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linux/arch/powerpc/lib/copy_mc_64.S

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powerpc/memcpy: Add memcpy_mcsafe for pmem The pmem infrastructure uses memcpy_mcsafe in the pmem layer so as to convert machine check exceptions into a return value on failure in case a machine check exception is encountered during the memcpy. The return value is the number of bytes remaining to be copied. This patch largely borrows from the copyuser_power7 logic and does not add the VMX optimizations, largely to keep the patch simple. If needed those optimizations can be folded in. Signed-off-by: Balbir Singh <bsingharora@gmail.com> [arbab@linux.ibm.com: Added symbol export] Co-developed-by: Santosh Sivaraj <santosh@fossix.org> Signed-off-by: Santosh Sivaraj <santosh@fossix.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20190820081352.8641-7-santosh@fossix.org
2019-08-20 11:13:51 +03:00
/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) IBM Corporation, 2011
* Derived from copyuser_power7.s by Anton Blanchard <anton@au.ibm.com>
* Author - Balbir Singh <bsingharora@gmail.com>
*/
#include <asm/ppc_asm.h>
#include <asm/errno.h>
#include <asm/export.h>
.macro err1
100:
EX_TABLE(100b,.Ldo_err1)
.endm
.macro err2
200:
EX_TABLE(200b,.Ldo_err2)
.endm
.macro err3
300: EX_TABLE(300b,.Ldone)
.endm
.Ldo_err2:
ld r22,STK_REG(R22)(r1)
ld r21,STK_REG(R21)(r1)
ld r20,STK_REG(R20)(r1)
ld r19,STK_REG(R19)(r1)
ld r18,STK_REG(R18)(r1)
ld r17,STK_REG(R17)(r1)
ld r16,STK_REG(R16)(r1)
ld r15,STK_REG(R15)(r1)
ld r14,STK_REG(R14)(r1)
addi r1,r1,STACKFRAMESIZE
.Ldo_err1:
/* Do a byte by byte copy to get the exact remaining size */
mtctr r7
46:
err3; lbz r0,0(r4)
addi r4,r4,1
err3; stb r0,0(r3)
addi r3,r3,1
bdnz 46b
li r3,0
blr
.Ldone:
mfctr r3
blr
x86, powerpc: Rename memcpy_mcsafe() to copy_mc_to_{user, kernel}() In reaction to a proposal to introduce a memcpy_mcsafe_fast() implementation Linus points out that memcpy_mcsafe() is poorly named relative to communicating the scope of the interface. Specifically what addresses are valid to pass as source, destination, and what faults / exceptions are handled. Of particular concern is that even though x86 might be able to handle the semantics of copy_mc_to_user() with its common copy_user_generic() implementation other archs likely need / want an explicit path for this case: On Fri, May 1, 2020 at 11:28 AM Linus Torvalds <torvalds@linux-foundation.org> wrote: > > On Thu, Apr 30, 2020 at 6:21 PM Dan Williams <dan.j.williams@intel.com> wrote: > > > > However now I see that copy_user_generic() works for the wrong reason. > > It works because the exception on the source address due to poison > > looks no different than a write fault on the user address to the > > caller, it's still just a short copy. So it makes copy_to_user() work > > for the wrong reason relative to the name. > > Right. > > And it won't work that way on other architectures. On x86, we have a > generic function that can take faults on either side, and we use it > for both cases (and for the "in_user" case too), but that's an > artifact of the architecture oddity. > > In fact, it's probably wrong even on x86 - because it can hide bugs - > but writing those things is painful enough that everybody prefers > having just one function. Replace a single top-level memcpy_mcsafe() with either copy_mc_to_user(), or copy_mc_to_kernel(). Introduce an x86 copy_mc_fragile() name as the rename for the low-level x86 implementation formerly named memcpy_mcsafe(). It is used as the slow / careful backend that is supplanted by a fast copy_mc_generic() in a follow-on patch. One side-effect of this reorganization is that separating copy_mc_64.S to its own file means that perf no longer needs to track dependencies for its memcpy_64.S benchmarks. [ bp: Massage a bit. ] Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Cc: <stable@vger.kernel.org> Link: http://lore.kernel.org/r/CAHk-=wjSqtXAqfUJxFtWNwmguFASTgB0dz1dT3V-78Quiezqbg@mail.gmail.com Link: https://lkml.kernel.org/r/160195561680.2163339.11574962055305783722.stgit@dwillia2-desk3.amr.corp.intel.com
2020-10-06 06:40:16 +03:00
_GLOBAL(copy_mc_generic)
powerpc/memcpy: Add memcpy_mcsafe for pmem The pmem infrastructure uses memcpy_mcsafe in the pmem layer so as to convert machine check exceptions into a return value on failure in case a machine check exception is encountered during the memcpy. The return value is the number of bytes remaining to be copied. This patch largely borrows from the copyuser_power7 logic and does not add the VMX optimizations, largely to keep the patch simple. If needed those optimizations can be folded in. Signed-off-by: Balbir Singh <bsingharora@gmail.com> [arbab@linux.ibm.com: Added symbol export] Co-developed-by: Santosh Sivaraj <santosh@fossix.org> Signed-off-by: Santosh Sivaraj <santosh@fossix.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20190820081352.8641-7-santosh@fossix.org
2019-08-20 11:13:51 +03:00
mr r7,r5
cmpldi r5,16
blt .Lshort_copy
.Lcopy:
/* Get the source 8B aligned */
neg r6,r4
