From 39c3e304567a013ac096ca8747fe53b44a76e44b Mon Sep 17 00:00:00 2001 From: Chris Packham Date: Tue, 9 Jun 2020 03:28:14 +0100 Subject: ARM: 8984/1: Kconfig: set default ZBOOT_ROM_TEXT/BSS value to 0x0 ZBOOT_ROM_TEXT and ZBOOT_ROM_BSS are defined as 'hex' but had a default of "0". Kconfig will helpfully expand a text entry of 0 to 0x0 but because this is not the same as the default value it was treated as being explicitly set when running 'make savedefconfig' so most arm defconfigs have CONFIG_ZBOOT_ROM_TEXT=0x0 and CONFIG_ZBOOT_ROM_BSS=0x0. Change the default to 0x0 which will mean next time the defconfigs are re-generated the spurious config entries will be removed. Signed-off-by: Chris Packham Signed-off-by: Russell King --- arch/arm/Kconfig | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index bbac2867062d..8789e0e96787 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 -- cgit v1.2.3 From db227c19e68db353e4cc6c99b6bc86bb24736943 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Fri, 12 Jun 2020 11:21:35 +0100 Subject: ARM: 8985/1: efi/decompressor: deal with HYP mode boot gracefully EFI on ARM only supports short descriptors, and given that it mandates that the MMU and caches are on, it is implied that booting in HYP mode is not supported. However, implementations of EFI exist (i.e., U-Boot) that ignore this requirement, which is not entirely unreasonable, given that it makes HYP mode inaccessible to the operating system. So let's make sure that we can deal with this condition gracefully. We already tolerate booting the EFI stub with the caches off (even though this violates the EFI spec as well), and so we should deal with HYP mode boot with MMU and caches either on or off. - When the MMU and caches are on, we can ignore the HYP stub altogether, since we can carry on executing at HYP. We do need to ensure that we disable the MMU at HYP before entering the kernel proper. - When the MMU and caches are off, we have to drop to SVC mode so that we can set up the page tables using short descriptors. In this case, we need to install the HYP stub as usual, so that we can return to HYP mode before handing over to the kernel proper. Tested-by: Heinrich Schuchardt Signed-off-by: Ard Biesheuvel Signed-off-by: Russell King --- arch/arm/boot/compressed/head.S | 62 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 62 insertions(+) diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S index c79db44ba128..434a16982e34 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 -- cgit v1.2.3