1 files changed, 703 insertions, 0 deletions

diff --git a/arch/parisc/kernel/syscall.S b/arch/parisc/kernel/syscall.S
new file mode 100644
index 000000000000..32ea701f4d20
--- /dev/null
+++ b/arch/parisc/kernel/syscall.S
@@ -0,0 +1,703 @@
+/* 
+ * Linux/PA-RISC Project (http://www.parisc-linux.org/)
+ * 
+ * System call entry code Copyright (c) Matthew Wilcox 1999 <willy@bofh.ai>
+ * Licensed under the GNU GPL.
+ * thanks to Philipp Rumpf, Mike Shaver and various others
+ * sorry about the wall, puffin..
+ */
+
+#include <asm/offsets.h>
+#include <asm/unistd.h>
+#include <asm/errno.h>
+#include <asm/psw.h>
+#include <asm/thread_info.h>
+
+#include <asm/assembly.h>
+#include <asm/processor.h>
+
+        /* We fill the empty parts of the gateway page with
+         * something that will kill the kernel or a
+         * userspace application.
+         */
+#define KILL_INSN       break   0,0
+
+#include <linux/config.h> /* for CONFIG_SMP */
+
+#ifdef __LP64__
+        .level          2.0w
+#else
+        .level          1.1
+#endif
+
+#ifndef __LP64__
+        .macro fixup_branch,lbl
+        b           \lbl
+        .endm
+#else
+        .macro fixup_branch,lbl
+        ldil        L%\lbl, %r1
+        ldo         R%\lbl(%r1), %r1
+        bv,n        %r0(%r1)
+        .endm
+#endif
+
+        .text
+
+        .import syscall_exit,code
+        .import syscall_exit_rfi,code
+        .export linux_gateway_page
+
+        /* Linux gateway page is aliased to virtual page 0 in the kernel
+         * address space. Since it is a gateway page it cannot be
+         * dereferenced, so null pointers will still fault. We start
+         * the actual entry point at 0x100. We put break instructions
+         * at the beginning of the page to trap null indirect function
+         * pointers.
+         */
+
+        .align 4096
+linux_gateway_page:
+
+        /* ADDRESS 0x00 to 0xb0 = 176 bytes / 4 bytes per insn = 44 insns */
+        .rept 44
+        KILL_INSN
+        .endr
+
+        /* ADDRESS 0xb0 to 0xb4, lws uses 1 insns for entry */
+        /* Light-weight-syscall entry must always be located at 0xb0 */
+        /* WARNING: Keep this number updated with table size changes */
+#define __NR_lws_entries (2)
+
+lws_entry:
+        /* Unconditional branch to lws_start, located on the 
+           same gateway page */
+        b,n     lws_start
+
+        /* Fill from 0xb4 to 0xe0 */
+        .rept 11
+        KILL_INSN
+        .endr
+
+        /* This function MUST be located at 0xe0 for glibc's threading 
+        mechanism to work. DO NOT MOVE THIS CODE EVER! */
+set_thread_pointer:
+        gate    .+8, %r0                /* increase privilege */
+        depi    3, 31, 2, %r31          /* Ensure we return into user mode. */
+        be      0(%sr7,%r31)            /* return to user space */
+        mtctl   %r26, %cr27             /* move arg0 to the control register */
+
+        /* Increase the chance of trapping if random jumps occur to this
+        address, fill from 0xf0 to 0x100 */
+        .rept 4
+        KILL_INSN
+        .endr
+
+/* This address must remain fixed at 0x100 for glibc's syscalls to work */
+        .align 256
+linux_gateway_entry:
+        gate    .+8, %r0                        /* become privileged */
+        mtsp    %r0,%sr4                        /* get kernel space into sr4 */
+        mtsp    %r0,%sr5                        /* get kernel space into sr5 */
+        mtsp    %r0,%sr6                        /* get kernel space into sr6 */
+        mfsp    %sr7,%r1                        /* save user sr7 */
+        mtsp    %r1,%sr3                        /* and store it in sr3 */
+
+#ifdef __LP64__
+        /* for now we can *always* set the W bit on entry to the syscall
+         * since we don't support wide userland processes.  We could
+         * also save the current SM other than in r0 and restore it on
+         * exit from the syscall, and also use that value to know
+         * whether to do narrow or wide syscalls. -PB
+         */
+        ssm     PSW_SM_W, %r1
+        extrd,u %r1,PSW_W_BIT,1,%r1
+        /* sp must be aligned on 4, so deposit the W bit setting into
+         * the bottom of sp temporarily */
+        or,ev   %r1,%r30,%r30
+        b,n     1f
+        /* The top halves of argument registers must be cleared on syscall
+         * entry from narrow executable.
