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-rw-r--r--arch/mips/include/asm/vdso/vdso.h75
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 000000000..a327ca212
--- /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 *)((unsigned long)data & PAGE_MASK) - PAGE_SIZE;
+}
+
+#endif /* CONFIG_CLKSRC_MIPS_GIC */
+
+#endif /* __ASSEMBLY__ */