linux/tools/objtool/check.h
Peter Zijlstra 882a0db9d1 objtool: Improve UACCESS coverage
A clang build reported an (obvious) double CLAC while a GCC build did not;
it turns out that objtool only re-visits instructions if the first visit
was with AC=0. If OTOH the first visit was with AC=1, it completely ignores
any subsequent visit, even when it has AC=0.

Fix this by using a visited mask instead of a boolean, and (explicitly)
mark the AC state.

$ ./objtool check -b --no-fp --retpoline --uaccess drivers/gpu/drm/i915/gem/i915_gem_execbuffer.o
drivers/gpu/drm/i915/gem/i915_gem_execbuffer.o: warning: objtool: .altinstr_replacement+0x22: redundant UACCESS disable
drivers/gpu/drm/i915/gem/i915_gem_execbuffer.o: warning: objtool:   eb_copy_relocations.isra.34()+0xea: (alt)
drivers/gpu/drm/i915/gem/i915_gem_execbuffer.o: warning: objtool:   .altinstr_replacement+0xffffffffffffffff: (branch)
drivers/gpu/drm/i915/gem/i915_gem_execbuffer.o: warning: objtool:   eb_copy_relocations.isra.34()+0xd9: (alt)
drivers/gpu/drm/i915/gem/i915_gem_execbuffer.o: warning: objtool:   eb_copy_relocations.isra.34()+0xb2: (branch)
drivers/gpu/drm/i915/gem/i915_gem_execbuffer.o: warning: objtool:   eb_copy_relocations.isra.34()+0x39: (branch)
drivers/gpu/drm/i915/gem/i915_gem_execbuffer.o: warning: objtool:   eb_copy_relocations.isra.34()+0x0: <=== (func)

Reported-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Link: https://github.com/ClangBuiltLinux/linux/issues/617
Link: https://lkml.kernel.org/r/5359166aad2d53f3145cd442d83d0e5115e0cd17.1564007838.git.jpoimboe@redhat.com
2019-07-25 08:36:39 +02:00

73 lines
1.7 KiB
C

/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
*/
#ifndef _CHECK_H
#define _CHECK_H
#include <stdbool.h>
#include "elf.h"
#include "cfi.h"
#include "arch.h"
#include "orc.h"
#include <linux/hashtable.h>
struct insn_state {
struct cfi_reg cfa;
struct cfi_reg regs[CFI_NUM_REGS];
int stack_size;
unsigned char type;
bool bp_scratch;
bool drap, end, uaccess, df;
unsigned int uaccess_stack;
int drap_reg, drap_offset;
struct cfi_reg vals[CFI_NUM_REGS];
};
struct instruction {
struct list_head list;
struct hlist_node hash;
struct section *sec;
unsigned long offset;
unsigned int len;
enum insn_type type;
unsigned long immediate;
bool alt_group, dead_end, ignore, hint, save, restore, ignore_alts;
bool retpoline_safe;
u8 visited;
struct symbol *call_dest;
struct instruction *jump_dest;
struct instruction *first_jump_src;
struct rela *jump_table;
struct list_head alts;
struct symbol *func;
struct stack_op stack_op;
struct insn_state state;
struct orc_entry orc;
};
struct objtool_file {
struct elf *elf;
struct list_head insn_list;
DECLARE_HASHTABLE(insn_hash, 16);
bool ignore_unreachables, c_file, hints, rodata;
};
int check(const char *objname, bool orc);
struct instruction *find_insn(struct objtool_file *file,
struct section *sec, unsigned long offset);
#define for_each_insn(file, insn) \
list_for_each_entry(insn, &file->insn_list, list)
#define sec_for_each_insn(file, sec, insn) \
for (insn = find_insn(file, sec, 0); \
insn && &insn->list != &file->insn_list && \
insn->sec == sec; \
insn = list_next_entry(insn, list))
#endif /* _CHECK_H */