tests/tcg/multiarch: Add tb-link test

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

tests/tcg/multiarch/Makefile.target

@@ -46,6 +46,8 @@ vma-pthread: LDFLAGS+=-pthread
 sigreturn-sigmask: CFLAGS+=-pthread
 sigreturn-sigmask: LDFLAGS+=-pthread
 
+tb-link: LDFLAGS+=-lpthread
+
 # GCC versions 12/13/14/15 at least incorrectly complain about
 # "'SHA1Transform' reading 64 bytes from a region of size 0"; see the gcc bug
 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106709

tests/tcg/multiarch/tb-link.c

@@ -0,0 +1,67 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Verify that a single TB spin-loop is properly invalidated,
+ * releasing the thread from the spin-loop.
+ */
+
+#include <assert.h>
+#include <sys/mman.h>
+#include <pthread.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <unistd.h>
+#include <sched.h>
+
+
+#ifdef __x86_64__
+#define READY   0x000047c6      /* movb $0,0(%rdi) */
+#define LOOP    0xfceb9090      /* 1: nop*2; jmp 1b */
+#define RETURN  0x909090c3      /* ret; nop*3 */
+#define NOP     0x90909090      /* nop*4 */
+#elif defined(__aarch64__)
+#define READY   0x3900001f      /* strb wzr,[x0] */
+#define LOOP    0x14000000      /* b . */
+#define RETURN  0xd65f03c0      /* ret */
+#define NOP     0xd503201f      /* nop */
+#elif defined(__riscv)
+#define READY   0x00050023      /* sb zero, (a0) */
+#define LOOP    0x0000006f      /* jal zero, #0 */
+#define RETURN  0x00008067      /* jalr zero, ra, 0 */
+#define NOP     0x00000013      /* nop */
+#endif
+
+
+int main()
+{
+#ifdef READY
+    int tmp;
+    pthread_t thread_id;
+    bool hold = true;
+    uint32_t *buf;
+
+    buf = mmap(NULL, 3 * sizeof(uint32_t),
+               PROT_READ | PROT_WRITE | PROT_EXEC,
+               MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+    assert(buf != MAP_FAILED);
+
+    buf[0] = READY;
+    buf[1] = LOOP;
+    buf[2] = RETURN;
+
+    alarm(2);
+
+    tmp = pthread_create(&thread_id, NULL, (void *(*)(void *))buf, &hold);
+    assert(tmp == 0);
+
+    while (hold) {
+        sched_yield();
+    }
+
+    buf[1] = NOP;
+    __builtin___clear_cache(&buf[1], &buf[2]);
+
+    tmp = pthread_join(thread_id, NULL);
+    assert(tmp == 0);
+#endif
+    return 0;
+}