/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __S390_EXTABLE_H
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#define __S390_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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* - Address of an instruction that is allowed to fault.
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* - Address at which the program should continue.
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* - Optional address of handler that takes pt_regs * argument and runs in
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* interrupt context.
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*
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* No registers are modified, so it is entirely up to the continuation code
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* to figure out what to do.
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*
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* All the routines below use bits of fixup code that are out of line
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* with the main instruction path. This means when everything is well,
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* we don't even have to jump over them. Further, they do not intrude
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* on our cache or tlb entries.
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*/
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struct exception_table_entry
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{
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int insn, fixup;
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long handler;
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};
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extern struct exception_table_entry *__start_dma_ex_table;
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extern struct exception_table_entry *__stop_dma_ex_table;
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const struct exception_table_entry *s390_search_extables(unsigned long addr);
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static inline unsigned long extable_fixup(const struct exception_table_entry *x)
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{
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return (unsigned long)&x->fixup + x->fixup;
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}
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typedef bool (*ex_handler_t)(const struct exception_table_entry *,
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struct pt_regs *);
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static inline ex_handler_t
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ex_fixup_handler(const struct exception_table_entry *x)
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{
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if (likely(!x->handler))
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return NULL;
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return (ex_handler_t)((unsigned long)&x->handler + x->handler);
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}
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static inline bool ex_handle(const struct exception_table_entry *x,
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struct pt_regs *regs)
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{
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ex_handler_t handler = ex_fixup_handler(x);
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if (unlikely(handler))
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return handler(x, regs);
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regs->psw.addr = extable_fixup(x);
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return true;
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}
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#define ARCH_HAS_RELATIVE_EXTABLE
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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->handler = b->handler;
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if (a->handler)
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a->handler += delta;
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b->handler = tmp.handler;
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if (b->handler)
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b->handler -= delta;
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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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