[RFC PATCH 1/5] gdb/arm: Introduce control_s and control_ns registers

[Tomas Vanek <vanekt@fbl.cz>]

The M-profile security extension registers will be used for stack
selection in FNC_RETURN and return from secure to non-secure state.

The presence of the registers is optional.
If one or both are missing the security extension profile is accepted.
The code using the registers must check m_profile_control_[n]?s_regnum
for -1.

Signed-off-by: Tomas Vanek <vanekt@fbl.cz>
---
 gdb/arm-tdep.c | 20 ++++++++++++++++++++
 gdb/arm-tdep.h |  2 ++
 2 files changed, 22 insertions(+)

diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c
index 3105543..564ee43 100644
--- a/gdb/arm-tdep.c
+++ b/gdb/arm-tdep.c
@@ -9996,6 +9996,8 @@ enum arm_vfp_cprc_base_type
   int m_profile_psp_ns_regnum = -1;
   int m_profile_msp_s_regnum = -1;
   int m_profile_psp_s_regnum = -1;
+  int m_profile_control_s_regnum = -1;
+  int m_profile_control_ns_regnum = -1;
   int tls_regnum = 0;
 
   /* If we have an object to base this architecture on, try to determine
@@ -10473,6 +10475,22 @@ enum arm_vfp_cprc_base_type
 		}
 	      m_profile_psp_s_regnum = register_count++;
 
+	      /* Regard the control_s and control_ns registers optional,
+	       * accept the security extension feature even without them */
+	      valid_p = tdesc_numbered_register (feature, tdesc_data.get (),
+						 register_count, "control_s");
+	      if (!valid_p)
+		warning (_("M-profile secext feature is missing required register control_s."));
+	      else
+		m_profile_control_s_regnum = register_count++;
+
+	      valid_p = tdesc_numbered_register (feature, tdesc_data.get (),
+						 register_count, "control_ns");
+	      if (!valid_p)
+		warning (_("M-profile secext feature is missing required register control_ns."));
+	      else
+		m_profile_control_ns_regnum = register_count++;
+
 	      have_sec_ext = true;
 	    }
 
@@ -10553,6 +10571,8 @@ enum arm_vfp_cprc_base_type
       tdep->m_profile_psp_ns_regnum = m_profile_psp_ns_regnum;
       tdep->m_profile_msp_s_regnum = m_profile_msp_s_regnum;
       tdep->m_profile_psp_s_regnum = m_profile_psp_s_regnum;
+      tdep->m_profile_control_s_regnum = m_profile_control_s_regnum;
+      tdep->m_profile_control_ns_regnum = m_profile_control_ns_regnum;
     }
 
   arm_register_g_packet_guesses (gdbarch);
diff --git a/gdb/arm-tdep.h b/gdb/arm-tdep.h
index bcd7e08..11670e9 100644
--- a/gdb/arm-tdep.h
+++ b/gdb/arm-tdep.h
@@ -133,6 +133,8 @@ struct arm_gdbarch_tdep : gdbarch_tdep_base
   int m_profile_psp_ns_regnum = ARM_SP_REGNUM;	/* M-profile PSP_NS register number.  */
   int m_profile_msp_s_regnum = ARM_SP_REGNUM;	/* M-profile MSP_S register number.  */
   int m_profile_psp_s_regnum = ARM_SP_REGNUM;	/* M-profile PSP_S register number.  */
+  int m_profile_control_s_regnum = -1;		/* M-profile CONTROL_S register number.  */
+  int m_profile_control_ns_regnum = -1;		/* M-profile CONTROL_NS register number.  */
 
   int tls_regnum = 0;		/* Number of the tpidruro register.  */
 
-- 
1.9.1