Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm

Pull ARM fixes from Russell King:

 - fix for "hex" Kconfig default to use 0x0 rather than 0 to allow these
   to be removed from defconfigs

 - fix from Ard Biesheuvel for EFI HYP mode booting

* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
  ARM: 8985/1: efi/decompressor: deal with HYP mode boot gracefully
  ARM: 8984/1: Kconfig: set default ZBOOT_ROM_TEXT/BSS value to 0x0

2 files changed, 64 insertions, 2 deletions

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index bbac2867062d87..8789e0e96787dd 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1749,7 +1749,7 @@ config DEPRECATED_PARAM_STRUCT
 # TEXT and BSS so we preserve their values in the config files.
 config ZBOOT_ROM_TEXT
 	hex "Compressed ROM boot loader base address"
-	default "0"
+	default 0x0
 	help
 	  The physical address at which the ROM-able zImage is to be
 	  placed in the target.  Platforms which normally make use of
@@ -1760,7 +1760,7 @@ config ZBOOT_ROM_TEXT
 
 config ZBOOT_ROM_BSS
 	hex "Compressed ROM boot loader BSS address"
-	default "0"
+	default 0x0
 	help
 	  The base address of an area of read/write memory in the target
 	  for the ROM-able zImage which must be available while the
diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
index c79db44ba1284b..434a16982e344f 100644
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -1410,7 +1410,11 @@ memdump:	mov	r12, r0
 __hyp_reentry_vectors:
 		W(b)	.			@ reset
 		W(b)	.			@ undef
+#ifdef CONFIG_EFI_STUB
+		W(b)	__enter_kernel_from_hyp	@ hvc from HYP
+#else
 		W(b)	.			@ svc
+#endif
 		W(b)	.			@ pabort
 		W(b)	.			@ dabort
 		W(b)	__enter_kernel		@ hyp
@@ -1429,14 +1433,72 @@ __enter_kernel:
 reloc_code_end:
 
 #ifdef CONFIG_EFI_STUB
+__enter_kernel_from_hyp:
+		mrc	p15, 4, r0, c1, c0, 0	@ read HSCTLR
+		bic	r0, r0, #0x5		@ disable MMU and caches
+		mcr	p15, 4, r0, c1, c0, 0	@ write HSCTLR
+		isb
+		b	__enter_kernel
+
 ENTRY(efi_enter_kernel)
 		mov	r4, r0			@ preserve image base
 		mov	r8, r1			@ preserve DT pointer
 
+ ARM(		adrl	r0, call_cache_fn	)
+ THUMB(		adr	r0, call_cache_fn	)
+		adr	r1, 0f			@ clean the region of code we
+		bl	cache_clean_flush	@ may run with the MMU off
+
+#ifdef CONFIG_ARM_VIRT_EXT
+		@
+		@ The EFI spec does not support booting on ARM in HYP mode,
+		@ since it mandates that the MMU and caches are on, with all
+		@ 32-bit addressable DRAM mapped 1:1 using short descriptors.
+		@
+		@ While the EDK2 reference implementation adheres to this,
+		@ U-Boot might decide to enter the EFI stub in HYP mode
+		@ anyway, with the MMU and caches either on or off.
+		@
+		mrs	r0, cpsr		@ get the current mode
+		msr	spsr_cxsf, r0		@ record boot mode
+		and	r0, r0, #MODE_MASK	@ are we running in HYP mode?
+		cmp	r0, #HYP_MODE
+		bne	.Lefi_svc
+
+		mrc	p15, 4, r1, c1, c0, 0	@ read HSCTLR
+		tst	r1, #0x1		@ MMU enabled at HYP?
+		beq	1f
+
+		@
+		@ When running in HYP mode with the caches on, we're better
+		@ off just carrying on using the cached 1:1 mapping that the
+		@ firmware provided. Set up the HYP vectors so HVC instructions
+		@ issued from HYP mode take us to the correct handler code. We
+		@ will disable the MMU before jumping to the kernel proper.
+		@
+		adr	r0, __hyp_reentry_vectors
+		mcr	p15, 4, r0, c12, c0, 0	@ set HYP vector base (HVBAR)
+		isb
+		b	.Lefi_hyp
+
+		@
+		@ When running in HYP mode with the caches off, we need to drop
+		@ into SVC mode now, and let the decompressor set up its cached
+		@ 1:1 mapping as usual.
+		@
+1:		mov	r9, r4			@ preserve image base
+		bl	__hyp_stub_install	@ install HYP stub vectors
+		safe_svcmode_maskall	r1	@ drop to SVC mode
+		msr	spsr_cxsf, r0		@ record boot mode
+		orr	r4, r9, #1		@ restore image base and set LSB
+		b	.Lefi_hyp
+.Lefi_svc:
+#endif
 		mrc	p15, 0, r0, c1, c0, 0	@ read SCTLR
 		tst	r0, #0x1		@ MMU enabled?
 		orreq	r4, r4, #1		@ set LSB if not
 
+.Lefi_hyp:
 		mov	r0, r8			@ DT start
 		add	r1, r8, r2		@ DT end
 		bl	cache_clean_flush