1 files changed, 496 insertions, 0 deletions

diff --git a/arch/i386/lib/checksum.S b/arch/i386/lib/checksum.S
new file mode 100644
index 000000000000..94c7867ddc33
--- /dev/null
+++ b/arch/i386/lib/checksum.S
@@ -0,0 +1,496 @@
+/*
+ * INET         An implementation of the TCP/IP protocol suite for the LINUX
+ *              operating system.  INET is implemented using the  BSD Socket
+ *              interface as the means of communication with the user level.
+ *
+ *              IP/TCP/UDP checksumming routines
+ *
+ * Authors:     Jorge Cwik, <jorge@laser.satlink.net>
+ *              Arnt Gulbrandsen, <agulbra@nvg.unit.no>
+ *              Tom May, <ftom@netcom.com>
+ *              Pentium Pro/II routines:
+ *              Alexander Kjeldaas <astor@guardian.no>
+ *              Finn Arne Gangstad <finnag@guardian.no>
+ *              Lots of code moved from tcp.c and ip.c; see those files
+ *              for more names.
+ *
+ * Changes:     Ingo Molnar, converted csum_partial_copy() to 2.1 exception
+ *                           handling.
+ *              Andi Kleen,  add zeroing on error
+ *                   converted to pure assembler
+ *
+ *              This program is free software; you can redistribute it and/or
+ *              modify it under the terms of the GNU General Public License
+ *              as published by the Free Software Foundation; either version
+ *              2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/config.h>
+#include <asm/errno.h>
+                                
+/*
+ * computes a partial checksum, e.g. for TCP/UDP fragments
+ */
+
+/*      
+unsigned int csum_partial(const unsigned char * buff, int len, unsigned int sum)
+ */
+                
+.text
+.align 4
+.globl csum_partial                                                             
+                
+#ifndef CONFIG_X86_USE_PPRO_CHECKSUM
+
+          /*            
+           * Experiments with Ethernet and SLIP connections show that buff
+           * is aligned on either a 2-byte or 4-byte boundary.  We get at
+           * least a twofold speedup on 486 and Pentium if it is 4-byte aligned.
+           * Fortunately, it is easy to convert 2-byte alignment to 4-byte
+           * alignment for the unrolled loop.
+           */           
+csum_partial:   
+        pushl %esi
+        pushl %ebx
+        movl 20(%esp),%eax      # Function arg: unsigned int sum
+        movl 16(%esp),%ecx      # Function arg: int len
+        movl 12(%esp),%esi      # Function arg: unsigned char *buff
+        testl $3, %esi          # Check alignment.
+        jz 2f                   # Jump if alignment is ok.
+        testl $1, %esi          # Check alignment.
+        jz 10f                  # Jump if alignment is boundary of 2bytes.
+
+        # buf is odd
+        dec %ecx
+        jl 8f
+        movzbl (%esi), %ebx
+        adcl %ebx, %eax
+        roll $8, %eax
+        inc %esi
+        testl $2, %esi
+        jz 2f
+10:
+        subl $2, %ecx           # Alignment uses up two bytes.
+        jae 1f                  # Jump if we had at least two bytes.
+        addl $2, %ecx           # ecx was < 2.  Deal with it.
