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| /*
| * Copyright 2008 Vitaly Mayatskikh <vmayatsk@redhat.com>
| * Copyright 2002 Andi Kleen, SuSE Labs.
| * Subject to the GNU Public License v2.
| *
| * Functions to copy from and to user space.
| */
|
| #include <linux/linkage.h>
| #include <asm/current.h>
| #include <asm/asm-offsets.h>
| #include <asm/thread_info.h>
| #include <asm/cpufeatures.h>
| #include <asm/alternative-asm.h>
| #include <asm/asm.h>
| #include <asm/smap.h>
| #include <asm/export.h>
|
| /*
| * copy_user_generic_unrolled - memory copy with exception handling.
| * This version is for CPUs like P4 that don't have efficient micro
| * code for rep movsq
| *
| * Input:
| * rdi destination
| * rsi source
| * rdx count
| *
| * Output:
| * eax uncopied bytes or 0 if successful.
| */
| ENTRY(copy_user_generic_unrolled)
| ASM_STAC
| cmpl $8,%edx
| jb 20f /* less then 8 bytes, go to byte copy loop */
| ALIGN_DESTINATION
| movl %edx,%ecx
| andl $63,%edx
| shrl $6,%ecx
| jz .L_copy_short_string
| 1: movq (%rsi),%r8
| 2: movq 1*8(%rsi),%r9
| 3: movq 2*8(%rsi),%r10
| 4: movq 3*8(%rsi),%r11
| 5: movq %r8,(%rdi)
| 6: movq %r9,1*8(%rdi)
| 7: movq %r10,2*8(%rdi)
| 8: movq %r11,3*8(%rdi)
| 9: movq 4*8(%rsi),%r8
| 10: movq 5*8(%rsi),%r9
| 11: movq 6*8(%rsi),%r10
| 12: movq 7*8(%rsi),%r11
| 13: movq %r8,4*8(%rdi)
| 14: movq %r9,5*8(%rdi)
| 15: movq %r10,6*8(%rdi)
| 16: movq %r11,7*8(%rdi)
| leaq 64(%rsi),%rsi
| leaq 64(%rdi),%rdi
| decl %ecx
| jnz 1b
| .L_copy_short_string:
| movl %edx,%ecx
| andl $7,%edx
| shrl $3,%ecx
| jz 20f
| 18: movq (%rsi),%r8
| 19: movq %r8,(%rdi)
| leaq 8(%rsi),%rsi
| leaq 8(%rdi),%rdi
| decl %ecx
| jnz 18b
| 20: andl %edx,%edx
| jz 23f
| movl %edx,%ecx
| 21: movb (%rsi),%al
| 22: movb %al,(%rdi)
| incq %rsi
| incq %rdi
| decl %ecx
| jnz 21b
| 23: xor %eax,%eax
| ASM_CLAC
| ret
|
| .section .fixup,"ax"
| 30: shll $6,%ecx
| addl %ecx,%edx
| jmp 60f
| 40: leal (%rdx,%rcx,8),%edx
| jmp 60f
| 50: movl %ecx,%edx
| 60: jmp copy_user_handle_tail /* ecx is zerorest also */
| .previous
|
| _ASM_EXTABLE(1b,30b)
| _ASM_EXTABLE(2b,30b)
| _ASM_EXTABLE(3b,30b)
| _ASM_EXTABLE(4b,30b)
| _ASM_EXTABLE(5b,30b)
| _ASM_EXTABLE(6b,30b)
| _ASM_EXTABLE(7b,30b)
| _ASM_EXTABLE(8b,30b)
| _ASM_EXTABLE(9b,30b)
| _ASM_EXTABLE(10b,30b)
| _ASM_EXTABLE(11b,30b)
| _ASM_EXTABLE(12b,30b)
| _ASM_EXTABLE(13b,30b)
| _ASM_EXTABLE(14b,30b)
| _ASM_EXTABLE(15b,30b)
| _ASM_EXTABLE(16b,30b)
| _ASM_EXTABLE(18b,40b)
| _ASM_EXTABLE(19b,40b)
| _ASM_EXTABLE(21b,50b)
| _ASM_EXTABLE(22b,50b)
| ENDPROC(copy_user_generic_unrolled)
| EXPORT_SYMBOL(copy_user_generic_unrolled)
|
| /* Some CPUs run faster using the string copy instructions.
| * This is also a lot simpler. Use them when possible.
