On 06/11/2022 19:12, Julien Grall wrote:
Hi Wei,
On 04/11/2022 10:07, Wei Chen wrote:
Current EFI boot services support of Arm64 could not
work well for Armv8-R64 system that only has MPU in
EL2. That is because EFI boot services may need some
relocation support or partial PIE/PIC support.
I am a bit confused with argument. We have nothing in Xen today to deal
with relocation/partial PIE/PIC support. So what is the exact problem?
Is it because UEFI can load Xen anywwhere?
But these will not be supported in the initial stage of
porting Xen to MPU systems. So in this patch, we
disable EFI boot services support for Arm MPU systems.
Signed-off-by: Wei Chen <wei.c...@arm.com>
---
xen/arch/arm/Kconfig | 2 +-
xen/arch/arm/arm64/head.S | 8 ++++++--
2 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig
index 1fe5faf847..ad592367bd 100644
--- a/xen/arch/arm/Kconfig
+++ b/xen/arch/arm/Kconfig
@@ -7,7 +7,7 @@ config ARM_64
def_bool y
depends on !ARM_32
select 64BIT
- select ARM_EFI
+ select ARM_EFI if !HAS_MPU
I think it would make sense to allow ARM_EFI to be disabled even without
the MPU support. So this would remove nearly 3K lines (just using wc -l
*.c in the efi directories) for someone that don't need to boot using EFI.
select HAS_FAST_MULTIPLY
config ARM
diff --git a/xen/arch/arm/arm64/head.S b/xen/arch/arm/arm64/head.S
index ad014716db..ccedf20dc7 100644
--- a/xen/arch/arm/arm64/head.S
+++ b/xen/arch/arm/arm64/head.S
@@ -172,8 +172,10 @@ efi_head:
.byte 0x52
.byte 0x4d
.byte 0x64
- .long pe_header - efi_head /* Offset to the PE
header. */
-
+#ifndef CONFIG_ARM_EFI
+ .long 0 /* 0 means no PE header. */
+#else
+ .long pe_header - efi_head /* Offset to the PE header. */
/*
* Add the PE/COFF header to the file. The address of this
header
* is at offset 0x3c in the file, and is part of Linux "Image"
@@ -279,6 +281,8 @@ section_table:
.short 0 /* NumberOfLineNumbers (0 for
executables) */
.long 0xe0500020 /* Characteristics (section flags) */
.align 5
+#endif /* CONFIG_ARM_EFI */
+
real_start:
/* BSS should be zeroed when booting without EFI */
mov x26, #0 /* x26 := skip_zero_bss */
Shouldn't the function efi_xen_start be stubbed as well?
Sorry, I mean protected rather than stubbed because there will be no
user when !CONFIG_ARM_EFI.
Cheers,
--
Julien Grall
