Re: [v3 5/7] powerpc/memcpy_mcsafe: return remaining bytes

Fri, 05 Jul 2019 23:17:20 -0700 



Le 05/07/2019 à 23:26, Santosh Sivaraj a écrit :

memcpy_mcsafe currently return -EFAULT on a machine check exception, change
it to return the remaining bytes that needs to be copied, so that machine
check safe copy_to_user can maintain the same behavior as copy_to_user.



AFAIU, this behaviour is the expected behaviour for memcpy_mcsafe(). Why 
implement a different behaviour in patch 3 and then change it here. 
Can't memcpy_mcsafe() return remaining bytes as expected from patch 3 ?


Christophe



Signed-off-by: Santosh Sivaraj <sant...@fossix.org>
---
  arch/powerpc/lib/memcpy_mcsafe_64.S | 142 ++++++++++++++++------------
  1 file changed, 83 insertions(+), 59 deletions(-)

diff --git a/arch/powerpc/lib/memcpy_mcsafe_64.S 
b/arch/powerpc/lib/memcpy_mcsafe_64.S
index 50f865db0338..4d8a3d315992 100644
--- a/arch/powerpc/lib/memcpy_mcsafe_64.S
+++ b/arch/powerpc/lib/memcpy_mcsafe_64.S
@@ -30,11 +30,25 @@
        ld      r14,STK_REG(R14)(r1)
        addi    r1,r1,STACKFRAMESIZE
  .Ldo_err1:
-       li      r3,-EFAULT
+       /* Do a byte by byte copy to get the exact remaining size */
+       mtctr   r7
+100:   EX_TABLE(100b, .Ldone)
+46:
+err1;  lbz     r0,0(r4)
+       addi    r4,r4,1
+err1;  stb     r0,0(r3)
+       addi    r3,r3,1
+       bdnz    46b
+       li      r3,0
+       blr
+
+.Ldone:
+       mfctr   r3
        blr

  
  
  _GLOBAL(memcpy_mcsafe)

+       mr      r7,r5
        cmpldi  r5,16
        blt     .Lshort_copy

  
@@ -49,18 +63,21 @@ err1;	lbz	r0,0(r4)

        addi    r4,r4,1
  err1; stb     r0,0(r3)
        addi    r3,r3,1
+       subi    r7,r7,1

  
  1:	bf	cr7*4+2,2f

  err1; lhz     r0,0(r4)
        addi    r4,r4,2
  err1; sth     r0,0(r3)
        addi    r3,r3,2
+       subi    r7,r7,2

  
  2:	bf	cr7*4+1,3f

  err1; lwz     r0,0(r4)
        addi    r4,r4,4
  err1; stw     r0,0(r3)
        addi    r3,r3,4
+       subi    r7,r7,4

  
  3:	sub	r5,r5,r6

        cmpldi  r5,128
@@ -87,43 +104,69 @@ err1;      stw     r0,0(r3)
  4:
  err2; ld      r0,0(r4)
  err2; ld      r6,8(r4)
-err2;  ld      r7,16(r4)
-err2;  ld      r8,24(r4)
-err2;  ld      r9,32(r4)
-err2;  ld      r10,40(r4)
-err2;  ld      r11,48(r4)
-err2;  ld      r12,56(r4)
-err2;  ld      r14,64(r4)
-err2;  ld      r15,72(r4)
-err2;  ld      r16,80(r4)
-err2;  ld      r17,88(r4)
-err2;  ld      r18,96(r4)
-err2;  ld      r19,104(r4)
-err2;  ld      r20,112(r4)
-err2;  ld      r21,120(r4)
+err2;  ld      r8,16(r4)
+err2;  ld      r9,24(r4)
+err2;  ld      r10,32(r4)
+err2;  ld      r11,40(r4)
+err2;  ld      r12,48(r4)
+err2;  ld      r14,56(r4)
+err2;  ld      r15,64(r4)
+err2;  ld      r16,72(r4)
+err2;  ld      r17,80(r4)
+err2;  ld      r18,88(r4)
+err2;  ld      r19,96(r4)
+err2;  ld      r20,104(r4)
+err2;  ld      r21,112(r4)
+err2;  ld      r22,120(r4)
        addi    r4,r4,128
  err2; std     r0,0(r3)
  err2; std     r6,8(r3)
-err2;  std     r7,16(r3)
-err2;  std     r8,24(r3)
-err2;  std     r9,32(r3)
-err2;  std     r10,40(r3)
-err2;  std     r11,48(r3)
-err2;  std     r12,56(r3)
-err2;  std     r14,64(r3)
-err2;  std     r15,72(r3)
-err2;  std     r16,80(r3)
-err2;  std     r17,88(r3)
-err2;  std     r18,96(r3)
-err2;  std     r19,104(r3)
-err2;  std     r20,112(r3)
-err2;  std     r21,120(r3)
+err2;  std     r8,16(r3)
+err2;  std     r9,24(r3)
+err2;  std     r10,32(r3)
+err2;  std     r11,40(r3)
+err2;  std     r12,48(r3)
+err2;  std     r14,56(r3)
+err2;  std     r15,64(r3)
+err2;  std     r16,72(r3)
+err2;  std     r17,80(r3)
+err2;  std     r18,88(r3)
+err2;  std     r19,96(r3)
+err2;  std     r20,104(r3)
+err2;  std     r21,112(r3)
+err2;  std     r22,120(r3)
        addi    r3,r3,128
+       subi    r7,r7,128
        bdnz    4b

  
  	clrldi	r5,r5,(64-7)
  
