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86 lines
1.8 KiB
86 lines
1.8 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Based on arch/arm/mm/extable.c |
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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/ptrace.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 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->pc = 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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pt_regs_write_reg(regs, reg_err, -EFAULT); |
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pt_regs_write_reg(regs, reg_zero, 0); |
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regs->pc = get_ex_fixup(ex); |
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return true; |
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} |
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static bool |
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ex_handler_load_unaligned_zeropad(const struct exception_table_entry *ex, |
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struct pt_regs *regs) |
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{ |
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int reg_data = FIELD_GET(EX_DATA_REG_DATA, ex->data); |
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int reg_addr = FIELD_GET(EX_DATA_REG_ADDR, ex->data); |
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unsigned long data, addr, offset; |
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addr = pt_regs_read_reg(regs, reg_addr); |
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offset = addr & 0x7UL; |
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addr &= ~0x7UL; |
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data = *(unsigned long*)addr; |
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#ifndef __AARCH64EB__ |
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data >>= 8 * offset; |
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#else |
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data <<= 8 * offset; |
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#endif |
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pt_regs_write_reg(regs, reg_data, data); |
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regs->pc = 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(instruction_pointer(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_BPF: |
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return ex_handler_bpf(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_LOAD_UNALIGNED_ZEROPAD: |
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return ex_handler_load_unaligned_zeropad(ex, regs); |
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} |
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BUG(); |
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}
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