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6ebbf2ce43
ARMv6 and greater introduced a new instruction ("bx") which can be used
to return from function calls. Recent CPUs perform better when the
"bx lr" instruction is used rather than the "mov pc, lr" instruction,
and this sequence is strongly recommended to be used by the ARM
architecture manual (section A.4.1.1).
We provide a new macro "ret" with all its variants for the condition
code which will resolve to the appropriate instruction.
Rather than doing this piecemeal, and miss some instances, change all
the "mov pc" instances to use the new macro, with the exception of
the "movs" instruction and the kprobes code. This allows us to detect
the "mov pc, lr" case and fix it up - and also gives us the possibility
of deploying this for other registers depending on the CPU selection.
Reported-by: Will Deacon <will.deacon@arm.com>
Tested-by: Stephen Warren <swarren@nvidia.com> # Tegra Jetson TK1
Tested-by: Robert Jarzmik <robert.jarzmik@free.fr> # mioa701_bootresume.S
Tested-by: Andrew Lunn <andrew@lunn.ch> # Kirkwood
Tested-by: Shawn Guo <shawn.guo@freescale.com>
Tested-by: Tony Lindgren <tony@atomide.com> # OMAPs
Tested-by: Gregory CLEMENT <gregory.clement@free-electrons.com> # Armada XP, 375, 385
Acked-by: Sekhar Nori <nsekhar@ti.com> # DaVinci
Acked-by: Christoffer Dall <christoffer.dall@linaro.org> # kvm/hyp
Acked-by: Haojian Zhuang <haojian.zhuang@gmail.com> # PXA3xx
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> # Xen
Tested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> # ARMv7M
Tested-by: Simon Horman <horms+renesas@verge.net.au> # Shmobile
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
106 lines
3.3 KiB
ArmAsm
106 lines
3.3 KiB
ArmAsm
/******************************************************************************
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* hypercall.S
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*
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* Xen hypercall wrappers
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*
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* Stefano Stabellini <stefano.stabellini@eu.citrix.com>, Citrix, 2012
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License version 2
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* as published by the Free Software Foundation; or, when distributed
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* separately from the Linux kernel or incorporated into other
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* software packages, subject to the following license:
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this source file (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use, copy, modify,
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* merge, publish, distribute, sublicense, and/or sell copies of the Software,
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* and to permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*/
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/*
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* The Xen hypercall calling convention is very similar to the ARM
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* procedure calling convention: the first paramter is passed in r0, the
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* second in r1, the third in r2 and the fourth in r3. Considering that
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* Xen hypercalls have 5 arguments at most, the fifth paramter is passed
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* in r4, differently from the procedure calling convention of using the
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* stack for that case.
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*
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* The hypercall number is passed in r12.
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*
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* The return value is in r0.
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*
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* The hvc ISS is required to be 0xEA1, that is the Xen specific ARM
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* hypercall tag.
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*/
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#include <linux/linkage.h>
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#include <asm/assembler.h>
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#include <asm/opcodes-virt.h>
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#include <xen/interface/xen.h>
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#define XEN_IMM 0xEA1
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#define HYPERCALL_SIMPLE(hypercall) \
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ENTRY(HYPERVISOR_##hypercall) \
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mov r12, #__HYPERVISOR_##hypercall; \
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__HVC(XEN_IMM); \
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ret lr; \
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ENDPROC(HYPERVISOR_##hypercall)
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#define HYPERCALL0 HYPERCALL_SIMPLE
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#define HYPERCALL1 HYPERCALL_SIMPLE
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#define HYPERCALL2 HYPERCALL_SIMPLE
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#define HYPERCALL3 HYPERCALL_SIMPLE
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#define HYPERCALL4 HYPERCALL_SIMPLE
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#define HYPERCALL5(hypercall) \
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ENTRY(HYPERVISOR_##hypercall) \
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stmdb sp!, {r4} \
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ldr r4, [sp, #4] \
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mov r12, #__HYPERVISOR_##hypercall; \
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__HVC(XEN_IMM); \
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ldm sp!, {r4} \
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ret lr \
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ENDPROC(HYPERVISOR_##hypercall)
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.text
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HYPERCALL2(xen_version);
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HYPERCALL3(console_io);
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HYPERCALL3(grant_table_op);
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HYPERCALL2(sched_op);
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HYPERCALL2(event_channel_op);
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HYPERCALL2(hvm_op);
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HYPERCALL2(memory_op);
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HYPERCALL2(physdev_op);
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HYPERCALL3(vcpu_op);
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HYPERCALL1(tmem_op);
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HYPERCALL2(multicall);
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ENTRY(privcmd_call)
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stmdb sp!, {r4}
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mov r12, r0
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mov r0, r1
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mov r1, r2
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mov r2, r3
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ldr r3, [sp, #8]
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ldr r4, [sp, #4]
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__HVC(XEN_IMM)
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ldm sp!, {r4}
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ret lr
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ENDPROC(privcmd_call);
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