[U-Boot,v2,1/3] ARM: HYP/non-sec: migrate stack

Message ID 20180613221645.12992-2-kettenis@openbsd.org
State Superseded
Delegated to: Alexander Graf
Headers show
  • efi_loader: ARM: add support for ARMV7_NONSEC=y
Related show

Commit Message

Mark Kettenis June 13, 2018, 10:16 p.m.
The current code that switches into HYP mode doesn't bother to set
up a stack for HYP mode.  This doesn't work for EFI applications
as they expect a usable stack.  Fix this by migrating the stack
pointer from SP_svc to SP_hyp while in Monitor mode.
This restores the stack pointer when we drop into HYP mode.

Signed-off-by: Mark Kettenis <kettenis@openbsd.org>
 arch/arm/cpu/armv7/nonsec_virt.S | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)


diff --git a/arch/arm/cpu/armv7/nonsec_virt.S b/arch/arm/cpu/armv7/nonsec_virt.S
index 56bdba1d38..a7764c1458 100644
--- a/arch/arm/cpu/armv7/nonsec_virt.S
+++ b/arch/arm/cpu/armv7/nonsec_virt.S
@@ -52,9 +52,9 @@  _secure_monitor:
 	bl	psci_stack_setup
 	@ Configure the PSCI backend
-	push	{r0, r1, r2, ip}
+	push	{r0, r1, r2, r3, ip}
 	bl	psci_arch_init
-	pop	{r0, r1, r2, ip}
+	pop	{r0, r1, r2, r3, ip}
 #ifdef CONFIG_ARM_ERRATA_773022
@@ -80,6 +80,8 @@  _secure_monitor:
 	orreq	r5, r5, #0x100			@ allow HVC instruction
 	moveq	r6, #HYP_MODE			@ Enter the kernel as HYP
+	mrseq	r3, sp_svc
+	msreq	sp_hyp, r3			@ migrate SP
 	mcr	p15, 0, r5, c1, c1, 0		@ write SCR (with NS bit set)