+         */
+        depdi   0, 31, 32, %r26
+        depdi   0, 31, 32, %r25
+        depdi   0, 31, 32, %r24
+        depdi   0, 31, 32, %r23
+        depdi   0, 31, 32, %r22
+        depdi   0, 31, 32, %r21
+1:      
+#endif
+        mfctl   %cr30,%r1
+        xor     %r1,%r30,%r30                   /* ye olde xor trick */
+        xor     %r1,%r30,%r1
+        xor     %r1,%r30,%r30
+        
+        ldo     THREAD_SZ_ALGN+FRAME_SIZE(%r30),%r30  /* set up kernel stack */
+
+        /* N.B.: It is critical that we don't set sr7 to 0 until r30
+         *       contains a valid kernel stack pointer. It is also
+         *       critical that we don't start using the kernel stack
+         *       until after sr7 has been set to 0.
+         */
+
+        mtsp    %r0,%sr7                        /* get kernel space into sr7 */
+        STREGM  %r1,FRAME_SIZE(%r30)            /* save r1 (usp) here for now */
+        mfctl   %cr30,%r1                       /* get task ptr in %r1 */
+        LDREG   TI_TASK(%r1),%r1
+
+        /* Save some registers for sigcontext and potential task
+           switch (see entry.S for the details of which ones are
+           saved/restored).  TASK_PT_PSW is zeroed so we can see whether
+           a process is on a syscall or not.  For an interrupt the real
+           PSW value is stored.  This is needed for gdb and sys_ptrace. */
+        STREG   %r0,  TASK_PT_PSW(%r1)
+        STREG   %r2,  TASK_PT_GR2(%r1)          /* preserve rp */
+        STREG   %r19, TASK_PT_GR19(%r1)
+
+        LDREGM  -FRAME_SIZE(%r30), %r2          /* get users sp back */
+#ifdef __LP64__
+        extrd,u %r2,63,1,%r19                   /* W hidden in bottom bit */
+#if 0
+        xor     %r19,%r2,%r2                    /* clear bottom bit */
+        depd,z  %r19,1,1,%r19
+        std     %r19,TASK_PT_PSW(%r1)
+#endif
+#endif
+        STREG   %r2,  TASK_PT_GR30(%r1)         /* ... and save it */
+        
+        STREG   %r20, TASK_PT_GR20(%r1)
+        STREG   %r21, TASK_PT_GR21(%r1)
+        STREG   %r22, TASK_PT_GR22(%r1)
+        STREG   %r23, TASK_PT_GR23(%r1)         /* 4th argument */
+        STREG   %r24, TASK_PT_GR24(%r1)         /* 3rd argument */
+        STREG   %r25, TASK_PT_GR25(%r1)         /* 2nd argument */
+        STREG   %r26, TASK_PT_GR26(%r1)         /* 1st argument */
+        STREG   %r27, TASK_PT_GR27(%r1)         /* user dp */
+        STREG   %r28, TASK_PT_GR28(%r1)         /* return value 0 */
+        STREG   %r28, TASK_PT_ORIG_R28(%r1)     /* return value 0 (saved for signals) */
+        STREG   %r29, TASK_PT_GR29(%r1)         /* return value 1 */
+        STREG   %r31, TASK_PT_GR31(%r1)         /* preserve syscall return ptr */
+        
+        ldo     TASK_PT_FR0(%r1), %r27          /* save fpregs from the kernel */
+        save_fp %r27                            /* or potential task switch  */
+
+        mfctl   %cr11, %r27                     /* i.e. SAR */
+        STREG   %r27, TASK_PT_SAR(%r1)
+
+        loadgp
+
+#ifdef __LP64__
