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