linux/arch/arm64/kvm/hyp.S
Ard Biesheuvel a0bf9776cd arm64: kvm: deal with kernel symbols outside of linear mapping
KVM on arm64 uses a fixed offset between the linear mapping at EL1 and
the HYP mapping at EL2. Before we can move the kernel virtual mapping
out of the linear mapping, we have to make sure that references to kernel
symbols that are accessed via the HYP mapping are translated to their
linear equivalent.

Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2016-02-18 18:16:40 +00:00

44 lines
1.6 KiB
ArmAsm

/*
* Copyright (C) 2012,2013 - ARM Ltd
* Author: Marc Zyngier <marc.zyngier@arm.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
/*
* u64 __kvm_call_hyp(void *hypfn, ...);
*
* This is not really a variadic function in the classic C-way and care must
* be taken when calling this to ensure parameters are passed in registers
* only, since the stack will change between the caller and the callee.
*
* Call the function with the first argument containing a pointer to the
* function you wish to call in Hyp mode, and subsequent arguments will be
* passed as x0, x1, and x2 (a maximum of 3 arguments in addition to the
* function pointer can be passed). The function being called must be mapped
* in Hyp mode (see init_hyp_mode in arch/arm/kvm/arm.c). Return values are
* passed in x0.
*
* A function pointer with a value of 0 has a special meaning, and is
* used to implement __hyp_get_vectors in the same way as in
* arch/arm64/kernel/hyp_stub.S.
*/
ENTRY(__kvm_call_hyp)
hvc #0
ret
ENDPROC(__kvm_call_hyp)