test/tcg/ppc64le: test mtfsf

Added tests for the mtfsf to check if FI bit of FPSCR is being set
and if exception calls are being made correctly.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Lucas Mateus Castro (alqotel) <lucas.araujo@eldorado.org.br>
Message-Id: <20211201163808.440385-3-lucas.araujo@eldorado.org.br>
Signed-off-by: Cédric Le Goater <clg@kaod.org>

3 files changed, 63 insertions, 0 deletions

diff --git a/tests/tcg/ppc64/Makefile.target b/tests/tcg/ppc64/Makefile.target
index 6ab7934..8f4c7ac 100644
--- a/tests/tcg/ppc64/Makefile.target
+++ b/tests/tcg/ppc64/Makefile.target
@@ -11,6 +11,7 @@ endif
 bcdsub: CFLAGS += -mpower8-vector
 
 PPC64_TESTS += byte_reverse
+PPC64_TESTS += mtfsf
 ifneq ($(DOCKER_IMAGE)$(CROSS_CC_HAS_POWER10),)
 run-byte_reverse: QEMU_OPTS+=-cpu POWER10
 run-plugin-byte_reverse-with-%: QEMU_OPTS+=-cpu POWER10
diff --git a/tests/tcg/ppc64le/Makefile.target b/tests/tcg/ppc64le/Makefile.target
index ba2fde5..e031f65 100644
--- a/tests/tcg/ppc64le/Makefile.target
+++ b/tests/tcg/ppc64le/Makefile.target
@@ -16,6 +16,7 @@ byte_reverse: CFLAGS += -mcpu=power10
 run-byte_reverse: QEMU_OPTS+=-cpu POWER10
 run-plugin-byte_reverse-with-%: QEMU_OPTS+=-cpu POWER10
 
+PPC64LE_TESTS += mtfsf
 PPC64LE_TESTS += signal_save_restore_xer
 
 TESTS += $(PPC64LE_TESTS)
diff --git a/tests/tcg/ppc64le/mtfsf.c b/tests/tcg/ppc64le/mtfsf.c
new file mode 100644
index 0000000..b3d31f3
--- /dev/null
+++ b/tests/tcg/ppc64le/mtfsf.c
@@ -0,0 +1,61 @@
+#include <stdlib.h>
+#include <assert.h>
+#include <signal.h>
+#include <sys/prctl.h>
+
+#define FPSCR_VE     7  /* Floating-point invalid operation exception enable */
+#define FPSCR_VXSOFT 10 /* Floating-point invalid operation exception (soft) */
+#define FPSCR_FI     17 /* Floating-point fraction inexact                   */
+
+#define FP_VE           (1ull << FPSCR_VE)
+#define FP_VXSOFT       (1ull << FPSCR_VXSOFT)
+#define FP_FI           (1ull << FPSCR_FI)
+
+void sigfpe_handler(int sig, siginfo_t *si, void *ucontext)
+{
+    if (si->si_code == FPE_FLTINV) {
+        exit(0);
+    }
+    exit(1);
+}
+
+int main(void)
+{
+    union {
+        double d;
+        long long ll;
+    } fpscr;
+
+    struct sigaction sa = {
+        .sa_sigaction = sigfpe_handler,
+        .sa_flags = SA_SIGINFO
+    };
+
+    /*
+     * Enable the MSR bits F0 and F1 to enable exceptions.
+     * This shouldn't be needed in linux-user as these bits are enabled by
+     * default, but this allows to execute either in a VM or a real machine
+     * to compare the behaviors.
+     */
+    prctl(PR_SET_FPEXC, PR_FP_EXC_PRECISE);
+
+    /* First test if the FI bit is being set correctly */
+    fpscr.ll = FP_FI;
+    __builtin_mtfsf(0b11111111, fpscr.d);
+    fpscr.d = __builtin_mffs();
+    assert((fpscr.ll & FP_FI) != 0);
+
+    /* Then test if the deferred exception is being called correctly */
+    sigaction(SIGFPE, &sa, NULL);
+
+    /*
+     * Although the VXSOFT exception has been chosen, based on test in a Power9
+     * any combination of exception bit + its enabling bit should work.
+     * But if a different exception is chosen si_code check should
+     * change accordingly.
+     */
+    fpscr.ll = FP_VE | FP_VXSOFT;
+    __builtin_mtfsf(0b11111111, fpscr.d);
+
+    return 1;
+}