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Diffstat (limited to 'arch/mips/kernel/scall32-o32.S')
| -rw-r--r-- | arch/mips/kernel/scall32-o32.S | 225 |
1 files changed, 225 insertions, 0 deletions
diff --git a/arch/mips/kernel/scall32-o32.S b/arch/mips/kernel/scall32-o32.S new file mode 100644 index 000000000..b449b6866 --- /dev/null +++ b/arch/mips/kernel/scall32-o32.S @@ -0,0 +1,225 @@ +/* + * 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) 1995-99, 2000- 02, 06 Ralf Baechle <ralf@linux-mips.org> + * Copyright (C) 2001 MIPS Technologies, Inc. + * Copyright (C) 2004 Thiemo Seufer + * Copyright (C) 2014 Imagination Technologies Ltd. + */ +#include <linux/errno.h> +#include <asm/asm.h> +#include <asm/asmmacro.h> +#include <asm/irqflags.h> +#include <asm/mipsregs.h> +#include <asm/regdef.h> +#include <asm/stackframe.h> +#include <asm/isadep.h> +#include <asm/sysmips.h> +#include <asm/thread_info.h> +#include <asm/unistd.h> +#include <asm/war.h> +#include <asm/asm-offsets.h> + + .align 5 +NESTED(handle_sys, PT_SIZE, sp) + .set noat + SAVE_SOME + TRACE_IRQS_ON_RELOAD + STI + .set at + + lw t1, PT_EPC(sp) # skip syscall on return + + addiu t1, 4 # skip to next instruction + sw t1, PT_EPC(sp) + + sw a3, PT_R26(sp) # save a3 for syscall restarting + + /* + * 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). + */ + lw t0, PT_R29(sp) # get old user stack pointer + + /* + * We intentionally keep the kernel stack a little below the top of + * userspace so we don't have to do a slower byte accurate check here. + */ + lw t5, TI_ADDR_LIMIT($28) + addu t4, t0, 32 + and t5, t4 + bltz t5, bad_stack # -> sp is bad + + /* + * Ok, copy the args from the luser stack to the kernel stack. + */ + + .set push + .set noreorder + .set nomacro + +load_a4: user_lw(t5, 16(t0)) # argument #5 from usp +load_a5: user_lw(t6, 20(t0)) # argument #6 from usp +load_a6: user_lw(t7, 24(t0)) # argument #7 from usp +load_a7: user_lw(t8, 28(t0)) # argument #8 from usp +loads_done: + + sw t5, 16(sp) # argument #5 to ksp + sw t6, 20(sp) # argument #6 to ksp + sw t7, 24(sp) # argument #7 to ksp + sw t8, 28(sp) # argument #8 to ksp + .set pop + + .section __ex_table,"a" + PTR load_a4, bad_stack_a4 + PTR load_a5, bad_stack_a5 + PTR load_a6, bad_stack_a6 + PTR load_a7, bad_stack_a7 + .previous + + lw t0, TI_FLAGS($28) # syscall tracing enabled? + li t1, _TIF_WORK_SYSCALL_ENTRY + and t0, t1 + bnez t0, syscall_trace_entry # -> yes +syscall_common: + subu v0, v0, __NR_O32_Linux # check syscall number + sltiu t0, v0, __NR_O32_Linux_syscalls + beqz t0, illegal_syscall + + sll t0, v0, 2 + la t1, sys_call_table + addu t1, t0 + lw t2, (t1) # syscall routine + + beqz t2, illegal_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 + + lw t1, PT_R2(sp) # syscall number + negu v0 # error + sw t1, PT_R0(sp) # save it for syscall restarting +1: sw v0, PT_R2(sp) # result + +o32_syscall_exit: + j syscall_exit_partial + +/* ------------------------------------------------------------------------ */ + +syscall_trace_entry: + SAVE_STATIC + move a0, sp + + /* + * syscall number is in v0 unless we called syscall(__NR_###) + * where the real syscall number is in a0 + */ + move a1, v0 + subu t2, v0, __NR_O32_Linux + bnez t2, 1f /* __NR_syscall at offset 0 */ + lw a1, PT_R4(sp) + +1: jal syscall_trace_enter + + bltz v0, 1f # seccomp failed? Skip syscall + + RESTORE_STATIC + lw v0, PT_R2(sp) # Restore syscall (maybe modified) + lw a0, PT_R4(sp) # Restore argument registers + lw a1, PT_R5(sp) + lw a2, PT_R6(sp) + lw a3, PT_R7(sp) + j syscall_common + +1: j syscall_exit + +/* ------------------------------------------------------------------------ */ + + /* + * Our open-coded access area sanity test for the stack pointer + * failed. We probably should handle this case a bit more drastic. + */ +bad_stack: + li v0, EFAULT + sw v0, PT_R2(sp) + li t0, 1 # set error flag + sw t0, PT_R7(sp) + j o32_syscall_exit + +bad_stack_a4: + li t5, 0 + b load_a5 + +bad_stack_a5: + li t6, 0 + b load_a6 + +bad_stack_a6: + li t7, 0 + b load_a7 + +bad_stack_a7: + li t8, 0 + b loads_done + + /* + * 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 o32_syscall_exit + END(handle_sys) + + LEAF(sys_syscall) + subu t0, a0, __NR_O32_Linux # check syscall number + sltiu v0, t0, __NR_O32_Linux_syscalls + beqz t0, einval # do not recurse + sll t1, t0, 2 + beqz v0, einval + lw t2, sys_call_table(t1) # syscall routine + + move a0, a1 # shift argument registers + move a1, a2 + move a2, a3 + lw a3, 16(sp) + lw t4, 20(sp) + lw t5, 24(sp) + lw t6, 28(sp) + sw t4, 16(sp) + sw t5, 20(sp) + sw t6, 24(sp) + jr t2 + /* Unreached */ + +einval: li v0, -ENOSYS + jr ra + END(sys_syscall) + +#ifdef CONFIG_MIPS_MT_FPAFF + /* + * For FPU affinity scheduling on MIPS MT processors, we need to + * intercept sys_sched_xxxaffinity() calls until we get a proper hook + * in kernel/sched/core.c. Considered only temporary we only support + * these hooks for the 32-bit kernel - there is no MIPS64 MT processor + * atm. + */ +#define sys_sched_setaffinity mipsmt_sys_sched_setaffinity +#define sys_sched_getaffinity mipsmt_sys_sched_getaffinity +#endif /* CONFIG_MIPS_MT_FPAFF */ + +#define __SYSCALL(nr, entry) PTR entry + .align 2 + .type sys_call_table, @object +EXPORT(sys_call_table) +#include <asm/syscall_table_32_o32.h> +#undef __SYSCALL |