| *
| * Only 4GB of copy is supported. This shouldn't be a problem
| * because the kernel normally only writes from/to page sized chunks
| * even if user space passed a longer buffer.
| * And more would be dangerous because both Intel and AMD have
| * errata with rep movsq > 4GB. If someone feels the need to fix
| * this please consider this.
| *
| * Input:
| * rdi destination
| * rsi source
| * rdx count
| *
| * Output:
| * eax uncopied bytes or 0 if successful.
| */
| ENTRY(copy_user_generic_string)
| ASM_STAC
| cmpl $8,%edx
| jb 2f /* less than 8 bytes, go to byte copy loop */
| ALIGN_DESTINATION
| movl %edx,%ecx
| shrl $3,%ecx
| andl $7,%edx
| 1: rep
| movsq
| 2: movl %edx,%ecx
| 3: rep
| movsb
| xorl %eax,%eax
| ASM_CLAC
| ret
|
| .section .fixup,"ax"
| 11: leal (%rdx,%rcx,8),%ecx
| 12: movl %ecx,%edx /* ecx is zerorest also */
| jmp copy_user_handle_tail
| .previous
|
| _ASM_EXTABLE(1b,11b)
| _ASM_EXTABLE(3b,12b)
| ENDPROC(copy_user_generic_string)
| EXPORT_SYMBOL(copy_user_generic_string)
|
| /*
| * Some CPUs are adding enhanced REP MOVSB/STOSB instructions.
| * It's recommended to use enhanced REP MOVSB/STOSB if it's enabled.
| *
| * Input:
| * rdi destination
| * rsi source
| * rdx count
| *
| * Output:
| * eax uncopied bytes or 0 if successful.
| */
| ENTRY(copy_user_enhanced_fast_string)
| ASM_STAC
| cmpl $64,%edx
| jb .L_copy_short_string /* less then 64 bytes, avoid the costly 'rep' */
| movl %edx,%ecx
| 1: rep
| movsb
| xorl %eax,%eax
| ASM_CLAC
| ret
|
| .section .fixup,"ax"
| 12: movl %ecx,%edx /* ecx is zerorest also */
| jmp copy_user_handle_tail
| .previous
|
| _ASM_EXTABLE(1b,12b)
| ENDPROC(copy_user_enhanced_fast_string)
| EXPORT_SYMBOL(copy_user_enhanced_fast_string)
|
| /*
| * copy_user_nocache - Uncached memory copy with exception handling
| * This will force destination out of cache for more performance.
| *
| * Note: Cached memory copy is used when destination or size is not
| * naturally aligned. That is:
| * - Require 8-byte alignment when size is 8 bytes or larger.
| * - Require 4-byte alignment when size is 4 bytes.
| */
| ENTRY(__copy_user_nocache)
| ASM_STAC
|
| /* If size is less than 8 bytes, go to 4-byte copy */
| cmpl $8,%edx
| jb .L_4b_nocache_copy_entry
|
| /* If destination is not 8-byte aligned, "cache" copy to align it */
| ALIGN_DESTINATION
|
| /* Set 4x8-byte copy count and remainder */
| movl %edx,%ecx
| andl $63,%edx
| shrl $6,%ecx
| jz .L_8b_nocache_copy_entry /* jump if count is 0 */
|
| /* Perform 4x8-byte nocache loop-copy */
| .L_4x8b_nocache_copy_loop:
| 1: movq (%rsi),%r8
| 2: movq 1*8(%rsi),%r9
| 3: movq 2*8(%rsi),%r10
| 4: movq 3*8(%rsi),%r11
| 5: movnti %r8,(%rdi)
| 6: movnti %r9,1*8(%rdi)
| 7: movnti %r10,2*8(%rdi)
| 8: movnti %r11,3*8(%rdi)
| 9: movq 4*8(%rsi),%r8
| 10: movq 5*8(%rsi),%r9
| 11: movq 6*8(%rsi),%r10
