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-rw-r--r--arch/powerpc/lib/memcmp_64.S638
1 files changed, 638 insertions, 0 deletions
diff --git a/arch/powerpc/lib/memcmp_64.S b/arch/powerpc/lib/memcmp_64.S
new file mode 100644
index 000000000..384218df7
--- /dev/null
+++ b/arch/powerpc/lib/memcmp_64.S
@@ -0,0 +1,638 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Author: Anton Blanchard <anton@au.ibm.com>
+ * Copyright 2015 IBM Corporation.
+ */
+#include <asm/ppc_asm.h>
+#include <asm/export.h>
+#include <asm/ppc-opcode.h>
+
+#define off8 r6
+#define off16 r7
+#define off24 r8
+
+#define rA r9
+#define rB r10
+#define rC r11
+#define rD r27
+#define rE r28
+#define rF r29
+#define rG r30
+#define rH r31
+
+#ifdef __LITTLE_ENDIAN__
+#define LH lhbrx
+#define LW lwbrx
+#define LD ldbrx
+#define LVS lvsr
+#define VPERM(_VRT,_VRA,_VRB,_VRC) \
+ vperm _VRT,_VRB,_VRA,_VRC
+#else
+#define LH lhzx
+#define LW lwzx
+#define LD ldx
+#define LVS lvsl
+#define VPERM(_VRT,_VRA,_VRB,_VRC) \
+ vperm _VRT,_VRA,_VRB,_VRC
+#endif
+
+#define VMX_THRESH 4096
+#define ENTER_VMX_OPS \
+ mflr r0; \
+ std r3,-STACKFRAMESIZE+STK_REG(R31)(r1); \
+ std r4,-STACKFRAMESIZE+STK_REG(R30)(r1); \
+ std r5,-STACKFRAMESIZE+STK_REG(R29)(r1); \
+ std r0,16(r1); \
+ stdu r1,-STACKFRAMESIZE(r1); \
+ bl enter_vmx_ops; \
+ cmpwi cr1,r3,0; \
+ ld r0,STACKFRAMESIZE+16(r1); \
+ ld r3,STK_REG(R31)(r1); \
+ ld r4,STK_REG(R30)(r1); \
+ ld r5,STK_REG(R29)(r1); \
+ addi r1,r1,STACKFRAMESIZE; \
+ mtlr r0
+
+#define EXIT_VMX_OPS \
+ mflr r0; \
+ std r3,-STACKFRAMESIZE+STK_REG(R31)(r1); \
+ std r4,-STACKFRAMESIZE+STK_REG(R30)(r1); \
+ std r5,-STACKFRAMESIZE+STK_REG(R29)(r1); \
+ std r0,16(r1); \
+ stdu r1,-STACKFRAMESIZE(r1); \
+ bl exit_vmx_ops; \
+ ld r0,STACKFRAMESIZE+16(r1); \
+ ld r3,STK_REG(R31)(r1); \
+ ld r4,STK_REG(R30)(r1); \
+ ld r5,STK_REG(R29)(r1); \
+ addi r1,r1,STACKFRAMESIZE; \
+ mtlr r0
+
+/*
+ * LD_VSR_CROSS16B load the 2nd 16 bytes for _vaddr which is unaligned with
+ * 16 bytes boundary and permute the result with the 1st 16 bytes.
+
+ * | y y y y y y y y y y y y y 0 1 2 | 3 4 5 6 7 8 9 a b c d e f z z z |
+ * ^ ^ ^
+ * 0xbbbb10 0xbbbb20 0xbbb30
+ * ^
+ * _vaddr
+ *
+ *
+ * _vmask is the mask generated by LVS
+ * _v1st_qw is the 1st aligned QW of current addr which is already loaded.
+ * for example: 0xyyyyyyyyyyyyy012 for big endian
+ * _v2nd_qw is the 2nd aligned QW of cur _vaddr to be loaded.
+ * for example: 0x3456789abcdefzzz for big endian
+ * The permute result is saved in _v_res.
+ * for example: 0x0123456789abcdef for big endian.
