[patch v3 16/16] btrace, x86: restrict to Atom

[markus.t.metzger@intel.com]

From: Markus Metzger <markus.t.metzger@intel.com>

Restrict branch tracing support to Atom processors.

2012-08-14 Markus Metzger <markus.t.metzger@intel.com>

	* amd64-linux-nat.c (_initialize_amd64_linux_nat): Change supports_btrace method.
	* i386-linux-nat.c (_initialize_i386_linux_nat): Change supports_btrace method.
	* i386-linux-tdep.h (i386_linux_supports_btrace): New function.
	* i386-linux-tdep.c: Add linux-btrace.h include.
	(i386_linux_supports_btrace): New function.

gdbserver/
	* linux-low.h (linux_target_ops): Add supports_btrace method.
	* linux-low.c (linux_low_supports_btrace): New function.
	(linux_target_ops): Change supports_btrace method.
	* linux-x86-low.c (x86_supports_btrace): New function.
	(the_low_target): Add supports_btrace method.


---
 gdb/amd64-linux-nat.c         |    2 +-
 gdb/gdbserver/linux-low.c     |   15 ++++++++++++++-
 gdb/gdbserver/linux-low.h     |    2 ++
 gdb/gdbserver/linux-x86-low.c |   31 +++++++++++++++++++++++++++++++
 gdb/i386-linux-nat.c          |    2 +-
 gdb/i386-linux-tdep.c         |   34 ++++++++++++++++++++++++++++++++++
 gdb/i386-linux-tdep.h         |    3 +++
 7 files changed, 86 insertions(+), 3 deletions(-)

diff --git a/gdb/amd64-linux-nat.c b/gdb/amd64-linux-nat.c
index 3cfa45c..b411beb 100644
--- a/gdb/amd64-linux-nat.c
+++ b/gdb/amd64-linux-nat.c
@@ -1162,7 +1162,7 @@ _initialize_amd64_linux_nat (void)
   t->to_read_description = amd64_linux_read_description;
 
   /* Add btrace methods.  */
-  t->to_supports_btrace = linux_supports_btrace;
+  t->to_supports_btrace = i386_linux_supports_btrace;
   t->to_enable_btrace = amd64_linux_enable_btrace;
   t->to_disable_btrace = amd64_linux_disable_btrace;
   t->to_btrace_has_changed = linux_btrace_has_changed;
diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index 20b1ca5..77ecbe0 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -5793,6 +5793,19 @@ linux_qxfer_libraries_svr4 (const char *annex, unsigned char *readbuf,
   return len;
 }
 
+/* See linux-low.h.  */
+static int
+linux_low_supports_btrace (void)
+{
+  if (!linux_supports_btrace ())
+    return 0;
+
+  if (*the_low_target.supports_btrace == NULL)
+    return 0;
+
+  return (*the_low_target.supports_btrace) ();
+}
+
 /* Read branch trace data for @tinfo as btrace xml document into @buffer.  */
 static void
 linux_low_read_btrace (struct btrace_target_info *tinfo, struct buffer *buffer)
@@ -5882,7 +5895,7 @@ static struct target_ops linux_target_ops = {
   linux_get_min_fast_tracepoint_insn_len,
   linux_qxfer_libraries_svr4,
   linux_supports_agent,
-  linux_supports_btrace,
+  linux_low_supports_btrace,
   linux_enable_btrace,
   linux_disable_btrace,
   linux_btrace_has_changed,
diff --git a/gdb/gdbserver/linux-low.h b/gdb/gdbserver/linux-low.h
index 99d882a..5768a77 100644
--- a/gdb/gdbserver/linux-low.h
+++ b/gdb/gdbserver/linux-low.h
@@ -169,6 +169,8 @@ struct linux_target_ops
      for use as a fast tracepoint.  */
   int (*get_min_fast_tracepoint_insn_len) (void);
 
