Initial import

1 files changed, 102 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/code-patching.h b/arch/powerpc/include/asm/code-patching.h
new file mode 100644
index 000000000..840a5509b
--- /dev/null
+++ b/arch/powerpc/include/asm/code-patching.h
@@ -0,0 +1,102 @@
+#ifndef _ASM_POWERPC_CODE_PATCHING_H
+#define _ASM_POWERPC_CODE_PATCHING_H
+
+/*
+ * Copyright 2008, Michael Ellerman, IBM Corporation.
+ *
+ * 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/types.h>
+#include <asm/ppc-opcode.h>
+
+/* Flags for create_branch:
+ * "b"   == create_branch(addr, target, 0);
+ * "ba"  == create_branch(addr, target, BRANCH_ABSOLUTE);
+ * "bl"  == create_branch(addr, target, BRANCH_SET_LINK);
+ * "bla" == create_branch(addr, target, BRANCH_ABSOLUTE | BRANCH_SET_LINK);
+ */
+#define BRANCH_SET_LINK	0x1
+#define BRANCH_ABSOLUTE	0x2
+
+unsigned int create_branch(const unsigned int *addr,
+			   unsigned long target, int flags);
+unsigned int create_cond_branch(const unsigned int *addr,
+				unsigned long target, int flags);
+int patch_branch(unsigned int *addr, unsigned long target, int flags);
+int patch_instruction(unsigned int *addr, unsigned int instr);
+
+int instr_is_relative_branch(unsigned int instr);
+int instr_is_branch_to_addr(const unsigned int *instr, unsigned long addr);
+unsigned long branch_target(const unsigned int *instr);
+unsigned int translate_branch(const unsigned int *dest,
+			      const unsigned int *src);
+#ifdef CONFIG_PPC_BOOK3E_64
+void __patch_exception(int exc, unsigned long addr);
+#define patch_exception(exc, name) do { \
+	extern unsigned int name; \
+	__patch_exception((exc), (unsigned long)&name); \
+} while (0)
+#endif
+
+#define OP_RT_RA_MASK	0xffff0000UL
+#define LIS_R2		0x3c020000UL
+#define ADDIS_R2_R12	0x3c4c0000UL
+#define ADDI_R2_R2	0x38420000UL
+
+static inline unsigned long ppc_function_entry(void *func)
+{
+#if defined(CONFIG_PPC64)
+#if defined(_CALL_ELF) && _CALL_ELF == 2
+	u32 *insn = func;
+
+	/*
+	 * A PPC64 ABIv2 function may have a local and a global entry
+	 * point. We need to use the local entry point when patching
+	 * functions, so identify and step over the global entry point
+	 * sequence.
+	 *
+	 * The global entry point sequence is always of the form:
+	 *
+	 * addis r2,r12,XXXX
+	 * addi  r2,r2,XXXX
+	 *
+	 * A linker optimisation may convert the addis to lis:
+	 *
+	 * lis   r2,XXXX
+	 * addi  r2,r2,XXXX
+	 */
+	if ((((*insn & OP_RT_RA_MASK) == ADDIS_R2_R12) ||
+	     ((*insn & OP_RT_RA_MASK) == LIS_R2)) &&
+	    ((*(insn+1) & OP_RT_RA_MASK) == ADDI_R2_R2))
+		return (unsigned long)(insn + 2);
+	else
+		return (unsigned long)func;
+#else
+	/*
+	 * On PPC64 ABIv1 the function pointer actually points to the
+	 * function's descriptor. The first entry in the descriptor is the
+	 * address of the function text.
+	 */
+	return ((func_descr_t *)func)->entry;
+#endif
+#else
+	return (unsigned long)func;
+#endif
+}
+
+static inline unsigned long ppc_global_function_entry(void *func)
+{
+#if defined(CONFIG_PPC64) && defined(_CALL_ELF) && _CALL_ELF == 2
+	/* PPC64 ABIv2 the global entry point is at the address */
+	return (unsigned long)func;
+#else
+	/* All other cases there is no change vs ppc_function_entry() */
+	return ppc_function_entry(func);
+#endif
+}
+
+#endif /* _ASM_POWERPC_CODE_PATCHING_H */