[1/2] tests/tcg/ppc64le: Added an overflow with OE=1 test

Commit Message

Lucas Mateus Martins Araujo e Castro Aug. 17, 2022, 4:57 p.m. UTC

From: "Lucas Mateus Castro (alqotel)" <[e-mail]>

Added a test to see if the adjustment is being made correctly when an
overflow occurs and OE is set.

Signed-off-by: Lucas Mateus Castro (alqotel) <[e-mail]>
---
The prctl patch is not ready yet, so this patch does as Richard
Henderson suggested and check the fp register in the signal handler

This patch will fail without the overflow with OE set bugfix
Message-Id:<[e-mail]>
---
 tests/tcg/ppc64/Makefile.target   |  1 +
 tests/tcg/ppc64le/Makefile.target |  1 +
 tests/tcg/ppc64le/oe_excp.c       | 54 +++++++++++++++++++++++++++++++
 3 files changed, 56 insertions(+)
 create mode 100644 tests/tcg/ppc64le/oe_excp.c

Comments

Richard Henderson Aug. 18, 2022, 3:32 p.m. UTC | #1

On 8/17/22 09:57, Lucas Mateus Castro(alqotel) wrote:
> +void sigfpe_handler(int sig, siginfo_t *si, void *ucontext)
> +{
> +    uint64_t t;
> +    uint64_t ch = 0x5fcfffe4965a17e0ull;
> +    asm (
> +        "stfd 2, %0\n\t"
> +        : "=m"(t)
> +        :
> +        : "memory", "fr2"
> +    );

No, you need to fetch f2 from ucontext.  There's no guarantee of any specific values being 
present in the signal handler otherwise.

> +    return -1;

exit(-1), which return from main equates to, helpful over EXIT_FAILURE.
But here I'd tend to abort(), since it really shouldn't be reachable.


r~

Lucas Mateus Martins Araujo e Castro Aug. 18, 2022, 4:14 p.m. UTC | #2

On 18/08/2022 12:32, Richard Henderson wrote:
> On 8/17/22 09:57, Lucas Mateus Castro(alqotel) wrote:
>> +void sigfpe_handler(int sig, siginfo_t *si, void *ucontext)
>> +{
>> +    uint64_t t;
>> +    uint64_t ch = 0x5fcfffe4965a17e0ull;
>> +    asm (
>> +        "stfd 2, %0\n\t"
>> +        : "=m"(t)
>> +        :
>> +        : "memory", "fr2"
>> +    );
>
> No, you need to fetch f2 from ucontext.  There's no guarantee of any 
> specific values being
> present in the signal handler otherwise.
Yeah, for some reason I completely forgot about this, my bad. I'll send 
a second version fixing this
>
>> +    return -1;
>
> exit(-1), which return from main equates to, helpful over EXIT_FAILURE.
> But here I'd tend to abort(), since it really shouldn't be reachable.
Good point, I'll change in v2
>
>
> r~

Patch

diff --git a/tests/tcg/ppc64/Makefile.target b/tests/tcg/ppc64/Makefile.target
index 331fae628e..43958ad87b 100644
--- a/tests/tcg/ppc64/Makefile.target
+++ b/tests/tcg/ppc64/Makefile.target
@@ -29,5 +29,6 @@  run-plugin-sha512-vector-with-%: QEMU_OPTS+=-cpu POWER10
 
 PPC64_TESTS += signal_save_restore_xer
 PPC64_TESTS += xxspltw
+PPC64_TESTS += oe_excp
 
 TESTS += $(PPC64_TESTS)
diff --git a/tests/tcg/ppc64le/Makefile.target b/tests/tcg/ppc64le/Makefile.target
index 6ca3003f02..8d11ac731d 100644
--- a/tests/tcg/ppc64le/Makefile.target
+++ b/tests/tcg/ppc64le/Makefile.target
@@ -27,5 +27,6 @@  PPC64LE_TESTS += mtfsf
 PPC64LE_TESTS += mffsce
 PPC64LE_TESTS += signal_save_restore_xer
 PPC64LE_TESTS += xxspltw
+PPC64LE_TESTS += oe_excp
 
 TESTS += $(PPC64LE_TESTS)
diff --git a/tests/tcg/ppc64le/oe_excp.c b/tests/tcg/ppc64le/oe_excp.c
new file mode 100644
index 0000000000..cfc364f5ed
--- /dev/null
+++ b/tests/tcg/ppc64le/oe_excp.c
@@ -0,0 +1,54 @@ 
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/prctl.h>
+#include <signal.h>
+#include <stdint.h>
+
+#define FP_OE (1ull << 6)
+#define MTFSF(FLM, FRB) asm volatile ("mtfsf %0, %1" :: "i" (FLM), "f" (FRB))
+
+void sigfpe_handler(int sig, siginfo_t *si, void *ucontext)
+{
+    uint64_t t;
+    uint64_t ch = 0x5fcfffe4965a17e0ull;
+    asm (
+        "stfd 2, %0\n\t"
+        : "=m"(t)
+        :
+        : "memory", "fr2"
+    );
+    if (t == ch) {
+        exit(0);
+    }
+    fprintf(stderr, "expected result: %lx\n         result: %lx\n", ch, t);
+    exit(1);
+}
+
+int main()
+{
+    uint64_t fpscr;
+    uint64_t a = 0x7fdfffe816d77b00ull;
+    uint64_t b = 0x7fdfffFC7F7FFF00ull;
+
+    struct sigaction sa = {
+        .sa_sigaction = sigfpe_handler,
+        .sa_flags = SA_SIGINFO
+    };
+
+    prctl(PR_SET_FPEXC, PR_FP_EXC_PRECISE);
+    sigaction(SIGFPE, &sa, NULL);
+
+    fpscr = FP_OE;
+    MTFSF(0b11111111, fpscr);
+
+    asm (
+        "lfd 0, %0\n\t"
+        "lfd 1, %1\n\t"
+        "fmul 2, 0, 1\n\t"
+        :
+        : "m"(a), "m"(b)
+        : "memory", "fr0", "fr1", "fr2"
+    );
+
+    return -1;
+}