+  /* Returns true if the low target supports btrace.  */
+  int (*supports_btrace) (void);
 };
 
 extern struct linux_target_ops the_low_target;
diff --git a/gdb/gdbserver/linux-x86-low.c b/gdb/gdbserver/linux-x86-low.c
index 1215bae..e12fccb 100644
--- a/gdb/gdbserver/linux-x86-low.c
+++ b/gdb/gdbserver/linux-x86-low.c
@@ -1859,6 +1859,36 @@ x86_get_min_fast_tracepoint_insn_len (void)
     }
 }
 
+/* See linux-low.h.  */
+static int
+x86_supports_btrace (void)
+{
+  unsigned int cpuid, model, family;
+
+  __asm__ __volatile__ ("movl   $1, %%eax;"
+			"cpuid;"
+			: "=a" (cpuid)
+			:: "%ebx", "%ecx", "%edx");
+
+  family = (cpuid >> 8) & 0xf;
+  model = (cpuid >> 4) & 0xf;
+
+  switch (family)
+    {
+    case 6:
+      model += (cpuid >> 12) & 0xf0;
+
+      switch (model)
+        {
+	case 28: /* Atom.  */
+	case 38:
+	  return 1;
+	}
+    }
+
+  return 0;
+}
+
 static void
 add_insns (unsigned char *start, int len)
 {
@@ -3214,4 +3244,5 @@ struct linux_target_ops the_low_target =
   x86_install_fast_tracepoint_jump_pad,
   x86_emit_ops,
   x86_get_min_fast_tracepoint_insn_len,
+  x86_supports_btrace,
 };
diff --git a/gdb/i386-linux-nat.c b/gdb/i386-linux-nat.c
index 0248fd7..35bc477 100644
--- a/gdb/i386-linux-nat.c
+++ b/gdb/i386-linux-nat.c
@@ -1086,7 +1086,7 @@ _initialize_i386_linux_nat (void)
   t->to_read_description = i386_linux_read_description;
 
   /* Add btrace methods.  */
-  t->to_supports_btrace = linux_supports_btrace;
+  t->to_supports_btrace = i386_linux_supports_btrace;
   t->to_enable_btrace = i386_linux_enable_btrace;
   t->to_disable_btrace = i386_linux_disable_btrace;
   t->to_btrace_has_changed = linux_btrace_has_changed;
diff --git a/gdb/i386-linux-tdep.c b/gdb/i386-linux-tdep.c
index 8475d7a..b0f7b43 100644
--- a/gdb/i386-linux-tdep.c
+++ b/gdb/i386-linux-tdep.c
@@ -37,6 +37,7 @@
 #include "symtab.h"
 #include "arch-utils.h"
 #include "xml-syscall.h"
+#include "linux-btrace.h"
 
 #include "i387-tdep.h"
 #include "i386-xstate.h"
@@ -704,6 +705,39 @@ i386_linux_displaced_step_copy_insn (struct gdbarch *gdbarch,
   return closure;
 }
 
+/* See i386-linux-tdep.h.  */
+int
+i386_linux_supports_btrace (void)
+{
+  unsigned int cpuid, model, family;
+
+  if (!linux_supports_btrace ())
+    return 0;
+
+  __asm__ __volatile__ ("movl   $1, %%eax;"
+			"cpuid;"
+			: "=a" (cpuid)
+			:: "%ebx", "%ecx", "%edx");
+
+  family = (cpuid >> 8) & 0xf;
+  model = (cpuid >> 4) & 0xf;
+
+  switch (family)
+    {
+    case 6:
+      model += (cpuid >> 12) & 0xf0;
+
+      switch (model)
+        {
+	case 28: /* Atom.  */
+	case 38:
+	  return 1;
+	}
+    }
+
+  return 0;
+}
+
 static void
 i386_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
diff --git a/gdb/i386-linux-tdep.h b/gdb/i386-linux-tdep.h
index c3a316f..45bdece 100644
--- a/gdb/i386-linux-tdep.h
+++ b/gdb/i386-linux-tdep.h
@@ -66,4 +66,7 @@ extern struct target_desc *tdesc_i386_avx_linux;
 
 extern int i386_linux_gregset_reg_offset[];
 
+/* Return 1 if target supports btrace.  */
+extern int i386_linux_supports_btrace (void);
+
 #endif /* i386-linux-tdep.h */
-- 
1.7.1