Fedora kernel-2.6.17-1.2142_FC4 patched with stable patch-2.6.17.4-vs2.0.2-rc26.diff

[linux-2.6.git] / arch / x86_64 / lib / copy_user.S

diff --git a/arch/x86_64/lib/copy_user.S b/arch/x86_64/lib/copy_user.S
index bd556c8..f64569b 100644 (file)
--- a/arch/x86_64/lib/copy_user.S
+++ b/arch/x86_64/lib/copy_user.S
@@ -5,9 +5,9 @@
  */             
 
 #define FIX_ALIGNMENT 1
-               
+
        #include <asm/current.h>
-       #include <asm/offset.h>
+       #include <asm/asm-offsets.h>
        #include <asm/thread_info.h>
        #include <asm/cpufeature.h>
 
@@ -21,7 +21,7 @@ copy_to_user:
        jc  bad_to_user
        cmpq threadinfo_addr_limit(%rax),%rcx
        jae bad_to_user
-2:     
+2:
        .byte 0xe9      /* 32bit jump */
        .long .Lcug-1f
 1:
@@ -34,7 +34,7 @@ copy_to_user:
        .align 8
        .quad  2b
        .quad  3b
-       .byte  X86_FEATURE_K8_C
+       .byte  X86_FEATURE_REP_GOOD
        .byte  5
        .byte  5
        .previous
@@ -75,12 +75,12 @@ bad_to_user:
  * Output:             
  * eax uncopied bytes or 0 if successful.
  */
-       .globl copy_user_generic        
+       .globl copy_user_generic
        .p2align 4
-copy_user_generic:     
-       .byte 0x66,0x66,0x90    /* 5 byte nop for replacement jump */   
+copy_user_generic:
+       .byte 0x66,0x66,0x90    /* 5 byte nop for replacement jump */
        .byte 0x66,0x90
-1:             
+1:
        .section .altinstr_replacement,"ax"
 2:     .byte 0xe9                   /* near jump with 32bit immediate */
        .long copy_user_generic_c-1b /* offset */
@@ -89,11 +89,11 @@ copy_user_generic:
        .align 8
        .quad  copy_user_generic
        .quad  2b
-       .byte  X86_FEATURE_K8_C
+       .byte  X86_FEATURE_REP_GOOD
        .byte  5
        .byte  5
        .previous
-.Lcug: 
+.Lcug:
        pushq %rbx
        xorl %eax,%eax          /*zero for the exception handler */
 
@@ -107,11 +107,11 @@ copy_user_generic:
 
        movq %rdx,%rcx
 
-       movl $64,%ebx   
+       movl $64,%ebx
        shrq $6,%rdx
        decq %rdx
        js   .Lhandle_tail
-       
+
        .p2align 4
 .Lloop:
 .Ls1:  movq (%rsi),%r11
@@ -122,7 +122,7 @@ copy_user_generic:
 .Ld2:  movq %r8,1*8(%rdi)
 .Ld3:  movq %r9,2*8(%rdi)
 .Ld4:  movq %r10,3*8(%rdi)
-               
+
 .Ls5:  movq 4*8(%rsi),%r11
 .Ls6:  movq 5*8(%rsi),%r8
 .Ls7:  movq 6*8(%rsi),%r9
@@ -131,12 +131,12 @@ copy_user_generic:
 .Ld6:  movq %r8,5*8(%rdi)
 .Ld7:  movq %r9,6*8(%rdi)
 .Ld8:  movq %r10,7*8(%rdi)
-       
+
        decq %rdx
 
        leaq 64(%rsi),%rsi
        leaq 64(%rdi),%rdi
-       
+
        jns  .Lloop
 
        .p2align 4
@@ -154,9 +154,9 @@ copy_user_generic:
        leaq 8(%rdi),%rdi
        leaq 8(%rsi),%rsi
        jnz .Lloop_8
-       
-.Lhandle_7:            
-       movl %edx,%ecx  
+
+.Lhandle_7:
+       movl %edx,%ecx
        andl $7,%ecx
        jz   .Lende
        .p2align 4
@@ -167,12 +167,12 @@ copy_user_generic:
        incq %rsi
        decl %ecx
        jnz .Lloop_1
-                       
+
 .Lende:
        popq %rbx
-       ret     
+       ret
 
-#ifdef FIX_ALIGNMENT                           
+#ifdef FIX_ALIGNMENT
        /* align destination */
        .p2align 4
 .Lbad_alignment:
@@ -182,7 +182,7 @@ copy_user_generic:
        cmpq %r9,%rdx
        jz   .Lhandle_7
        js   .Lhandle_7
-.Lalign_1:             
+.Lalign_1:
 .Ls11: movb (%rsi),%bl
 .Ld11: movb %bl,(%rdi)
        incq %rsi
@@ -192,14 +192,14 @@ copy_user_generic:
        subq %r9,%rdx
        jmp .Lafter_bad_alignment
 #endif
-       
-       /* table sorted by exception address */ 
+
+       /* table sorted by exception address */
        .section __ex_table,"a"
        .align 8
        .quad .Ls1,.Ls1e
        .quad .Ls2,.Ls2e
        .quad .Ls3,.Ls3e
-       .quad .Ls4,.Ls4e        
+       .quad .Ls4,.Ls4e
        .quad .Ld1,.Ls1e
        .quad .Ld2,.Ls2e
        .quad .Ld3,.Ls3e
@@ -207,7 +207,7 @@ copy_user_generic:
        .quad .Ls5,.Ls5e
        .quad .Ls6,.Ls6e
        .quad .Ls7,.Ls7e
-       .quad .Ls8,.Ls8e        
+       .quad .Ls8,.Ls8e
        .quad .Ld5,.Ls5e
        .quad .Ld6,.Ls6e
        .quad .Ld7,.Ls7e
@@ -216,16 +216,16 @@ copy_user_generic:
        .quad .Ld9,.Le_quad
        .quad .Ls10,.Le_byte
        .quad .Ld10,.Le_byte
-#ifdef FIX_ALIGNMENT   
+#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. */        
+       /* 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
@@ -255,25 +255,32 @@ copy_user_generic:
        movq %rdx,%rcx
 .Le_byte:
        xorl %eax,%eax
-.Le5:  rep 
+.Le5:  rep
        stosb
        /* when there is another exception while zeroing the rest just return */
-.Le_zero:              
+.Le_zero:
        movq %rdx,%rax
        jmp .Lende
 
-       /* C stepping K8 run faster using the string copy instructions.
+       /* Some CPUs run faster using the string copy instructions.
           This is also a lot simpler. Use them when possible.
           Patch in jmps to this code instead of copying it fully
           to avoid unwanted aliasing in the exception tables. */
-               
+
  /* rdi        destination
   * rsi source
   * rdx count
   *
-  * Output:            
+  * Output:
   * eax uncopied bytes or 0 if successfull.
-  */                   
+  *
+  * 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.
+   */
 copy_user_generic_c:
        movl %edx,%ecx
        shrl $3,%ecx
@@ -287,7 +294,7 @@ copy_user_generic_c:
        ret
 3:     lea (%rdx,%rcx,8),%rax
        ret
-       
+
        .section __ex_table,"a"
        .quad 1b,3b
        .quad 2b,4b