+        ldo     -16(%r30),%r29                  /* Reference param save area */
+        copy    %r19,%r2                        /* W bit back to r2 */
+#else
+        /* no need to save these on stack in wide mode because the first 8
+         * args are passed in registers */
+        stw     %r22, -52(%r30)                 /* 5th argument */
+        stw     %r21, -56(%r30)                 /* 6th argument */
+#endif
+
+        /* Are we being ptraced? */
+        mfctl   %cr30, %r1
+        LDREG   TI_TASK(%r1),%r1
+        LDREG   TASK_PTRACE(%r1), %r1
+        bb,<,n  %r1,31,.Ltracesys
+        
+        /* Note!  We cannot use the syscall table that is mapped
+        nearby since the gateway page is mapped execute-only. */
+
+#ifdef __LP64__
+        ldil    L%sys_call_table, %r1
+        or,=    %r2,%r2,%r2
+        addil   L%(sys_call_table64-sys_call_table), %r1
+        ldo     R%sys_call_table(%r1), %r19
+        or,=    %r2,%r2,%r2
+        ldo     R%sys_call_table64(%r1), %r19
+#else
+        ldil    L%sys_call_table, %r1
+        ldo     R%sys_call_table(%r1), %r19
+#endif  
+        comiclr,>>=     __NR_Linux_syscalls, %r20, %r0
+        b,n     .Lsyscall_nosys
+        
+        LDREGX  %r20(%r19), %r19
+
+        /* If this is a sys_rt_sigreturn call, and the signal was received
+         * when not in_syscall, then we want to return via syscall_exit_rfi,
+         * not syscall_exit.  Signal no. in r20, in_syscall in r25 (see
+         * trampoline code in signal.c).
+         */
+        ldi     __NR_rt_sigreturn,%r2
+        comb,=  %r2,%r20,.Lrt_sigreturn
+.Lin_syscall:
+        ldil    L%syscall_exit,%r2
+        be      0(%sr7,%r19)
+        ldo     R%syscall_exit(%r2),%r2
+.Lrt_sigreturn:
+        comib,<> 0,%r25,.Lin_syscall
+        ldil    L%syscall_exit_rfi,%r2
+        be      0(%sr7,%r19)
+        ldo     R%syscall_exit_rfi(%r2),%r2
+
+        /* Note!  Because we are not running where we were linked, any
+        calls to functions external to this file must be indirect.  To
+        be safe, we apply the opposite rule to functions within this
+        file, with local labels given to them to ensure correctness. */
+        
+.Lsyscall_nosys:
+syscall_nosys:
+        ldil    L%syscall_exit,%r1
+        be      R%syscall_exit(%sr7,%r1)
+        ldo     -ENOSYS(%r0),%r28                  /* set errno */
+
+
+/* Warning! This trace code is a virtual duplicate of the code above so be
+ * sure to maintain both! */
+.Ltracesys:
+tracesys:
+        /* Need to save more registers so the debugger can see where we
+         * are.  This saves only the lower 8 bits of PSW, so that the C
+         * bit is still clear on syscalls, and the D bit is set if this
+         * full register save path has been executed.  We check the D
+         * bit on syscall_return_rfi to determine which registers to
+         * restore.  An interrupt results in a full PSW saved with the
+         * C bit set, a non-straced syscall entry results in C and D clear
+         * in the saved PSW.
