Hi Michael,
On Thu, Oct 03, 2019 at 07:03:19PM +0000, Michael Kelley wrote:
> Add ARM64-specific code to make Hyper-V hypercalls and to
> access virtual processor synthetic registers via hypercalls.
> Hypercalls use a Hyper-V specific calling sequence with a non-zero
> immediate value per Section 2.9 of the SMC Calling Convention
> spec.
>
> This code is architecture dependent and is mostly driven by
> architecture independent code in the VMbus driver and the
> Hyper-V timer clocksource driver.
>
> This code is built only when CONFIG_HYPERV is enabled.
>
> Signed-off-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>
> ---
> MAINTAINERS | 1 +
> arch/arm64/Kbuild | 1 +
> arch/arm64/hyperv/Makefile | 2 +
> arch/arm64/hyperv/hv_hvc.S | 44 +++++++++++++++
> arch/arm64/hyperv/hv_init.c | 133 ++++++++++++++++++++++++++++++++++++++++++++
> 5 files changed, 181 insertions(+)
> create mode 100644 arch/arm64/hyperv/Makefile
> create mode 100644 arch/arm64/hyperv/hv_hvc.S
> create mode 100644 arch/arm64/hyperv/hv_init.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index d464067..84f76f9 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -7566,6 +7566,7 @@ F: arch/x86/kernel/cpu/mshyperv.c
> F: arch/x86/hyperv
> F: arch/arm64/include/asm/hyperv-tlfs.h
> F: arch/arm64/include/asm/mshyperv.h
> +F: arch/arm64/hyperv
> F: drivers/clocksource/hyperv_timer.c
> F: drivers/hid/hid-hyperv.c
> F: drivers/hv/
> diff --git a/arch/arm64/Kbuild b/arch/arm64/Kbuild
> index d646582..2469421 100644
> --- a/arch/arm64/Kbuild
> +++ b/arch/arm64/Kbuild
> @@ -3,4 +3,5 @@ obj-y += kernel/ mm/
> obj-$(CONFIG_NET) += net/
> obj-$(CONFIG_KVM) += kvm/
> obj-$(CONFIG_XEN) += xen/
> +obj-$(CONFIG_HYPERV) += hyperv/
I did a kernel built with CONFIG_HYPERV=m today, and found out this line
should be (similar to x86):
+obj-$(subst m,y,$(CONFIG_HYPERV)) += hyperv/
, otherwise, when CONFIG_HYPERV=m, files in arch/arm64/hyperv/ will be
compiled as obj-m, and symbols defined in those files cannot be
used by kernel builtin, e.g. hyperv_timer (since CONFIG_HYPERV_TIMER=y
in this case).
A compile/link error I hit today is:
| /home/boqun/linux-arm64/drivers/clocksource/hyperv_timer.c:98: undefined reference to `hv_set_vpreg'
| aarch64-linux-gnu-ld: /home/boqun/linux-arm64/drivers/clocksource/hyperv_timer.c:98: undefined reference to `hv_set_vpreg'
[...]
Besides, another problem I hit when compiled with CONFIG_HYPERV=m is:
| ERROR: "screen_info" [drivers/hv/hv_vmbus.ko] undefined!
, which can be fixed by the following change.
Regards,
Boqun
---------------->8
diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
index d0cf596db82c..8ff557ae5cc6 100644
--- a/arch/arm64/kernel/efi.c
+++ b/arch/arm64/kernel/efi.c
@@ -55,6 +55,7 @@ static __init pteval_t create_mapping_protection(efi_memory_desc_t *md)
/* we will fill this structure from the stub, so don't put it in .bss */
struct screen_info screen_info __section(.data);
+EXPORT_SYMBOL(screen_info);
int __init efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md)
{
