summaryrefslogtreecommitdiff
path: root/arch/alpha
diff options
context:
space:
mode:
authorMatthew Wilcox (Oracle) <willy@infradead.org>2023-10-04 19:53:08 +0300
committerAndrew Morton <akpm@linux-foundation.org>2023-10-19 00:34:16 +0300
commite28ff5dc8cf6aec042741f1ea62089dca6a894ab (patch)
treeee9cd4ca0837e2a4e4381cfce7105c4c64903a2e /arch/alpha
parent247dbcdbf790c52fc76cf8e327cd0a5778e41e66 (diff)
downloadlinux-e28ff5dc8cf6aec042741f1ea62089dca6a894ab.tar.xz
alpha: implement xor_unlock_is_negative_byte
Inspired by the alpha clear_bit() and arch_atomic_add_return(), this will surely be more efficient than the generic one defined in filemap.c. Link: https://lkml.kernel.org/r/20231004165317.1061855-9-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Richard Henderson <richard.henderson@linaro.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'arch/alpha')
-rw-r--r--arch/alpha/include/asm/bitops.h21
1 files changed, 21 insertions, 0 deletions
diff --git a/arch/alpha/include/asm/bitops.h b/arch/alpha/include/asm/bitops.h
index bafb1c1f0fdc..b50ad6b83e85 100644
--- a/arch/alpha/include/asm/bitops.h
+++ b/arch/alpha/include/asm/bitops.h
@@ -286,6 +286,27 @@ arch___test_and_change_bit(unsigned long nr, volatile unsigned long *addr)
#define arch_test_bit generic_test_bit
#define arch_test_bit_acquire generic_test_bit_acquire
+static inline bool xor_unlock_is_negative_byte(unsigned long mask,
+ volatile unsigned long *p)
+{
+ unsigned long temp, old;
+
+ __asm__ __volatile__(
+ "1: ldl_l %0,%4\n"
+ " mov %0,%2\n"
+ " xor %0,%3,%0\n"
+ " stl_c %0,%1\n"
+ " beq %0,2f\n"
+ ".subsection 2\n"
+ "2: br 1b\n"
+ ".previous"
+ :"=&r" (temp), "=m" (*p), "=&r" (old)
+ :"Ir" (mask), "m" (*p));
+
+ return (old & BIT(7)) != 0;
+}
+#define xor_unlock_is_negative_byte xor_unlock_is_negative_byte
+
/*
* ffz = Find First Zero in word. Undefined if no zero exists,
* so code should check against ~0UL first..