Merge branch 'master'

1 files changed, 226 insertions, 21 deletions

diff --git a/arch/x86_64/lib/copy_user.S b/arch/x86_64/lib/copy_user.S
index 79422b6559c..f64569b83b5 100644
--- a/arch/x86_64/lib/copy_user.S
+++ b/arch/x86_64/lib/copy_user.S
@@ -4,9 +4,12 @@
  * Functions to copy from and to user space.		
  */		 
 
+#define FIX_ALIGNMENT 1
+
 	#include <asm/current.h>
 	#include <asm/asm-offsets.h>
 	#include <asm/thread_info.h>
+	#include <asm/cpufeature.h>
 
 /* Standard copy_to_user with segment limit checking */		
 	.globl copy_to_user
@@ -18,7 +21,23 @@ copy_to_user:
 	jc  bad_to_user
 	cmpq threadinfo_addr_limit(%rax),%rcx
 	jae bad_to_user
-	jmp copy_user_generic
+2:
+	.byte 0xe9	/* 32bit jump */
+	.long .Lcug-1f
+1:
+
+	.section .altinstr_replacement,"ax"
+3:	.byte 0xe9			/* replacement jmp with 8 bit immediate */
+	.long copy_user_generic_c-1b	/* offset */
+	.previous
+	.section .altinstructions,"a"
+	.align 8
+	.quad  2b
+	.quad  3b
+	.byte  X86_FEATURE_REP_GOOD
+	.byte  5
+	.byte  5
+	.previous
 
 /* Standard copy_from_user with segment limit checking */	
 	.globl copy_from_user
@@ -53,44 +72,230 @@ bad_to_user:
  * rsi source
  * rdx count
  *
- * 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.
- *
  * Output:		
  * eax uncopied bytes or 0 if successful.
  */
-
 	.globl copy_user_generic
+	.p2align 4
 copy_user_generic:
+	.byte 0x66,0x66,0x90	/* 5 byte nop for replacement jump */
+	.byte 0x66,0x90
+1:
+	.section .altinstr_replacement,"ax"
+2:	.byte 0xe9	             /* near jump with 32bit immediate */
+	.long copy_user_generic_c-1b /* offset */
+	.previous
+	.section .altinstructions,"a"
+	.align 8
+	.quad  copy_user_generic
+	.quad  2b
+	.byte  X86_FEATURE_REP_GOOD
+	.byte  5
+	.byte  5
+	.previous
+.Lcug:
+	pushq %rbx
+	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:	movq %r11,(%rdi)
+.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
+.Ls8:	movq 7*8(%rsi),%r10
+.Ld5:	movq %r11,4*8(%rdi)
+.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
+.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:	movq %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
+
+.Lende:
+	popq %rbx
+	ret
+
+#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:
+	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
+
+	/* 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:
+  * 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
 	andl $7,%edx	
-	jz   5f
 1:	rep 
 	movsq 
 	movl %edx,%ecx
-	xor %eax,%eax
 2:	rep
 	movsb
+4:	movl %ecx,%eax
 	ret
-	/* align here? */
-5: 	xorl %eax,%eax
-6:	rep movsq
-	ret
-
-	.section .fixup,"ax"
 3:	lea (%rdx,%rcx,8),%rax
 	ret
-4:	movl %ecx,%eax
-	ret
-	.previous
 
 	.section __ex_table,"a"
 	.quad 1b,3b
 	.quad 2b,4b
-	.quad 6b,4b
 	.previous