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/* SPDX-License-Identifier: GPL-2.0 */ #ifndef __PARISC_EXTABLE_H #define __PARISC_EXTABLE_H #include <asm/ptrace.h> #include <linux/compiler.h> /* * The exception table consists of three addresses: * * - A relative address to the instruction that is allowed to fault. * - A relative address at which the program should continue (fixup routine) * - An asm statement which specifies which CPU register will * receive -EFAULT when an exception happens if the lowest bit in * the fixup address is set. * * Note: The register specified in the err_opcode instruction will be * modified at runtime if a fault happens. Register %r0 will be ignored. * * Since relative addresses are used, 32bit values are sufficient even on * 64bit kernel. */ struct pt_regs; int fixup_exception(struct pt_regs *regs); #define ARCH_HAS_RELATIVE_EXTABLE struct exception_table_entry { int insn; /* relative address of insn that is allowed to fault. */ int fixup; /* relative address of fixup routine */ int err_opcode; /* sample opcode with register which holds error code */ }; #define ASM_EXCEPTIONTABLE_ENTRY( fault_addr, except_addr, opcode )\ ".section __ex_table,\"aw\"\n" \ ".align 4\n" \ ".word (" #fault_addr " - .), (" #except_addr " - .)\n" \ opcode "\n" \ ".previous\n" /* * ASM_EXCEPTIONTABLE_ENTRY_EFAULT() creates a special exception table entry * (with lowest bit set) for which the fault handler in fixup_exception() will * load -EFAULT on fault into the register specified by the err_opcode instruction, * and zeroes the target register in case of a read fault in get_user(). */ #define ASM_EXCEPTIONTABLE_VAR(__err_var) \ int __err_var = 0 #define ASM_EXCEPTIONTABLE_ENTRY_EFAULT( fault_addr, except_addr, register )\ ASM_EXCEPTIONTABLE_ENTRY( fault_addr, except_addr + 1, "or %%r0,%%r0," register) static inline void swap_ex_entry_fixup(struct exception_table_entry *a, struct exception_table_entry *b, struct exception_table_entry tmp, int delta) { a->fixup = b->fixup + delta; b->fixup = tmp.fixup - delta; a->err_opcode = b->err_opcode; b->err_opcode = tmp.err_opcode; } #define swap_ex_entry_fixup swap_ex_entry_fixup #endif |