summaryrefslogtreecommitdiffstats
path: root/arch/loongarch/include/asm/alternative-asm.h
diff options
context:
space:
mode:
authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
commitace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch)
treeb2d64bc10158fdd5497876388cd68142ca374ed3 /arch/loongarch/include/asm/alternative-asm.h
parentInitial commit. (diff)
downloadlinux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz
linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/loongarch/include/asm/alternative-asm.h')
-rw-r--r--arch/loongarch/include/asm/alternative-asm.h82
1 files changed, 82 insertions, 0 deletions
diff --git a/arch/loongarch/include/asm/alternative-asm.h b/arch/loongarch/include/asm/alternative-asm.h
new file mode 100644
index 0000000000..ff3d10ac39
--- /dev/null
+++ b/arch/loongarch/include/asm/alternative-asm.h
@@ -0,0 +1,82 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_ALTERNATIVE_ASM_H
+#define _ASM_ALTERNATIVE_ASM_H
+
+#ifdef __ASSEMBLY__
+
+#include <asm/asm.h>
+
+/*
+ * Issue one struct alt_instr descriptor entry (need to put it into
+ * the section .altinstructions, see below). This entry contains
+ * enough information for the alternatives patching code to patch an
+ * instruction. See apply_alternatives().
+ */
+.macro altinstruction_entry orig alt feature orig_len alt_len
+ .long \orig - .
+ .long \alt - .
+ .short \feature
+ .byte \orig_len
+ .byte \alt_len
+.endm
+
+/*
+ * Define an alternative between two instructions. If @feature is
+ * present, early code in apply_alternatives() replaces @oldinstr with
+ * @newinstr. ".fill" directive takes care of proper instruction padding
+ * in case @newinstr is longer than @oldinstr.
+ */
+.macro ALTERNATIVE oldinstr, newinstr, feature
+140 :
+ \oldinstr
+141 :
+ .fill - (((144f-143f)-(141b-140b)) > 0) * ((144f-143f)-(141b-140b)) / 4, 4, 0x03400000
+142 :
+
+ .pushsection .altinstructions, "a"
+ altinstruction_entry 140b, 143f, \feature, 142b-140b, 144f-143f
+ .popsection
+
+ .subsection 1
+143 :
+ \newinstr
+144 :
+ .previous
+.endm
+
+#define old_len (141b-140b)
+#define new_len1 (144f-143f)
+#define new_len2 (145f-144f)
+
+#define alt_max_short(a, b) ((a) ^ (((a) ^ (b)) & -(-((a) < (b)))))
+
+/*
+ * Same as ALTERNATIVE macro above but for two alternatives. If CPU
+ * has @feature1, it replaces @oldinstr with @newinstr1. If CPU has
+ * @feature2, it replaces @oldinstr with @feature2.
+ */
+.macro ALTERNATIVE_2 oldinstr, newinstr1, feature1, newinstr2, feature2
+140 :
+ \oldinstr
+141 :
+ .fill - ((alt_max_short(new_len1, new_len2) - (old_len)) > 0) * \
+ (alt_max_short(new_len1, new_len2) - (old_len)) / 4, 4, 0x03400000
+142 :
+
+ .pushsection .altinstructions, "a"
+ altinstruction_entry 140b, 143f, \feature1, 142b-140b, 144f-143f, 142b-141b
+ altinstruction_entry 140b, 144f, \feature2, 142b-140b, 145f-144f, 142b-141b
+ .popsection
+
+ .subsection 1
+143 :
+ \newinstr1
+144 :
+ \newinstr2
+145 :
+ .previous
+.endm
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* _ASM_ALTERNATIVE_ASM_H */