+ */
+#define LD_VSR_CROSS16B(_vaddr,_vmask,_v1st_qw,_v2nd_qw,_v_res) \
+ lvx _v2nd_qw,_vaddr,off16; \
+ VPERM(_v_res,_v1st_qw,_v2nd_qw,_vmask)
+
+/*
+ * There are 2 categories for memcmp:
+ * 1) src/dst has the same offset to the 8 bytes boundary. The handlers
+ * are named like .Lsameoffset_xxxx
+ * 2) src/dst has different offset to the 8 bytes boundary. The handlers
+ * are named like .Ldiffoffset_xxxx
+ */
+_GLOBAL_TOC(memcmp)
+ cmpdi cr1,r5,0
+
+ /* Use the short loop if the src/dst addresses are not
+ * with the same offset of 8 bytes align boundary.
+ */
+ xor r6,r3,r4
+ andi. r6,r6,7
+
+ /* Fall back to short loop if compare at aligned addrs
+ * with less than 8 bytes.
+ */
+ cmpdi cr6,r5,7
+
+ beq cr1,.Lzero
+ bgt cr6,.Lno_short
+
+.Lshort:
+ mtctr r5
+1: lbz rA,0(r3)
+ lbz rB,0(r4)
+ subf. rC,rB,rA
+ bne .Lnon_zero
+ bdz .Lzero
+
+ lbz rA,1(r3)
+ lbz rB,1(r4)
+ subf. rC,rB,rA
+ bne .Lnon_zero
+ bdz .Lzero
+
+ lbz rA,2(r3)
+ lbz rB,2(r4)
+ subf. rC,rB,rA
+ bne .Lnon_zero
+ bdz .Lzero
+
+ lbz rA,3(r3)
+ lbz rB,3(r4)
+ subf. rC,rB,rA
+ bne .Lnon_zero
+
+ addi r3,r3,4
+ addi r4,r4,4
+
+ bdnz 1b
+
+.Lzero:
+ li r3,0
+ blr
+
+.Lno_short:
+ dcbt 0,r3
+ dcbt 0,r4
+ bne .Ldiffoffset_8bytes_make_align_start
+
+
+.Lsameoffset_8bytes_make_align_start:
+ /* attempt to compare bytes not aligned with 8 bytes so that
+ * rest comparison can run based on 8 bytes alignment.
+ */
+ andi. r6,r3,7
+
+ /* Try to compare the first double word which is not 8 bytes aligned:
+ * load the first double word at (src & ~7UL) and shift left appropriate
+ * bits before comparision.
+ */
+ rlwinm r6,r3,3,26,28
+ beq .Lsameoffset_8bytes_aligned
+ clrrdi r3,r3,3
+ clrrdi r4,r4,3
+ LD rA,0,r3
+ LD rB,0,r4
+ sld rA,rA,r6
+ sld rB,rB,r6
+ cmpld cr0,rA,rB
+ srwi r6,r6,3
+ bne cr0,.LcmpAB_lightweight
+ subfic r6,r6,8
+ subf. r5,r6,r5
+ addi r3,r3,8
+ addi r4,r4,8
+ beq .Lzero
+
+.Lsameoffset_8bytes_aligned:
+ /* now we are aligned with 8 bytes.
+ * Use .Llong loop if left cmp bytes are equal or greater than 32B.
+ */
+ cmpdi cr6,r5,31
+ bgt cr6,.Llong
+
+.Lcmp_lt32bytes:
+ /* compare 1 ~ 31 bytes, at least r3 addr is 8 bytes aligned now */
+ cmpdi cr5,r5,7
+ srdi r0,r5,3
+ ble cr5,.Lcmp_rest_lt8bytes
+
+ /* handle 8 ~ 31 bytes */
+ clrldi r5,r5,61
+ mtctr r0
+2:
+ LD rA,0,r3
+ LD rB,0,r4
+ cmpld cr0,rA,rB
+ addi r3,r3,8
+ addi r4,r4,8
+ bne cr0,.LcmpAB_lightweight
+ bdnz 2b
+
+ cmpwi r5,0
+ beq .Lzero
+
+.Lcmp_rest_lt8bytes:
+ /*
+ * Here we have less than 8 bytes to compare. At least s1 is aligned to
+ * 8 bytes, but s2 may not be. We must make sure s2 + 7 doesn't cross a
+ * page boundary, otherwise we might read past the end of the buffer and
+ * trigger a page fault. We use 4K as the conservative minimum page
+ * size. If we detect that case we go to the byte-by-byte loop.
