1 files changed, 75 insertions, 0 deletions
diff --git a/arch/mips/include/asm/vdso/vdso.h b/arch/mips/include/asm/vdso/vdso.h
new file mode 100644
index 000000000000..737ddfc3411c
--- /dev/null
+++ b/arch/mips/include/asm/vdso/vdso.h
@@ -0,0 +1,75 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2015 Imagination Technologies
+ * Author: Alex Smith <alex.smith@imgtec.com>
+ */
+
+#include <asm/sgidefs.h>
+
+#ifndef __ASSEMBLY__
+
+#include <asm/asm.h>
+#include <asm/page.h>
+#include <asm/vdso.h>
+
+static inline unsigned long get_vdso_base(void)
+{
+	unsigned long addr;
+
+	/*
+	 * We can't use cpu_has_mips_r6 since it needs the cpu_data[]
+	 * kernel symbol.
+	 */
+#ifdef CONFIG_CPU_MIPSR6
+	/*
+	 * lapc <symbol> is an alias to addiupc reg, <symbol> - .
+	 *
+	 * We can't use addiupc because there is no label-label
+	 * support for the addiupc reloc
+	 */
+	__asm__("lapc	%0, _start			\n"
+		: "=r" (addr) : :);
+#else
+	/*
+	 * Get the base load address of the VDSO. We have to avoid generating
+	 * relocations and references to the GOT because ld.so does not peform
+	 * relocations on the VDSO. We use the current offset from the VDSO base
+	 * and perform a PC-relative branch which gives the absolute address in
+	 * ra, and take the difference. The assembler chokes on
+	 * "li %0, _start - .", so embed the offset as a word and branch over
+	 * it.
+	 *
+	 */
+
+	__asm__(
+	"	.set push				\n"
+	"	.set noreorder				\n"
+	"	bal	1f				\n"
+	"	 nop					\n"
+	"	.word	_start - .			\n"
+	"1:	lw	%0, 0($31)			\n"
+	"	" STR(PTR_ADDU) " %0, $31, %0		\n"
+	"	.set pop				\n"
+	: "=r" (addr)
+	:
+	: "$31");
+#endif /* CONFIG_CPU_MIPSR6 */
+
+	return addr;
+}
+
+static inline const struct vdso_data *get_vdso_data(void)
+{
+	return (const struct vdso_data *)(get_vdso_base() - PAGE_SIZE);
+}
+
+#ifdef CONFIG_CLKSRC_MIPS_GIC
+
+static inline void __iomem *get_gic(const struct vdso_data *data)
+{
+	return (void __iomem *)data - PAGE_SIZE;
+}
+
+#endif /* CONFIG_CLKSRC_MIPS_GIC */
+
+#endif /* __ASSEMBLY__ */