objtool: Implement noinstr validation

Validate that any call out of .noinstr.text is in between
instr_begin() and instr_end() annotations.

This annotation is useful to ensure correct behaviour wrt tracing
sensitive code like entry/exit and idle code. When we run code in a
sensitive context we want a guarantee no unknown code is ran.

Since this validation relies on knowing the section of call
destination symbols, we must run it on vmlinux.o instead of on
individual object files.

Add two options:

 -d/--duplicate "duplicate validation for vmlinux"
 -l/--vmlinux "vmlinux.o validation"

Where the latter auto-detects when objname ends with "vmlinux.o" and
the former will force all validations, also those already done on
!vmlinux object files.

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/20200416115119.106268040@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra
2020-03-10 18:57:41 +01:00
committed by Ingo Molnar
parent e7c0219b32
commit c4a33939a7
5 changed files with 112 additions and 4 deletions

View File

@@ -14,10 +14,11 @@
*/
#include <subcmd/parse-options.h>
#include <string.h>
#include "builtin.h"
#include "check.h"
bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats;
bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats, validate_dup, vmlinux;
static const char * const check_usage[] = {
"objtool check [<options>] file.o",
@@ -32,12 +33,14 @@ const struct option check_options[] = {
OPT_BOOLEAN('b', "backtrace", &backtrace, "unwind on error"),
OPT_BOOLEAN('a', "uaccess", &uaccess, "enable uaccess checking"),
OPT_BOOLEAN('s', "stats", &stats, "print statistics"),
OPT_BOOLEAN('d', "duplicate", &validate_dup, "duplicate validation for vmlinux.o"),
OPT_BOOLEAN('l', "vmlinux", &vmlinux, "vmlinux.o validation"),
OPT_END(),
};
int cmd_check(int argc, const char **argv)
{
const char *objname;
const char *objname, *s;
argc = parse_options(argc, argv, check_options, check_usage, 0);
@@ -46,5 +49,9 @@ int cmd_check(int argc, const char **argv)
objname = argv[0];
s = strstr(objname, "vmlinux.o");
if (s && !s[9])
vmlinux = true;
return check(objname, false);
}