* x86 bugfixes

* OpenBSD support for naming threads
 * Refined Python support policy
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Merge tag 'for-upstream' of https://gitlab.com/bonzini/qemu into staging

* x86 bugfixes
* OpenBSD support for naming threads
* Refined Python support policy

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# gpg: Signature made Tue 21 Feb 2023 13:10:49 GMT
# gpg:                using RSA key F13338574B662389866C7682BFFBD25F78C7AE83
# gpg:                issuer "pbonzini@redhat.com"
# gpg: Good signature from "Paolo Bonzini <bonzini@gnu.org>" [full]
# gpg:                 aka "Paolo Bonzini <pbonzini@redhat.com>" [full]
# Primary key fingerprint: 46F5 9FBD 57D6 12E7 BFD4  E2F7 7E15 100C CD36 69B1
#      Subkey fingerprint: F133 3857 4B66 2389 866C  7682 BFFB D25F 78C7 AE83

* tag 'for-upstream' of https://gitlab.com/bonzini/qemu:
  target/i386/gdbstub: Fix a bug about order of FPU stack in 'g' packets.
  docs: build-platforms: refine requirements on Python build dependencies
  thread-posix: add support for setting threads name on OpenBSD
  target/i386: Fix 32-bit AD[CO]X insns in 64-bit mode

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

docs/about/build-platforms.rst

@@ -86,6 +86,38 @@ respective ports repository, while NetBSD will use the pkgsrc repository.
 For macOS, `Homebrew`_ will be used, although `MacPorts`_ is expected to carry
 similar versions.
 
+Some build dependencies may follow less conservative rules:
+
+Python runtime
+  Distributions with long-term support often provide multiple versions
+  of the Python runtime.  While QEMU will initially aim to support the
+  distribution's default runtime, it may later increase its minimum version
+  to any newer python that is available as an option from the vendor.
+  In this case, it will be necessary to use the ``--python`` command line
+  option of the ``configure`` script to point QEMU to a supported
+  version of the Python runtime.
+
+  As of QEMU |version|, the minimum supported version of Python is 3.6.
+
+Python build dependencies
+  Some of QEMU's build dependencies are written in Python.  Usually these
+  are only packaged by distributions for the default Python runtime.
+  If QEMU bumps its minimum Python version and a non-default runtime is
+  required, it may be necessary to fetch python modules from the Python
+  Package Index (PyPI) via ``pip``, in order to build QEMU.
+
+Optional build dependencies
+  Build components whose absence does not affect the ability to build
+  QEMU may not be available in distros, or may be too old for QEMU's
+  requirements.  Many of these, such as the Avocado testing framework
+  or various linters, are written in Python and therefore can also
+  be installed using ``pip``.  Cross compilers are another example
+  of optional build-time dependency; in this case it is possible to
+  download them from repositories such as EPEL, to use container-based
+  cross compilation using ``docker`` or ``podman``, or to use pre-built
+  binaries distributed with QEMU.
+
+
 Windows
 -------
 

meson.build

@@ -2129,6 +2129,18 @@ config_host_data.set('CONFIG_PTHREAD_SETNAME_NP_WO_TID', cc.links(gnu_source_pre
     pthread_create(&thread, 0, f, 0);
     return 0;
   }''', dependencies: threads))
+config_host_data.set('CONFIG_PTHREAD_SET_NAME_NP', cc.links(gnu_source_prefix + '''
+  #include <pthread.h>
+  #include <pthread_np.h>
+
+  static void *f(void *p) { return NULL; }
+  int main(void)
+  {
+    pthread_t thread;
+    pthread_create(&thread, 0, f, 0);
+    pthread_set_name_np(thread, "QEMU");
+    return 0;
+  }''', dependencies: threads))
 config_host_data.set('CONFIG_PTHREAD_CONDATTR_SETCLOCK', cc.links(gnu_source_prefix + '''
   #include <pthread.h>
   #include <time.h>

target/i386/gdbstub.c

@@ -121,7 +121,9 @@ int x86_cpu_gdb_read_register(CPUState *cs, GByteArray *mem_buf, int n)
             return gdb_get_reg32(mem_buf, env->regs[gpr_map32[n]]);
         }
     } else if (n >= IDX_FP_REGS && n < IDX_FP_REGS + 8) {
-        floatx80 *fp = (floatx80 *) &env->fpregs[n - IDX_FP_REGS];
+        int st_index = n - IDX_FP_REGS;
+        int r_index = (st_index + env->fpstt) % 8;
+        floatx80 *fp = &env->fpregs[r_index].d;
         int len = gdb_get_reg64(mem_buf, cpu_to_le64(fp->low));
         len += gdb_get_reg16(mem_buf, cpu_to_le16(fp->high));
         return len;

