/* + * This is the really slow path. We're going to be doing + * context switches, and waiting for our parent to respond. + */ +__sys_trace: + move $r0, $sp + bal syscall_trace_enter + move $r7, $r0 + la $lp, __sys_trace_return ! return address + + addi $p1, $r7, #1 + beqz $p1, ret_slow_syscall ! fatal signal is pending + + addi $p1, $sp, #R0_OFFSET ! pointer to regs + lmw.bi $r0, [$p1], $r5 ! have to reload $r0 - $r5 + b jmp_systbl + +__sys_trace_return: + swi $r0, [$sp+#R0_OFFSET] ! T: save returned $r0 + move $r0, $sp ! set pt_regs for syscall_trace_leave + bal syscall_trace_leave + b ret_slow_syscall + +ENTRY(sys_rt_sigreturn_wrapper) + addi $r0, $sp, #0 + b sys_rt_sigreturn +ENDPROC(sys_rt_sigreturn_wrapper) |