summaryrefslogtreecommitdiffstats
path: root/arch/alpha/lib/ev67-strlen.S
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2026-09-25 15:55:03 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-09-25 15:55:03 -0700
commit75467f60a3d14f08f86f2b353298d2826382ff23 (patch)
treeacd8a7d5b5a675042449386efa5b42ec44d8bf81 /arch/alpha/lib/ev67-strlen.S
downloadlinux-stable-75467f60a3d14f08f86f2b353298d2826382ff23.tar.gz
linux-stable-75467f60a3d14f08f86f2b353298d2826382ff23.zip
Merge tag 'ipe-pr-20260925' of git://git.kernel.org/pub/scm/linux/kernel/git/wufan/ipegrafted
Pull IPE fixes from Fan Wu: "Two fixes for use-after-free issues found by recent LLM-assisted code analysis. - move successful policy load auditing under the new policy directory's inode lock, preventing a concurrent policy deletion from freeing the policy while it is still being audited - protect the dm-verity root hash with RCU, preventing policy evaluation from racing with root hash replacement during preresume" * tag 'ipe-pr-20260925' of git://git.kernel.org/pub/scm/linux/kernel/git/wufan/ipe: ipe: protect the dm-verity root hash with RCU ipe: fix use-after-free when auditing a newly loaded policy
Diffstat (limited to 'arch/alpha/lib/ev67-strlen.S')
-rw-r--r--arch/alpha/lib/ev67-strlen.S51
1 files changed, 51 insertions, 0 deletions
diff --git a/arch/alpha/lib/ev67-strlen.S b/arch/alpha/lib/ev67-strlen.S
new file mode 100644
index 000000000..3d9078807
--- /dev/null
+++ b/arch/alpha/lib/ev67-strlen.S
@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * arch/alpha/lib/ev67-strlen.S
+ * 21264 version by Rick Gorton <rick.gorton@alpha-processor.com>
+ *
+ * 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
+ *
+ * Much of the information about 21264 scheduling/coding comes from:
+ * Compiler Writer's Guide for the Alpha 21264
+ * abbreviated as 'CWG' in other comments here
+ * ftp.digital.com/pub/Digital/info/semiconductor/literature/dsc-library.html
+ * Scheduling notation:
+ * E - either cluster
+ * U - upper subcluster; U0 - subcluster U0; U1 - subcluster U1
+ * L - lower subcluster; L0 - subcluster L0; L1 - subcluster L1
+ */
+#include <linux/export.h>
+ .set noreorder
+ .set noat
+
+ .globl strlen
+ .ent strlen
+ .align 4
+strlen:
+ ldq_u $1, 0($16) # L : load first quadword ($16 may be misaligned)
+ lda $2, -1($31) # E :
+ insqh $2, $16, $2 # U :
+ andnot $16, 7, $0 # E :
+
+ or $2, $1, $1 # E :
+ cmpbge $31, $1, $2 # E : $2 <- bitmask: bit i == 1 <==> i-th byte == 0
+ nop # E :
+ bne $2, $found # U :
+
+$loop: ldq $1, 8($0) # L :
+ addq $0, 8, $0 # E : addr += 8
+ cmpbge $31, $1, $2 # E :
+ beq $2, $loop # U :
+
+$found:
+ cttz $2, $3 # U0 :
+ addq $0, $3, $0 # E :
+ subq $0, $16, $0 # E :
+ ret $31, ($26) # L0 :
+
+ .end strlen
+ EXPORT_SYMBOL(strlen)