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authorChang S. Bae <chang.seok.bae@intel.com>2019-05-08 03:02:30 -0700
committerThomas Gleixner <tglx@linutronix.de>2019-06-22 11:38:56 +0200
commita87730cc3acc475eff12ddde3f7d5687371b5c76 (patch)
treed2f1499223715f4b96267c9899dd8d598b25cb9b /tools/testing/selftests/x86
parent9ad75a0922e1533b08f3d1451bd908d19e5db41e (diff)
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 <luto@kernel.org> Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andi Kleen <ak@linux.intel.com> Cc: Ravi Shankar <ravi.v.shankar@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Link: https://lkml.kernel.org/r/1557309753-24073-16-git-send-email-chang.seok.bae@intel.com
Diffstat (limited to 'tools/testing/selftests/x86')
-rw-r--r--tools/testing/selftests/x86/fsgsbase.c11
1 files 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");
}
}