1 // SPDX-License-Identifier: GPL-2.0
3 * Based on arch/arm/mm/extable.c
6 #include <linux/bitfield.h>
7 #include <linux/extable.h>
8 #include <linux/uaccess.h>
10 #include <asm/asm-extable.h>
11 #include <asm/ptrace.h>
13 static inline unsigned long
14 get_ex_fixup(const struct exception_table_entry *ex)
16 return ((unsigned long)&ex->fixup + ex->fixup);
19 static bool ex_handler_uaccess_err_zero(const struct exception_table_entry *ex,
22 int reg_err = FIELD_GET(EX_DATA_REG_ERR, ex->data);
23 int reg_zero = FIELD_GET(EX_DATA_REG_ZERO, ex->data);
25 pt_regs_write_reg(regs, reg_err, -EFAULT);
26 pt_regs_write_reg(regs, reg_zero, 0);
28 regs->pc = get_ex_fixup(ex);
33 ex_handler_load_unaligned_zeropad(const struct exception_table_entry *ex,
36 int reg_data = FIELD_GET(EX_DATA_REG_DATA, ex->data);
37 int reg_addr = FIELD_GET(EX_DATA_REG_ADDR, ex->data);
38 unsigned long data, addr, offset;
40 addr = pt_regs_read_reg(regs, reg_addr);
42 offset = addr & 0x7UL;
45 data = *(unsigned long*)addr;
53 pt_regs_write_reg(regs, reg_data, data);
55 regs->pc = get_ex_fixup(ex);
59 bool fixup_exception(struct pt_regs *regs)
61 const struct exception_table_entry *ex;
63 ex = search_exception_tables(instruction_pointer(regs));
69 return ex_handler_bpf(ex, regs);
70 case EX_TYPE_UACCESS_ERR_ZERO:
71 case EX_TYPE_KACCESS_ERR_ZERO:
72 return ex_handler_uaccess_err_zero(ex, regs);
73 case EX_TYPE_LOAD_UNALIGNED_ZEROPAD:
74 return ex_handler_load_unaligned_zeropad(ex, regs);