Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
objtool: Improve tracing of alternative instructions
When tracing function validation, improve the reporting of
alternative instruction by more clearly showing the different
alternatives beginning and end.
Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://patch.msgid.link/20251121095340.464045-16-alexandre.chartre@oracle.com
authored by
Alexandre Chartre
and committed by
Peter Zijlstra
350c7ab8
9b580acc
+125
-13
+6
-12
tools/objtool/check.c
+6
-12
tools/objtool/check.c
···
3564
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/* ANNOTATE_IGNORE_ALTERNATIVE */
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if (insn->alt_group->ignore) {
3567
-
TRACE_INSN(insn, "alt group ignored");
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+
TRACE_ALT(insn, "alt group ignored");
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return true;
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}
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3570
···
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struct instruction *prev_insn, struct instruction *next_insn,
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bool *dead_end)
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{
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-
/* prev_state is not used if there is no disassembly support */
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+
/* prev_state and alt_name are not used if there is no disassembly support */
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struct insn_state prev_state __maybe_unused;
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+
char *alt_name __maybe_unused = NULL;
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struct alternative *alt;
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u8 visited;
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int ret;
···
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return 1;
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if (insn->alts) {
3772
-
int i, num_alts;
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-
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-
num_alts = 0;
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-
for (alt = insn->alts; alt; alt = alt->next)
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-
num_alts++;
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-
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i = 1;
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for (alt = insn->alts; alt; alt = alt->next) {
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-
TRACE_INSN(insn, "alternative %d/%d", i, num_alts);
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+
TRACE_ALT_BEGIN(insn, alt, alt_name);
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ret = validate_branch(file, func, alt->insn, *statep);
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+
TRACE_ALT_END(insn, alt, alt_name);
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if (ret) {
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BT_INSN(insn, "(alt)");
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return ret;
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}
3786
-
i++;
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}
3788
-
TRACE_INSN(insn, "alternative DEFAULT");
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+
TRACE_ALT_INFO_NOADDR(insn, "/ ", "DEFAULT");
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}
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if (skip_alt_group(insn))
+64
-1
tools/objtool/include/objtool/trace.h
+64
-1
tools/objtool/include/objtool/trace.h
···
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fprintf(stderr, fmt, ##__VA_ARGS__); \
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})
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+
/*
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* Print the instruction address and a message. The instruction
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* itself is not printed.
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*/
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+
#define TRACE_ADDR(insn, fmt, ...) \
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+
({ \
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+
if (trace) { \
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+
disas_print_info(stderr, insn, trace_depth - 1, \
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fmt "\n", ##__VA_ARGS__); \
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} \
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})
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+
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+
/*
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* Print the instruction address, the instruction and a message.
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+
*/
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#define TRACE_INSN(insn, fmt, ...) \
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({ \
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if (trace) { \
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disas_print_insn(stderr, objtool_disas_ctx, \
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-
insn, trace_depth - 1, \
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+
insn, trace_depth - 1, \
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fmt, ##__VA_ARGS__); \
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fprintf(stderr, "\n"); \
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insn->trace = 1; \
···
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({ \
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if (trace) \
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trace_insn_state(insn, sprev, snext); \
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+
})
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+
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#define TRACE_ALT_FMT(pfx, fmt) pfx "<%s.%lx> " fmt
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+
#define TRACE_ALT_ARG(insn) disas_alt_type_name(insn), (insn)->offset
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+
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+
#define TRACE_ALT(insn, fmt, ...) \
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TRACE_INSN(insn, TRACE_ALT_FMT("", fmt), \
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TRACE_ALT_ARG(insn), ##__VA_ARGS__)
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+
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+
#define TRACE_ALT_INFO(insn, pfx, fmt, ...) \
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TRACE_ADDR(insn, TRACE_ALT_FMT(pfx, fmt), \
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TRACE_ALT_ARG(insn), ##__VA_ARGS__)
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+
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#define TRACE_ALT_INFO_NOADDR(insn, pfx, fmt, ...) \
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TRACE_ADDR(NULL, TRACE_ALT_FMT(pfx, fmt), \
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TRACE_ALT_ARG(insn), ##__VA_ARGS__)
