powerpc: Add new code patching routines
This commit adds some new routines for patching code, which will be used in a following commit. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
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@ -41,3 +41,110 @@ unsigned int create_branch(const unsigned int *addr,
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return instruction;
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return instruction;
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}
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}
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unsigned int create_cond_branch(const unsigned int *addr,
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unsigned long target, int flags)
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{
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unsigned int instruction;
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long offset;
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offset = target;
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if (! (flags & BRANCH_ABSOLUTE))
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offset = offset - (unsigned long)addr;
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/* Check we can represent the target in the instruction format */
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if (offset < -0x8000 || offset > 0x7FFF || offset & 0x3)
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return 0;
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/* Mask out the flags and target, so they don't step on each other. */
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instruction = 0x40000000 | (flags & 0x3FF0003) | (offset & 0xFFFC);
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return instruction;
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}
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static unsigned int branch_opcode(unsigned int instr)
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{
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return (instr >> 26) & 0x3F;
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}
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static int instr_is_branch_iform(unsigned int instr)
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{
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return branch_opcode(instr) == 18;
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}
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static int instr_is_branch_bform(unsigned int instr)
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{
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return branch_opcode(instr) == 16;
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}
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int instr_is_relative_branch(unsigned int instr)
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{
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if (instr & BRANCH_ABSOLUTE)
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return 0;
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return instr_is_branch_iform(instr) || instr_is_branch_bform(instr);
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}
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static unsigned long branch_iform_target(const unsigned int *instr)
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{
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signed long imm;
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imm = *instr & 0x3FFFFFC;
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/* If the top bit of the immediate value is set this is negative */
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if (imm & 0x2000000)
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imm -= 0x4000000;
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if ((*instr & BRANCH_ABSOLUTE) == 0)
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imm += (unsigned long)instr;
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return (unsigned long)imm;
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}
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static unsigned long branch_bform_target(const unsigned int *instr)
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{
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signed long imm;
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imm = *instr & 0xFFFC;
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/* If the top bit of the immediate value is set this is negative */
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if (imm & 0x8000)
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imm -= 0x10000;
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if ((*instr & BRANCH_ABSOLUTE) == 0)
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imm += (unsigned long)instr;
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return (unsigned long)imm;
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}
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unsigned long branch_target(const unsigned int *instr)
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{
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if (instr_is_branch_iform(*instr))
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return branch_iform_target(instr);
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else if (instr_is_branch_bform(*instr))
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return branch_bform_target(instr);
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return 0;
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}
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int instr_is_branch_to_addr(const unsigned int *instr, unsigned long addr)
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{
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if (instr_is_branch_iform(*instr) || instr_is_branch_bform(*instr))
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return branch_target(instr) == addr;
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return 0;
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}
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unsigned int translate_branch(const unsigned int *dest, const unsigned int *src)
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{
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unsigned long target;
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target = branch_target(src);
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if (instr_is_branch_iform(*src))
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return create_branch(dest, target, *src);
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else if (instr_is_branch_bform(*src))
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return create_cond_branch(dest, target, *src);
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return 0;
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}
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@ -23,9 +23,17 @@
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unsigned int create_branch(const unsigned int *addr,
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unsigned int create_branch(const unsigned int *addr,
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unsigned long target, int flags);
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unsigned long target, int flags);
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unsigned int create_cond_branch(const unsigned int *addr,
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unsigned long target, int flags);
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void patch_branch(unsigned int *addr, unsigned long target, int flags);
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void patch_branch(unsigned int *addr, unsigned long target, int flags);
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void patch_instruction(unsigned int *addr, unsigned int instr);
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void patch_instruction(unsigned int *addr, unsigned int instr);
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int instr_is_relative_branch(unsigned int instr);
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int instr_is_branch_to_addr(const unsigned int *instr, unsigned long addr);
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unsigned long branch_target(const unsigned int *instr);
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unsigned int translate_branch(const unsigned int *dest,
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const unsigned int *src);
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static inline unsigned long ppc_function_entry(void *func)
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static inline unsigned long ppc_function_entry(void *func)
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{
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{
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#ifdef CONFIG_PPC64
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#ifdef CONFIG_PPC64
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