+         */
+        ldo     -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1      /* get task ptr */
+        LDREG   TI_TASK(%r1), %r1
+        ssm     0,%r2
+        STREG   %r2,TASK_PT_PSW(%r1)            /* Lower 8 bits only!! */
+        mfsp    %sr0,%r2
+        STREG   %r2,TASK_PT_SR0(%r1)
+        mfsp    %sr1,%r2
+        STREG   %r2,TASK_PT_SR1(%r1)
+        mfsp    %sr2,%r2
+        STREG   %r2,TASK_PT_SR2(%r1)
+        mfsp    %sr3,%r2
+        STREG   %r2,TASK_PT_SR3(%r1)
+        STREG   %r2,TASK_PT_SR4(%r1)
+        STREG   %r2,TASK_PT_SR5(%r1)
+        STREG   %r2,TASK_PT_SR6(%r1)
+        STREG   %r2,TASK_PT_SR7(%r1)
+        STREG   %r2,TASK_PT_IASQ0(%r1)
+        STREG   %r2,TASK_PT_IASQ1(%r1)
+        LDREG   TASK_PT_GR31(%r1),%r2
+        STREG   %r2,TASK_PT_IAOQ0(%r1)
+        ldo     4(%r2),%r2
+        STREG   %r2,TASK_PT_IAOQ1(%r1)
+        ldo     TASK_REGS(%r1),%r2
+        /* reg_save %r2 */
+        STREG   %r3,PT_GR3(%r2)
+        STREG   %r4,PT_GR4(%r2)
+        STREG   %r5,PT_GR5(%r2)
+        STREG   %r6,PT_GR6(%r2)
+        STREG   %r7,PT_GR7(%r2)
+        STREG   %r8,PT_GR8(%r2)
+        STREG   %r9,PT_GR9(%r2)
+        STREG   %r10,PT_GR10(%r2)
+        STREG   %r11,PT_GR11(%r2)
+        STREG   %r12,PT_GR12(%r2)
+        STREG   %r13,PT_GR13(%r2)
+        STREG   %r14,PT_GR14(%r2)
+        STREG   %r15,PT_GR15(%r2)
+        STREG   %r16,PT_GR16(%r2)
+        STREG   %r17,PT_GR17(%r2)
+        STREG   %r18,PT_GR18(%r2)
+        /* Finished saving things for the debugger */
+
+        ldil    L%syscall_trace,%r1
+        ldil    L%tracesys_next,%r2
+        be      R%syscall_trace(%sr7,%r1)
+        ldo     R%tracesys_next(%r2),%r2
+        
+tracesys_next:  
+        ldil    L%sys_call_table,%r1
+        ldo     R%sys_call_table(%r1), %r19
+
+        ldo     -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1      /* get task ptr */
+        LDREG   TI_TASK(%r1), %r1
+        LDREG   TASK_PT_GR20(%r1), %r20
+        LDREG   TASK_PT_GR26(%r1), %r26         /* Restore the users args */
+        LDREG   TASK_PT_GR25(%r1), %r25
+        LDREG   TASK_PT_GR24(%r1), %r24
+        LDREG   TASK_PT_GR23(%r1), %r23
+#ifdef __LP64__
+        LDREG   TASK_PT_GR22(%r1), %r22
+        LDREG   TASK_PT_GR21(%r1), %r21
+        ldo     -16(%r30),%r29                  /* Reference param save area */
+#endif
+
+        comiclr,>>=     __NR_Linux_syscalls, %r20, %r0
+        b,n     .Lsyscall_nosys
+
+        LDREGX  %r20(%r19), %r19
+
+        /* If this is a sys_rt_sigreturn call, and the signal was received
+         * when not in_syscall, then we want to return via syscall_exit_rfi,
+         * not syscall_exit.  Signal no. in r20, in_syscall in r25 (see
+         * trampoline code in signal.c).
