64 lines
1.5 KiB
C
64 lines
1.5 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2020-2022 Loongson Technology Corporation Limited
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*/
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#include <linux/bitfield.h>
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#include <linux/extable.h>
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#include <linux/uaccess.h>
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#include <asm/asm-extable.h>
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#include <asm/branch.h>
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static inline unsigned long
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get_ex_fixup(const struct exception_table_entry *ex)
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{
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return ((unsigned long)&ex->fixup + ex->fixup);
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}
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static inline void regs_set_gpr(struct pt_regs *regs,
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unsigned int offset, unsigned long val)
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{
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if (offset && offset <= MAX_REG_OFFSET)
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*(unsigned long *)((unsigned long)regs + offset) = val;
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}
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static bool ex_handler_fixup(const struct exception_table_entry *ex,
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struct pt_regs *regs)
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{
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regs->csr_era = get_ex_fixup(ex);
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return true;
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}
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static bool ex_handler_uaccess_err_zero(const struct exception_table_entry *ex,
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struct pt_regs *regs)
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{
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int reg_err = FIELD_GET(EX_DATA_REG_ERR, ex->data);
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int reg_zero = FIELD_GET(EX_DATA_REG_ZERO, ex->data);
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regs_set_gpr(regs, reg_err * sizeof(unsigned long), -EFAULT);
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regs_set_gpr(regs, reg_zero * sizeof(unsigned long), 0);
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regs->csr_era = get_ex_fixup(ex);
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return true;
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}
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bool fixup_exception(struct pt_regs *regs)
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{
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const struct exception_table_entry *ex;
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ex = search_exception_tables(exception_era(regs));
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if (!ex)
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return false;
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switch (ex->type) {
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case EX_TYPE_FIXUP:
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return ex_handler_fixup(ex, regs);
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case EX_TYPE_UACCESS_ERR_ZERO:
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return ex_handler_uaccess_err_zero(ex, regs);
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case EX_TYPE_BPF:
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return ex_handler_bpf(ex, regs);
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}
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BUG();
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}
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