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authorAndy Lutomirski <luto@kernel.org>2019-07-15 07:21:44 -0700
committerThomas Gleixner <tglx@linutronix.de>2019-07-15 17:12:31 +0200
commitc7ca0b614513afba57824cae68447f9c32b1ee61 (patch)
tree59f54e34f9a3b9aee5abad16813894adf20a19b5 /tools/testing/selftests/x86
parentMerge tag 'for-linus-hmm' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma (diff)
downloadwireguard-linux-c7ca0b614513afba57824cae68447f9c32b1ee61.tar.xz
wireguard-linux-c7ca0b614513afba57824cae68447f9c32b1ee61.zip
Revert "x86/ptrace: Prevent ptrace from clearing the FS/GS selector" and fix the test
This reverts commit 48f5e52e916b55fb73754833efbacc7f8081a159. The ptrace ABI change was a prerequisite to the proposed design for FSGSBASE. Since FSGSBASE support has been reverted, and since I'm not convinced that the ABI was ever adequately tested, revert the ABI change as well. This also modifies the test case so that it tests the preexisting behavior. Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/fca39c478ea7fb15bc76fe8a36bd180810a067f6.1563200250.git.luto@kernel.org
Diffstat (limited to 'tools/testing/selftests/x86')
-rw-r--r--tools/testing/selftests/x86/fsgsbase.c22
1 files changed, 4 insertions, 18 deletions
diff --git a/tools/testing/selftests/x86/fsgsbase.c b/tools/testing/selftests/x86/fsgsbase.c
index 5ab4c60c100e..15a329da59fa 100644
--- a/tools/testing/selftests/x86/fsgsbase.c
+++ b/tools/testing/selftests/x86/fsgsbase.c
@@ -489,25 +489,11 @@ static void test_ptrace_write_gsbase(void)
* selector value is changed or not by the GSBASE write in
* a ptracer.
*/
- if (gs != *shared_scratch) {
- nerrs++;
- printf("[FAIL]\tGS changed to %lx\n", gs);
-
- /*
- * On older kernels, poking a nonzero value into the
- * base would zero the selector. On newer kernels,
- * this behavior has changed -- poking the base
- * changes only the base and, if FSGSBASE is not
- * available, this may have no effect.
- */
- if (gs == 0)
- printf("\tNote: this is expected behavior on older kernels.\n");
- } else if (have_fsgsbase && (base != 0xFF)) {
- nerrs++;
- printf("[FAIL]\tGSBASE changed to %lx\n", base);
+ if (gs == 0 && base == 0xFF) {
+ printf("[OK]\tGS was reset as expected\n");
} else {
- printf("[OK]\tGS remained 0x%hx%s", *shared_scratch, have_fsgsbase ? " and GSBASE changed to 0xFF" : "");
- printf("\n");
+ nerrs++;
+ printf("[FAIL]\tGS=0x%lx, GSBASE=0x%lx (should be 0, 0xFF)\n", gs, base);
}
}