4 files changed, 233 insertions, 1 deletions

diff --git a/arch/x86_64/kernel/x8664_ksyms.c b/arch/x86_64/kernel/x8664_ksyms.c
index 6d77e4797a4..23a7da312f3 100644
--- a/arch/x86_64/kernel/x8664_ksyms.c
+++ b/arch/x86_64/kernel/x8664_ksyms.c
@@ -26,6 +26,7 @@ EXPORT_SYMBOL(__put_user_4);
 EXPORT_SYMBOL(__put_user_8);
 
 EXPORT_SYMBOL(copy_user_generic);
+EXPORT_SYMBOL(__copy_user_nocache);
 EXPORT_SYMBOL(copy_from_user);
 EXPORT_SYMBOL(copy_to_user);
 EXPORT_SYMBOL(__copy_from_user_inatomic);
diff --git a/arch/x86_64/lib/Makefile b/arch/x86_64/lib/Makefile
index b78d4170fce..8d5f835af48 100644
--- a/arch/x86_64/lib/Makefile
+++ b/arch/x86_64/lib/Makefile
@@ -9,4 +9,4 @@ obj-y := io.o iomap_copy.o
 lib-y := csum-partial.o csum-copy.o csum-wrappers.o delay.o \
         usercopy.o getuser.o putuser.o  \
         thunk.o clear_page.o copy_page.o bitstr.o bitops.o
-lib-y += memcpy.o memmove.o memset.o copy_user.o rwlock.o
+lib-y += memcpy.o memmove.o memset.o copy_user.o rwlock.o copy_user_nocache.o
diff --git a/arch/x86_64/lib/copy_user_nocache.S b/arch/x86_64/lib/copy_user_nocache.S
new file mode 100644
index 00000000000..4620efb12f1
--- /dev/null
+++ b/arch/x86_64/lib/copy_user_nocache.S
@@ -0,0 +1,217 @@
+/* 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/dwarf2.h>
+
+#define FIX_ALIGNMENT 1
+
+#include <asm/current.h>
+#include <asm/asm-offsets.h>
+#include <asm/thread_info.h>
+#include <asm/cpufeature.h>
+
+/*
+ * copy_user_nocache - Uncached memory copy with exception handling
+ * This will force destination/source out of cache for more performance.
+ *
+ * Input:
+ * rdi destination
+ * rsi source
+ * rdx count
+ * rcx zero flag        when 1 zero on exception
+ *
+ * Output:
+ * eax uncopied bytes or 0 if successful.
+ */
+ENTRY(__copy_user_nocache)
+        CFI_STARTPROC
+        pushq %rbx
+        CFI_ADJUST_CFA_OFFSET 8
+        CFI_REL_OFFSET rbx, 0
+        pushq %rcx              /* save zero flag */
+        CFI_ADJUST_CFA_OFFSET 8
+        CFI_REL_OFFSET rcx, 0
+
+        xorl %eax,%eax          /* zero for the exception handler */
+
+#ifdef FIX_ALIGNMENT
+        /* check for bad alignment of destination */
+        movl %edi,%ecx
+        andl $7,%ecx
+        jnz  .Lbad_alignment
+.Lafter_bad_alignment:
+#endif
+
+        movq %rdx,%rcx
+
+        movl $64,%ebx
+        shrq $6,%rdx
+        decq %rdx
+        js   .Lhandle_tail
+
+        .p2align 4
+.Lloop:
+.Ls1:   movq (%rsi),%r11
+.Ls2:   movq 1*8(%rsi),%r8
+.Ls3:   movq 2*8(%rsi),%r9
+.Ls4:   movq 3*8(%rsi),%r10
+.Ld1:   movnti %r11,(%rdi)
+.Ld2:   movnti %r8,1*8(%rdi)
+.Ld3:   movnti %r9,2*8(%rdi)
+.Ld4:   movnti %r10,3*8(%rdi)
+
+.Ls5:   movq 4*8(%rsi),%r11
+.Ls6:   movq 5*8(%rsi),%r8
+.Ls7:   movq 6*8(%rsi),%r9
+.Ls8:   movq 7*8(%rsi),%r10
+.Ld5:   movnti %r11,4*8(%rdi)
+.Ld6:   movnti %r8,5*8(%rdi)
+.Ld7:   movnti %r9,6*8(%rdi)
+.Ld8:   movnti %r10,7*8(%rdi)
+
+        dec  %rdx
+
+        leaq 64(%rsi),%rsi
+        leaq 64(%rdi),%rdi
+
+        jns  .Lloop
+
+        .p2align 4
+.Lhandle_tail:
+        movl %ecx,%edx
+        andl $63,%ecx
+        shrl $3,%ecx
+        jz   .Lhandle_7
+        movl $8,%ebx
+        .p2align 4
+.Lloop_8:
+.Ls9:   movq (%rsi),%r8
+.Ld9:   movnti %r8,(%rdi)
+        decl %ecx
+        leaq 8(%rdi),%rdi
+        leaq 8(%rsi),%rsi
+        jnz .Lloop_8
+
+.Lhandle_7:
+        movl %edx,%ecx
+        andl $7,%ecx
+        jz   .Lende
+        .p2align 4
+.Lloop_1:
+.Ls10:  movb (%rsi),%bl
+.Ld10:  movb %bl,(%rdi)
+        incq %rdi
+        incq %rsi
+        decl %ecx
+        jnz .Lloop_1
+
+        CFI_REMEMBER_STATE
+.Lende:
+        popq %rcx
