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https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
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653884f887
A subsequent patch will use CPY* instructions to copy between user and kernel memory. Add a new exception fixup type to avoid fixing up faults on kernel memory accesses, 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/20250228170006.390100-2-kristina.martsenko@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
138 lines
3.8 KiB
C
138 lines
3.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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#ifndef __ASM_ASM_EXTABLE_H
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#define __ASM_ASM_EXTABLE_H
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#include <linux/bits.h>
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#include <asm/gpr-num.h>
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#define EX_TYPE_NONE 0
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#define EX_TYPE_BPF 1
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#define EX_TYPE_UACCESS_ERR_ZERO 2
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#define EX_TYPE_KACCESS_ERR_ZERO 3
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#define EX_TYPE_UACCESS_CPY 4
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#define EX_TYPE_LOAD_UNALIGNED_ZEROPAD 5
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/* Data fields for EX_TYPE_UACCESS_ERR_ZERO */
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#define EX_DATA_REG_ERR_SHIFT 0
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#define EX_DATA_REG_ERR GENMASK(4, 0)
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#define EX_DATA_REG_ZERO_SHIFT 5
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#define EX_DATA_REG_ZERO GENMASK(9, 5)
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/* Data fields for EX_TYPE_LOAD_UNALIGNED_ZEROPAD */
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#define EX_DATA_REG_DATA_SHIFT 0
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#define EX_DATA_REG_DATA GENMASK(4, 0)
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#define EX_DATA_REG_ADDR_SHIFT 5
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#define EX_DATA_REG_ADDR GENMASK(9, 5)
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/* Data fields for EX_TYPE_UACCESS_CPY */
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#define EX_DATA_UACCESS_WRITE BIT(0)
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#ifdef __ASSEMBLY__
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#define __ASM_EXTABLE_RAW(insn, fixup, type, data) \
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.pushsection __ex_table, "a"; \
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.align 2; \
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.long ((insn) - .); \
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.long ((fixup) - .); \
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.short (type); \
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.short (data); \
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.popsection;
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#define EX_DATA_REG(reg, gpr) \
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(.L__gpr_num_##gpr << EX_DATA_REG_##reg##_SHIFT)
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#define _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, zero) \
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__ASM_EXTABLE_RAW(insn, fixup, \
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EX_TYPE_UACCESS_ERR_ZERO, \
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( \
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EX_DATA_REG(ERR, err) | \
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EX_DATA_REG(ZERO, zero) \
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))
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#define _ASM_EXTABLE_UACCESS_ERR(insn, fixup, err) \
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_ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, wzr)
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#define _ASM_EXTABLE_UACCESS(insn, fixup) \
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_ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, wzr, wzr)
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/*
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* Create an exception table entry for uaccess `insn`, which will branch to `fixup`
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* when an unhandled fault is taken.
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*/
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.macro _asm_extable_uaccess, insn, fixup
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_ASM_EXTABLE_UACCESS(\insn, \fixup)
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.endm
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/*
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* Create an exception table entry for `insn` if `fixup` is provided. Otherwise
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* do nothing.
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*/
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.macro _cond_uaccess_extable, insn, fixup
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.ifnc \fixup,
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_asm_extable_uaccess \insn, \fixup
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.endif
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.endm
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.macro _asm_extable_uaccess_cpy, insn, fixup, uaccess_is_write
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__ASM_EXTABLE_RAW(\insn, \fixup, EX_TYPE_UACCESS_CPY, \uaccess_is_write)
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.endm
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#else /* __ASSEMBLY__ */
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#include <linux/stringify.h>
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#define __ASM_EXTABLE_RAW(insn, fixup, type, data) \
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".pushsection __ex_table, \"a\"\n" \
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".align 2\n" \
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".long ((" insn ") - .)\n" \
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".long ((" fixup ") - .)\n" \
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".short (" type ")\n" \
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".short (" data ")\n" \
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".popsection\n"
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#define EX_DATA_REG(reg, gpr) \
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"((.L__gpr_num_" #gpr ") << " __stringify(EX_DATA_REG_##reg##_SHIFT) ")"
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#define _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, zero) \
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__DEFINE_ASM_GPR_NUMS \
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__ASM_EXTABLE_RAW(#insn, #fixup, \
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__stringify(EX_TYPE_UACCESS_ERR_ZERO), \
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"(" \
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EX_DATA_REG(ERR, err) " | " \
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EX_DATA_REG(ZERO, zero) \
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")")
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#define _ASM_EXTABLE_KACCESS_ERR_ZERO(insn, fixup, err, zero) \
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__DEFINE_ASM_GPR_NUMS \
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__ASM_EXTABLE_RAW(#insn, #fixup, \
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__stringify(EX_TYPE_KACCESS_ERR_ZERO), \
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"(" \
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EX_DATA_REG(ERR, err) " | " \
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EX_DATA_REG(ZERO, zero) \
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")")
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#define _ASM_EXTABLE_UACCESS_ERR(insn, fixup, err) \
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_ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, wzr)
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#define _ASM_EXTABLE_UACCESS(insn, fixup) \
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_ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, wzr, wzr)
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#define _ASM_EXTABLE_KACCESS_ERR(insn, fixup, err) \
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_ASM_EXTABLE_KACCESS_ERR_ZERO(insn, fixup, err, wzr)
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#define _ASM_EXTABLE_KACCESS(insn, fixup) \
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_ASM_EXTABLE_KACCESS_ERR_ZERO(insn, fixup, wzr, wzr)
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#define _ASM_EXTABLE_LOAD_UNALIGNED_ZEROPAD(insn, fixup, data, addr) \
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__DEFINE_ASM_GPR_NUMS \
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__ASM_EXTABLE_RAW(#insn, #fixup, \
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__stringify(EX_TYPE_LOAD_UNALIGNED_ZEROPAD), \
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"(" \
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EX_DATA_REG(DATA, data) " | " \
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EX_DATA_REG(ADDR, addr) \
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")")
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#endif /* __ASSEMBLY__ */
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#endif /* __ASM_ASM_EXTABLE_H */
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