[Morello] Generate target descriptions based on runtime capability feature checks

This patch adds code to do runtime checks for Morello, so GDB can pick the
correct target description and register set.

gdb/ChangeLog:

2020-10-20  Luis Machado  <luis.machado@arm.com>

	* aarch64-linux-nat.c (aarch64_linux_nat_target::read_description):
	Check for HWCAP2_MORELLO.
	* aarch64-linux-tdep.c (aarch64_linux_core_read_description): Likewise.
	* aarch64-tdep.c (tdesc_aarch64_list): Add one more dimension.
	(aarch64_read_description): New parameter capability_p, use it to
	generate the proper target description.
	(aarch64_gdbarch_init): Update invocation of aarch64_read_description.
	* aarch64-tdep.h (aarch64_read_description): New parameter capability_p.
	* arch/aarch64.c (aarch64_create_target_description): New parameter
	capability_p. Use it.
	* arch/aarch64.h (aarch64_create_target_description): New parameter
	capability_p.

gdbserver/ChangeLog:

2020-10-20  Luis Machado  <luis.machado@arm.com>

	* linux-aarch64-ipa.cc (get_ipa_tdesc): Update.
	* linux-aarch64-low.cc (aarch64_target::low_arch_setup): Check for
	HWCAP2_MORELLO and use it.
	* linux-aarch64-tdesc.cc (tdesc_aarch64_list): Add one more dimension.
	(aarch64_linux_read_description): New parameter capability_p. Use it.
	* linux-aarch64-tdesc.h (aarch64_linux_read_description): New parameter
	capability_p.

diff --git a/gdb/aarch64-linux-nat.c b/gdb/aarch64-linux-nat.c
index 9cde72b247b1e97339ca7c227a0cb20ffcf9455c..b429fa31a03b3b1484b9b5b8692ca8676cdc5f3e 100644 (file)
--- a/gdb/aarch64-linux-nat.c
+++ b/gdb/aarch64-linux-nat.c
@@ -714,6 +714,7 @@ aarch64_linux_nat_target::read_description ()
   features.pauth = hwcap & AARCH64_HWCAP_PACA;
   features.mte = hwcap2 & HWCAP2_MTE;
   features.tls = true;
+  features.capacity = hwcap2 & HWCAP2_MORELLO;
 
   return aarch64_read_description (features);
 }

diff --git a/gdb/aarch64-linux-tdep.c b/gdb/aarch64-linux-tdep.c
index f626d499215156b79359deff763936b515bf7572..f63759f98c6011e92fc0f80df650df3c22acba7d 100644 (file)
--- a/gdb/aarch64-linux-tdep.c
+++ b/gdb/aarch64-linux-tdep.c
@@ -787,6 +787,7 @@ aarch64_linux_core_read_description (struct gdbarch *gdbarch,
   features.pauth = hwcap & AARCH64_HWCAP_PACA;
   features.mte = hwcap2 & HWCAP2_MTE;
   features.tls = tls != nullptr;
+  features.capability = hwcap2 & HWCAP2_MORELLO;
 
   return aarch64_read_description (features);
 }

diff --git a/gdb/aarch64-tdep.c b/gdb/aarch64-tdep.c
index 5f7ec0356c82c551c7a26b99a643d8dcfafcccaf..14974230f0ed04bfc1c45677754d4a4893299d05 100644 (file)
--- a/gdb/aarch64-tdep.c
+++ b/gdb/aarch64-tdep.c
@@ -3476,6 +3476,10 @@ aarch64_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
        return best_arch->gdbarch;
     }
 
+  /* FIXME-Morello: Put a check in place so we can determine, from ELF, if
+     we are dealing with a capability-enabled binary or not.  */
+  bool have_capability = false;
+
   /* Ensure we always have a target descriptor, and that it is for the given VQ
      value.  */
   const struct target_desc *tdesc = info.target_desc;
@@ -3483,6 +3487,7 @@ aarch64_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
     {
       aarch64_features features;
       features.vq = vq;
+      features.capability = have_capability;
       tdesc = aarch64_read_description (features);
     }
   gdb_assert (tdesc);

diff --git a/gdb/arch/aarch64.c b/gdb/arch/aarch64.c
index e74dcfa4ae68aa31ff103a85855e617a78478819..edfd8f5710fbdba36895696a6b878ce5e6771593 100644 (file)
--- a/gdb/arch/aarch64.c
+++ b/gdb/arch/aarch64.c
@@ -61,7 +61,8 @@ aarch64_create_target_description (const aarch64_features &features)
      the existing target description.  Figure out how to do that.
      Maybe replace the general purpose register description with
      the capability registers.  */
-  regnum = create_feature_aarch64_capability (tdesc.get (), regnum);
+  if (features.capability)
+    regnum = create_feature_aarch64_capability (tdesc.get (), regnum);
 
   return tdesc.release ();
 }

diff --git a/gdb/arch/aarch64.h b/gdb/arch/aarch64.h
index 8e3fd36726a8b30c52cf4405f4e86ff3dfb3f463..19f418478cc6d67b3983ac95c4bae47bb44c9cf0 100644 (file)
--- a/gdb/arch/aarch64.h
+++ b/gdb/arch/aarch64.h
@@ -34,6 +34,7 @@ struct aarch64_features
   bool pauth = false;
   bool mte = false;
   bool tls = false;
+  bool capability = false;
 };
 
 inline bool operator==(const aarch64_features &lhs, const aarch64_features &rhs)
@@ -41,7 +42,8 @@ inline bool operator==(const aarch64_features &lhs, const aarch64_features &rhs)
   return lhs.vq == rhs.vq
     && lhs.pauth == rhs.pauth
     && lhs.mte == rhs.mte
-    && lhs.tls == rhs.tls;
+    && lhs.tls == rhs.tls
+    && lhs.capability == rhs.capability;
 }
 
 namespace std
@@ -57,6 +59,7 @@ namespace std
       h = h << 1 | features.pauth;
       h = h << 1 | features.mte;
       h = h << 1 | features.tls;
+      h = h << 1 | features.capability;
       return h;
     }
   };

diff --git a/gdbserver/linux-aarch64-low.cc b/gdbserver/linux-aarch64-low.cc
index 1b9a1cdabbad36db52f4817044a20e8edef6327c..9f7a636fc425c2e942425311185a21ffe38fb979 100644 (file)
--- a/gdbserver/linux-aarch64-low.cc
+++ b/gdbserver/linux-aarch64-low.cc
@@ -830,6 +830,8 @@ aarch64_target::low_arch_setup ()
       /* A-profile MTE is 64-bit only.  */
       features.mte = linux_get_hwcap2 (8) & HWCAP2_MTE;
       features.tls = true;
+      /* Morello is 64-bit only.  */
+      features.capability = linux_get_hwcap2 (8) & HWCAP2_MORELLO;
 
       current_process ()->tdesc = aarch64_linux_read_description (features);