Initialize target description early in IPA

Target descriptions are allocated lazily, that is fine in GDBserver,
but it is not safe to call malloc in gdb_collect in IPA, because we
can set a fast tracepoint in malloc, and when the tracepoint is hit,
gdb_collect/malloc is called, deadlock or memory corruption may be
triggered.

 #0  0xf7cfc200 in malloc ()
 #1  0xf7efdc07 in operator new(unsigned int) ()
 #2  0xf7ef7636 in allocate_target_description() ()
 #3  0xf7efcbe1 in i386_create_target_description(unsigned long long, bool) ()
 #4  0xf7efb474 in i386_linux_read_description(unsigned long long) ()
 #5  0xf7efb190 in get_ipa_tdesc(int) ()
 #6  0xf7ef9baa in gdb_collect ()

The fix is to initialize all target descriptions earlier, when the
IPA is loaded.  In order to guarantee malloc is not called in IPA
in gdb_collect, I change the test to set a breakpoint on malloc, if
IPA gdb_collect calls malloc, program will hit the breakpoint, and
test fail.

continue
Continuing.

Thread 1 "" hit Breakpoint 5, 0xf7cfc200 in malloc ()
(gdb) FAIL: gdb.trace/ftrace.exp: advance through tracing

gdb/gdbserver:

2017-12-07  Yao Qi  <yao.qi@linaro.org>

	* linux-aarch64-ipa.c (initialize_low_tracepoint): Call
	aarch64_linux_read_description.
	* linux-amd64-ipa.c (idx2mask): New array.
	(get_ipa_tdesc): Move idx2mask out.
	(initialize_low_tracepoint): Initialize target descriptions.
	* linux-i386-ipa.c (idx2mask): New array.
	(get_ipa_tdesc): Move idx2mask out.
	(initialize_low_tracepoint): Initialize target descriptions.

gdb/testsuite:

2017-12-07  Yao Qi  <yao.qi@linaro.org>

	* gdb.trace/ftrace.exp (run_trace_experiment): Set breakpoint on
	malloc and catch syscall.

4 files changed, 46 insertions, 23 deletions

diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index 171bc53cae7..c84dcac9cde 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,3 +1,14 @@
+2017-12-07  Yao Qi  <yao.qi@linaro.org>
+
+	* linux-aarch64-ipa.c (initialize_low_tracepoint): Call
+	aarch64_linux_read_description.
+	* linux-amd64-ipa.c (idx2mask): New array.
+	(get_ipa_tdesc): Move idx2mask out.
+	(initialize_low_tracepoint): Initialize target descriptions.
+	* linux-i386-ipa.c (idx2mask): New array.
+	(get_ipa_tdesc): Move idx2mask out.
+	(initialize_low_tracepoint): Initialize target descriptions.
+
 2017-12-05  Simon Marchi  <simon.marchi@polymtl.ca>
 
 	* tdesc.c (struct tdesc_type): Change return type.
diff --git a/gdb/gdbserver/linux-aarch64-ipa.c b/gdb/gdbserver/linux-aarch64-ipa.c
index b240100a13e..c39b7ec7611 100644
--- a/gdb/gdbserver/linux-aarch64-ipa.c
+++ b/gdb/gdbserver/linux-aarch64-ipa.c
@@ -204,4 +204,5 @@ alloc_jump_pad_buffer (size_t size)
 void
 initialize_low_tracepoint (void)
 {
+  aarch64_linux_read_description ();
 }
diff --git a/gdb/gdbserver/linux-amd64-ipa.c b/gdb/gdbserver/linux-amd64-ipa.c
index 85d0d453746..81070df84c1 100644
--- a/gdb/gdbserver/linux-amd64-ipa.c
+++ b/gdb/gdbserver/linux-amd64-ipa.c
@@ -169,6 +169,19 @@ supply_static_tracepoint_registers (struct regcache *regcache,
 
