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/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1997, 1998, 1999, 2000 by Ralf Baechle
*/
#include <asm/asm.h>
#include <linux/errno.h>
#include <asm/current.h>
#include <asm/mipsregs.h>
#include <asm/regdef.h>
#include <asm/stackframe.h>
#include <asm/isadep.h>
#include <asm/unistd.h>
/* This duplicates the definition from <linux/sched.h> */
#define PT_TRACESYS 0x00000002 /* tracing system calls */
/* This duplicates the definition from <asm/signal.h> */
#define SIGILL 4 /* Illegal instruction (ANSI). */
/* Highest syscall used of any syscall flavour */
#define MAX_SYSCALL_NO __NR_Linux + __NR_Linux_syscalls
.align 5
NESTED(handle_sys, PT_SIZE, sp)
.set noat
SAVE_SOME
STI
.set at
lw t1, PT_EPC(sp) # skip syscall on return
sltiu t0, v0, MAX_SYSCALL_NO + 1 # check syscall number
addiu t1, 4 # skip to next instruction
beqz t0, illegal_syscall
sw t1, PT_EPC(sp)
/* XXX Put both in one cacheline, should save a bit. */
sll t0, v0, 2
lw t2, sys_call_table(t0) # syscall routine
lbu t3, sys_narg_table(v0) # number of arguments
beqz t2, illegal_syscall;
subu t0, t3, 5 # 5 or more arguments?
sw a3, PT_R26(sp) # save a3 for syscall restarting
bgez t0, stackargs
stack_done:
sw a3, PT_R26(sp) # save for syscall restart
lw t0, TASK_PTRACE($28) # syscall tracing enabled?
andi t0, PT_TRACESYS
bnez t0, trace_a_syscall
jalr t2 # Do The Real Thing (TM)
li t0, -EMAXERRNO - 1 # error?
sltu t0, t0, v0
sw t0, PT_R7(sp) # set error flag
beqz t0, 1f
negu v0 # error
sw v0, PT_R0(sp) # set flag for syscall restarting
1: sw v0, PT_R2(sp) # result
EXPORT(o32_ret_from_sys_call)
mfc0 t0, CP0_STATUS # need_resched and signals atomic test
ori t0, t0, 1
xori t0, t0, 1
mtc0 t0, CP0_STATUS
lw t2, TASK_NEED_RESCHED($28)
bnez t2, o32_reschedule
lw v0, TASK_SIGPENDING($28)
bnez v0, signal_return
restore_all:
RESTORE_SOME
RESTORE_SP_AND_RET
/* Put this behind restore_all for the sake of the branch prediction. */
signal_return:
.type signal_return, @function
mfc0 t0, CP0_STATUS
ori t0, t0, 1
mtc0 t0, CP0_STATUS
move a0, zero
move a1, sp
jal do_signal
b restore_all
o32_reschedule:
SAVE_STATIC
jal schedule
b o32_ret_from_sys_call
/* ------------------------------------------------------------------------ */
trace_a_syscall:
SAVE_STATIC
sw t2, PT_R1(sp)
jal syscall_trace
lw t2, PT_R1(sp)
lw a0, PT_R4(sp) # Restore argument registers
lw a1, PT_R5(sp)
lw a2, PT_R6(sp)
lw a3, PT_R7(sp)
jalr t2
li t0, -EMAXERRNO - 1 # error?
sltu t0, t0, v0
sw t0, PT_R7(sp) # set error flag
beqz t0, 1f
negu v0 # error
sw v0, PT_R0(sp) # set flag for syscall restarting
1: sw v0, PT_R2(sp) # result
jal syscall_trace
j ret_from_sys_call
/* ------------------------------------------------------------------------ */
/*
* More than four arguments. Try to deal with it by copying the
* stack arguments from the user stack to the kernel stack.
* This Sucks (TM).
*/
stackargs:
lw t0, PT_R29(sp) # get old user stack pointer
subu t3, 4
sll t1, t3, 2 # stack valid?
addu t1, t0 # end address
or t0, t1
bltz t0, bad_stack # -> sp is bad
lw t0, PT_R29(sp) # get old user stack pointer
la t1, 3f # copy 1 to 2 arguments
sll t3, t3, 4
subu t1, t3
jr t1
/* Ok, copy the args from the luser stack to the kernel stack */
/*
* I know Ralf doesn't like nops but this avoids code
* duplication for R3000 targets (and this is the
* only place where ".set reorder" doesn't help).
* Harald.
*/
.set push
.set noreorder
1: lw t1, 20(t0) # argument #6 from usp
nop
sw t1, 20(sp)
nop
2: lw t1, 16(t0) # argument #5 from usp
nop
sw t1, 16(sp)
nop
.set pop
3: j stack_done # go back
.section __ex_table,"a"
PTR 1b,bad_stack
PTR 2b,bad_stack
.previous
/*
* The stackpointer for a call with more than 4 arguments is bad.
* We probably should handle this case a bit more drastic.
*/
bad_stack:
negu v0 # error
sw v0, PT_R0(sp)
sw v0, PT_R2(sp)
li t0, 1 # set error flag
sw t0, PT_R7(sp)
j ret_from_sys_call
/*
* The system call does not exist in this kernel
*/
illegal_syscall:
li v0, ENOSYS # error
sw v0, PT_R2(sp)
li t0, 1 # set error flag
sw t0, PT_R7(sp)
j ret_from_sys_call
END(handle_sys)
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