+ *
+ * Otherwise the next double word is loaded from s1 and s2, and shifted
+ * right to compare the appropriate bits.
+ */
+ clrldi r6,r4,(64-12) // r6 = r4 & 0xfff
+ cmpdi r6,0xff8
+ bgt .Lshort
+
+ subfic r6,r5,8
+ slwi r6,r6,3
+ LD rA,0,r3
+ LD rB,0,r4
+ srd rA,rA,r6
+ srd rB,rB,r6
+ cmpld cr0,rA,rB
+ bne cr0,.LcmpAB_lightweight
+ b .Lzero
+
+.Lnon_zero:
+ mr r3,rC
+ blr
+
+.Llong:
+#ifdef CONFIG_ALTIVEC
+BEGIN_FTR_SECTION
+ /* Try to use vmx loop if length is equal or greater than 4K */
+ cmpldi cr6,r5,VMX_THRESH
+ bge cr6,.Lsameoffset_vmx_cmp
+END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
+
+.Llong_novmx_cmp:
+#endif
+ /* At least s1 addr is aligned with 8 bytes */
+ li off8,8
+ li off16,16
+ li off24,24
+
+ std r31,-8(r1)
+ std r30,-16(r1)
+ std r29,-24(r1)
+ std r28,-32(r1)
+ std r27,-40(r1)
+
+ srdi r0,r5,5
+ mtctr r0
+ andi. r5,r5,31
+
+ LD rA,0,r3
+ LD rB,0,r4
+
+ LD rC,off8,r3
+ LD rD,off8,r4
+
+ LD rE,off16,r3
+ LD rF,off16,r4
+
+ LD rG,off24,r3
+ LD rH,off24,r4
+ cmpld cr0,rA,rB
+
+ addi r3,r3,32
+ addi r4,r4,32
+
+ bdz .Lfirst32
+
+ LD rA,0,r3
+ LD rB,0,r4
+ cmpld cr1,rC,rD
+
+ LD rC,off8,r3
+ LD rD,off8,r4
+ cmpld cr6,rE,rF
+
+ LD rE,off16,r3
+ LD rF,off16,r4
+ cmpld cr7,rG,rH
+ bne cr0,.LcmpAB
+
+ LD rG,off24,r3
+ LD rH,off24,r4
+ cmpld cr0,rA,rB
+ bne cr1,.LcmpCD
+
+ addi r3,r3,32
+ addi r4,r4,32
+
+ bdz .Lsecond32
+
+ .balign 16
+
+1: LD rA,0,r3
+ LD rB,0,r4
+ cmpld cr1,rC,rD
+ bne cr6,.LcmpEF
+
+ LD rC,off8,r3
+ LD rD,off8,r4
+ cmpld cr6,rE,rF
+ bne cr7,.LcmpGH
+
+ LD rE,off16,r3
+ LD rF,off16,r4
+ cmpld cr7,rG,rH
+ bne cr0,.LcmpAB
+
+ LD rG,off24,r3
+ LD rH,off24,r4
+ cmpld cr0,rA,rB
+ bne cr1,.LcmpCD
+
+ addi r3,r3,32
+ addi r4,r4,32
+
+ bdnz 1b
+
+.Lsecond32:
+ cmpld cr1,rC,rD
+ bne cr6,.LcmpEF
+
+ cmpld cr6,rE,rF
+ bne cr7,.LcmpGH
+
+ cmpld cr7,rG,rH
+ bne cr0,.LcmpAB
+
+ bne cr1,.LcmpCD
+ bne cr6,.LcmpEF
+ bne cr7,.LcmpGH
+
+.Ltail:
+ ld r31,-8(r1)
+ ld r30,-16(r1)
+ ld r29,-24(r1)
+ ld r28,-32(r1)
+ ld r27,-40(r1)
+
+ cmpdi r5,0
+ beq .Lzero
+ b .Lshort
+
+.Lfirst32:
+ cmpld cr1,rC,rD
+ cmpld cr6,rE,rF
+ cmpld cr7,rG,rH
+
+ bne cr0,.LcmpAB
+ bne cr1,.LcmpCD
+ bne cr6,.LcmpEF
+ bne cr7,.LcmpGH
+
+ b .Ltail
+
+.LcmpAB:
+ li r3,1
+ bgt cr0,.Lout
+ li r3,-1
+ b .Lout
+
+.LcmpCD:
+ li r3,1
+ bgt cr1,.Lout
+ li r3,-1
+ b .Lout
+
+.LcmpEF:
+ li r3,1
+ bgt cr6,.Lout
+ li r3,-1
+ b .Lout
+
+.LcmpGH:
+ li r3,1
+ bgt cr7,.Lout
+ li r3,-1
+
+.Lout:
+ ld r31,-8(r1)
+ ld r30,-16(r1)
+ ld r29,-24(r1)
+ ld r28,-32(r1)
+ ld r27,-40(r1)
+ blr
+
+.LcmpAB_lightweight: /* skip NV GPRS restore */
+ li r3,1
+ bgtlr
+ li r3,-1
+ blr
+
+#ifdef CONFIG_ALTIVEC
+.Lsameoffset_vmx_cmp:
+ /* Enter with src/dst addrs has the same offset with 8 bytes
+ * align boundary.
