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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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e25eea89bb
Normally objtool ensures a function keeps the stack layout invariant. But there is a useful exception, it is possible to stuff the return stack in order to 'inject' a 'call': push $fun ret In this case the invariant mentioned above is violated. Add an objtool HINT to annotate this and allow a function exit with a modified stack frame. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lkml.kernel.org/r/20200416115118.690601403@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
75 lines
1.7 KiB
C
75 lines
1.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
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*/
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#ifndef _CHECK_H
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#define _CHECK_H
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#include <stdbool.h>
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#include "elf.h"
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#include "cfi.h"
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#include "arch.h"
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#include "orc.h"
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#include <linux/hashtable.h>
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struct insn_state {
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struct cfi_reg cfa;
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struct cfi_reg regs[CFI_NUM_REGS];
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int stack_size;
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unsigned char type;
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bool bp_scratch;
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bool drap, end, uaccess, df;
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unsigned int uaccess_stack;
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int drap_reg, drap_offset;
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struct cfi_reg vals[CFI_NUM_REGS];
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};
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struct instruction {
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struct list_head list;
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struct hlist_node hash;
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struct section *sec;
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unsigned long offset;
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unsigned int len;
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enum insn_type type;
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unsigned long immediate;
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bool alt_group, dead_end, ignore, ignore_alts;
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bool hint, save, restore;
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bool retpoline_safe;
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u8 visited;
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u8 ret_offset;
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struct symbol *call_dest;
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struct instruction *jump_dest;
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struct instruction *first_jump_src;
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struct rela *jump_table;
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struct list_head alts;
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struct symbol *func;
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struct list_head stack_ops;
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struct insn_state state;
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struct orc_entry orc;
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};
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struct objtool_file {
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struct elf *elf;
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struct list_head insn_list;
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DECLARE_HASHTABLE(insn_hash, 20);
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bool ignore_unreachables, c_file, hints, rodata;
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};
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int check(const char *objname, bool orc);
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struct instruction *find_insn(struct objtool_file *file,
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struct section *sec, unsigned long offset);
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#define for_each_insn(file, insn) \
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list_for_each_entry(insn, &file->insn_list, list)
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#define sec_for_each_insn(file, sec, insn) \
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for (insn = find_insn(file, sec, 0); \
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insn && &insn->list != &file->insn_list && \
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insn->sec == sec; \
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insn = list_next_entry(insn, list))
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#endif /* _CHECK_H */
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