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+
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+
#define TRACE_ALT_BEGIN(insn, alt, alt_name) \
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({ \
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+
if (trace) { \
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+
alt_name = disas_alt_name(alt); \
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+
trace_alt_begin(insn, alt, alt_name); \
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+
} \
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+
})
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+
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+
#define TRACE_ALT_END(insn, alt, alt_name) \
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({ \
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+
if (trace) { \
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trace_alt_end(insn, alt, alt_name); \
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+
free(alt_name); \
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+
} \
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})
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static inline void trace_enable(void)
···
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61
108
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void trace_insn_state(struct instruction *insn, struct insn_state *sprev,
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struct insn_state *snext);
64
+
void trace_alt_begin(struct instruction *orig_insn, struct alternative *alt,
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char *alt_name);
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void trace_alt_end(struct instruction *orig_insn, struct alternative *alt,
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char *alt_name);
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#else /* DISAS */
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#define TRACE(fmt, ...) ({})
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#define TRACE_ADDR(insn, fmt, ...) ({})
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#define TRACE_INSN(insn, fmt, ...) ({})
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#define TRACE_INSN_STATE(insn, sprev, snext) ({})
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+
#define TRACE_ALT(insn, fmt, ...) ({})
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+
#define TRACE_ALT_INFO(insn, fmt, ...) ({})
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#define TRACE_ALT_INFO_NOADDR(insn, fmt, ...) ({})
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+
#define TRACE_ALT_BEGIN(insn, alt, alt_name) ({})
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+
#define TRACE_ALT_END(insn, alt, alt_name) ({})
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+
116
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static inline void trace_enable(void) {}
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static inline void trace_disable(void) {}
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static inline void trace_depth_inc(void) {}
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static inline void trace_depth_dec(void) {}
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+
static inline void trace_alt_begin(struct instruction *orig_insn,
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struct alternative *alt,
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char *alt_name) {};
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static inline void trace_alt_end(struct instruction *orig_insn,
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struct alternative *alt,
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char *alt_name) {};
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#endif
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+55
tools/objtool/trace.c
+55
tools/objtool/trace.c
···
146
146
147
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insn->trace = 1;
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}
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+
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+
void trace_alt_begin(struct instruction *orig_insn, struct alternative *alt,
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+
char *alt_name)
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{
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+
struct instruction *alt_insn;
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char suffix[2];
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+
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alt_insn = alt->insn;
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+
158
+
if (alt->type == ALT_TYPE_EX_TABLE) {
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+
/*
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* When there is an exception table then the instruction
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* at the original location is executed but it can cause
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+
* an exception. In that case, the execution will be
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+
* redirected to the alternative instruction.
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*
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* The instruction at the original location can have
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* instruction alternatives, so we just print the location
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* of the instruction that can cause the exception and
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* not the instruction itself.
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+
*/
170
+
TRACE_ALT_INFO_NOADDR(orig_insn, "/ ", "%s for instruction at 0x%lx <%s+0x%lx>",
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alt_name,
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+
orig_insn->offset, orig_insn->sym->name,
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+
orig_insn->offset - orig_insn->sym->offset);
174
+
} else {
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+
TRACE_ALT_INFO_NOADDR(orig_insn, "/ ", "%s", alt_name);
176
+
}
177
+
178
+
if (alt->type == ALT_TYPE_JUMP_TABLE) {
179
+
/*
180
+
* For a jump alternative, if the default instruction is
181
+
* a NOP then it is replaced with the jmp instruction,
182
+
* otherwise it is replaced with a NOP instruction.
183
+
*/
184
+
trace_depth++;
185
+
if (orig_insn->type == INSN_NOP) {
186
+
suffix[0] = (orig_insn->len == 5) ? 'q' : '\0';
187
+
TRACE_ADDR(orig_insn, "jmp%-3s %lx <%s+0x%lx>", suffix,
188
+
alt_insn->offset, alt_insn->sym->name,
189
+
alt_insn->offset - alt_insn->sym->offset);
190
+
} else {
191
+
TRACE_ADDR(orig_insn, "nop%d", orig_insn->len);
192
+
trace_depth--;
193
+
}
194
+
}
195
+
}
196
+
197
+
void trace_alt_end(struct instruction *orig_insn, struct alternative *alt,
198
+
char *alt_name)
199
+
{
200
+
if (alt->type == ALT_TYPE_JUMP_TABLE && orig_insn->type == INSN_NOP)
201
+
trace_depth--;
202
+
TRACE_ALT_INFO_NOADDR(orig_insn, "\\ ", "%s", alt_name);
203
+
}