cbf82a3dc2
Teach objtool about the the low bits in the struct static_key pointer.
That is, the low two bits of @key in:
struct jump_entry {
s32 code;
s32 target;
long key;
}
as found in the __jump_table section. Since @key has a relocation to
the variable (to be resolved by the linker), the low two bits will be
reflected in the relocation's addend.
As such, find the reloc and store the addend, such that we can access
these bits.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210506194158.028024143@infradead.org
43 lines
959 B
C
43 lines
959 B
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* Copyright (C) 2015 Josh Poimboeuf <jpoimboe@redhat.com>
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*/
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#ifndef _SPECIAL_H
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#define _SPECIAL_H
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#include <stdbool.h>
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#include <objtool/check.h>
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#include <objtool/elf.h>
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#define C_JUMP_TABLE_SECTION ".rodata..c_jump_table"
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struct special_alt {
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struct list_head list;
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bool group;
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bool skip_orig;
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bool skip_alt;
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bool jump_or_nop;
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struct section *orig_sec;
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unsigned long orig_off;
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struct section *new_sec;
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unsigned long new_off;
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unsigned int orig_len, new_len; /* group only */
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u8 key_addend;
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};
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int special_get_alts(struct elf *elf, struct list_head *alts);
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void arch_handle_alternative(unsigned short feature, struct special_alt *alt);
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bool arch_support_alt_relocation(struct special_alt *special_alt,
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struct instruction *insn,
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struct reloc *reloc);
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struct reloc *arch_find_switch_table(struct objtool_file *file,
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struct instruction *insn);
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#endif /* _SPECIAL_H */
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