selftests/powerpc: Add checks for transactional VSXs in signal contexts

If a thread receives a signal while transactional the kernel creates a
second context to show the transactional state of the process. This
test loads some known values and waits for a signal and confirms that
the expected values are in the signal context.

Signed-off-by: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

2 files changed, 126 insertions, 1 deletions

diff --git a/tools/testing/selftests/powerpc/tm/Makefile b/tools/testing/selftests/powerpc/tm/Makefile
index d550ebca2a94..c6c53c82fdd6 100644
--- a/tools/testing/selftests/powerpc/tm/Makefile
+++ b/tools/testing/selftests/powerpc/tm/Makefile
@@ -1,5 +1,5 @@
 SIGNAL_CONTEXT_CHK_TESTS := tm-signal-context-chk-gpr tm-signal-context-chk-fpu \
-        tm-signal-context-chk-vmx
+        tm-signal-context-chk-vmx tm-signal-context-chk-vsx
 
 TEST_PROGS := tm-resched-dscr tm-syscall tm-signal-msr-resv tm-signal-stack \
         tm-vmxcopy tm-fork tm-tar tm-tmspr $(SIGNAL_CONTEXT_CHK_TESTS)
diff --git a/tools/testing/selftests/powerpc/tm/tm-signal-context-chk-vsx.c b/tools/testing/selftests/powerpc/tm/tm-signal-context-chk-vsx.c
new file mode 100644
index 000000000000..b99c3d835957
--- /dev/null
+++ b/tools/testing/selftests/powerpc/tm/tm-signal-context-chk-vsx.c
@@ -0,0 +1,125 @@
+/*
+ * Copyright 2016, Cyril Bur, IBM Corp.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ *
+ * Test the kernel's signal frame code.
+ *
+ * The kernel sets up two sets of ucontexts if the signal was to be
+ * delivered while the thread was in a transaction.
+ * Expected behaviour is that the checkpointed state is in the user
+ * context passed to the signal handler. The speculated state can be
+ * accessed with the uc_link pointer.
+ *
+ * The rationale for this is that if TM unaware code (which linked
+ * against TM libs) installs a signal handler it will not know of the
+ * speculative nature of the 'live' registers and may infer the wrong
+ * thing.
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <signal.h>
+#include <unistd.h>
+
+#include <altivec.h>
+
+#include "utils.h"
+#include "tm.h"
+
+#define MAX_ATTEMPT 500000
+
+#define NV_VSX_REGS 12
+
+long tm_signal_self_context_load(pid_t pid, long *gprs, double *fps, vector int *vms, vector int *vss);
+
+static sig_atomic_t fail;
+
+vector int vss[] = {
+        {1, 2, 3, 4 },{5, 6, 7, 8 },{9, 10,11,12},
+        {13,14,15,16},{17,18,19,20},{21,22,23,24},
+        {25,26,27,28},{29,30,31,32},{33,34,35,36},
+        {37,38,39,40},{41,42,43,44},{45,46,47,48},
+        {-1, -2, -3, -4 },{-5, -6, -7, -8 },{-9, -10,-11,-12},
+        {-13,-14,-15,-16},{-17,-18,-19,-20},{-21,-22,-23,-24},
+        {-25,-26,-27,-28},{-29,-30,-31,-32},{-33,-34,-35,-36},
+        {-37,-38,-39,-40},{-41,-42,-43,-44},{-45,-46,-47,-48}
+};
+
+static void signal_usr1(int signum, siginfo_t *info, void *uc)
+{
+        int i;
+        uint8_t vsc[sizeof(vector int)];
+        uint8_t vst[sizeof(vector int)];
+        ucontext_t *ucp = uc;
+        ucontext_t *tm_ucp = ucp->uc_link;
+
+        /*
+         * The other half of the VSX regs will be after v_regs.
+         *
+         * In short, vmx_reserve array holds everything. v_regs is a 16
+         * byte aligned pointer at the start of vmx_reserve (vmx_reserve
+         * may or may not be 16 aligned) where the v_regs structure exists.
+         * (half of) The VSX regsters are directly after v_regs so the
+         * easiest way to find them below.
+         */
+        long *vsx_ptr = (long *)(ucp->uc_mcontext.v_regs + 1);
+        long *tm_vsx_ptr = (long *)(tm_ucp->uc_mcontext.v_regs + 1);
+        for (i = 0; i < NV_VSX_REGS && !fail; i++) {
+                memcpy(vsc, &ucp->uc_mcontext.fp_regs[i + 20], 8);
+                memcpy(vsc + 8, &vsx_ptr[20 + i], 8);
+                fail = memcmp(vsc, &vss[i], sizeof(vector int));
+                memcpy(vst, &tm_ucp->uc_mcontext.fp_regs[i + 20], 8);
+                memcpy(vst + 8, &tm_vsx_ptr[20 + i], 8);
+                fail |= memcmp(vst, &vss[i + NV_VSX_REGS], sizeof(vector int));
+
+                if (fail) {
+                        int j;
+
+                        fprintf(stderr, "Failed on %d vsx 0x", i);
+                        for (j = 0; j < 16; j++)
+                                fprintf(stderr, "%02x", vsc[j]);
+                        fprintf(stderr, " vs 0x");
+                        for (j = 0; j < 16; j++)
+                                fprintf(stderr, "%02x", vst[j]);
+                        fprintf(stderr, "\n");
+                }
+        }
+}
+
+static int tm_signal_context_chk()
+{
+        struct sigaction act;
+        int i;
+        long rc;
+        pid_t pid = getpid();
+
+        SKIP_IF(!have_htm());
+
+        act.sa_sigaction = signal_usr1;
+        sigemptyset(&act.sa_mask);
+        act.sa_flags = SA_SIGINFO;
+        if (sigaction(SIGUSR1, &act, NULL) < 0) {
+                perror("sigaction sigusr1");
+                exit(1);
+        }
+
+        i = 0;
+        while (i < MAX_ATTEMPT && !fail) {
+                rc = tm_signal_self_context_load(pid, NULL, NULL, NULL, vss);
+                FAIL_IF(rc != pid);
+                i++;
+        }
+
+        return fail;
+}
+
+int main(void)
+{
+        return test_harness(tm_signal_context_chk, "tm_signal_context_chk_vsx");
+}