Move EL drop definition out of boot.S

PSCI needs to be able to drop cores to EL2 repeatedly, and it doesn't
make sense to always throw CPUs through the original boot path.

This patch changes the EL drop into a macro, and moves it to a common
file that can be used by different boot protocol / service
implementations. While doing so, the SPSR value used is split out to be
more legible.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>

diff --git a/boot.S b/boot.S
index 95dc41efce6fb2e9da9a4afe0f4abe2c306e6ca1..9cc382b08ba53a085f593d58f0f7bf48ae933c07 100644 (file)
--- a/boot.S
+++ b/boot.S
@@ -7,6 +7,8 @@
  * found in the LICENSE.txt file.
  */
 
+#include "common.S"
+
        .text
 
        .globl  _start
@@ -61,10 +63,8 @@ _start:
         * Prepare the switch to the EL2_SP1 mode from EL3
         */
        ldr     x0, =start_ns                   // Return after mode switch
-       mov     x1, #0x3c9                      // EL2_SP1 | D | A | I | F
-       msr     elr_el3, x0
-       msr     spsr_el3, x1
-       eret
+       mov     x1, #SPSR_KERNEL
+       drop_el x1, x0
 
 start_ns:
        /*

diff --git a/common.S b/common.S
new file mode 100644 (file)
index 0000000..d82d11b
--- /dev/null
+++ b/common.S
@@ -0,0 +1,26 @@
+/*
+ * common.S - common definitions useful for boot code
+ *
+ * Copyright (C) 2013 ARM Limited. All rights reserved.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE.txt file.
+ */
+
+#define SPSR_A         (1 << 8)        /* System Error masked */
+#define SPSR_D         (1 << 9)        /* Debug masked */
+#define SPSR_I         (1 << 7)        /* IRQ masked */
+#define SPSR_F         (1 << 6)        /* FIQ masked */
+#define SPSR_EL2H      (9 << 0)        /* EL2 Handler mode */
+
+#define SPSR_KERNEL    (SPSR_A | SPSR_D | SPSR_I | SPSR_F | SPSR_EL2H)
+
+       /*
+        * Drop EL to that specified by the spsr value in register mode, at
+        * the address specified in register addr.
+        */
+       .macro  drop_el mode addr
+       msr     elr_el3, \addr
+       msr     spsr_el3, \mode
+       eret
+       .endm