@@ -1,3 +1,4 @@
+objtool-y += arch_special.o
objtool-y += decode.o
objtool-y += orc_dump.o
objtool-y += orc_gen.o
new file mode 100644
@@ -0,0 +1,22 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+#include "../../special.h"
+#include "arch_special.h"
+
+void arch_force_alt_path(unsigned short feature,
+ bool uaccess,
+ struct special_alt *alt)
+{
+}
@@ -30,7 +30,13 @@
#define ALT_ORIG_LEN_OFFSET 10
#define ALT_NEW_LEN_OFFSET 11
-#define X86_FEATURE_POPCNT (4 * 32 + 23)
-#define X86_FEATURE_SMAP (9 * 32 + 20)
+static inline bool arch_should_ignore_feature(unsigned short feature)
+{
+ return false;
+}
+static inline bool arch_support_switch_table(void)
+{
+ return false;
+}
#endif /* _ARM64_ARCH_SPECIAL_H */
@@ -1,3 +1,4 @@
+objtool-y += arch_special.o
objtool-y += decode.o
objtool-y += orc_dump.o
objtool-y += orc_gen.o
new file mode 100644
@@ -0,0 +1,28 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+#include "../../special.h"
+#include "arch_special.h"
+
+void arch_force_alt_path(unsigned short feature,
+ bool uaccess,
+ struct special_alt *alt)
+{
+ if (feature == X86_FEATURE_SMAP) {
+ if (uaccess)
+ alt->skip_orig = true;
+ else
+ alt->skip_alt = true;
+ }
+}
@@ -33,4 +33,13 @@
#define X86_FEATURE_POPCNT (4 * 32 + 23)
#define X86_FEATURE_SMAP (9 * 32 + 20)
+static inline bool arch_should_ignore_feature(unsigned short feature)
+{
+ return feature == X86_FEATURE_POPCNT;
+}
+
+static inline bool arch_support_switch_table(void)
+{
+ return true;
+}
#endif /* _X86_ARCH_SPECIAL_H */
@@ -729,7 +729,7 @@ static int handle_group_alt(struct objtool_file *file,
last_orig_insn = insn;
}
- if (next_insn_same_sec(file, last_orig_insn)) {
+ if (last_orig_insn && next_insn_same_sec(file, last_orig_insn)) {
fake_jump = malloc(sizeof(*fake_jump));
if (!fake_jump) {
WARN("malloc failed");
@@ -1045,6 +1045,17 @@ static struct rela *find_switch_table(struct objtool_file *file,
if (find_symbol_containing(rodata_sec, table_offset))
continue;
+ /*
+ * If we are on arm64 architecture, we now that we
+ * are in presence of a switch table thanks to
+ * the `br <Xn>` insn. but we can't retrieve it yet.
+ * So we just ignore unreachable for this file.
+ */
+ if (!arch_support_switch_table()) {
+ file->ignore_unreachables = true;
+ return NULL;
+ }
+
rodata_rela = find_rela_by_dest(rodata_sec, table_offset);
if (rodata_rela) {
/*
@@ -1844,7 +1855,7 @@ static int validate_branch(struct objtool_file *file, struct instruction *first,
insn = first;
sec = insn->sec;
- if (insn->alt_group && list_empty(&insn->alts)) {
+ if (!insn->visited && insn->alt_group && list_empty(&insn->alts)) {
WARN_FUNC("don't know how to handle branch to middle of alternative instruction group",
sec, insn->offset);
return 1;
@@ -81,7 +81,7 @@ static int get_alt_entry(struct elf *elf, struct special_entry *entry,
* feature path which is a "very very small percentage of
* machines".
*/
- if (feature == X86_FEATURE_POPCNT)
+ if (arch_should_ignore_feature(feature))
alt->skip_orig = true;
/*
@@ -93,12 +93,7 @@ static int get_alt_entry(struct elf *elf, struct special_entry *entry,
* find paths that see the STAC but take the NOP instead of
* CLAC and the other way around.
*/
- if (feature == X86_FEATURE_SMAP) {
- if (uaccess)
- alt->skip_orig = true;
- else
- alt->skip_alt = true;
- }
+ arch_force_alt_path(feature, uaccess, alt);
}
orig_rela = find_rela_by_dest(sec, offset + entry->orig);
@@ -27,5 +27,8 @@ struct special_alt {
};
int special_get_alts(struct elf *elf, struct list_head *alts);
+void arch_force_alt_path(unsigned short feature,
+ bool uaccess,
+ struct special_alt *alt);
#endif /* _SPECIAL_H */
This patch abstracts the few architecture dependent tests that are perform when handling special section and switch tables. It enables any architecture to ignore a particular CPU feature or not to handle switch tables. Signed-off-by: Raphael Gault <raphael.gault@arm.com> --- tools/objtool/arch/arm64/Build | 1 + tools/objtool/arch/arm64/arch_special.c | 22 +++++++++++++++ .../objtool/arch/arm64/include/arch_special.h | 10 +++++-- tools/objtool/arch/x86/Build | 1 + tools/objtool/arch/x86/arch_special.c | 28 +++++++++++++++++++ tools/objtool/arch/x86/include/arch_special.h | 9 ++++++ tools/objtool/check.c | 15 ++++++++-- tools/objtool/special.c | 9 ++---- tools/objtool/special.h | 3 ++ 9 files changed, 87 insertions(+), 11 deletions(-) create mode 100644 tools/objtool/arch/arm64/arch_special.c create mode 100644 tools/objtool/arch/x86/arch_special.c