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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-09-05 11:59:05 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-09-05 11:59:05 -0700 |
| commit | 9f0346dcbea363787186c94ef94dd01aaa215afa (patch) | |
| tree | b81c168f4d0dbe4c7f4750f4598d48a6deb72094 /arch/alpha/lib/strlen.S | |
| download | linux-stable-9f0346dcbea363787186c94ef94dd01aaa215afa.tar.gz linux-stable-9f0346dcbea363787186c94ef94dd01aaa215afa.zip | |
Merge tag 'driver-core-7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/driver-core/driver-coregrafted
Pull driver core fixes from Danilo Krummrich:
- Fix kernfs listxattr() not returning security xattr names (e.g.
SELinux labels) when the kernfs node has no allocated kernfs_iattrs
- Fix silent truncation of IRQ vector indices in the Rust PCI
abstractions
- Don't select OF from DRIVER_PE_KUNIT_TEST; skip the test when OF is
disabled instead of silently enabling extra kernel functionality
- Russ Weight is retiring from kernel development; update the Firmware
Loader sysfs contact to the driver-core mailing list, add a CREDITS
entry for Firmware Upload, and update MAINTAINERS accordingly
* tag 'driver-core-7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/driver-core/driver-core:
MAINTAINERS: Remove Russ Weight from Firmware Loader
CREDITS: Add CREDITS entry for Firmware Upload
firmware_loader: Change contact for sysfs nodes
rust: pci: reject IRQ vector indices that do not fit in u32
kernfs: preserve security xattrs without allocating iattrs
drivers: base: test: DRIVER_PE_KUNIT_TEST should not select OF
Diffstat (limited to 'arch/alpha/lib/strlen.S')
| -rw-r--r-- | arch/alpha/lib/strlen.S | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/arch/alpha/lib/strlen.S b/arch/alpha/lib/strlen.S new file mode 100644 index 000000000..4fc6a6ff2 --- /dev/null +++ b/arch/alpha/lib/strlen.S @@ -0,0 +1,59 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * strlen.S (c) 1995 David Mosberger (davidm@cs.arizona.edu) + * + * Finds length of a 0-terminated string. Optimized for the + * Alpha architecture: + * + * - memory accessed as aligned quadwords only + * - uses bcmpge to compare 8 bytes in parallel + * - does binary search to find 0 byte in last + * quadword (HAKMEM needed 12 instructions to + * do this instead of the 9 instructions that + * binary search needs). + */ +#include <linux/export.h> + .set noreorder + .set noat + + .align 3 + + .globl strlen + .ent strlen + +strlen: + ldq_u $1, 0($16) # load first quadword ($16 may be misaligned) + lda $2, -1($31) + insqh $2, $16, $2 + andnot $16, 7, $0 + or $2, $1, $1 + cmpbge $31, $1, $2 # $2 <- bitmask: bit i == 1 <==> i-th byte == 0 + bne $2, found + +loop: ldq $1, 8($0) + addq $0, 8, $0 # addr += 8 + nop # helps dual issue last two insns + cmpbge $31, $1, $2 + beq $2, loop + +found: blbs $2, done # make aligned case fast + negq $2, $3 + and $2, $3, $2 + + and $2, 0x0f, $1 + addq $0, 4, $3 + cmoveq $1, $3, $0 + + and $2, 0x33, $1 + addq $0, 2, $3 + cmoveq $1, $3, $0 + + and $2, 0x55, $1 + addq $0, 1, $3 + cmoveq $1, $3, $0 + +done: subq $0, $16, $0 + ret $31, ($26) + + .end strlen + EXPORT_SYMBOL(strlen) |
