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authorLinus Torvalds <torvalds@linux-foundation.org>2023-03-03 09:32:51 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2023-03-03 09:32:51 -0800
commitbf1a1bad82407ad81130c065f6495ec0f939ae60 (patch)
tree1067a74a84186de39a94dd1e1ff6faae6c8ebe36 /arch
parent271d89394e33aae5391fd886c046ce54c8240e5b (diff)
parent61fc1ee8be26bc192d691932b0a67eabee45d12f (diff)
Merge tag 'riscv-for-linus-6.3-mw2' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux
Pull more RISC-V updates from Palmer Dabbelt: - Some cleanups and fixes for the Zbb-optimized string routines - Support for custom (vendor or implementation defined) perf events - COMMAND_LINE_SIZE has been increased to 1024 * tag 'riscv-for-linus-6.3-mw2' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: riscv: Bump COMMAND_LINE_SIZE value to 1024 drivers/perf: RISC-V: Allow programming custom firmware events riscv, lib: Fix Zbb strncmp RISC-V: improve string-function assembly
Diffstat (limited to 'arch')
-rw-r--r--arch/riscv/include/uapi/asm/setup.h8
-rw-r--r--arch/riscv/lib/strcmp.S6
-rw-r--r--arch/riscv/lib/strlen.S10
-rw-r--r--arch/riscv/lib/strncmp.S20
4 files changed, 27 insertions, 17 deletions
diff --git a/arch/riscv/include/uapi/asm/setup.h b/arch/riscv/include/uapi/asm/setup.h
new file mode 100644
index 000000000000..66b13a522880
--- /dev/null
+++ b/arch/riscv/include/uapi/asm/setup.h
@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0-only WITH Linux-syscall-note */
+
+#ifndef _UAPI_ASM_RISCV_SETUP_H
+#define _UAPI_ASM_RISCV_SETUP_H
+
+#define COMMAND_LINE_SIZE 1024
+
+#endif /* _UAPI_ASM_RISCV_SETUP_H */
diff --git a/arch/riscv/lib/strcmp.S b/arch/riscv/lib/strcmp.S
index 986ab23fe787..c42a8412547f 100644
--- a/arch/riscv/lib/strcmp.S
+++ b/arch/riscv/lib/strcmp.S
@@ -40,7 +40,9 @@ SYM_FUNC_START(strcmp)
ret
/*
- * Variant of strcmp using the ZBB extension if available
+ * Variant of strcmp using the ZBB extension if available.
+ * The code was published as part of the bitmanip manual
+ * in Appendix A.
*/
#ifdef CONFIG_RISCV_ISA_ZBB
strcmp_zbb:
@@ -57,7 +59,7 @@ strcmp_zbb:
* a1 - string2
*
* Clobbers
- * t0, t1, t2, t3, t4, t5
+ * t0, t1, t2, t3, t4
*/
or t2, a0, a1
diff --git a/arch/riscv/lib/strlen.S b/arch/riscv/lib/strlen.S
index 8345ceeee3f6..15bb8f3aa959 100644
--- a/arch/riscv/lib/strlen.S
+++ b/arch/riscv/lib/strlen.S
@@ -96,7 +96,7 @@ strlen_zbb:
* of valid bytes in this chunk.
*/
srli a0, t1, 3
- bgtu t3, a0, 3f
+ bgtu t3, a0, 2f
/* Prepare for the word comparison loop. */
addi t2, t0, SZREG
@@ -112,20 +112,20 @@ strlen_zbb:
addi t0, t0, SZREG
orc.b t1, t1
beq t1, t3, 1b
-2:
+
not t1, t1
CZ t1, t1
+ srli t1, t1, 3
- /* Get number of processed words. */
+ /* Get number of processed bytes. */
sub t2, t0, t2
/* Add number of characters in the first word. */
add a0, a0, t2
- srli t1, t1, 3
/* Add number of characters in the last word. */
add a0, a0, t1
-3:
+2:
ret
.option pop
diff --git a/arch/riscv/lib/strncmp.S b/arch/riscv/lib/strncmp.S
index ee49595075be..7ac2f667285a 100644
--- a/arch/riscv/lib/strncmp.S
+++ b/arch/riscv/lib/strncmp.S
@@ -70,7 +70,7 @@ strncmp_zbb:
li t5, -1
and t2, t2, SZREG-1
add t4, a0, a2
- bnez t2, 4f
+ bnez t2, 3f
/* Adjust limit for fast-path. */
andi t6, t4, -SZREG
@@ -78,11 +78,13 @@ strncmp_zbb:
/* Main loop for aligned string. */
.p2align 3
1:
- bgt a0, t6, 3f
+ bge a0, t6, 3f
REG_L t0, 0(a0)
REG_L t1, 0(a1)
orc.b t3, t0
bne t3, t5, 2f
+ orc.b t3, t1
+ bne t3, t5, 2f
addi a0, a0, SZREG
addi a1, a1, SZREG
beq t0, t1, 1b
@@ -114,23 +116,21 @@ strncmp_zbb:
ret
/* Simple loop for misaligned strings. */
-3:
- /* Restore limit for slow-path. */
.p2align 3
-4:
- bge a0, t4, 6f
+3:
+ bge a0, t4, 5f
lbu t0, 0(a0)
lbu t1, 0(a1)
addi a0, a0, 1
addi a1, a1, 1
- bne t0, t1, 5f
- bnez t0, 4b
+ bne t0, t1, 4f
+ bnez t0, 3b
-5:
+4:
sub a0, t0, t1
ret
-6:
+5:
li a0, 0
ret