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Diffstat (limited to 'arch/mips/kernel/scall64-o32.S')
| -rw-r--r-- | arch/mips/kernel/scall64-o32.S | 221 |
1 files changed, 221 insertions, 0 deletions
diff --git a/arch/mips/kernel/scall64-o32.S b/arch/mips/kernel/scall64-o32.S new file mode 100644 index 000000000..50c9a57e0 --- /dev/null +++ b/arch/mips/kernel/scall64-o32.S @@ -0,0 +1,221 @@ +/* + * 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 - 2000, 2001 by Ralf Baechle + * Copyright (C) 1999, 2000 Silicon Graphics, Inc. + * Copyright (C) 2001 MIPS Technologies, Inc. + * Copyright (C) 2004 Thiemo Seufer + * + * Hairy, the userspace application uses a different argument passing + * convention than the kernel, so we have to translate things from o32 + * to ABI64 calling convention. 64-bit syscalls are also processed + * here for now. + */ +#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/thread_info.h> +#include <asm/unistd.h> +#include <asm/sysmips.h> + + .align 5 +NESTED(handle_sys, PT_SIZE, sp) + .set noat + SAVE_SOME + TRACE_IRQS_ON_RELOAD + STI + .set at + ld t1, PT_EPC(sp) # skip syscall on return + + dsubu t0, v0, __NR_O32_Linux # check syscall number + sltiu t0, t0, __NR_O32_Linux_syscalls + daddiu t1, 4 # skip to next instruction + sd t1, PT_EPC(sp) + beqz t0, not_o32_scall +#if 0 + SAVE_ALL + move a1, v0 + ASM_PRINT("Scall %ld\n") + RESTORE_ALL +#endif + + /* We don't want to stumble over broken sign extensions from + userland. O32 does never use the upper half. */ + sll a0, a0, 0 + sll a1, a1, 0 + sll a2, a2, 0 + sll a3, a3, 0 + + sd 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). + * + * 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. + */ + ld t0, PT_R29(sp) # get old user stack pointer + daddu t1, t0, 32 + bltz t1, bad_stack + +load_a4: lw a4, 16(t0) # argument #5 from usp +load_a5: lw a5, 20(t0) # argument #6 from usp +load_a6: lw a6, 24(t0) # argument #7 from usp +load_a7: lw a7, 28(t0) # argument #8 from usp +loads_done: + + .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 + + li t1, _TIF_WORK_SYSCALL_ENTRY + LONG_L t0, TI_FLAGS($28) # syscall tracing enabled? + and t0, t1, t0 + bnez t0, trace_a_syscall + +syscall_common: + dsll t0, v0, 3 # offset into table + ld t2, (sys32_call_table - (__NR_O32_Linux * 8))(t0) + + jalr t2 # Do The Real Thing (TM) + + li t0, -EMAXERRNO - 1 # error? + sltu t0, t0, v0 + sd t0, PT_R7(sp) # set error flag + beqz t0, 1f + + ld t1, PT_R2(sp) # syscall number + dnegu v0 # error + sd t1, PT_R0(sp) # save it for syscall restarting +1: sd v0, PT_R2(sp) # result + +o32_syscall_exit: + j syscall_exit_partial + +/* ------------------------------------------------------------------------ */ + +trace_a_syscall: + SAVE_STATIC + sd a4, PT_R8(sp) # Save argument registers + sd a5, PT_R9(sp) + sd a6, PT_R10(sp) + sd a7, PT_R11(sp) # For indirect syscalls + + move a0, sp + /* + * absolute syscall number is in v0 unless we called syscall(__NR_###) + * where the real syscall number is in a0 + * note: NR_syscall is the first O32 syscall but the macro is + * only defined when compiling with -mabi=32 (CONFIG_32BIT) + * therefore __NR_O32_Linux is used (4000) + */ + .set push + .set reorder + subu t1, v0, __NR_O32_Linux + move a1, v0 + bnez t1, 1f /* __NR_syscall at offset 0 */ + ld a1, PT_R4(sp) /* Arg1 for __NR_syscall case */ + .set pop + +1: jal syscall_trace_enter + + bltz v0, 1f # seccomp failed? Skip syscall + + RESTORE_STATIC + ld v0, PT_R2(sp) # Restore syscall (maybe modified) + ld a0, PT_R4(sp) # Restore argument registers + ld a1, PT_R5(sp) + ld a2, PT_R6(sp) + ld a3, PT_R7(sp) + ld a4, PT_R8(sp) + ld a5, PT_R9(sp) + ld a6, PT_R10(sp) + ld a7, PT_R11(sp) # For indirect syscalls + + dsubu t0, v0, __NR_O32_Linux # check (new) syscall number + sltiu t0, t0, __NR_O32_Linux_syscalls + beqz t0, not_o32_scall + + j syscall_common + +1: j syscall_exit + +/* ------------------------------------------------------------------------ */ + + /* + * The stackpointer for a call with more than 4 arguments is bad. + */ +bad_stack: + li v0, EFAULT + sd v0, PT_R2(sp) + li t0, 1 # set error flag + sd t0, PT_R7(sp) + j o32_syscall_exit + +bad_stack_a4: + li a4, 0 + b load_a5 + +bad_stack_a5: + li a5, 0 + b load_a6 + +bad_stack_a6: + li a6, 0 + b load_a7 + +bad_stack_a7: + li a7, 0 + b loads_done + +not_o32_scall: + /* + * This is not an o32 compatibility syscall, pass it on + * to the 64-bit syscall handlers. + */ +#ifdef CONFIG_MIPS32_N32 + j handle_sysn32 +#else + j handle_sys64 +#endif + END(handle_sys) + +LEAF(sys32_syscall) + subu t0, a0, __NR_O32_Linux # check syscall number + sltiu v0, t0, __NR_O32_Linux_syscalls + beqz t0, einval # do not recurse + dsll t1, t0, 3 + beqz v0, einval + ld t2, sys32_call_table(t1) # syscall routine + + move a0, a1 # shift argument registers + move a1, a2 + move a2, a3 + move a3, a4 + move a4, a5 + move a5, a6 + move a6, a7 + jr t2 + /* Unreached */ + +einval: li v0, -ENOSYS + jr ra + END(sys32_syscall) + +#define __SYSCALL(nr, entry) PTR entry + .align 3 + .type sys32_call_table,@object +EXPORT(sys32_call_table) +#include <asm/syscall_table_64_o32.h> +#undef __SYSCALL |