Commit c9129cf0 authored by Sohil Mehta's avatar Sohil Mehta Committed by Dave Hansen
Browse files

selftests/x86: Update the negative vsyscall tests to expect a #GP 



Some of the vsyscall selftests expect a #PF when vsyscalls are disabled.
However, with LASS enabled, an invalid access results in a SIGSEGV due
to a #GP instead of a #PF. One such negative test fails because it is
expecting X86_PF_INSTR to be set.

Update the failing test to expect either a #GP or a #PF. Also, update
the printed messages to show the trap number (denoting the type of
fault) instead of assuming a #PF.

Signed-off-by: default avatarSohil Mehta <sohil.mehta@intel.com>
Signed-off-by: default avatarDave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: default avatarDave Hansen <dave.hansen@linux.intel.com>
Link: https://patch.msgid.link/20251118182911.2983253-8-sohil.mehta%40intel.com
parent 42fea0a3

tools/testing/selftests/x86/test_vsyscall.c

+12 −9
Original line number Diff line number Diff line
@@ -308,12 +308,13 @@ static void test_getcpu(int cpu) 
#ifdef __x86_64__



static jmp_buf jmpbuf;

static volatile unsigned long segv_err;

static volatile unsigned long segv_err, segv_trapno;



static void sigsegv(int sig, siginfo_t *info, void *ctx_void)

{

	ucontext_t *ctx = (ucontext_t *)ctx_void;



	segv_trapno = ctx->uc_mcontext.gregs[REG_TRAPNO];

	segv_err =  ctx->uc_mcontext.gregs[REG_ERR];

	siglongjmp(jmpbuf, 1);

}
@@ -336,7 +337,8 @@ static void test_vsys_r(void) 
	else if (can_read)

		ksft_test_result_pass("We have read access\n");

	else

		ksft_test_result_pass("We do not have read access: #PF(0x%lx)\n", segv_err);

		ksft_test_result_pass("We do not have read access (trap=%ld, error=0x%lx)\n",

				      segv_trapno, segv_err);

}



static void test_vsys_x(void)
@@ -347,7 +349,7 @@ static void test_vsys_x(void) 
		return;

	}



	ksft_print_msg("Make sure that vsyscalls really page fault\n");

	ksft_print_msg("Make sure that vsyscalls really cause a fault\n");



	bool can_exec;

	if (sigsetjmp(jmpbuf, 1) == 0) {
@@ -358,13 +360,14 @@ static void test_vsys_x(void) 
	}



	if (can_exec)

		ksft_test_result_fail("Executing the vsyscall did not page fault\n");

	else if (segv_err & (1 << 4)) /* INSTR */

		ksft_test_result_pass("Executing the vsyscall page failed: #PF(0x%lx)\n",

				      segv_err);

		ksft_test_result_fail("Executing the vsyscall did not fault\n");

	/* #GP or #PF (with X86_PF_INSTR) */

	else if ((segv_trapno == 13) || ((segv_trapno == 14) && (segv_err & (1 << 4))))

		ksft_test_result_pass("Executing the vsyscall page failed (trap=%ld, error=0x%lx)\n",

				      segv_trapno, segv_err);

	else

		ksft_test_result_fail("Execution failed with the wrong error: #PF(0x%lx)\n",

				      segv_err);

		ksft_test_result_fail("Execution failed with the wrong error (trap=%ld, error=0x%lx)\n",

				      segv_trapno, segv_err);

}



/*