Access system registers directly in assembler
Instead of using the system register helper functions to read
or write system registers, assembler coded functions should
use MRS/MSR instructions. This results in faster and more
compact code.
This change replaces all usage of the helper functions with
direct register accesses.
Change-Id: I791d5f11f257010bb3e6a72c6c5ab8779f1982b3
diff --git a/lib/aarch64/cpu_helpers.S b/lib/aarch64/cpu_helpers.S
index 4e5eb5b..abb996d 100644
--- a/lib/aarch64/cpu_helpers.S
+++ b/lib/aarch64/cpu_helpers.S
@@ -35,13 +35,11 @@
func cpu_reset_handler
- mov x19, x30 // lr
-
/* ---------------------------------------------
* As a bare minimal enable the SMP bit.
* ---------------------------------------------
*/
- bl read_midr
+ mrs x0, midr_el1
lsr x0, x0, #MIDR_PN_SHIFT
and x0, x0, #MIDR_PN_MASK
cmp x0, #MIDR_PN_A57
@@ -49,9 +47,9 @@
cmp x0, #MIDR_PN_A53
b.ne smp_setup_end
smp_setup_begin:
- bl read_cpuectlr
+ mrs x0, CPUECTLR_EL1
orr x0, x0, #CPUECTLR_SMP_BIT
- bl write_cpuectlr
+ msr CPUECTLR_EL1, x0
isb
smp_setup_end:
- ret x19
+ ret