[PATCH] xtensa: fix system call interface
This is a long outstanding patch to finally fix the syscall interface. The
constants used for the system calls are those we have provided in our libc
patches. This patch also fixes the shmbuf and stat structure, and fcntl
definitions.
Signed-off-by: Chris Zankel <chris@zankel.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S
index c0b56b1..9e271ba 100644
--- a/arch/xtensa/kernel/entry.S
+++ b/arch/xtensa/kernel/entry.S
@@ -1004,13 +1004,10 @@
rsr a0, DEPC # get syscall-nr
_beqz a0, fast_syscall_spill_registers
-
- addi a0, a0, -__NR_sysxtensa
- _beqz a0, fast_syscall_sysxtensa
+ _beqi a0, __NR_xtensa, fast_syscall_xtensa
j kernel_exception
-
ENTRY(fast_syscall_user)
/* Skip syscall. */
@@ -1024,9 +1021,7 @@
rsr a0, DEPC # get syscall-nr
_beqz a0, fast_syscall_spill_registers
-
- addi a0, a0, -__NR_sysxtensa
- _beqz a0, fast_syscall_sysxtensa
+ _beqi a0, __NR_xtensa, fast_syscall_xtensa
j user_exception
@@ -1047,18 +1042,19 @@
/*
* sysxtensa syscall handler
*
- * int sysxtensa (XTENSA_ATOMIC_SET, ptr, val, unused);
- * int sysxtensa (XTENSA_ATOMIC_ADD, ptr, val, unused);
- * int sysxtensa (XTENSA_ATOMIC_EXG_ADD, ptr, val, unused);
- * int sysxtensa (XTENSA_ATOMIC_CMP_SWP, ptr, oldval, newval);
- * a2 a6 a3 a4 a5
+ * int sysxtensa (SYS_XTENSA_ATOMIC_SET, ptr, val, unused);
+ * int sysxtensa (SYS_XTENSA_ATOMIC_ADD, ptr, val, unused);
+ * int sysxtensa (SYS_XTENSA_ATOMIC_EXG_ADD, ptr, val, unused);
+ * int sysxtensa (SYS_XTENSA_ATOMIC_CMP_SWP, ptr, oldval, newval);
+ * a2 a6 a3 a4 a5
*
* Entry condition:
*
- * a0: trashed, original value saved on stack (PT_AREG0)
+ * a0: a2 (syscall-nr), original value saved on stack (PT_AREG0)
* a1: a1
- * a2: new stack pointer, original in DEPC
- * a3: dispatch table
+ * a2: new stack pointer, original in a0 and DEPC
+ * a3: dispatch table, original in excsave_1
+ * a4..a15: unchanged
* depc: a2, original value saved on stack (PT_DEPC)
* excsave_1: a3
*
@@ -1091,59 +1087,62 @@
#define CATCH \
67:
-ENTRY(fast_syscall_sysxtensa)
+ENTRY(fast_syscall_xtensa)
- _beqz a6, 1f
- _blti a6, SYSXTENSA_COUNT, 2f
+ xsr a3, EXCSAVE_1 # restore a3, excsave1
-1: j user_exception
-
-2: xsr a3, EXCSAVE_1 # restore a3, excsave1
- s32i a7, a2, PT_AREG7
-
+ s32i a7, a2, PT_AREG7 # we need an additional register
movi a7, 4 # sizeof(unsigned int)
- access_ok a0, a3, a7, a2, .Leac
+ access_ok a3, a7, a0, a2, .Leac # a0: scratch reg, a2: sp
- _beqi a6, SYSXTENSA_ATOMIC_SET, .Lset
- _beqi a6, SYSXTENSA_ATOMIC_EXG_ADD, .Lexg
- _beqi a6, SYSXTENSA_ATOMIC_ADD, .Ladd
+ addi a6, a6, -1 # assuming SYS_XTENSA_ATOMIC_SET = 1
+ _bgeui a6, SYS_XTENSA_COUNT - 1, .Lill
+ _bnei a6, SYS_XTENSA_ATOMIC_CMP_SWP - 1, .Lnswp
- /* Fall through for SYSXTENSA_ATOMIC_CMP_SWP */
+ /* Fall through for ATOMIC_CMP_SWP. */
.Lswp: /* Atomic compare and swap */
-TRY l32i a7, a3, 0 # read old value
- bne a7, a4, 1f # same as old value? jump
- s32i a5, a3, 0 # different, modify value
- movi a7, 1 # and return 1
- j .Lret
+TRY l32i a0, a3, 0 # read old value
+ bne a0, a4, 1f # same as old value? jump
+TRY s32i a5, a3, 0 # different, modify value
+ l32i a7, a2, PT_AREG7 # restore a7
+ l32i a0, a2, PT_AREG0 # restore a0
+ movi a2, 1 # and return 1
+ addi a6, a6, 1 # restore a6 (really necessary?)
+ rfe
-1: movi a7, 0 # same values: return 0
- j .Lret
+1: l32i a7, a2, PT_AREG7 # restore a7
+ l32i a0, a2, PT_AREG0 # restore a0
+ movi a2, 0 # return 0 (note that we cannot set
+ addi a6, a6, 1 # restore a6 (really necessary?)
