From db168da2e0d7ea01d0a8ed4bdd0e035e47094fed Mon Sep 17 00:00:00 2001
From: Andrea Corallo <andrea.corallo@arm.com>
Date: Tue, 12 Sep 2023 11:23:52 +0100
Subject: aarch64: Add FEAT_ECBHB support

This patch add support for FEAT_ECBHB "Exploitative control using
branch history information" adding the "clrbhb" instruction.  AFAIU
the same alias was originally added as "clearbhb" before the
architecture was finalized (Mandatory v8.9-a/v9.4-a; Optional
v8.0-a+/v9.0-a+).
---
 gas/testsuite/gas/aarch64/clrbhb-1.d | 9 +++++++++
 gas/testsuite/gas/aarch64/clrbhb-1.s | 2 ++
 gas/testsuite/gas/aarch64/system.d   | 4 ++--
 opcodes/aarch64-asm-2.c              | 1 +
 opcodes/aarch64-dis-2.c              | 3 ++-
 opcodes/aarch64-tbl.h                | 4 ++++
 6 files changed, 20 insertions(+), 3 deletions(-)
 create mode 100644 gas/testsuite/gas/aarch64/clrbhb-1.d
 create mode 100644 gas/testsuite/gas/aarch64/clrbhb-1.s

diff --git a/gas/testsuite/gas/aarch64/clrbhb-1.d b/gas/testsuite/gas/aarch64/clrbhb-1.d
new file mode 100644
index 0000000..272ee23
--- /dev/null
+++ b/gas/testsuite/gas/aarch64/clrbhb-1.d
@@ -0,0 +1,9 @@
+#objdump: -dr
+
+.*:     file format .*
+
+Disassembly of section \.text:
+
+0+ <.*>:
+   0:	d50322df 	clrbhb
+
diff --git a/gas/testsuite/gas/aarch64/clrbhb-1.s b/gas/testsuite/gas/aarch64/clrbhb-1.s
new file mode 100644
index 0000000..edf8846
--- /dev/null
+++ b/gas/testsuite/gas/aarch64/clrbhb-1.s
@@ -0,0 +1,2 @@
+	clrbhb
+
diff --git a/gas/testsuite/gas/aarch64/system.d b/gas/testsuite/gas/aarch64/system.d
index dbb7c0a..c140077 100644
--- a/gas/testsuite/gas/aarch64/system.d
+++ b/gas/testsuite/gas/aarch64/system.d
@@ -14,7 +14,7 @@ Disassembly of section \.text:
 .*:	d503207f 	wfi
 .*:	d503209f 	sev
 .*:	d50320bf 	sevl
-.*:	d50322df 	clearbhb
+.*:	d50322df 	clrbhb
 .*:	d503201f 	nop
 .*:	d503203f 	yield
 .*:	d503205f 	wfe
@@ -37,7 +37,7 @@ Disassembly of section \.text:
 .*:	d503227f 	(hint	#0x13|gcsb	dsync)
 .*:	d503229f 	(hint	#0x14|csdb)
 .*:	d50322bf 	hint	#0x15
-.*:	d50322df 	(hint	#0x16|clearbhb)
+.*:	d50322df 	(hint	#0x16|clrbhb)
 .*:	d50322ff 	hint	#0x17
 .*:	d503231f 	(hint	#0x18|paciaz)
 .*:	d503233f 	(hint	#0x19|paciasp)
diff --git a/opcodes/aarch64-asm-2.c b/opcodes/aarch64-asm-2.c
index ae0119a..e9b9ce2 100644
--- a/opcodes/aarch64-asm-2.c
+++ b/opcodes/aarch64-asm-2.c
@@ -426,6 +426,7 @@ aarch64_find_real_opcode (const aarch64_opcode *opcode)
     case 1200:	/* movz */
       value = 1200;	/* --> movz.  */
       break;
+    case 3193:	/* clrbhb */
     case 1276:	/* autibsp */
     case 1275:	/* autibz */
     case 1274:	/* autiasp */
diff --git a/opcodes/aarch64-dis-2.c b/opcodes/aarch64-dis-2.c
index 38d72a7..977b1c1 100644
--- a/opcodes/aarch64-dis-2.c
+++ b/opcodes/aarch64-dis-2.c
@@ -31321,7 +31321,7 @@ aarch64_find_alias_opcode (const aarch64_opcode *opcode)
     case 1136: value = 1185; break;	/* lduminl --> stuminl.  */
     case 1198: value = 1199; break;	/* movn --> mov.  */
     case 1200: value = 1201; break;	/* movz --> mov.  */
-    case 1215: value = 1276; break;	/* hint --> autibsp.  */
+    case 1215: value = 3193; break;	/* hint --> clrbhb.  */
     case 1235: value = 1239; break;	/* dsb --> pssbb.  */
     case 1236: value = 1236; break;	/* dsb --> dsb.  */
     case 1254: value = 1264; break;	/* sys --> cosp.  */
@@ -31481,6 +31481,7 @@ aarch64_find_next_alias_opcode (const aarch64_opcode *opcode)
     case 1185: value = 1136; break;	/* stuminl --> lduminl.  */
     case 1199: value = 1198; break;	/* mov --> movn.  */
     case 1201: value = 1200; break;	/* mov --> movz.  */
+    case 3193: value = 1276; break;	/* clrbhb --> autibsp.  */
     case 1276: value = 1275; break;	/* autibsp --> autibz.  */
     case 1275: value = 1274; break;	/* autibz --> autiasp.  */
     case 1274: value = 1273; break;	/* autiasp --> autiaz.  */
diff --git a/opcodes/aarch64-tbl.h b/opcodes/aarch64-tbl.h
index 4ef28be..6734794 100644
--- a/opcodes/aarch64-tbl.h
+++ b/opcodes/aarch64-tbl.h
@@ -6113,6 +6113,10 @@ const struct aarch64_opcode aarch64_opcode_table[] =
   CSSC_INSN ("smin", 0x1ac06800, 0x7fe0fc00, OP3 (Rd, Rn, Rm), QL_I3SAMER, F_SF),
   CSSC_INSN ("umin", 0x1ac06c00, 0x7fe0fc00, OP3 (Rd, Rn, Rm), QL_I3SAMER, F_SF),
 
+  /* FEAT_CLRBHB part of the hint space and available without special
+     command-line flags.  */
+  CORE_INSN ("clrbhb", 0xd50322df, 0xffffffff, ic_system, 0, OP0 (), {}, F_ALIAS),
+
   {0, 0, 0, 0, 0, 0, {}, {}, 0, 0, 0, NULL},
 };
 
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