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-rw-r--r--arch/mips/kernel/scall32-o32.S225
1 files changed, 225 insertions, 0 deletions
diff --git a/arch/mips/kernel/scall32-o32.S b/arch/mips/kernel/scall32-o32.S
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index 000000000..b449b6866
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+++ 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