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-rw-r--r--arch/mips/kernel/scall64-o32.S221
1 files changed, 221 insertions, 0 deletions
diff --git a/arch/mips/kernel/scall64-o32.S b/arch/mips/kernel/scall64-o32.S
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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) 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_WD load_a4, bad_stack_a4
+ PTR_WD load_a5, bad_stack_a5
+ PTR_WD load_a6, bad_stack_a6
+ PTR_WD 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_WITH_COMPAT(nr, native, compat) __SYSCALL(nr, compat)
+#define __SYSCALL(nr, entry) PTR_WD entry
+ .align 3
+ .type sys32_call_table,@object
+EXPORT(sys32_call_table)
+#include <asm/syscall_table_o32.h>