+        jmp 4f
+1:      movw (%esi), %bx
+        addl $2, %esi
+        addw %bx, %ax
+        adcl $0, %eax
+2:
+        movl %ecx, %edx
+        shrl $5, %ecx
+        jz 2f
+        testl %esi, %esi
+1:      movl (%esi), %ebx
+        adcl %ebx, %eax
+        movl 4(%esi), %ebx
+        adcl %ebx, %eax
+        movl 8(%esi), %ebx
+        adcl %ebx, %eax
+        movl 12(%esi), %ebx
+        adcl %ebx, %eax
+        movl 16(%esi), %ebx
+        adcl %ebx, %eax
+        movl 20(%esi), %ebx
+        adcl %ebx, %eax
+        movl 24(%esi), %ebx
+        adcl %ebx, %eax
+        movl 28(%esi), %ebx
+        adcl %ebx, %eax
+        lea 32(%esi), %esi
+        dec %ecx
+        jne 1b
+        adcl $0, %eax
+2:      movl %edx, %ecx
+        andl $0x1c, %edx
+        je 4f
+        shrl $2, %edx           # This clears CF
+3:      adcl (%esi), %eax
+        lea 4(%esi), %esi
+        dec %edx
+        jne 3b
+        adcl $0, %eax
+4:      andl $3, %ecx
+        jz 7f
+        cmpl $2, %ecx
+        jb 5f
+        movw (%esi),%cx
+        leal 2(%esi),%esi
+        je 6f
+        shll $16,%ecx
+5:      movb (%esi),%cl
+6:      addl %ecx,%eax
+        adcl $0, %eax 
+7:      
+        testl $1, 12(%esp)
+        jz 8f
+        roll $8, %eax
+8:
+        popl %ebx
+        popl %esi
+        ret
+
+#else
+
+/* Version for PentiumII/PPro */
+
+csum_partial:
+        pushl %esi
+        pushl %ebx
+        movl 20(%esp),%eax      # Function arg: unsigned int sum
+        movl 16(%esp),%ecx      # Function arg: int len
+        movl 12(%esp),%esi      # Function arg: const unsigned char *buf
+
+        testl $3, %esi         
+        jnz 25f                 
+10:
+        movl %ecx, %edx
+        movl %ecx, %ebx
+        andl $0x7c, %ebx
+        shrl $7, %ecx
+        addl %ebx,%esi
+        shrl $2, %ebx  
+        negl %ebx
+        lea 45f(%ebx,%ebx,2), %ebx
+        testl %esi, %esi
+        jmp *%ebx
+
+        # Handle 2-byte-aligned regions
+20:     addw (%esi), %ax
+        lea 2(%esi), %esi
+        adcl $0, %eax
+        jmp 10b
+25:
+        testl $1, %esi         
+        jz 30f                 
+        # buf is odd
+        dec %ecx
+        jl 90f
+        movzbl (%esi), %ebx
+        addl %ebx, %eax
+        adcl $0, %eax
+        roll $8, %eax
+        inc %esi
+        testl $2, %esi
+        jz 10b
+
+30:     subl $2, %ecx          
+        ja 20b                 
+        je 32f
+        addl $2, %ecx
+        jz 80f
+        movzbl (%esi),%ebx      # csumming 1 byte, 2-aligned
+        addl %ebx, %eax
+        adcl $0, %eax
+        jmp 80f
+32:
+        addw (%esi), %ax        # csumming 2 bytes, 2-aligned
+        adcl $0, %eax
+        jmp 80f
+
+40: 
+        addl -128(%esi), %eax
+        adcl -124(%esi), %eax
+        adcl -120(%esi), %eax
+        adcl -116(%esi), %eax   
+        adcl -112(%esi), %eax   
+        adcl -108(%esi), %eax
+        adcl -104(%esi), %eax
+        adcl -100(%esi), %eax
+        adcl -96(%esi), %eax
+        adcl -92(%esi), %eax
+        adcl -88(%esi), %eax
+        adcl -84(%esi), %eax
+        adcl -80(%esi), %eax
+        adcl -76(%esi), %eax
+        adcl -72(%esi), %eax
+        adcl -68(%esi), %eax
+        adcl -64(%esi), %eax     
+        adcl -60(%esi), %eax     
+        adcl -56(%esi), %eax     
+        adcl -52(%esi), %eax   
+        adcl -48(%esi), %eax   
+        adcl -44(%esi), %eax
+        adcl -40(%esi), %eax
+        adcl -36(%esi), %eax
+        adcl -32(%esi), %eax
+        adcl -28(%esi), %eax
+        adcl -24(%esi), %eax
+        adcl -20(%esi), %eax
+        adcl -16(%esi), %eax
+        adcl -12(%esi), %eax
+        adcl -8(%esi), %eax
+        adcl -4(%esi), %eax
+45:
+        lea 128(%esi), %esi
+        adcl $0, %eax
+        dec %ecx
+        jge 40b
+        movl %edx, %ecx
+50:     andl $3, %ecx
+        jz 80f
+
+        # Handle the last 1-3 bytes without jumping
+        notl %ecx               # 1->2, 2->1, 3->0, higher bits are masked
+        movl $0xffffff,%ebx     # by the shll and shrl instructions
+        shll $3,%ecx
+        shrl %cl,%ebx
+        andl -128(%esi),%ebx    # esi is 4-aligned so should be ok
+        addl %ebx,%eax
+        adcl $0,%eax
+80: 
+        testl $1, 12(%esp)
+        jz 90f
+        roll $8, %eax
+90: 
+        popl %ebx
+        popl %esi
+        ret
+                                
+#endif
+
+/*
+unsigned int csum_partial_copy_generic (const char *src, char *dst,
+                                  int len, int sum, int *src_err_ptr, int *dst_err_ptr)
+ */ 
+
+/*
+ * Copy from ds while checksumming, otherwise like csum_partial
+ *
+ * The macros SRC and DST specify the type of access for the instruction.