+         */
+        ldi     __NR_rt_sigreturn,%r2
+        comb,=  %r2,%r20,.Ltrace_rt_sigreturn
+.Ltrace_in_syscall:
+        ldil    L%tracesys_exit,%r2
+        be      0(%sr7,%r19)
+        ldo     R%tracesys_exit(%r2),%r2
+
+        /* Do *not* call this function on the gateway page, because it
+        makes a direct call to syscall_trace. */
+        
+tracesys_exit:
+        ldo     -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1      /* get task ptr */
+        LDREG   TI_TASK(%r1), %r1
+#ifdef __LP64__
+        ldo     -16(%r30),%r29                  /* Reference param save area */
+#endif
+        bl      syscall_trace, %r2
+        STREG   %r28,TASK_PT_GR28(%r1)          /* save return value now */
+        ldo     -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1      /* get task ptr */
+        LDREG   TI_TASK(%r1), %r1
+        LDREG   TASK_PT_GR28(%r1), %r28         /* Restore return val. */
+
+        ldil    L%syscall_exit,%r1
+        be,n    R%syscall_exit(%sr7,%r1)
+
+.Ltrace_rt_sigreturn:
+        comib,<> 0,%r25,.Ltrace_in_syscall
+        ldil    L%tracesys_sigexit,%r2
+        be      0(%sr7,%r19)
+        ldo     R%tracesys_sigexit(%r2),%r2
+
+tracesys_sigexit:
+        ldo     -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1      /* get task ptr */
+        LDREG   0(%r1), %r1
+#ifdef __LP64__
+        ldo     -16(%r30),%r29                  /* Reference param save area */
+#endif
+        bl      syscall_trace, %r2
+        nop
+
+        ldil    L%syscall_exit_rfi,%r1
+        be,n    R%syscall_exit_rfi(%sr7,%r1)
+
+
+        /*********************************************************
+                Light-weight-syscall code
+
+                r20 - lws number
+                r26,r25,r24,r23,r22 - Input registers
+                r28 - Function return register
+                r21 - Error code.
+
+                Scracth: Any of the above that aren't being
+                currently used, including r1. 
+
+                Return pointer: r31 (Not usable)
+
+                Error codes returned by entry path:
+
+                ENOSYS - r20 was an invalid LWS number.
+
+        *********************************************************/
+lws_start:
+        /* Gate and ensure we return to userspace */
+        gate    .+8, %r0
+        depi    3, 31, 2, %r31  /* Ensure we return to userspace */
+
+#ifdef __LP64__
+        /* FIXME: If we are a 64-bit kernel just
+         *        turn this on unconditionally.
+         */
+        ssm     PSW_SM_W, %r1
+        extrd,u %r1,PSW_W_BIT,1,%r1
+        /* sp must be aligned on 4, so deposit the W bit setting into
+         * the bottom of sp temporarily */
+        or,ev   %r1,%r30,%r30
+
+        /* Clip LWS number to a 32-bit value always */
+        depdi   0, 31, 32, %r20
+#endif  
+
+        /* Is the lws entry number valid? */
+        comiclr,>>=     __NR_lws_entries, %r20, %r0
+        b,n     lws_exit_nosys
+
+        /* WARNING: Trashing sr2 and sr3 */
+        mfsp    %sr7,%r1                        /* get userspace into sr3 */
+        mtsp    %r1,%sr3
+        mtsp    %r0,%sr2                        /* get kernel space into sr2 */
+
+        /* Load table start */
+        ldil    L%lws_table, %r1
+        ldo     R%lws_table(%r1), %r28  /* Scratch use of r28 */
+        LDREGX  %r20(%sr2,r28), %r21    /* Scratch use of r21 */
+
+        /* Jump to lws, lws table pointers already relocated */
+        be,n    0(%sr2,%r21)
+
+lws_exit_nosys:
+        ldo     -ENOSYS(%r0),%r21                  /* set errno */
+        /* Fall through: Return to userspace */
+
+lws_exit:
+#ifdef __LP64__
+        /* decide whether to reset the wide mode bit
+         *
+         * For a syscall, the W bit is stored in the lowest bit
+         * of sp.  Extract it and reset W if it is zero */
+        extrd,u,*<>     %r30,63,1,%r1
+        rsm     PSW_SM_W, %r0
+        /* now reset the lowest bit of sp if it was set */
+        xor     %r30,%r1,%r30
+#endif
+        be,n    0(%sr3, %r31)
+
+
+        
+        /***************************************************
+                Implementing CAS as an atomic operation:
+
+                %r26 - Address to examine
+                %r25 - Old value to check (old)
+                %r24 - New value to set (new)
+                %r28 - Return prev through this register.
