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-rw-r--r--arch/mips/vdso/vdso.h89
1 files changed, 89 insertions, 0 deletions
diff --git a/arch/mips/vdso/vdso.h b/arch/mips/vdso/vdso.h
new file mode 100644
index 000000000000..cfb1be441dec
--- /dev/null
+++ b/arch/mips/vdso/vdso.h
@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 2015 Imagination Technologies
+ * Author: Alex Smith <alex.smith@imgtec.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ */
+
+#include <asm/sgidefs.h>
+
+#if _MIPS_SIM != _MIPS_SIM_ABI64 && defined(CONFIG_64BIT)
+
+/* Building 32-bit VDSO for the 64-bit kernel. Fake a 32-bit Kconfig. */
+#undef CONFIG_64BIT
+#define CONFIG_32BIT 1
+#ifndef __ASSEMBLY__
+#include <asm-generic/atomic64.h>
+#endif
+#endif
+
+#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 union mips_vdso_data *get_vdso_data(void)
+{
+ return (const union mips_vdso_data *)(get_vdso_base() - PAGE_SIZE);
+}
+
+#ifdef CONFIG_CLKSRC_MIPS_GIC
+
+static inline void __iomem *get_gic(const union mips_vdso_data *data)
+{
+ return (void __iomem *)data - PAGE_SIZE;
+}
+
+#endif /* CONFIG_CLKSRC_MIPS_GIC */
+
+#endif /* __ASSEMBLY__ */