mtocrf 0x01,r6
clrldi r6,r6,(64-3)
bf cr7*4+3,1f
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
mflr r0
stdu r1,-STACKFRAMESIZE(r1)
std r14,STK_REG(R14)(r1)
std r15,STK_REG(R15)(r1)
std r16,STK_REG(R16)(r1)
std r17,STK_REG(R17)(r1)
std r18,STK_REG(R18)(r1)
std r19,STK_REG(R19)(r1)
std r20,STK_REG(R20)(r1)
std r21,STK_REG(R21)(r1)
std r22,STK_REG(R22)(r1)
std r0,STACKFRAMESIZE+16(r1)
powerpc/memcpy: Fix stack corruption for smaller sizes For sizes lesser than 128 bytes, the code branches out early without saving the stack frame, which when restored later drops frame of the caller. Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Signed-off-by: Santosh Sivaraj <santosh@fossix.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20190903214359.23887-1-santosh@fossix.org
2019-09-04 00:43:58 +03:00
blt 5f
powerpc/memcpy: Add memcpy_mcsafe for pmem The pmem infrastructure uses memcpy_mcsafe in the pmem layer so as to convert machine check exceptions into a return value on failure in case a machine check exception is encountered during the memcpy. The return value is the number of bytes remaining to be copied. This patch largely borrows from the copyuser_power7 logic and does not add the VMX optimizations, largely to keep the patch simple. If needed those optimizations can be folded in. Signed-off-by: Balbir Singh <bsingharora@gmail.com> [arbab@linux.ibm.com: Added symbol export] Co-developed-by: Santosh Sivaraj <santosh@fossix.org> Signed-off-by: Santosh Sivaraj <santosh@fossix.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20190820081352.8641-7-santosh@fossix.org
2019-08-20 11:13:51 +03:00
srdi r6,r5,7
mtctr r6
/* Now do cacheline (128B) sized loads and stores. */
.align 5
4:
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)
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 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)
/* 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)
ld r18,STK_REG(R18)(r1)
ld r19,STK_REG(R19)(r1)
ld r20,STK_REG(R20)(r1)
ld r21,STK_REG(R21)(r1)
ld r22,STK_REG(R22)(r1)
addi r1,r1,STACKFRAMESIZE
/* Up to 63B to go */
bf cr7*4+2,8f
err1; ld r0,0(r4)
err1; ld r6,8(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 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
err1; ld r0,0(r4)
err1; ld r6,8(r4)
addi r4,r4,16
err1; std r0,0(r3)
err1; std r6,8(r3)
addi r3,r3,16
subi r7,r7,16
9: clrldi r5,r5,(64-4)
/* Up to 15B to go */
.Lshort_copy:
mtocrf 0x01,r5
bf cr7*4+0,12f
err1; lwz r0,0(r4) /* Less chance of a reject with word ops */
err1; lwz r6,4(r4)
addi r4,r4,8
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)
err1; stb r0,0(r3)
15: li r3,0
blr
x86, powerpc: Rename memcpy_mcsafe() to copy_mc_to_{user, kernel}() In reaction to a proposal to introduce a memcpy_mcsafe_fast() implementation Linus points out that memcpy_mcsafe() is poorly named relative to communicating the scope of the interface. Specifically what addresses are valid to pass as source, destination, and what faults / exceptions are handled. Of particular concern is that even though x86 might be able to handle the semantics of copy_mc_to_user() with its common copy_user_generic() implementation other archs likely need / want an explicit path for this case: On Fri, May 1, 2020 at 11:28 AM Linus Torvalds <torvalds@linux-foundation.org> wrote: > > On Thu, Apr 30, 2020 at 6:21 PM Dan Williams <dan.j.williams@intel.com> wrote: > > > > However now I see that copy_user_generic() works for the wrong reason. > > It works because the exception on the source address due to poison > > looks no different than a write fault on the user address to the > > caller, it's still just a short copy. So it makes copy_to_user() work > > for the wrong reason relative to the name. > > Right. > > And it won't work that way on other architectures. On x86, we have a > generic function that can take faults on either side, and we use it > for both cases (and for the "in_user" case too), but that's an > artifact of the architecture oddity. > > In fact, it's probably wrong even on x86 - because it can hide bugs - > but writing those things is painful enough that everybody prefers > having just one function. Replace a single top-level memcpy_mcsafe() with either copy_mc_to_user(), or copy_mc_to_kernel(). Introduce an x86 copy_mc_fragile() name as the rename for the low-level x86 implementation formerly named memcpy_mcsafe(). It is used as the slow / careful backend that is supplanted by a fast copy_mc_generic() in a follow-on patch. One side-effect of this reorganization is that separating copy_mc_64.S to its own file means that perf no longer needs to track dependencies for its memcpy_64.S benchmarks. [ bp: Massage a bit. ] Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Cc: <stable@vger.kernel.org> Link: http://lore.kernel.org/r/CAHk-=wjSqtXAqfUJxFtWNwmguFASTgB0dz1dT3V-78Quiezqbg@mail.gmail.com Link: https://lkml.kernel.org/r/160195561680.2163339.11574962055305783722.stgit@dwillia2-desk3.amr.corp.intel.com
2020-10-06 06:40:16 +03:00
EXPORT_SYMBOL_GPL(copy_mc_generic);
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