+                %r21 - Kernel error code
+
+                If debugging is DISabled:
+
+                %r21 has the following meanings:
+
+                EAGAIN - CAS is busy, ldcw failed, try again.
+                EFAULT - Read or write failed.          
+
+                If debugging is enabled:
+
+                EDEADLOCK - CAS called recursively.
+                EAGAIN && r28 == 1 - CAS is busy. Lock contended.
+                EAGAIN && r28 == 2 - CAS is busy. ldcw failed.
+                EFAULT - Read or write failed.
+
+                Scratch: r20, r28, r1
+
+        ****************************************************/
+
+        /* Do not enable LWS debugging */
+#define ENABLE_LWS_DEBUG 0 
+
+        /* ELF64 Process entry path */
+lws_compare_and_swap64:
+#ifdef __LP64__
+        b,n     lws_compare_and_swap
+#else
+        /* If we are not a 64-bit kernel, then we don't
+         * implement having 64-bit input registers
+         */
+        b,n     lws_exit_nosys
+#endif
+
+        /* ELF32 Process entry path */
+lws_compare_and_swap32:
+#ifdef __LP64__
+        /* Clip all the input registers */
+        depdi   0, 31, 32, %r26
+        depdi   0, 31, 32, %r25
+        depdi   0, 31, 32, %r24
+#endif
+
+lws_compare_and_swap:
+#ifdef CONFIG_SMP
+        /* Load start of lock table */
+        ldil    L%lws_lock_start, %r20
+        ldo     R%lws_lock_start(%r20), %r28
+
+        /* Extract four bits from r26 and hash lock (Bits 4-7) */
+        extru  %r26, 27, 4, %r20
+
+        /* Find lock to use, the hash is either one of 0 to
+           15, multiplied by 16 (keep it 16-byte aligned)
+           and add to the lock table offset. */
+        shlw    %r20, 4, %r20
+        add     %r20, %r28, %r20
+
+# ifdef ENABLE_LWS_DEBUG
+        /*      
+                DEBUG, check for deadlock! 
+                If the thread register values are the same
+                then we were the one that locked it last and
+                this is a recurisve call that will deadlock.
+                We *must* giveup this call and fail.
+        */
+        ldw     4(%sr2,%r20), %r28                      /* Load thread register */
+        mfctl   %cr27, %r21                             /* Get current thread register */
+        cmpb,<>,n       %r21, %r28, cas_lock            /* Called recursive? */
+        b       lws_exit                                /* Return error! */
+        ldo     -EDEADLOCK(%r0), %r21
+cas_lock:
+        cmpb,=,n        %r0, %r28, cas_nocontend        /* Is nobody using it? */
+        ldo     1(%r0), %r28                            /* 1st case */
+        b       lws_exit                                /* Contended... */
+        ldo     -EAGAIN(%r0), %r21                      /* Spin in userspace */
+cas_nocontend:
+# endif
+/* ENABLE_LWS_DEBUG */
+
+        ldcw    0(%sr2,%r20), %r28                      /* Try to acquire the lock */
+        cmpb,<>,n       %r0, %r28, cas_action           /* Did we get it? */
+cas_wouldblock:
+        ldo     2(%r0), %r28                            /* 2nd case */
+        b       lws_exit                                /* Contended... */
+        ldo     -EAGAIN(%r0), %r21                      /* Spin in userspace */
+#endif
+/* CONFIG_SMP */
+
+        /*
+                prev = *addr;
+                if ( prev == old )
+                  *addr = new;
+                return prev;
+        */
+
+        /* NOTES:
+                This all works becuse intr_do_signal
+                and schedule both check the return iasq
+                and see that we are on the kernel page
+                so this process is never scheduled off
+                or is ever sent any signal of any sort,
+                thus it is wholly atomic from usrspaces
+                perspective
+        */
+cas_action:
+#if defined CONFIG_SMP && defined ENABLE_LWS_DEBUG
+        /* DEBUG */
+        mfctl   %cr27, %r1
+        stw     %r1, 4(%sr2,%r20)
+#endif
+        /* The load and store could fail */
+1:      ldw     0(%sr3,%r26), %r28
+        sub,<>  %r28, %r25, %r0
+2:      stw     %r24, 0(%sr3,%r26)
+#ifdef CONFIG_SMP
+        /* Free lock */
+        stw     %r20, 0(%sr2,%r20)
+# ifdef ENABLE_LWS_DEBUG
+        /* Clear thread register indicator */
+        stw     %r0, 4(%sr2,%r20)
+# endif
+#endif
+        /* Return to userspace, set no error */
+        b       lws_exit
+        copy    %r0, %r21
+
+3:              
+        /* Error occured on load or store */
+#ifdef CONFIG_SMP
+        /* Free lock */
+        stw     %r20, 0(%sr2,%r20)
+# ifdef ENABLE_LWS_DEBUG
+        stw     %r0, 4(%sr2,%r20)
+# endif
+#endif
+        b       lws_exit
+        ldo     -EFAULT(%r0),%r21       /* set errno */
+        nop
+        nop
+        nop
+        nop
+
+        /* Two exception table entries, one for the load,
+           the other for the store. Either return -EFAULT.