target/i386/tcg/emit.c.inc

@@ -1037,6 +1037,8 @@ static void gen_ADCOX(DisasContext *s, CPUX86State *env, MemOp ot, int cc_op)
 #ifdef TARGET_X86_64
     case MO_32:
         /* If TL is 64-bit just do everything in 64-bit arithmetic.  */
+        tcg_gen_ext32u_tl(s->T0, s->T0);
+        tcg_gen_ext32u_tl(s->T1, s->T1);
         tcg_gen_add_i64(s->T0, s->T0, s->T1);
         tcg_gen_add_i64(s->T0, s->T0, carry_in);
         tcg_gen_shri_i64(carry_out, s->T0, 32);

tests/tcg/x86_64/Makefile.target

@@ -12,11 +12,14 @@ ifeq ($(filter %-linux-user, $(TARGET)),$(TARGET))
 X86_64_TESTS += vsyscall
 X86_64_TESTS += noexec
 X86_64_TESTS += cmpxchg
+X86_64_TESTS += adox
 TESTS=$(MULTIARCH_TESTS) $(X86_64_TESTS) test-x86_64
 else
 TESTS=$(MULTIARCH_TESTS)
 endif
 
+adox: CFLAGS=-O2
+
 run-test-i386-ssse3: QEMU_OPTS += -cpu max
 run-plugin-test-i386-ssse3-%: QEMU_OPTS += -cpu max
 

tests/tcg/x86_64/adox.c

@@ -0,0 +1,69 @@
+/* See if ADOX give expected results */
+
+#include <assert.h>
+#include <stdint.h>
+#include <stdbool.h>
+
+static uint64_t adoxq(bool *c_out, uint64_t a, uint64_t b, bool c)
+{
+    asm ("addl $0x7fffffff, %k1\n\t"
+         "adoxq %2, %0\n\t"
+         "seto %b1"
+         : "+r"(a), "=&r"(c) : "r"(b), "1"((int)c));
+    *c_out = c;
+    return a;
+}
+
+static uint64_t adoxl(bool *c_out, uint64_t a, uint64_t b, bool c)
+{
+    asm ("addl $0x7fffffff, %k1\n\t"
+         "adoxl %k2, %k0\n\t"
+         "seto %b1"
+         : "+r"(a), "=&r"(c) : "r"(b), "1"((int)c));
+    *c_out = c;
+    return a;
+}
+
+int main()
+{
+    uint64_t r;
+    bool c;
+
+    r = adoxq(&c, 0, 0, 0);
+    assert(r == 0);
+    assert(c == 0);
+
+    r = adoxl(&c, 0, 0, 0);
+    assert(r == 0);
+    assert(c == 0);
+
+    r = adoxl(&c, 0x100000000, 0, 0);
+    assert(r == 0);
+    assert(c == 0);
+
+    r = adoxq(&c, 0, 0, 1);
+    assert(r == 1);
+    assert(c == 0);
+
+    r = adoxl(&c, 0, 0, 1);
+    assert(r == 1);
+    assert(c == 0);
+
+    r = adoxq(&c, -1, -1, 0);
+    assert(r == -2);
+    assert(c == 1);
+
+    r = adoxl(&c, -1, -1, 0);
+    assert(r == 0xfffffffe);
+    assert(c == 1);
+
+    r = adoxq(&c, -1, -1, 1);
+    assert(r == -1);
+    assert(c == 1);
+
+    r = adoxl(&c, -1, -1, 1);
+    assert(r == 0xffffffff);
+    assert(c == 1);
+
+    return 0;
+}

util/qemu-thread-posix.c

@@ -18,6 +18,10 @@
 #include "qemu/tsan.h"
 #include "qemu/bitmap.h"
 
+#ifdef CONFIG_PTHREAD_SET_NAME_NP
+#include <pthread_np.h>
+#endif
+
 static bool name_threads;
 
 void qemu_thread_naming(bool enable)
@@ -25,7 +29,8 @@ void qemu_thread_naming(bool enable)
     name_threads = enable;
 
 #if !defined CONFIG_PTHREAD_SETNAME_NP_W_TID && \
-    !defined CONFIG_PTHREAD_SETNAME_NP_WO_TID
+    !defined CONFIG_PTHREAD_SETNAME_NP_WO_TID && \
+    !defined CONFIG_PTHREAD_SET_NAME_NP
     /* This is a debugging option, not fatal */
     if (enable) {
         fprintf(stderr, "qemu: thread naming not supported on this host\n");
@@ -480,6 +485,8 @@ static void *qemu_thread_start(void *args)
         pthread_setname_np(pthread_self(), qemu_thread_args->name);
 # elif defined(CONFIG_PTHREAD_SETNAME_NP_WO_TID)
         pthread_setname_np(qemu_thread_args->name);
+# elif defined(CONFIG_PTHREAD_SET_NAME_NP)
+        pthread_set_name_np(pthread_self(), qemu_thread_args->name);
 # endif
     }
     QEMU_TSAN_ANNOTATE_THREAD_NAME(qemu_thread_args->name);