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04a9f771d8
A subsequent patch will use CPY* instructions to copy between user and kernel memory. Add handling for PAN faults caused by an intended kernel memory access erroneously accessing user memory, in order to make it easier to debug kernel bugs and to keep the same behavior as with regular loads/stores. Signed-off-by: Kristina Martšenko <kristina.martsenko@arm.com> Reviewed-by: Robin Murphy <robin.murphy@arm.com> Link: https://lore.kernel.org/r/20250228170006.390100-3-kristina.martsenko@arm.com [catalin.marinas@arm.com: Folded the extable search into insn_may_access_user()] Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
51 lines
1.4 KiB
C
51 lines
1.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __ASM_EXTABLE_H
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#define __ASM_EXTABLE_H
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/*
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* The exception table consists of pairs of relative offsets: the first
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* is the relative offset to an instruction that is allowed to fault,
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* and the second is the relative offset at which the program should
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* continue. No registers are modified, so it is entirely up to the
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* continuation code 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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short type, data;
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};
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#define ARCH_HAS_RELATIVE_EXTABLE
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#define swap_ex_entry_fixup(a, b, tmp, delta) \
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do { \
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(a)->fixup = (b)->fixup + (delta); \
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(b)->fixup = (tmp).fixup - (delta); \
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(a)->type = (b)->type; \
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(b)->type = (tmp).type; \
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(a)->data = (b)->data; \
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(b)->data = (tmp).data; \
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} while (0)
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bool insn_may_access_user(unsigned long addr, unsigned long esr);
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#ifdef CONFIG_BPF_JIT
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bool ex_handler_bpf(const struct exception_table_entry *ex,
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struct pt_regs *regs);
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#else /* !CONFIG_BPF_JIT */
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static inline
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bool ex_handler_bpf(const struct exception_table_entry *ex,
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struct pt_regs *regs)
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{
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return false;
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}
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#endif /* !CONFIG_BPF_JIT */
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bool fixup_exception(struct pt_regs *regs, unsigned long esr);
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#endif
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