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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /arch/riscv/include/asm/vdso/processor.h
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/riscv/include/asm/vdso/processor.h')
-rw-r--r--arch/riscv/include/asm/vdso/processor.h36
1 files changed, 36 insertions, 0 deletions
diff --git a/arch/riscv/include/asm/vdso/processor.h b/arch/riscv/include/asm/vdso/processor.h
new file mode 100644
index 000000000..fa70cfe50
--- /dev/null
+++ b/arch/riscv/include/asm/vdso/processor.h
@@ -0,0 +1,36 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef __ASM_VDSO_PROCESSOR_H
+#define __ASM_VDSO_PROCESSOR_H
+
+#ifndef __ASSEMBLY__
+
+#include <linux/jump_label.h>
+#include <asm/barrier.h>
+#include <asm/hwcap.h>
+
+static inline void cpu_relax(void)
+{
+ if (!static_branch_likely(&riscv_isa_ext_keys[RISCV_ISA_EXT_KEY_ZIHINTPAUSE])) {
+#ifdef __riscv_muldiv
+ int dummy;
+ /* In lieu of a halt instruction, induce a long-latency stall. */
+ __asm__ __volatile__ ("div %0, %0, zero" : "=r" (dummy));
+#endif
+ } else {
+ /*
+ * Reduce instruction retirement.
+ * This assumes the PC changes.
+ */
+#ifdef CONFIG_TOOLCHAIN_HAS_ZIHINTPAUSE
+ __asm__ __volatile__ ("pause");
+#else
+ /* Encoding of the pause instruction */
+ __asm__ __volatile__ (".4byte 0x100000F");
+#endif
+ }
+ barrier();
+}
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* __ASM_VDSO_PROCESSOR_H */