| 12: movq 7*8(%rsi),%r11
| 13: movnti %r8,4*8(%rdi)
| 14: movnti %r9,5*8(%rdi)
| 15: movnti %r10,6*8(%rdi)
| 16: movnti %r11,7*8(%rdi)
| leaq 64(%rsi),%rsi
| leaq 64(%rdi),%rdi
| decl %ecx
| jnz .L_4x8b_nocache_copy_loop
|
| /* Set 8-byte copy count and remainder */
| .L_8b_nocache_copy_entry:
| movl %edx,%ecx
| andl $7,%edx
| shrl $3,%ecx
| jz .L_4b_nocache_copy_entry /* jump if count is 0 */
|
| /* Perform 8-byte nocache loop-copy */
| .L_8b_nocache_copy_loop:
| 20: movq (%rsi),%r8
| 21: movnti %r8,(%rdi)
| leaq 8(%rsi),%rsi
| leaq 8(%rdi),%rdi
| decl %ecx
| jnz .L_8b_nocache_copy_loop
|
| /* If no byte left, we're done */
| .L_4b_nocache_copy_entry:
| andl %edx,%edx
| jz .L_finish_copy
|
| /* If destination is not 4-byte aligned, go to byte copy: */
| movl %edi,%ecx
| andl $3,%ecx
| jnz .L_1b_cache_copy_entry
|
| /* Set 4-byte copy count (1 or 0) and remainder */
| movl %edx,%ecx
| andl $3,%edx
| shrl $2,%ecx
| jz .L_1b_cache_copy_entry /* jump if count is 0 */
|
| /* Perform 4-byte nocache copy: */
| 30: movl (%rsi),%r8d
| 31: movnti %r8d,(%rdi)
| leaq 4(%rsi),%rsi
| leaq 4(%rdi),%rdi
|
| /* If no bytes left, we're done: */
| andl %edx,%edx
| jz .L_finish_copy
|
| /* Perform byte "cache" loop-copy for the remainder */
| .L_1b_cache_copy_entry:
| movl %edx,%ecx
| .L_1b_cache_copy_loop:
| 40: movb (%rsi),%al
| 41: movb %al,(%rdi)
| incq %rsi
| incq %rdi
| decl %ecx
| jnz .L_1b_cache_copy_loop
|
| /* Finished copying; fence the prior stores */
| .L_finish_copy:
| xorl %eax,%eax
| ASM_CLAC
| sfence
| ret
|
| .section .fixup,"ax"
| .L_fixup_4x8b_copy:
| shll $6,%ecx
| addl %ecx,%edx
| jmp .L_fixup_handle_tail
| .L_fixup_8b_copy:
| lea (%rdx,%rcx,8),%rdx
| jmp .L_fixup_handle_tail
| .L_fixup_4b_copy:
| lea (%rdx,%rcx,4),%rdx
| jmp .L_fixup_handle_tail
| .L_fixup_1b_copy:
| movl %ecx,%edx
| .L_fixup_handle_tail:
| sfence
| jmp copy_user_handle_tail
| .previous
|
| _ASM_EXTABLE(1b,.L_fixup_4x8b_copy)
| _ASM_EXTABLE(2b,.L_fixup_4x8b_copy)
| _ASM_EXTABLE(3b,.L_fixup_4x8b_copy)
| _ASM_EXTABLE(4b,.L_fixup_4x8b_copy)
| _ASM_EXTABLE(5b,.L_fixup_4x8b_copy)
| _ASM_EXTABLE(6b,.L_fixup_4x8b_copy)
| _ASM_EXTABLE(7b,.L_fixup_4x8b_copy)
| _ASM_EXTABLE(8b,.L_fixup_4x8b_copy)
| _ASM_EXTABLE(9b,.L_fixup_4x8b_copy)
| _ASM_EXTABLE(10b,.L_fixup_4x8b_copy)
| _ASM_EXTABLE(11b,.L_fixup_4x8b_copy)
| _ASM_EXTABLE(12b,.L_fixup_4x8b_copy)
| _ASM_EXTABLE(13b,.L_fixup_4x8b_copy)
| _ASM_EXTABLE(14b,.L_fixup_4x8b_copy)
| _ASM_EXTABLE(15b,.L_fixup_4x8b_copy)
| _ASM_EXTABLE(16b,.L_fixup_4x8b_copy)
| _ASM_EXTABLE(20b,.L_fixup_8b_copy)
| _ASM_EXTABLE(21b,.L_fixup_8b_copy)
| _ASM_EXTABLE(30b,.L_fixup_4b_copy)
| _ASM_EXTABLE(31b,.L_fixup_4b_copy)
| _ASM_EXTABLE(40b,.L_fixup_1b_copy)
| _ASM_EXTABLE(41b,.L_fixup_1b_copy)
| ENDPROC(__copy_user_nocache)
| EXPORT_SYMBOL(__copy_user_nocache)
|
|
