Commit-ID: a87730cc3acc475eff12ddde3f7d5687371b5c76 Gitweb: https://git.kernel.org/tip/a87730cc3acc475eff12ddde3f7d5687371b5c76 Author: Chang S. Bae <chang.seok....@intel.com> AuthorDate: Wed, 8 May 2019 03:02:30 -0700 Committer: Thomas Gleixner <t...@linutronix.de> CommitDate: Sat, 22 Jun 2019 11:38:56 +0200
selftests/x86/fsgsbase: Test ptracer-induced GSBASE write with FSGSBASE This validates that GS and GSBASE are independently preserved in ptracer commands. Suggested-by: Andy Lutomirski <l...@kernel.org> Signed-off-by: Chang S. Bae <chang.seok....@intel.com> Signed-off-by: Thomas Gleixner <t...@linutronix.de> Cc: Andi Kleen <a...@linux.intel.com> Cc: Ravi Shankar <ravi.v.shan...@intel.com> Cc: H. Peter Anvin <h...@zytor.com> Link: https://lkml.kernel.org/r/1557309753-24073-16-git-send-email-chang.seok....@intel.com --- tools/testing/selftests/x86/fsgsbase.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/x86/fsgsbase.c b/tools/testing/selftests/x86/fsgsbase.c index afd029897c79..21fd4f94b5b0 100644 --- a/tools/testing/selftests/x86/fsgsbase.c +++ b/tools/testing/selftests/x86/fsgsbase.c @@ -470,7 +470,7 @@ static void test_ptrace_write_gsbase(void) wait(&status); if (WSTOPSIG(status) == SIGTRAP) { - unsigned long gs; + unsigned long gs, base; unsigned long gs_offset = USER_REGS_OFFSET(gs); unsigned long base_offset = USER_REGS_OFFSET(gs_base); @@ -486,6 +486,7 @@ static void test_ptrace_write_gsbase(void) err(1, "PTRACE_POKEUSER"); gs = ptrace(PTRACE_PEEKUSER, child, gs_offset, NULL); + base = ptrace(PTRACE_PEEKUSER, child, base_offset, NULL); /* * In a non-FSGSBASE system, the nonzero selector will load @@ -496,8 +497,14 @@ static void test_ptrace_write_gsbase(void) if (gs != 0x7) { nerrs++; printf("[FAIL]\tGS changed to %lx\n", gs); + } else if (have_fsgsbase && (base != 0xFF)) { + nerrs++; + printf("[FAIL]\tGSBASE changed to %lx\n", base); } else { - printf("[OK]\tGS remained 0x7\n"); + printf("[OK]\tGS remained 0x7 %s"); + if (have_fsgsbase) + printf("and GSBASE changed to 0xFF"); + printf("\n"); } }
