1 files changed, 150 insertions, 78 deletions

diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S
index c0b56b17927f..9e271ba009bf 100644
--- a/arch/xtensa/kernel/entry.S
+++ b/arch/xtensa/kernel/entry.S
@@ -1004,13 +1004,10 @@ ENTRY(fast_syscall_kernel)
 
         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 @@ ENTRY(fast_syscall_user)
 
         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 @@ ENTRY(fast_syscall_unrecoverable)
 /*
  * 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 @@ ENTRY(fast_syscall_unrecoverable)
 #define CATCH                                                           \
 67:
 
-ENTRY(fast_syscall_sysxtensa)
-
-        _beqz   a6, 1f
-        _blti   a6, SYSXTENSA_COUNT, 2f
+ENTRY(fast_syscall_xtensa)
 
-1:      j       user_exception
-
-2:      xsr     a3, EXCSAVE_1           # restore a3, excsave1
-        s32i    a7, a2, PT_AREG7
+        xsr     a3, EXCSAVE_1           # restore a3, excsave1
 
+        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
-
-1:      movi    a7, 0                   # same values: return 0
-        j       .Lret
-
-.Ladd:  /* Atomic add */
-.Lexg:  /* Atomic (exchange) add */
+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
 
-TRY     l32i    a7, a3, 0
-        add     a4, a4, a7
-        s32i    a4, a3, 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
 
-.Lset:  /* Atomic set */
+.Lnswp: /* Atomic set, add, and exg_add. */
 
-TRY     l32i    a7, a3, 0               # read old value as return value
-        s32i    a4, a3, 0               # write new value
+TRY     l32i    a7, a3, 0               # orig
+        add     a0, a4, a7              # + arg
+        moveqz  a0, a4, a6              # set
+TRY     s32i    a0, 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 @@ ENTRY(fast_coprocessor)
 #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 @@ ENTRY(ret_from_fork)
         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"
-