+ *
+ * There is an optimization based on following fact: memcmp()
+ * prones to fail early at the first 32 bytes.
+ * Before applying VMX instructions which will lead to 32x128bits
+ * VMX regs load/restore penalty, we compare the first 32 bytes
+ * so that we can catch the ~80% fail cases.
+ */
+
+ li r0,4
+ mtctr r0
+.Lsameoffset_prechk_32B_loop:
+ LD rA,0,r3
+ LD rB,0,r4
+ cmpld cr0,rA,rB
+ addi r3,r3,8
+ addi r4,r4,8
+ bne cr0,.LcmpAB_lightweight
+ addi r5,r5,-8
+ bdnz .Lsameoffset_prechk_32B_loop
+
+ ENTER_VMX_OPS
+ beq cr1,.Llong_novmx_cmp
+
+3:
+ /* need to check whether r4 has the same offset with r3
+ * for 16 bytes boundary.
+ */
+ xor r0,r3,r4
+ andi. r0,r0,0xf
+ bne .Ldiffoffset_vmx_cmp_start
+
+ /* len is no less than 4KB. Need to align with 16 bytes further.
+ */
+ andi. rA,r3,8
+ LD rA,0,r3
+ beq 4f
+ LD rB,0,r4
+ cmpld cr0,rA,rB
+ addi r3,r3,8
+ addi r4,r4,8
+ addi r5,r5,-8
+
+ beq cr0,4f
+ /* save and restore cr0 */
+ mfocrf r5,128
+ EXIT_VMX_OPS
+ mtocrf 128,r5
+ b .LcmpAB_lightweight
+
+4:
+ /* compare 32 bytes for each loop */
+ srdi r0,r5,5
+ mtctr r0
+ clrldi r5,r5,59
+ li off16,16
+
+.balign 16
+5:
+ lvx v0,0,r3
+ lvx v1,0,r4
+ VCMPEQUD_RC(v0,v0,v1)
+ bnl cr6,7f
+ lvx v0,off16,r3
+ lvx v1,off16,r4
+ VCMPEQUD_RC(v0,v0,v1)
+ bnl cr6,6f
+ addi r3,r3,32
+ addi r4,r4,32
+ bdnz 5b
+
+ EXIT_VMX_OPS
+ cmpdi r5,0
+ beq .Lzero
+ b .Lcmp_lt32bytes
+
+6:
+ addi r3,r3,16
+ addi r4,r4,16
+
+7:
+ /* diff the last 16 bytes */
+ EXIT_VMX_OPS
+ LD rA,0,r3
+ LD rB,0,r4
+ cmpld cr0,rA,rB
+ li off8,8
+ bne cr0,.LcmpAB_lightweight
+
+ LD rA,off8,r3
+ LD rB,off8,r4
+ cmpld cr0,rA,rB
+ bne cr0,.LcmpAB_lightweight
+ b .Lzero
+#endif
+
+.Ldiffoffset_8bytes_make_align_start:
+ /* now try to align s1 with 8 bytes */
+ rlwinm r6,r3,3,26,28
+ beq .Ldiffoffset_align_s1_8bytes
+
+ clrrdi r3,r3,3
+ LD rA,0,r3
+ LD rB,0,r4 /* unaligned load */
+ sld rA,rA,r6
+ srd rA,rA,r6
+ srd rB,rB,r6
+ cmpld cr0,rA,rB
+ srwi r6,r6,3
+ bne cr0,.LcmpAB_lightweight
+
+ subfic r6,r6,8
+ subf. r5,r6,r5
+ addi r3,r3,8
+ add r4,r4,r6
+
+ beq .Lzero
+
+.Ldiffoffset_align_s1_8bytes:
+ /* now s1 is aligned with 8 bytes. */
+#ifdef CONFIG_ALTIVEC
+BEGIN_FTR_SECTION
+ /* only do vmx ops when the size equal or greater than 4K bytes */
+ cmpdi cr5,r5,VMX_THRESH
+ bge cr5,.Ldiffoffset_vmx_cmp
+END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
+
+.Ldiffoffset_novmx_cmp:
+#endif
+
+
+ cmpdi cr5,r5,31
+ ble cr5,.Lcmp_lt32bytes
+
+#ifdef CONFIG_ALTIVEC
+ b .Llong_novmx_cmp
+#else
+ b .Llong
+#endif
+
+#ifdef CONFIG_ALTIVEC
+.Ldiffoffset_vmx_cmp:
+ /* perform a 32 bytes pre-checking before
+ * enable VMX operations.
