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1 /* Test if SSE valus are correctly propagated into and out of a signal handler
2    and also check that the same applies for uninitialised values and their
3    origins. */
4 
5 #include <assert.h>
6 #include <signal.h>
7 #include <stdio.h>
8 #include <stdlib.h>
9 #include <unistd.h>
10 #include <sys/syscall.h>
11 #include <sys/ucontext.h>
12 
13 static siginfo_t si;
14 static ucontext_t uc;
15 /* x0 is always zero, but is visible to Valgrind as uninitialised. */
16 static upad128_t x0;
17 static upad128_t d0 = {0};
18 
sighandler(int sig,siginfo_t * sip,ucontext_t * ucp)19 static void sighandler(int sig, siginfo_t *sip, ucontext_t *ucp)
20 {
21    si = *sip;
22    uc = *ucp;
23 
24    ucp->uc_mcontext.fpregs.fp_reg_set.fpchip_state.xmm[0] = d0;
25    ucp->uc_mcontext.fpregs.fp_reg_set.fpchip_state.xmm[1] = x0;
26 }
27 
main(void)28 int main(void)
29 {
30    struct sigaction sa;
31    pid_t pid;
32    upad128_t out[8];
33    upad128_t y0;
34    struct fpchip_state *fs = &uc.uc_mcontext.fpregs.fp_reg_set.fpchip_state;
35 
36    /* Uninitialised, but we know px[0] is 0x0. */
37    upad128_t *px = malloc(sizeof(*px));
38    x0 = px[0];
39 
40    /* Uninitialised, but we know py[0] is 0x0. */
41    upad128_t *py = malloc(sizeof(*py));
42    y0 = py[0];
43 
44    sa.sa_handler = sighandler;
45    sa.sa_flags = SA_SIGINFO;
46    if (sigfillset(&sa.sa_mask)) {
47       perror("sigfillset");
48       return 1;
49    }
50    if (sigaction(SIGUSR1, &sa, NULL)) {
51       perror("sigaction");
52       return 1;
53    }
54 
55    pid = getpid();
56 
57    __asm__ __volatile__(
58       /* Set values in the SSE registers. */
59       "movups %[y0], %%xmm0\n"
60       "movups %[d0], %%xmm1\n"
61       "movups %[d0], %%xmm2\n"
62       "movups %[y0], %%xmm3\n"
63       "movups %[y0], %%xmm4\n"
64       "movups %[d0], %%xmm5\n"
65       "movups %[d0], %%xmm6\n"
66       "movups %[y0], %%xmm7\n"
67 
68       /* Trigger the signal handler. */
69       "syscall\n"
70       "movups %%xmm0, 0x00 + %[out]\n"
71       "movups %%xmm1, 0x10 + %[out]\n"
72       "movups %%xmm2, 0x20 + %[out]\n"
73       "movups %%xmm3, 0x30 + %[out]\n"
74       "movups %%xmm4, 0x40 + %[out]\n"
75       "movups %%xmm5, 0x50 + %[out]\n"
76       "movups %%xmm6, 0x60 + %[out]\n"
77       "movups %%xmm7, 0x70 + %[out]\n"
78       : [out] "=m" (out[0])
79       : "a" (SYS_kill), "D" (pid), "S" (SIGUSR1), [y0] "m" (y0), [d0] "m" (d0)
80       : "rdx", "cc", "memory");
81 
82    printf("Values in the signal handler:\n");
83    printf("  xmm1=%Lf, xmm2=%Lf, xmm5=%Lf, xmm6=%Lf\n",
84           fs->xmm[1]._q, fs->xmm[2]._q, fs->xmm[5]._q, fs->xmm[6]._q);
85    /* Check that fs->xmm[0], fs->xmm[3], fs->xmm[4] and fs->xmm[7] contain
86       uninitialised values (origin is py[0]). */
87    if (fs->xmm[0]._q || fs->xmm[3]._q || fs->xmm[4]._q || fs->xmm[7]._q)
88       assert(0);
89 
90    printf("Values after the return from the signal handler:\n");
91    printf("  xmm0=%Lf, xmm2=%Lf, xmm5=%Lf, xmm6=%Lf\n",
92           out[0]._q, out[2]._q, out[5]._q, out[6]._q);
93    /* Check that out[1], out[3], out[4] and out[7] contain uninitialised
94       values (origin is px[0]). */
95    if (out[1]._q || out[3]._q || out[4]._q || out[7]._q)
96       assert(0);
97 
98    return 0;
99 }
100 
101