+ * thus we can call a custom exception handler for all access types.
+ *
+ * FIXME: could someone double-check whether I haven't mixed up some SRC and
+ *        DST definitions? It's damn hard to trigger all cases.  I hope I got
+ *        them all but there's no guarantee.
+ */
+
+#define SRC(y...)                       \
+        9999: y;                        \
+        .section __ex_table, "a";       \
+        .long 9999b, 6001f      ;       \
+        .previous
+
+#define DST(y...)                       \
+        9999: y;                        \
+        .section __ex_table, "a";       \
+        .long 9999b, 6002f      ;       \
+        .previous
+
+.align 4
+.globl csum_partial_copy_generic
+                                
+#ifndef CONFIG_X86_USE_PPRO_CHECKSUM
+
+#define ARGBASE 16              
+#define FP              12
+                
+csum_partial_copy_generic:
+        subl  $4,%esp   
+        pushl %edi
+        pushl %esi
+        pushl %ebx
+        movl ARGBASE+16(%esp),%eax      # sum
+        movl ARGBASE+12(%esp),%ecx      # len
+        movl ARGBASE+4(%esp),%esi       # src
+        movl ARGBASE+8(%esp),%edi       # dst
+
+        testl $2, %edi                  # Check alignment. 
+        jz 2f                           # Jump if alignment is ok.
+        subl $2, %ecx                   # Alignment uses up two bytes.
+        jae 1f                          # Jump if we had at least two bytes.
+        addl $2, %ecx                   # ecx was < 2.  Deal with it.
+        jmp 4f
+SRC(1:  movw (%esi), %bx        )
+        addl $2, %esi
+DST(    movw %bx, (%edi)        )
+        addl $2, %edi
+        addw %bx, %ax   
+        adcl $0, %eax
+2:
+        movl %ecx, FP(%esp)
+        shrl $5, %ecx
+        jz 2f
+        testl %esi, %esi
+SRC(1:  movl (%esi), %ebx       )
+SRC(    movl 4(%esi), %edx      )
+        adcl %ebx, %eax
+DST(    movl %ebx, (%edi)       )
+        adcl %edx, %eax
+DST(    movl %edx, 4(%edi)      )
+
+SRC(    movl 8(%esi), %ebx      )
+SRC(    movl 12(%esi), %edx     )
+        adcl %ebx, %eax
+DST(    movl %ebx, 8(%edi)      )
+        adcl %edx, %eax
+DST(    movl %edx, 12(%edi)     )
+
+SRC(    movl 16(%esi), %ebx     )
+SRC(    movl 20(%esi), %edx     )
+        adcl %ebx, %eax
+DST(    movl %ebx, 16(%edi)     )
+        adcl %edx, %eax
+DST(    movl %edx, 20(%edi)     )
+
+SRC(    movl 24(%esi), %ebx     )
+SRC(    movl 28(%esi), %edx     )
+        adcl %ebx, %eax
+DST(    movl %ebx, 24(%edi)     )
+        adcl %edx, %eax
+DST(    movl %edx, 28(%edi)     )
+
+        lea 32(%esi), %esi
+        lea 32(%edi), %edi
+        dec %ecx
+        jne 1b
+        adcl $0, %eax
+2:      movl FP(%esp), %edx
+        movl %edx, %ecx
+        andl $0x1c, %edx
+        je 4f
+        shrl $2, %edx                   # This clears CF
+SRC(3:  movl (%esi), %ebx       )
+        adcl %ebx, %eax
+DST(    movl %ebx, (%edi)       )
+        lea 4(%esi), %esi
+        lea 4(%edi), %edi
+        dec %edx
+        jne 3b
+        adcl $0, %eax
+4:      andl $3, %ecx
+        jz 7f
+        cmpl $2, %ecx
+        jb 5f
+SRC(    movw (%esi), %cx        )
+        leal 2(%esi), %esi
+DST(    movw %cx, (%edi)        )
+        leal 2(%edi), %edi
+        je 6f
+        shll $16,%ecx
+SRC(5:  movb (%esi), %cl        )
+DST(    movb %cl, (%edi)        )