+           Each of the entries must be relocated. */
+        .section __ex_table,"aw"
+#ifdef __LP64__
+        /* Pad the address calculation */
+        .word   0,(2b - linux_gateway_page)
+        .word   0,(3b - linux_gateway_page)
+#else
+        .word   (2b - linux_gateway_page)
+        .word   (3b - linux_gateway_page)
+#endif
+        .previous
+
+        .section __ex_table,"aw"
+#ifdef __LP64__
+        /* Pad the address calculation */
+        .word   0,(1b - linux_gateway_page)
+        .word   0,(3b - linux_gateway_page)
+#else
+        .word   (1b - linux_gateway_page)
+        .word   (3b - linux_gateway_page)
+#endif
+        .previous
+
+end_compare_and_swap:
+
+        /* Make sure nothing else is placed on this page */
+        .align 4096
+        .export end_linux_gateway_page
+end_linux_gateway_page:
+
+        /* Relocate symbols assuming linux_gateway_page is mapped
+           to virtual address 0x0 */
+#ifdef __LP64__
+        /* FIXME: The code will always be on the gateay page
+                  and thus it will be on the first 4k, the
+                  assembler seems to think that the final
+                  subtraction result is only a word in
+                  length, so we pad the value.
+        */
+#define LWS_ENTRY(_name_) .word 0,(lws_##_name_ - linux_gateway_page)
+#else
+#define LWS_ENTRY(_name_) .word  (lws_##_name_ - linux_gateway_page)
+#endif
+
+        .align 4096
+        /* Light-weight-syscall table */
+        /* Start of lws table. */
+        .export lws_table
+.Llws_table:
+lws_table:
+        LWS_ENTRY(compare_and_swap32)   /* 0 - ELF32 Atomic compare and swap */
+        LWS_ENTRY(compare_and_swap64)   /* 1 - ELF64 Atomic compare and swap */
+        /* End of lws table */
+
+        .align 4096
+        .export sys_call_table
+.Lsys_call_table:
+sys_call_table:
+#include "syscall_table.S"
+
+#ifdef __LP64__
+        .align 4096
+        .export sys_call_table64
+.Lsys_call_table64:
+sys_call_table64:
+#define SYSCALL_TABLE_64BIT
+#include "syscall_table.S"
+#endif
+
+#ifdef CONFIG_SMP
+        /*
+                All light-weight-syscall atomic operations 
+                will use this set of locks 
+        */
+        .section .data
+        .align 4096
+        .export lws_lock_start
+.Llws_lock_start:
+lws_lock_start:
+        /* lws locks */
+        .align 16
+        .rept 16
+        /* Keep locks aligned at 16-bytes */
+        .word 1
+        .word 0 
+        .word 0
+        .word 0
+        .endr
+        .previous
+#endif
+/* CONFIG_SMP for lws_lock_start */
+
+.end
+
+