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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>
156 lines
4.3 KiB
ArmAsm
156 lines
4.3 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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#include <asm/assembler.h>
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#include <asm/unified.h>
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#include <asm/asm-offsets.h>
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#include <asm/kvm_asm.h>
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#include <asm/kvm_arm.h>
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#include <asm/kvm_mmu.h>
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/********************************************************************
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* Hypervisor initialization
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* - should be called with:
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* r0 = top of Hyp stack (kernel VA)
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* r1 = pointer to hyp vectors
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* r2,r3 = Hypervisor pgd pointer
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*
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* The init scenario is:
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* - We jump in HYP with four parameters: boot HYP pgd, runtime HYP pgd,
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* runtime stack, runtime vectors
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* - Enable the MMU with the boot pgd
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* - Jump to a target into the trampoline page (remember, this is the same
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* physical page!)
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* - Now switch to the runtime pgd (same VA, and still the same physical
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* page!)
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* - Invalidate TLBs
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* - Set stack and vectors
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* - Profit! (or eret, if you only care about the code).
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*
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* As we only have four registers available to pass parameters (and we
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* need six), we split the init in two phases:
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* - Phase 1: r0 = 0, r1 = 0, r2,r3 contain the boot PGD.
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* Provides the basic HYP init, and enable the MMU.
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* - Phase 2: r0 = ToS, r1 = vectors, r2,r3 contain the runtime PGD.
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* Switches to the runtime PGD, set stack and vectors.
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*/
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.text
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.pushsection .hyp.idmap.text,"ax"
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.align 5
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__kvm_hyp_init:
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.globl __kvm_hyp_init
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@ Hyp-mode exception vector
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W(b) .
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W(b) .
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W(b) .
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W(b) .
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W(b) .
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W(b) __do_hyp_init
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W(b) .
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W(b) .
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__do_hyp_init:
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cmp r0, #0 @ We have a SP?
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bne phase2 @ Yes, second stage init
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@ Set the HTTBR to point to the hypervisor PGD pointer passed
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mcrr p15, 4, r2, r3, c2
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@ Set the HTCR and VTCR to the same shareability and cacheability
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@ settings as the non-secure TTBCR and with T0SZ == 0.
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mrc p15, 4, r0, c2, c0, 2 @ HTCR
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ldr r2, =HTCR_MASK
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bic r0, r0, r2
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mrc p15, 0, r1, c2, c0, 2 @ TTBCR
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and r1, r1, #(HTCR_MASK & ~TTBCR_T0SZ)
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orr r0, r0, r1
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mcr p15, 4, r0, c2, c0, 2 @ HTCR
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mrc p15, 4, r1, c2, c1, 2 @ VTCR
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ldr r2, =VTCR_MASK
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bic r1, r1, r2
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bic r0, r0, #(~VTCR_HTCR_SH) @ clear non-reusable HTCR bits
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orr r1, r0, r1
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orr r1, r1, #(KVM_VTCR_SL0 | KVM_VTCR_T0SZ | KVM_VTCR_S)
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mcr p15, 4, r1, c2, c1, 2 @ VTCR
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@ Use the same memory attributes for hyp. accesses as the kernel
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@ (copy MAIRx ro HMAIRx).
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mrc p15, 0, r0, c10, c2, 0
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mcr p15, 4, r0, c10, c2, 0
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mrc p15, 0, r0, c10, c2, 1
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mcr p15, 4, r0, c10, c2, 1
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@ Set the HSCTLR to:
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@ - ARM/THUMB exceptions: Kernel config (Thumb-2 kernel)
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@ - Endianness: Kernel config
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@ - Fast Interrupt Features: Kernel config
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@ - Write permission implies XN: disabled
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@ - Instruction cache: enabled
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@ - Data/Unified cache: enabled
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@ - Memory alignment checks: enabled
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@ - MMU: enabled (this code must be run from an identity mapping)
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mrc p15, 4, r0, c1, c0, 0 @ HSCR
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ldr r2, =HSCTLR_MASK
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bic r0, r0, r2
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mrc p15, 0, r1, c1, c0, 0 @ SCTLR
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ldr r2, =(HSCTLR_EE | HSCTLR_FI | HSCTLR_I | HSCTLR_C)
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and r1, r1, r2
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ARM( ldr r2, =(HSCTLR_M | HSCTLR_A) )
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THUMB( ldr r2, =(HSCTLR_M | HSCTLR_A | HSCTLR_TE) )
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orr r1, r1, r2
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orr r0, r0, r1
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isb
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mcr p15, 4, r0, c1, c0, 0 @ HSCR
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@ End of init phase-1
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eret
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phase2:
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@ Set stack pointer
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mov sp, r0
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@ Set HVBAR to point to the HYP vectors
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mcr p15, 4, r1, c12, c0, 0 @ HVBAR
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@ Jump to the trampoline page
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ldr r0, =TRAMPOLINE_VA
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adr r1, target
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bfi r0, r1, #0, #PAGE_SHIFT
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ret r0
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target: @ We're now in the trampoline code, switch page tables
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mcrr p15, 4, r2, r3, c2
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isb
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@ Invalidate the old TLBs
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mcr p15, 4, r0, c8, c7, 0 @ TLBIALLH
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dsb ish
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eret
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.ltorg
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.globl __kvm_hyp_init_end
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__kvm_hyp_init_end:
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.popsection
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