+ rfe
-.Ladd: /* Atomic add */
-.Lexg: /* Atomic (exchange) add */
+.Lnswp: /* Atomic set, add, and exg_add. */
-TRY l32i a7, a3, 0
- add a4, a4, a7
- s32i a4, a3, 0
- j .Lret
+TRY l32i a7, a3, 0 # orig
+ add a0, a4, a7 # + arg
+ moveqz a0, a4, a6 # set
+TRY s32i a0, a3, 0 # write new value
-.Lset: /* Atomic set */
-
-TRY l32i a7, a3, 0 # read old value as return value
- s32i a4, a3, 0 # write new value
-
-.Lret: mov a0, a2
+ mov a0, a2
mov a2, a7
- l32i a7, a0, PT_AREG7
- l32i a3, a0, PT_AREG3
- l32i a0, a0, PT_AREG0
+ l32i a7, a0, PT_AREG7 # restore a7
+ l32i a0, a0, PT_AREG0 # restore a0
+ addi a6, a6, 1 # restore a6 (really necessary?)
rfe
CATCH
-.Leac: movi a7, -EFAULT
- j .Lret
+.Leac: l32i a7, a2, PT_AREG7 # restore a7
+ l32i a0, a2, PT_AREG0 # restore a0
+ movi a2, -EFAULT
+ rfe
+
+.Lill: l32i a7, a2, PT_AREG0 # restore a7
+ l32i a0, a2, PT_AREG0 # restore a0
+ movi a2, -EINVAL
+ rfe
+
@@ -1907,6 +1906,103 @@
#endif /* XCHAL_EXTRA_SA_SIZE */
/*
+ * System Calls.
+ *
+ * void system_call (struct pt_regs* regs, int exccause)
+ * a2 a3
+ */
+
+ENTRY(system_call)
+ entry a1, 32
+
+ /* regs->syscall = regs->areg[2] */
+
+ l32i a3, a2, PT_AREG2
+ mov a6, a2
+ movi a4, do_syscall_trace_enter
+ s32i a3, a2, PT_SYSCALL
+ callx4 a4
+
+ /* syscall = sys_call_table[syscall_nr] */
+
+ movi a4, sys_call_table;
+ movi a5, __NR_syscall_count
+ movi a6, -ENOSYS
+ bgeu a3, a5, 1f
+
+ addx4 a4, a3, a4
+ l32i a4, a4, 0
+ movi a5, sys_ni_syscall;
+ beq a4, a5, 1f
+
+ /* Load args: arg0 - arg5 are passed via regs. */
+
+ l32i a6, a2, PT_AREG6
+ l32i a7, a2, PT_AREG3
+ l32i a8, a2, PT_AREG4
+ l32i a9, a2, PT_AREG5
+ l32i a10, a2, PT_AREG8
+ l32i a11, a2, PT_AREG9
+
+ /* Pass one additional argument to the syscall: pt_regs (on stack) */
+ s32i a2, a1, 0
+
+ callx4 a4
+
+1: /* regs->areg[2] = return_value */
+
+ s32i a6, a2, PT_AREG2
+ movi a4, do_syscall_trace_leave
+ mov a6, a2
+ callx4 a4
+ retw
+
+
+/*
+ * Create a kernel thread
+ *
+ * int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
+ * a2 a2 a3 a4
+ */
+
+ENTRY(kernel_thread)
+ entry a1, 16
+
+ mov a5, a2 # preserve fn over syscall
+ mov a7, a3 # preserve args over syscall
+
+ movi a3, _CLONE_VM | _CLONE_UNTRACED
+ movi a2, __NR_clone
+ or a6, a4, a3 # arg0: flags
+ mov a3, a1 # arg1: sp
+ syscall
+
+ beq a3, a1, 1f # branch if parent
+ mov a6, a7 # args
+ callx4 a5 # fn(args)
+
+ movi a2, __NR_exit
+ syscall # return value of fn(args) still in a6
+
+1: retw
+
+/*
+ * Do a system call from kernel instead of calling sys_execve, so we end up
+ * with proper pt_regs.
+ *
+ * int kernel_execve(const char *fname, char *const argv[], charg *const envp[])
+ * a2 a2 a3 a4
+ */
+
+ENTRY(kernel_execve)
+ entry a1, 16
+ mov a6, a2 # arg0 is in a6
+ movi a2, __NR_execve
+ syscall
+
+ retw
+
+/*
* Task switch.
*
* struct task* _switch_to (struct task* prev, struct task* next)
@@ -1964,33 +2060,9 @@
movi a4, schedule_tail
callx4 a4
- movi a4, do_syscall_trace
+ movi a4, do_syscall_trace_leave
+ mov a6, a1
callx4 a4
j common_exception_return
-
-
-/*
- * Table of syscalls
- */
-
-.data
-.align 4
-.global sys_call_table
-sys_call_table:
-
-#define SYSCALL(call, narg) .word call
-#include "syscalls.h"
-
-/*
- * Number of arguments of each syscall
- */
-
-.global sys_narg_table
-sys_narg_table:
-
-#undef SYSCALL
-#define SYSCALL(call, narg) .byte narg
-#include "syscalls.h"
-