gdbserver: Add a function to set the XSAVE mask and size.

Make x86_xcr0 private to i387-fp.cc and use i387_set_xsave_mask to set
the value instead.  Add a static global instance of x86_xsave_layout
and initialize it in the new function as well to be used in a future
commit to parse XSAVE extended state regions.

Update the Linux port to use this function rather than setting
x86_xcr0 directly.  In the case that XML is not supported, don't
bother setting x86_xcr0 to the default value but just omit the call to
i387_set_xsave_mask as i387-fp.cc defaults to the SSE case used for
non-XML.

In addition, use x86_xsave_length to determine the size of the XSAVE
register set via CPUID.

Approved-By: Simon Marchi <simon.marchi@efficios.com>

1 files changed, 14 insertions, 2 deletions

diff --git a/gdbserver/i387-fp.cc b/gdbserver/i387-fp.cc
index 49795ac..b8d7a91 100644
--- a/gdbserver/i387-fp.cc
+++ b/gdbserver/i387-fp.cc
@@ -19,12 +19,18 @@
 #include "server.h"
 #include "i387-fp.h"
 #include "gdbsupport/x86-xstate.h"
+#include "nat/x86-xstate.h"
+
+/* Default to SSE.  */
+static unsigned long long x86_xcr0 = X86_XSTATE_SSE_MASK;
 
 static const int num_mpx_bnd_registers = 4;
 static const int num_mpx_cfg_registers = 2;
 static const int num_avx512_k_registers = 8;
 static const int num_pkeys_registers = 1;
 
+static x86_xsave_layout xsave_layout;
+
 /* Note: These functions preserve the reserved bits in control registers.
    However, gdbserver promptly throws away that information.  */
 
@@ -974,5 +980,11 @@ i387_xsave_to_cache (struct regcache *regcache, const void *buf)
     }
 }
 
-/* Default to SSE.  */
-unsigned long long x86_xcr0 = X86_XSTATE_SSE_MASK;
+/* See i387-fp.h.  */
+
+void
+i387_set_xsave_mask (uint64_t xcr0, int len)
+{
+  x86_xcr0 = xcr0;
+  xsave_layout = x86_fetch_xsave_layout (xcr0, len);
+}