+6:      addl %ecx, %eax
+        adcl $0, %eax
+7:
+5000:
+
+# Exception handler:
+.section .fixup, "ax"                                                   
+
+6001:
+        movl ARGBASE+20(%esp), %ebx     # src_err_ptr
+        movl $-EFAULT, (%ebx)
+
+        # zero the complete destination - computing the rest
+        # is too much work 
+        movl ARGBASE+8(%esp), %edi      # dst
+        movl ARGBASE+12(%esp), %ecx     # len
+        xorl %eax,%eax
+        rep ; stosb
+
+        jmp 5000b
+
+6002:
+        movl ARGBASE+24(%esp), %ebx     # dst_err_ptr
+        movl $-EFAULT,(%ebx)
+        jmp 5000b
+
+.previous
+
+        popl %ebx
+        popl %esi
+        popl %edi
+        popl %ecx                       # equivalent to addl $4,%esp
+        ret     
+
+#else
+
+/* Version for PentiumII/PPro */
+
+#define ROUND1(x) \
+        SRC(movl x(%esi), %ebx  )       ;       \
+        addl %ebx, %eax                 ;       \
+        DST(movl %ebx, x(%edi)  )       ; 
+
+#define ROUND(x) \
+        SRC(movl x(%esi), %ebx  )       ;       \
+        adcl %ebx, %eax                 ;       \
+        DST(movl %ebx, x(%edi)  )       ;
+
+#define ARGBASE 12
+                
+csum_partial_copy_generic:
+        pushl %ebx
+        pushl %edi
+        pushl %esi
+        movl ARGBASE+4(%esp),%esi       #src
+        movl ARGBASE+8(%esp),%edi       #dst    
+        movl ARGBASE+12(%esp),%ecx      #len
+        movl ARGBASE+16(%esp),%eax      #sum
+#       movl %ecx, %edx  
+        movl %ecx, %ebx  
+        movl %esi, %edx
+        shrl $6, %ecx     
+        andl $0x3c, %ebx  
+        negl %ebx
+        subl %ebx, %esi  
+        subl %ebx, %edi  
+        lea  -1(%esi),%edx
+        andl $-32,%edx
+        lea 3f(%ebx,%ebx), %ebx
+        testl %esi, %esi 
+        jmp *%ebx
+1:      addl $64,%esi
+        addl $64,%edi 
+        SRC(movb -32(%edx),%bl) ; SRC(movb (%edx),%bl)
+        ROUND1(-64) ROUND(-60) ROUND(-56) ROUND(-52)    
+        ROUND (-48) ROUND(-44) ROUND(-40) ROUND(-36)    
+        ROUND (-32) ROUND(-28) ROUND(-24) ROUND(-20)    
+        ROUND (-16) ROUND(-12) ROUND(-8)  ROUND(-4)     
+3:      adcl $0,%eax
+        addl $64, %edx
+        dec %ecx
+        jge 1b
+4:      movl ARGBASE+12(%esp),%edx      #len
+        andl $3, %edx
+        jz 7f
+        cmpl $2, %edx
+        jb 5f
+SRC(    movw (%esi), %dx         )
+        leal 2(%esi), %esi
+DST(    movw %dx, (%edi)         )
+        leal 2(%edi), %edi
+        je 6f
+        shll $16,%edx
+5:
+SRC(    movb (%esi), %dl         )
+DST(    movb %dl, (%edi)         )
+6:      addl %edx, %eax
+        adcl $0, %eax
+7:
+.section .fixup, "ax"
+6001:   movl    ARGBASE+20(%esp), %ebx  # src_err_ptr   
+        movl $-EFAULT, (%ebx)
+        # zero the complete destination (computing the rest is too much work)
+        movl ARGBASE+8(%esp),%edi       # dst
+        movl ARGBASE+12(%esp),%ecx      # len
+        xorl %eax,%eax
+        rep; stosb
+        jmp 7b
+6002:   movl ARGBASE+24(%esp), %ebx     # dst_err_ptr
+        movl $-EFAULT, (%ebx)
+        jmp  7b                 
+.previous                               
+
+        popl %esi
+        popl %edi
+        popl %ebx
+        ret
+                                
+#undef ROUND
+#undef ROUND1           
+                
+#endif