arm: highbank: Implement PSCI and dummy monitor

Firstly, enable monitor mode and PSCI, both of which are features of
this board.

In addition to PSCI, this board also uses SMC for cache maintenance
ops. This means we need a secure monitor to catch these and nop them.
Use the ARM boot board-setup feature to implement this. The SMC trap
implements the needed nop while all other traps will pen the CPU.

As a KVM CPU cannot run in secure mode, do not do the board-setup if
not running TCG. Report a warning explaining the limitation in this
case.
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NPeter Crosthwaite <crosthwaite.peter@gmail.com>
Message-id: 0fd0d12f0fa666c86616c89447861a70dbe27312.1447007690.git.crosthwaite.peter@gmail.com
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

hw/arm/highbank.c

@@ -22,6 +22,7 @@
 #include "hw/devices.h"
 #include "hw/loader.h"
 #include "net/net.h"
+#include "sysemu/kvm.h"
 #include "sysemu/sysemu.h"
 #include "hw/boards.h"
 #include "sysemu/block-backend.h"
@@ -32,10 +33,52 @@
 #define SMP_BOOT_REG            0x40
 #define MPCORE_PERIPHBASE       0xfff10000
 
+#define MVBAR_ADDR              0x200
+
 #define NIRQ_GIC                160
 
 /* Board init.  */
 
+/* MVBAR_ADDR is limited by precision of movw */
+
+QEMU_BUILD_BUG_ON(MVBAR_ADDR >= (1 << 16));
+
+#define ARMV7_IMM16(x) (extract32((x),  0, 12) | \
+                        extract32((x), 12,  4) << 16)
+
+static void hb_write_board_setup(ARMCPU *cpu,
+                                 const struct arm_boot_info *info)
+{
+    int n;
+    uint32_t board_setup_blob[] = {
+        /* MVBAR_ADDR */
+        /* Default unimplemented and unused vectors to spin. Makes it
+         * easier to debug (as opposed to the CPU running away).
+         */
+        0xeafffffe, /* notused1: b notused */
+        0xeafffffe, /* notused2: b notused */
+        0xe1b0f00e, /* smc: movs pc, lr - exception return */
+        0xeafffffe, /* prefetch_abort: b prefetch_abort */
+        0xeafffffe, /* data_abort: b data_abort */
+        0xeafffffe, /* notused3: b notused3 */
+        0xeafffffe, /* irq: b irq */
+        0xeafffffe, /* fiq: b fiq */
+#define BOARD_SETUP_ADDR (MVBAR_ADDR + 8 * sizeof(uint32_t))
+        0xe3000000 + ARMV7_IMM16(MVBAR_ADDR), /* movw r0, MVBAR_ADDR */
+        0xee0c0f30, /* mcr p15, 0, r0, c12, c0, 1 - set MVBAR */
+        0xee110f11, /* mrc p15, 0, r0, c1 , c1, 0 - get SCR */
+        0xe3810001, /* orr r0, #1 - set NS */
+        0xee010f11, /* mcr p15, 0, r0, c1 , c1, 0 - set SCR */
+        0xe1600070, /* smc - go to monitor mode to flush NS change */
+        0xe12fff1e, /* bx lr - return to caller */
+    };
+    for (n = 0; n < ARRAY_SIZE(board_setup_blob); n++) {
+        board_setup_blob[n] = tswap32(board_setup_blob[n]);
+    }
+    rom_add_blob_fixed("board-setup", board_setup_blob,
+                       sizeof(board_setup_blob), MVBAR_ADDR);
+}
+
 static void hb_write_secondary(ARMCPU *cpu, const struct arm_boot_info *info)
 {
     int n;
@@ -241,16 +284,13 @@ static void calxeda_init(MachineState *machine, enum cxmachines machine_id)
         cpuobj = object_new(object_class_get_name(oc));
         cpu = ARM_CPU(cpuobj);
 
-        /* By default A9 and A15 CPUs have EL3 enabled.  This board does not
-         * currently support EL3 so the CPU EL3 property is disabled before
-         * realization.
-         */
-        if (object_property_find(cpuobj, "has_el3", NULL)) {
-            object_property_set_bool(cpuobj, false, "has_el3", &err);
-            if (err) {
-                error_report_err(err);
-                exit(1);
-            }
+        object_property_set_int(cpuobj, QEMU_PSCI_CONDUIT_SMC,
+                                "psci-conduit", &error_abort);
+
+        if (n) {
+            /* Secondary CPUs start in PSCI powered-down state */
+            object_property_set_bool(cpuobj, true,
+                                     "start-powered-off", &error_abort);
         }
 
         if (object_property_find(cpuobj, "reset-cbar", NULL)) {
@@ -371,6 +411,16 @@ static void calxeda_init(MachineState *machine, enum cxmachines machine_id)
     highbank_binfo.loader_start = 0;
     highbank_binfo.write_secondary_boot = hb_write_secondary;
     highbank_binfo.secondary_cpu_reset_hook = hb_reset_secondary;
+    if (!kvm_enabled()) {
+        highbank_binfo.board_setup_addr = BOARD_SETUP_ADDR;
+        highbank_binfo.write_board_setup = hb_write_board_setup;
+        highbank_binfo.secure_board_setup = true;
+    } else {
+        error_report("WARNING: cannot load built-in Monitor support "
+                     "if KVM is enabled. Some guests (such as Linux) "
+                     "may not boot.");
+    }
+
     arm_load_kernel(ARM_CPU(first_cpu), &highbank_binfo);
 }