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https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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20802d8d47
Inspired by commit 2e77a62cb3 ("arm64: extable: add a dedicated
uaccess handler"), do similar to riscv to add a dedicated uaccess
exception handler to update registers in exception context and
subsequently return back into the function which faulted, so we remove
the need for fixups specialized to each faulting instruction.
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
65 lines
1.7 KiB
C
65 lines
1.7 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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#define EX_TYPE_NONE 0
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#define EX_TYPE_FIXUP 1
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#define EX_TYPE_BPF 2
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#define EX_TYPE_UACCESS_ERR_ZERO 3
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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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.balign 4; \
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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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.macro _asm_extable, insn, fixup
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__ASM_EXTABLE_RAW(\insn, \fixup, EX_TYPE_FIXUP, 0)
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.endm
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#else /* __ASSEMBLY__ */
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#include <linux/bits.h>
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#include <linux/stringify.h>
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#include <asm/gpr-num.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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".balign 4\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 _ASM_EXTABLE(insn, fixup) \
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__ASM_EXTABLE_RAW(#insn, #fixup, __stringify(EX_TYPE_FIXUP), "0")
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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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#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_UACCESS_ERR(insn, fixup, err) \
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_ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, zero)
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#endif /* __ASSEMBLY__ */
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#endif /* __ASM_ASM_EXTABLE_H */
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