From 119e9db233ad0f4cbd4cfb9f9385a7bca378b37d Mon Sep 17 00:00:00 2001 From: Zeng Chi Date: Mon, 21 Sep 2026 18:24:42 +0800 Subject: KVM: Don't pre-reserve xarray entries when storing empty/NULL attributes Skip the xarray reservation loop when clearing all memory attributes, as storing NULL only erases the entry and never needs to allocate, so no reservation (and no cleanup of a failed one) is required in that case. Suggested-by: Sean Christopherson Cc: David Ballesteros Signed-off-by: Zeng Chi Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com [sean: split to separate patch] Signed-off-by: Sean Christopherson --- arch/arc/lib/strlen.S | 80 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 80 insertions(+) create mode 100644 arch/arc/lib/strlen.S (limited to 'arch/arc/lib/strlen.S') diff --git a/arch/arc/lib/strlen.S b/arch/arc/lib/strlen.S new file mode 100644 index 000000000..dae428ceb --- /dev/null +++ b/arch/arc/lib/strlen.S @@ -0,0 +1,80 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) + */ + +#include + +ENTRY_CFI(strlen) + or r3,r0,7 + ld r2,[r3,-7] + ld.a r6,[r3,-3] + mov r4,0x01010101 + ; uses long immediate +#ifdef __LITTLE_ENDIAN__ + asl_s r1,r0,3 + btst_s r0,2 + asl r7,r4,r1 + ror r5,r4 + sub r1,r2,r7 + bic_s r1,r1,r2 + mov.eq r7,r4 + sub r12,r6,r7 + bic r12,r12,r6 + or.eq r12,r12,r1 + and r12,r12,r5 + brne r12,0,.Learly_end +#else /* BIG ENDIAN */ + ror r5,r4 + btst_s r0,2 + mov_s r1,31 + sub3 r7,r1,r0 + sub r1,r2,r4 + bic_s r1,r1,r2 + bmsk r1,r1,r7 + sub r12,r6,r4 + bic r12,r12,r6 + bmsk.ne r12,r12,r7 + or.eq r12,r12,r1 + and r12,r12,r5 + brne r12,0,.Learly_end +#endif /* ENDIAN */ + +.Loop: + ld_s r2,[r3,4] + ld.a r6,[r3,8] + ; stall for load result + sub r1,r2,r4 + bic_s r1,r1,r2 + sub r12,r6,r4 + bic r12,r12,r6 + or r12,r12,r1 + and r12,r12,r5 + breq r12,0,.Loop +.Lend: + and.f r1,r1,r5 + sub.ne r3,r3,4 + mov.eq r1,r12 +#ifdef __LITTLE_ENDIAN__ + sub_s r2,r1,1 + bic_s r2,r2,r1 + norm r1,r2 + sub_s r0,r0,3 + lsr_s r1,r1,3 + sub r0,r3,r0 + j_s.d [blink] + sub r0,r0,r1 +#else /* BIG ENDIAN */ + lsr_s r1,r1,7 + mov.eq r2,r6 + bic_s r1,r1,r2 + norm r1,r1 + sub r0,r3,r0 + lsr_s r1,r1,3 + j_s.d [blink] + add r0,r0,r1 +#endif /* ENDIAN */ +.Learly_end: + b.d .Lend + sub_s.ne r1,r1,r1 +END_CFI(strlen) -- cgit v1.3.1