feat(cpus): make revision procedure call optional
For runtime errata, we should avoid generating calls to
`cpu_get_rev_var` unless its necessary. Make the path that generates
this call parameterized, and cache the result in a temporary register to
allow future calls that go down the alternate path to retrieve the cache
CPU revision.
Change-Id: I9882ede76568fbd9a7ccd4caa74eff0c66a7b20e
Signed-off-by: Harrison Mutai <harrison.mutai@arm.com>
diff --git a/include/lib/cpus/aarch64/cpu_macros.S b/include/lib/cpus/aarch64/cpu_macros.S
index d945d7c..6faef5d 100644
--- a/include/lib/cpus/aarch64/cpu_macros.S
+++ b/include/lib/cpus/aarch64/cpu_macros.S
@@ -472,15 +472,25 @@
* _chosen:
* Compile time flag on whether the erratum is included
*
- * clobbers: x0-x9 (PCS compliant)
+ * _get_rev:
+ * Optional parameter that determines whether to insert a call to the CPU revision fetching
+ * procedure. Stores the result of this in the temporary register x10.
+ *
+ * clobbers: x0-x10 (PCS compliant)
*/
-.macro apply_erratum _cpu:req, _cve:req, _id:req, _chosen:req
- .if \_chosen
+.macro apply_erratum _cpu:req, _cve:req, _id:req, _chosen:req, _get_rev=GET_CPU_REV
+ .if (\_chosen & \_get_rev)
mov x9, x30
bl cpu_get_rev_var
+ mov x10, x0
+ .elseif (\_chosen)
+ mov x9, x30
+ mov x0, x10
+ .endif
+
+ .if \_chosen
bl erratum_\_cpu\()_\_id\()_wa
mov x30, x9
-
.endif
.endm
diff --git a/include/lib/cpus/errata.h b/include/lib/cpus/errata.h
index b280435..2080898 100644
--- a/include/lib/cpus/errata.h
+++ b/include/lib/cpus/errata.h
@@ -66,6 +66,9 @@
#define NO_ASSERT 0
#define NO_APPLY_AT_RESET 0
#define APPLY_AT_RESET 1
+#define GET_CPU_REV 1
+#define NO_GET_CPU_REV 0
+
/* useful for errata that end up always being worked around */
#define ERRATUM_ALWAYS_CHOSEN 1