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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/parisc/kernel/jump_label.c
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/parisc/kernel/jump_label.c')
-rw-r--r--arch/parisc/kernel/jump_label.c44
1 files changed, 44 insertions, 0 deletions
diff --git a/arch/parisc/kernel/jump_label.c b/arch/parisc/kernel/jump_label.c
new file mode 100644
index 0000000000..e253b13450
--- /dev/null
+++ b/arch/parisc/kernel/jump_label.c
@@ -0,0 +1,44 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2019 Helge Deller <deller@gmx.de>
+ *
+ * Based on arch/arm64/kernel/jump_label.c
+ */
+#include <linux/kernel.h>
+#include <linux/jump_label.h>
+#include <linux/bug.h>
+#include <asm/alternative.h>
+#include <asm/patch.h>
+
+static inline int reassemble_17(int as17)
+{
+ return (((as17 & 0x10000) >> 16) |
+ ((as17 & 0x0f800) << 5) |
+ ((as17 & 0x00400) >> 8) |
+ ((as17 & 0x003ff) << 3));
+}
+
+void arch_jump_label_transform(struct jump_entry *entry,
+ enum jump_label_type type)
+{
+ void *addr = (void *)jump_entry_code(entry);
+ u32 insn;
+
+ if (type == JUMP_LABEL_JMP) {
+ void *target = (void *)jump_entry_target(entry);
+ int distance = target - addr;
+ /*
+ * Encode the PA1.1 "b,n" instruction with a 17-bit
+ * displacement. In case we hit the BUG(), we could use
+ * another branch instruction with a 22-bit displacement on
+ * 64-bit CPUs instead. But this seems sufficient for now.
+ */
+ distance -= 8;
+ BUG_ON(distance > 262143 || distance < -262144);
+ insn = 0xe8000002 | reassemble_17(distance >> 2);
+ } else {
+ insn = INSN_NOP;
+ }
+
+ patch_text(addr, insn);
+}