+        CFI_ADJUST_CFA_OFFSET -8
+        CFI_RESTORE %rcx
+        popq %rbx
+        CFI_ADJUST_CFA_OFFSET -8
+        CFI_RESTORE rbx
+        ret
+        CFI_RESTORE_STATE
+
+#ifdef FIX_ALIGNMENT
+        /* align destination */
+        .p2align 4
+.Lbad_alignment:
+        movl $8,%r9d
+        subl %ecx,%r9d
+        movl %r9d,%ecx
+        cmpq %r9,%rdx
+        jz   .Lhandle_7
+        js   .Lhandle_7
+.Lalign_1:
+.Ls11:  movb (%rsi),%bl
+.Ld11:  movb %bl,(%rdi)
+        incq %rsi
+        incq %rdi
+        decl %ecx
+        jnz .Lalign_1
+        subq %r9,%rdx
+        jmp .Lafter_bad_alignment
+#endif
+
+        /* table sorted by exception address */
+        .section __ex_table,"a"
+        .align 8
+        .quad .Ls1,.Ls1e
+        .quad .Ls2,.Ls2e
+        .quad .Ls3,.Ls3e
+        .quad .Ls4,.Ls4e
+        .quad .Ld1,.Ls1e
+        .quad .Ld2,.Ls2e
+        .quad .Ld3,.Ls3e
+        .quad .Ld4,.Ls4e
+        .quad .Ls5,.Ls5e
+        .quad .Ls6,.Ls6e
+        .quad .Ls7,.Ls7e
+        .quad .Ls8,.Ls8e
+        .quad .Ld5,.Ls5e
+        .quad .Ld6,.Ls6e
+        .quad .Ld7,.Ls7e
+        .quad .Ld8,.Ls8e
+        .quad .Ls9,.Le_quad
+        .quad .Ld9,.Le_quad
+        .quad .Ls10,.Le_byte
+        .quad .Ld10,.Le_byte
+#ifdef FIX_ALIGNMENT
+        .quad .Ls11,.Lzero_rest
+        .quad .Ld11,.Lzero_rest
+#endif
+        .quad .Le5,.Le_zero
+        .previous
+
+        /* compute 64-offset for main loop. 8 bytes accuracy with error on the
+           pessimistic side. this is gross. it would be better to fix the
+           interface. */
+        /* eax: zero, ebx: 64 */
+.Ls1e:  addl $8,%eax
+.Ls2e:  addl $8,%eax
+.Ls3e:  addl $8,%eax
+.Ls4e:  addl $8,%eax
+.Ls5e:  addl $8,%eax
+.Ls6e:  addl $8,%eax
+.Ls7e:  addl $8,%eax
+.Ls8e:  addl $8,%eax
+        addq %rbx,%rdi  /* +64 */
+        subq %rax,%rdi  /* correct destination with computed offset */
+
+        shlq $6,%rdx    /* loop counter * 64 (stride length) */
+        addq %rax,%rdx  /* add offset to loopcnt */
+        andl $63,%ecx   /* remaining bytes */
+        addq %rcx,%rdx  /* add them */
+        jmp .Lzero_rest
+
+        /* exception on quad word loop in tail handling */
+        /* ecx: loopcnt/8, %edx: length, rdi: correct */
+.Le_quad:
+        shll $3,%ecx
+        andl $7,%edx
+        addl %ecx,%edx
+        /* edx: bytes to zero, rdi: dest, eax:zero */
+.Lzero_rest:
+        cmpl $0,(%rsp)  /* zero flag set? */
+        jz   .Le_zero
+        movq %rdx,%rcx
+.Le_byte:
+        xorl %eax,%eax
+.Le5:   rep
+        stosb
+        /* when there is another exception while zeroing the rest just return */
+.Le_zero:
+        movq %rdx,%rax
+        jmp .Lende
+        CFI_ENDPROC
+ENDPROC(__copy_user_nocache)
+
+
diff --git a/include/asm-x86_64/uaccess.h b/include/asm-x86_64/uaccess.h
index 8079e29c14f..1981f70fcad 100644
--- a/include/asm-x86_64/uaccess.h
+++ b/include/asm-x86_64/uaccess.h
@@ -367,4 +367,18 @@ __copy_to_user_inatomic(void __user *dst, const void *src, unsigned size)
         return copy_user_generic((__force void *)dst, src, size);
 }
 
+#define ARCH_HAS_NOCACHE_UACCESS 1
+extern long __copy_user_nocache(void *dst, const void __user *src, unsigned size, int zerorest);
+
+static inline int __copy_from_user_nocache(void *dst, const void __user *src, unsigned size)
+{
+        might_sleep();
+        return __copy_user_nocache(dst, (__force void *)src, size, 1);
+}
+
+static inline int __copy_from_user_inatomic_nocache(void *dst, const void __user *src, unsigned size)
+{
+        return __copy_user_nocache(dst, (__force void *)src, size, 0);
+}
+
 #endif /* __X86_64_UACCESS_H */