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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
* Lennox Wu <lennox.wu@sunplusct.com>
* Chen Liqin <liqin.chen@sunplusct.com>
* Copyright (C) 2013 Regents of the University of California
*/
#include <linux/bitfield.h>
#include <linux/extable.h>
#include <linux/module.h>
#include <linux/uaccess.h>
#include <asm/asm-extable.h>
#include <asm/ptrace.h>
static inline unsigned long
get_ex_fixup(const struct exception_table_entry *ex)
{
return ((unsigned long)&ex->fixup + ex->fixup);
}
static bool ex_handler_fixup(const struct exception_table_entry *ex,
struct pt_regs *regs)
{
regs->epc = get_ex_fixup(ex);
return true;
}
static inline unsigned long regs_get_gpr(struct pt_regs *regs, unsigned int offset)
{
if (unlikely(!offset || offset > MAX_REG_OFFSET))
return 0;
return *(unsigned long *)((unsigned long)regs + offset);
}
static inline void regs_set_gpr(struct pt_regs *regs, unsigned int offset,
unsigned long val)
{
if (unlikely(offset > MAX_REG_OFFSET))
return;
if (offset)
*(unsigned long *)((unsigned long)regs + offset) = val;
}
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->epc = get_ex_fixup(ex);
return true;
}
static bool
ex_handler_load_unaligned_zeropad(const struct exception_table_entry *ex,
struct pt_regs *regs)
{
int reg_data = FIELD_GET(EX_DATA_REG_DATA, ex->data);
int reg_addr = FIELD_GET(EX_DATA_REG_ADDR, ex->data);
unsigned long data, addr, offset;
addr = regs_get_gpr(regs, reg_addr * sizeof(unsigned long));
offset = addr & 0x7UL;
addr &= ~0x7UL;
data = *(unsigned long *)addr >> (offset * 8);
regs_set_gpr(regs, reg_data * sizeof(unsigned long), data);
regs->epc = get_ex_fixup(ex);
return true;
}
bool fixup_exception(struct pt_regs *regs)
{
const struct exception_table_entry *ex;
ex = search_exception_tables(regs->epc);
if (!ex)
return false;
switch (ex->type) {
case EX_TYPE_FIXUP:
return ex_handler_fixup(ex, regs);
case EX_TYPE_BPF:
return ex_handler_bpf(ex, regs);
case EX_TYPE_UACCESS_ERR_ZERO:
return ex_handler_uaccess_err_zero(ex, regs);
case EX_TYPE_LOAD_UNALIGNED_ZEROPAD:
return ex_handler_load_unaligned_zeropad(ex, regs);
}
BUG();
}
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