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d18232ea8a
Just like on arm64, and for the same reasons, kvm_call_hyp removes any form of type safety when calling into HYP. But we can still try to tell the compiler what we're trying to achieve. Here, we can add code that would do the function call if it wasn't guarded by an always-false predicate. Hopefully, the compiler is dumb enough to do the type checking and clever enough to not emit the corresponding code... Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Acked-by: Christoffer Dall <christoffer.dall@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
49 lines
1.8 KiB
ArmAsm
49 lines
1.8 KiB
ArmAsm
/*
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* Copyright (C) 2012 - Virtual Open Systems and Columbia University
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* Author: Christoffer Dall <c.dall@virtualopensystems.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License, version 2, as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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#include <linux/linkage.h>
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.text
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/********************************************************************
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* Call function in Hyp mode
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*
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*
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* unsigned long kvm_call_hyp(void *hypfn, ...);
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*
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* This is not really a variadic function in the classic C-way and care must
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* be taken when calling this to ensure parameters are passed in registers
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* only, since the stack will change between the caller and the callee.
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*
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* Call the function with the first argument containing a pointer to the
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* function you wish to call in Hyp mode, and subsequent arguments will be
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* passed as r0, r1, and r2 (a maximum of 3 arguments in addition to the
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* function pointer can be passed). The function being called must be mapped
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* in Hyp mode (see init_hyp_mode in arch/arm/kvm/arm.c). Return values are
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* passed in r0 (strictly 32bit).
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*
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* The calling convention follows the standard AAPCS:
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* r0 - r3: caller save
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* r12: caller save
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* rest: callee save
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*/
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ENTRY(__kvm_call_hyp)
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hvc #0
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bx lr
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ENDPROC(__kvm_call_hyp)
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