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| /*
| * 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/linkage.h>
| #include <asm/errno.h>
| #include <asm/asm.h>
| #include <asm/export.h>
| #include <asm/nospec-branch.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
|
| #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.
| */
| ENTRY(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 2 bytes.
|
| # 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:
| testb $1, 12(%esp)
| jz 8f
| roll $8, %eax
| 8:
| popl %ebx
| popl %esi
| ret
| ENDPROC(csum_partial)
|
| #else
|
| /* Version for PentiumII/PPro */
|
| ENTRY(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_NOSPEC %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:
| testb $1, 12(%esp)
| jz 90f
| roll $8, %eax
| 90:
| popl %ebx
| popl %esi
| ret
| ENDPROC(csum_partial)
|
| #endif
| EXPORT_SYMBOL(csum_partial)
|
| /*
| 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; \
| _ASM_EXTABLE(9999b, 6001f)
|
| #define DST(y...) \
| 9999: y; \
| _ASM_EXTABLE(9999b, 6002f)
|
| #ifndef CONFIG_X86_USE_PPRO_CHECKSUM
|
| #define ARGBASE 16
| #define FP 12
|
| ENTRY(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
| ENDPROC(csum_partial_copy_generic)
|
| #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
|
| ENTRY(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_NOSPEC %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
| ENDPROC(csum_partial_copy_generic)
|
| #undef ROUND
| #undef ROUND1
|
| #endif
| EXPORT_SYMBOL(csum_partial_copy_generic)
|
|