 #endif /* HAVE_UST */
 
+#if !defined __ILP32__
+/* Map the tdesc index to xcr0 mask.  */
+static uint64_t idx2mask[X86_TDESC_LAST] = {
+  X86_XSTATE_X87_MASK,
+  X86_XSTATE_SSE_MASK,
+  X86_XSTATE_AVX_MASK,
+  X86_XSTATE_MPX_MASK,
+  X86_XSTATE_AVX_MPX_MASK,
+  X86_XSTATE_AVX_AVX512_MASK,
+  X86_XSTATE_AVX_MPX_AVX512_PKU_MASK,
+};
+#endif
+
 /* Return target_desc to use for IPA, given the tdesc index passed by
    gdbserver.  */
 
@@ -194,17 +207,6 @@ get_ipa_tdesc (int idx)
       break;
     }
 #else
-  /* Map the tdesc index to xcr0 mask.  */
-  uint64_t idx2mask[X86_TDESC_LAST] = {
-    X86_XSTATE_X87_MASK,
-    X86_XSTATE_SSE_MASK,
-    X86_XSTATE_AVX_MASK,
-    X86_XSTATE_MPX_MASK,
-    X86_XSTATE_AVX_MPX_MASK,
-    X86_XSTATE_AVX_AVX512_MASK,
-    X86_XSTATE_AVX_MPX_AVX512_PKU_MASK,
-  };
-
   return amd64_linux_read_description (idx2mask[idx], false);
 #endif
 
@@ -276,4 +278,12 @@ alloc_jump_pad_buffer (size_t size)
 void
 initialize_low_tracepoint (void)
 {
+#if defined __ILP32__
+  amd64_linux_read_description (X86_XSTATE_SSE_MASK, true);
+  amd64_linux_read_description (X86_XSTATE_AVX_MASK, true);
+  amd64_linux_read_description (X86_XSTATE_AVX_AVX512_MASK, true);
+#else
+  for (auto i = 0; i < X86_TDESC_LAST; i++)
+    amd64_linux_read_description (idx2mask[i], false);
+#endif
 }
diff --git a/gdb/gdbserver/linux-i386-ipa.c b/gdb/gdbserver/linux-i386-ipa.c
index 785a63ed66e..a1a35db7575 100644
--- a/gdb/gdbserver/linux-i386-ipa.c
+++ b/gdb/gdbserver/linux-i386-ipa.c
@@ -245,6 +245,17 @@ initialize_fast_tracepoint_trampoline_buffer (void)
     }
 }
 
+/* Map the tdesc index to xcr0 mask.  */
+static uint64_t idx2mask[X86_TDESC_LAST] = {
+  X86_XSTATE_X87_MASK,
+  X86_XSTATE_SSE_MASK,
+  X86_XSTATE_AVX_MASK,
+  X86_XSTATE_MPX_MASK,
+  X86_XSTATE_AVX_MPX_MASK,
+  X86_XSTATE_AVX_AVX512_MASK,
+  X86_XSTATE_AVX_MPX_AVX512_PKU_MASK,
+};
+
 /* Return target_desc to use for IPA, given the tdesc index passed by
    gdbserver.  */
 
@@ -256,18 +267,6 @@ get_ipa_tdesc (int idx)
       internal_error (__FILE__, __LINE__,
 		      "unknown ipa tdesc index: %d", idx);
     }
-
-  /* Map the tdesc index to xcr0 mask.  */
-  uint64_t idx2mask[X86_TDESC_LAST] = {
-    X86_XSTATE_X87_MASK,
-    X86_XSTATE_SSE_MASK,
-    X86_XSTATE_AVX_MASK,
-    X86_XSTATE_MPX_MASK,
-    X86_XSTATE_AVX_MPX_MASK,
-    X86_XSTATE_AVX_AVX512_MASK,
-    X86_XSTATE_AVX_MPX_AVX512_PKU_MASK,
-  };
-
   return i386_linux_read_description (idx2mask[idx]);
 }
 
@@ -290,4 +289,6 @@ void
 initialize_low_tracepoint (void)
 {
   initialize_fast_tracepoint_trampoline_buffer ();
+  for (auto i = 0; i < X86_TDESC_LAST; i++)
+    i386_linux_read_description (idx2mask[i]);
 }