[PATCH] x86/math-emu, selftests: Add test for FISTTP insns

From: Denys Vlasenko
Date: Sun Sep 20 2015 - 10:03:18 EST


$ ./test_FISTTP_32
[RUN] Testing fisttp instructions
[OK] fisttp

Signed-off-by: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
CC: Ingo Molnar <mingo@xxxxxxxxxx>
CC: Borislav Petkov <bp@xxxxxxxxx>
CC: "H. Peter Anvin" <hpa@xxxxxxxxx>
CC: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
CC: Kees Cook <keescook@xxxxxxxxxxxx>
CC: x86@xxxxxxxxxx
CC: linux-kernel@xxxxxxxxxxxxxxx
---
tools/testing/selftests/x86/Makefile | 2 +-
tools/testing/selftests/x86/test_FISTTP.c | 137 ++++++++++++++++++++++++++++++
2 files changed, 138 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/selftests/x86/test_FISTTP.c

diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile
index 7de4684..f981b36 100644
--- a/tools/testing/selftests/x86/Makefile
+++ b/tools/testing/selftests/x86/Makefile
@@ -6,7 +6,7 @@ include ../lib.mk

TARGETS_C_BOTHBITS := single_step_syscall sysret_ss_attrs ldt_gdt syscall_nt
TARGETS_C_32BIT_ONLY := entry_from_vm86 syscall_arg_fault sigreturn test_syscall_vdso \
- test_FCMOV test_FCOMI
+ test_FCMOV test_FCOMI test_FISTTP

TARGETS_C_32BIT_ALL := $(TARGETS_C_BOTHBITS) $(TARGETS_C_32BIT_ONLY)
BINARIES_32 := $(TARGETS_C_32BIT_ALL:%=%_32)
diff --git a/tools/testing/selftests/x86/test_FISTTP.c b/tools/testing/selftests/x86/test_FISTTP.c
new file mode 100644
index 0000000..b8e61a0
--- /dev/null
+++ b/tools/testing/selftests/x86/test_FISTTP.c
@@ -0,0 +1,137 @@
+#undef _GNU_SOURCE
+#define _GNU_SOURCE 1
+#undef __USE_GNU
+#define __USE_GNU 1
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <signal.h>
+#include <sys/types.h>
+#include <sys/select.h>
+#include <sys/time.h>
+#include <sys/wait.h>
+#include <fenv.h>
+
+unsigned long long res64 = -1;
+unsigned int res32 = -1;
+unsigned short res16 = -1;
+
+int test(void)
+{
+ int ex;
+
+ feclearexcept(FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW);
+ asm volatile ("\n"
+ " fld1""\n"
+ " fisttp res16""\n"
+ " fld1""\n"
+ " fisttpl res32""\n"
+ " fld1""\n"
+ " fisttpll res64""\n"
+ : : : "memory"
+ );
+ if (res16 != 1 || res32 != 1 || res64 != 1) {
+ printf("[BAD]\tfisttp 1\n");
+ return 1;
+ }
+ ex = fetestexcept(FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW);
+ if (ex != 0) {
+ printf("[BAD]\tfisttp 1: wrong exception state\n");
+ return 1;
+ }
+
+ feclearexcept(FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW);
+ asm volatile ("\n"
+ " fldpi""\n"
+ " fisttp res16""\n"
+ " fldpi""\n"
+ " fisttpl res32""\n"
+ " fldpi""\n"
+ " fisttpll res64""\n"
+ : : : "memory"
+ );
+ if (res16 != 3 || res32 != 3 || res64 != 3) {
+ printf("[BAD]\tfisttp pi\n");
+ return 1;
+ }
+ ex = fetestexcept(FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW);
+ if (ex != FE_INEXACT) {
+ printf("[BAD]\tfisttp pi: wrong exception state\n");
+ return 1;
+ }
+
+ feclearexcept(FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW);
+ asm volatile ("\n"
+ " fldpi""\n"
+ " fchs""\n"
+ " fisttp res16""\n"
+ " fldpi""\n"
+ " fchs""\n"
+ " fisttpl res32""\n"
+ " fldpi""\n"
+ " fchs""\n"
+ " fisttpll res64""\n"
+ : : : "memory"
+ );
+ if (res16 != 0xfffd || res32 != 0xfffffffd || res64 != 0xfffffffffffffffdULL) {
+ printf("[BAD]\tfisttp -pi\n");
+ return 1;
+ }
+ ex = fetestexcept(FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW);
+ if (ex != FE_INEXACT) {
+ printf("[BAD]\tfisttp -pi: wrong exception state\n");
+ return 1;
+ }
+
+ feclearexcept(FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW);
+ asm volatile ("\n"
+ " fldln2""\n"
+ " fisttp res16""\n"
+ " fldln2""\n"
+ " fisttpl res32""\n"
+ " fldln2""\n"
+ " fisttpll res64""\n"
+ : : : "memory"
+ );
+ /* Test truncation to zero (round-to-nearest would give 1 here) */
+ if (res16 != 0 || res32 != 0 || res64 != 0) {
+ printf("[BAD]\tfisttp ln2\n");
+ return 1;
+ }
+ ex = fetestexcept(FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW);
+ if (ex != FE_INEXACT) {
+ printf("[BAD]\tfisttp ln2: wrong exception state\n");
+ return 1;
+ }
+
+ return 0;
+}
+
+void sighandler(int sig)
+{
+ printf("[FAIL]\tGot signal %d, exiting\n", sig);
+ exit(1);
+}
+
+int main(int argc, char **argv, char **envp)
+{
+ int err = 0;
+
+ /* SIGILL triggers on 32-bit kernels w/o fisttp emulation
+ * when run with "no387 nofxsr". Other signals are caught
+ * just in case.
+ */
+ signal(SIGILL, sighandler);
+ signal(SIGFPE, sighandler);
+ signal(SIGSEGV, sighandler);
+
+ printf("[RUN]\tTesting fisttp instructions\n");
+ err |= test();
+ if (!err)
+ printf("[OK]\tfisttp\n");
+ else
+ printf("[FAIL]\tfisttp errors: %d\n", err);
+
+ return err;
+}
--
1.8.1.4

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