+ */
+ li r0,4
+ mtctr r0
+.Ldiffoffset_prechk_32B_loop:
+ LD rA,0,r3
+ LD rB,0,r4
+ cmpld cr0,rA,rB
+ addi r3,r3,8
+ addi r4,r4,8
+ bne cr0,.LcmpAB_lightweight
+ addi r5,r5,-8
+ bdnz .Ldiffoffset_prechk_32B_loop
+
+ ENTER_VMX_OPS
+ beq cr1,.Ldiffoffset_novmx_cmp
+
+.Ldiffoffset_vmx_cmp_start:
+ /* Firstly try to align r3 with 16 bytes */
+ andi. r6,r3,0xf
+ li off16,16
+ beq .Ldiffoffset_vmx_s1_16bytes_align
+
+ LVS v3,0,r3
+ LVS v4,0,r4
+
+ lvx v5,0,r3
+ lvx v6,0,r4
+ LD_VSR_CROSS16B(r3,v3,v5,v7,v9)
+ LD_VSR_CROSS16B(r4,v4,v6,v8,v10)
+
+ VCMPEQUB_RC(v7,v9,v10)
+ bnl cr6,.Ldiffoffset_vmx_diff_found
+
+ subfic r6,r6,16
+ subf r5,r6,r5
+ add r3,r3,r6
+ add r4,r4,r6
+
+.Ldiffoffset_vmx_s1_16bytes_align:
+ /* now s1 is aligned with 16 bytes */
+ lvx v6,0,r4
+ LVS v4,0,r4
+ srdi r6,r5,5 /* loop for 32 bytes each */
+ clrldi r5,r5,59
+ mtctr r6
+
+.balign 16
+.Ldiffoffset_vmx_32bytesloop:
+ /* the first qw of r4 was saved in v6 */
+ lvx v9,0,r3
+ LD_VSR_CROSS16B(r4,v4,v6,v8,v10)
+ VCMPEQUB_RC(v7,v9,v10)
+ vor v6,v8,v8
+ bnl cr6,.Ldiffoffset_vmx_diff_found
+
+ addi r3,r3,16
+ addi r4,r4,16
+
+ lvx v9,0,r3
+ LD_VSR_CROSS16B(r4,v4,v6,v8,v10)
+ VCMPEQUB_RC(v7,v9,v10)
+ vor v6,v8,v8
+ bnl cr6,.Ldiffoffset_vmx_diff_found
+
+ addi r3,r3,16
+ addi r4,r4,16
+
+ bdnz .Ldiffoffset_vmx_32bytesloop
+
+ EXIT_VMX_OPS
+
+ cmpdi r5,0
+ beq .Lzero
+ b .Lcmp_lt32bytes
+
+.Ldiffoffset_vmx_diff_found:
+ EXIT_VMX_OPS
+ /* anyway, the diff will appear in next 16 bytes */
+ li r5,16
+ b .Lcmp_lt32bytes
+
+#endif
+EXPORT_SYMBOL(memcmp)
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-06 16:54:27 +0000