Add a simple test for checking FPU state in signal

test/src/apps/scripts/process.sh

@@ -43,6 +43,7 @@ sched/sched_attr
 sched/sched_attr_idle
 shm/posix_shm
 signal_c/parent_death_signal
+signal_c/signal_fpu
 signal_c/signal_test
 signal_c/signal_test2
 "

test/src/apps/signal_c/signal_fpu.c

@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: MPL-2.0
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <unistd.h>
+#include <signal.h>
+#include <stdint.h>
+#include <stdbool.h>
+
+volatile bool ok = true;
+
+void set_xmm8(uint64_t xmm8_low, uint64_t xmm8_high)
+{
+	// Create a buffer to hold 128 bits (16 bytes)
+	uint8_t xmm8_buffer[16] = {
+		(uint8_t)(xmm8_low),	    (uint8_t)(xmm8_low >> 8),
+		(uint8_t)(xmm8_low >> 16),  (uint8_t)(xmm8_low >> 24),
+		(uint8_t)(xmm8_low >> 32),  (uint8_t)(xmm8_low >> 40),
+		(uint8_t)(xmm8_low >> 48),  (uint8_t)(xmm8_low >> 56),
+		(uint8_t)(xmm8_high),	    (uint8_t)(xmm8_high >> 8),
+		(uint8_t)(xmm8_high >> 16), (uint8_t)(xmm8_high >> 24),
+		(uint8_t)(xmm8_high >> 32), (uint8_t)(xmm8_high >> 40),
+		(uint8_t)(xmm8_high >> 48), (uint8_t)(xmm8_high >> 56)
+	};
+
+	// Load xmm8 with the 128-bit value from xmm8_buffer
+	asm volatile(
+		"movdqu %0, %%xmm8" // Load xmm8 with the value in xmm8_buffer
+		:
+		: "m"(xmm8_buffer) // Input: xmm8_buffer
+	);
+}
+
+void print_assert_xmm8(const char *prompt, uint64_t expected_xmm8_low,
+		       uint64_t expected_xmm8_high)
+{
+	// Read xmm8 in the signal handler (128 bits into a buffer)
+	uint8_t xmm8_buffer[16]; // 128 bits
+	asm volatile(
+		"movdqu %%xmm8, %0" // Move the entire xmm8 register to memory
+		: "=m"(xmm8_buffer) // Output the value to xmm8_buffer
+	);
+
+	uint64_t xmm8_low, xmm8_high;
+	// Now extract the low and high 64-bits from the buffer
+	xmm8_low = *(uint64_t *)&xmm8_buffer[0]; // First 64 bits (low part)
+	xmm8_high = *(uint64_t *)&xmm8_buffer[8]; // Second 64 bits (high part)
+
+	// Output xmm8 value (NOTE: dprintf might destroy xmm8, it can be only used once!)
+	dprintf(STDOUT_FILENO, "%s: xmm8 = 0x%016lx%016lx\n", prompt, xmm8_high,
+		xmm8_low);
+
+	// Assert
+	if (expected_xmm8_low != xmm8_low || expected_xmm8_high != xmm8_high) {
+		ok = false;
+	}
+}
+
+// Signal handler
+void signal_handler(int signum)
+{
+	print_assert_xmm8("In signal", 0, 0);
+	set_xmm8(0x1234567890abcdef, 0xabcdef1234567890);
+}
+
+int main()
+{
+	uint64_t xmm8_low = 0xcafebabecafebabe;
+	uint64_t xmm8_high = 0xdeadbeefdeadbeef;
+
+	// Install signal handler
+	signal(SIGUSR1, signal_handler);
+
+	// Load xmm8 with the values
+	set_xmm8(xmm8_low, xmm8_high);
+
+	// Trigger the signal handler
+	kill(getpid(), SIGUSR1);
+
+	// After the signal handler returns, read and output xmm8 value again
+	print_assert_xmm8("After signal", xmm8_low, xmm8_high);
+
+	// Check result
+	if (ok) {
+		dprintf(STDOUT_FILENO, "All tests passed\n");
+		return 0;
+	} else {
+		dprintf(STDOUT_FILENO, "ERROR: test failed!\n");
+		exit(EXIT_FAILURE);
+	}
+}