diff --git a/gas/config/tc-aarch64.c b/gas/config/tc-aarch64.c
index 3d0436d538c856a418f6949fb47998f69558b6fc..5735d127848bdf22685b436b541424f4af0ae636 100644
--- a/gas/config/tc-aarch64.c
+++ b/gas/config/tc-aarch64.c
@@ -75,7 +75,9 @@ enum aarch64_abi_type
 {
   AARCH64_ABI_NONE = 0,
   AARCH64_ABI_LP64 = 1,
-  AARCH64_ABI_ILP32 = 2
+  AARCH64_ABI_ILP32 = 2,
+  AARCH64_ABI_PURECAP = 3,
+  AARCH64_ABI_HYBRID = 4,
 };
 
 #ifndef DEFAULT_ARCH
@@ -10048,6 +10050,10 @@ struct aarch64_option_abi_value_table
 static const struct aarch64_option_abi_value_table aarch64_abis[] = {
   {"ilp32",		AARCH64_ABI_ILP32},
   {"lp64",		AARCH64_ABI_LP64},
+  /* Note that these values are accepted since they are valid parameters to
+     the -mabi argument for GCC.  However we base no decision on them.  */
+  {"purecap",		AARCH64_ABI_PURECAP},
+  {"hybrid",		AARCH64_ABI_HYBRID},
 };
 
 static int
diff --git a/gas/testsuite/gas/aarch64/morello-abis-ignored.d b/gas/testsuite/gas/aarch64/morello-abis-ignored.d
new file mode 100644
index 0000000000000000000000000000000000000000..37d7735ac674389be82547c7896d5dd950630bff
--- /dev/null
+++ b/gas/testsuite/gas/aarch64/morello-abis-ignored.d
@@ -0,0 +1,18 @@
+#name: Morello ABI arguments accepted but ignored.
+#as: -mabi=purecap
+#as: -mabi=lp64
+#as: -mabi=hybrid
+#readelf: --syms
+
+Symbol table '\.symtab' contains 10 entries:
+   Num:    Value          Size Type    Bind   Vis      Ndx Name
+     0: 0000000000000000     0 NOTYPE  LOCAL  DEFAULT  UND 
+     1: 0000000000000000     0 SECTION LOCAL  DEFAULT    1 
+     2: 0000000000000000     0 SECTION LOCAL  DEFAULT    2 
+     3: 0000000000000000     0 SECTION LOCAL  DEFAULT    3 
+     4: 0000000000000001     0 FUNC    LOCAL  DEFAULT    1 foo
+     5: 0000000000000000     0 NOTYPE  LOCAL  DEFAULT    1 \$c
+     6: 0000000000000008     0 FUNC    LOCAL  DEFAULT    1 bar
+     7: 0000000000000008     0 NOTYPE  LOCAL  DEFAULT    1 \$x
+     8: 0000000000000011     0 FUNC    LOCAL  DEFAULT    1 baz
+     9: 0000000000000010     0 NOTYPE  LOCAL  DEFAULT    1 \$c
diff --git a/gas/testsuite/gas/aarch64/morello-abis-ignored.s b/gas/testsuite/gas/aarch64/morello-abis-ignored.s
new file mode 100644
index 0000000000000000000000000000000000000000..39590632b607d3a3f45da39c2d042b1d52ad1cf5
--- /dev/null
+++ b/gas/testsuite/gas/aarch64/morello-abis-ignored.s
@@ -0,0 +1,15 @@
+  .arch morello+c64
+  .type foo, @function
+foo:
+  mov x0, #0
+  ret c30
+  .arch morello
+  .type bar,@function
+bar:
+  mov x0, #0
+  ret c30
+  .arch morello+c64
+  .type baz, @function
+baz:
+  mov x0, #0
+  ret c30