ARM: extend non-secure switch to also go into HYP mode

For the KVM and XEN hypervisors to be usable, we need to enter the
kernel in HYP mode. Now that we already are in non-secure state,
HYP mode switching is within short reach.

While doing the non-secure switch, we have to enable the HVC
instruction and setup the HYP mode HVBAR (while still secure).

The actual switch is done by dropping back from a HYP mode handler
without actually leaving HYP mode, so we introduce a new handler
routine in our new secure exception vector table.

In the assembly switching routine we save and restore the banked LR
and SP registers around the hypercall to do the actual HYP mode
switch.

The C routine first checks whether we are in HYP mode already and
also whether the virtualization extensions are available. It also
checks whether the HYP mode switch was finally successful.
The bootm command part only calls the new function after the
non-secure switch.

Signed-off-by: Andre Przywara <andre.przywara@linaro.org>

1 files changed, 6 insertions, 1 deletions

diff --git a/arch/arm/lib/bootm.c b/arch/arm/lib/bootm.c
index b3a961a825..f476a89702 100644
--- a/arch/arm/lib/bootm.c
+++ b/arch/arm/lib/bootm.c
@@ -22,7 +22,7 @@
 #include <asm/bootm.h>
 #include <linux/compiler.h>
 
-#ifdef CONFIG_ARMV7_NONSEC
+#if defined(CONFIG_ARMV7_NONSEC) || defined(CONFIG_ARMV7_VIRT)
 #include <asm/armv7.h>
 #endif
 
@@ -189,8 +189,13 @@ static void do_nonsec_virt_switch(void)
 {
 #if defined(CONFIG_ARMV7_NONSEC) || defined(CONFIG_ARMV7_VIRT)
 	if (armv7_switch_nonsec() == 0)
+#ifdef CONFIG_ARMV7_VIRT
+		if (armv7_switch_hyp() == 0)
+			debug("entered HYP mode\n");
+#else
 		debug("entered non-secure state\n");
 #endif
+#endif
 }
 
 /* Subcommand: PREP */