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