-	ld	r14,STK_REG(R14)(r1)

+       /* Up to 127B to go */
+5:     srdi    r6,r5,4
+       mtocrf  0x01,r6
+
+6:     bf      cr7*4+1,7f
+err2;  ld      r0,0(r4)
+err2;  ld      r6,8(r4)
+err2;  ld      r8,16(r4)
+err2;  ld      r9,24(r4)
+err2;  ld      r10,32(r4)
+err2;  ld      r11,40(r4)
+err2;  ld      r12,48(r4)
+err2;  ld      r14,56(r4)
+       addi    r4,r4,64
+err2;  std     r0,0(r3)
+err2;  std     r6,8(r3)
+err2;  std     r8,16(r3)
+err2;  std     r9,24(r3)
+err2;  std     r10,32(r3)
+err2;  std     r11,40(r3)
+err2;  std     r12,48(r3)
+err2;  std     r14,56(r3)
+       addi    r3,r3,64
+       subi    r7,r7,64
+
+7:     ld      r14,STK_REG(R14)(r1)
        ld      r15,STK_REG(R15)(r1)
        ld      r16,STK_REG(R16)(r1)
        ld      r17,STK_REG(R17)(r1)
@@ -134,42 +177,19 @@ err2;     std     r21,120(r3)
        ld      r22,STK_REG(R22)(r1)
        addi    r1,r1,STACKFRAMESIZE

  
-	/* Up to 127B to go */

-5:     srdi    r6,r5,4
-       mtocrf  0x01,r6
-
-6:     bf      cr7*4+1,7f
-err1;  ld      r0,0(r4)
-err1;  ld      r6,8(r4)
-err1;  ld      r7,16(r4)
-err1;  ld      r8,24(r4)
-err1;  ld      r9,32(r4)
-err1;  ld      r10,40(r4)
-err1;  ld      r11,48(r4)
-err1;  ld      r12,56(r4)
-       addi    r4,r4,64
-err1;  std     r0,0(r3)
-err1;  std     r6,8(r3)
-err1;  std     r7,16(r3)
-err1;  std     r8,24(r3)
-err1;  std     r9,32(r3)
-err1;  std     r10,40(r3)
-err1;  std     r11,48(r3)
-err1;  std     r12,56(r3)
-       addi    r3,r3,64
-
        /* Up to 63B to go */
-7:     bf      cr7*4+2,8f
+       bf      cr7*4+2,8f
  err1; ld      r0,0(r4)
  err1; ld      r6,8(r4)
-err1;  ld      r7,16(r4)
-err1;  ld      r8,24(r4)
+err1;  ld      r8,16(r4)
+err1;  ld      r9,24(r4)
        addi    r4,r4,32
  err1; std     r0,0(r3)
  err1; std     r6,8(r3)
-err1;  std     r7,16(r3)
-err1;  std     r8,24(r3)
+err1;  std     r8,16(r3)
+err1;  std     r9,24(r3)
        addi    r3,r3,32
+       subi    r7,r7,32

  
  	/* Up to 31B to go */

  8:    bf      cr7*4+3,9f
@@ -179,6 +199,7 @@ err1;       ld      r6,8(r4)
  err1; std     r0,0(r3)
  err1; std     r6,8(r3)
        addi    r3,r3,16
+       subi    r7,r7,16

  
  9:	clrldi	r5,r5,(64-4)
  
@@ -192,18 +213,21 @@ err1;	lwz	r6,4(r4)

  err1; stw     r0,0(r3)
  err1; stw     r6,4(r3)
        addi    r3,r3,8
+       subi    r7,r7,8

  
  12:	bf	cr7*4+1,13f

  err1; lwz     r0,0(r4)
        addi    r4,r4,4
  err1; stw     r0,0(r3)
        addi    r3,r3,4
+       subi    r7,r7,4

  
  13:	bf	cr7*4+2,14f

  err1; lhz     r0,0(r4)
        addi    r4,r4,2
  err1; sth     r0,0(r3)
        addi    r3,r3,2
+       subi    r7,r7,2

  
  14:	bf	cr7*4+3,15f

  err1; lbz     r0,0(r4)
























					Reply via email to