78fd6dcf11
We currently have the SCTLR_EL2.A bit set, trapping unaligned accesses at EL2, but we're not really prepared to deal with it. So far, this has been unnoticed, until GCC 7 started emitting those (in particular 64bit writes on a 32bit boundary). Since the rest of the kernel is pretty happy about that, let's follow its example and set SCTLR_EL2.A to zero. Modern CPUs don't really care. Cc: stable@vger.kernel.org Reported-by: Alexander Graf <agraf@suse.de> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <cdall@linaro.org>
171 lines
4 KiB
ArmAsm
171 lines
4 KiB
ArmAsm
/*
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* Copyright (C) 2012,2013 - ARM Ltd
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* Author: Marc Zyngier <marc.zyngier@arm.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, see <http://www.gnu.org/licenses/>.
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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/kvm_arm.h>
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#include <asm/kvm_mmu.h>
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#include <asm/pgtable-hwdef.h>
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#include <asm/sysreg.h>
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#include <asm/virt.h>
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.text
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.pushsection .hyp.idmap.text, "ax"
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.align 11
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ENTRY(__kvm_hyp_init)
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ventry __invalid // Synchronous EL2t
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ventry __invalid // IRQ EL2t
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ventry __invalid // FIQ EL2t
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ventry __invalid // Error EL2t
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ventry __invalid // Synchronous EL2h
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ventry __invalid // IRQ EL2h
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ventry __invalid // FIQ EL2h
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ventry __invalid // Error EL2h
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ventry __do_hyp_init // Synchronous 64-bit EL1
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ventry __invalid // IRQ 64-bit EL1
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ventry __invalid // FIQ 64-bit EL1
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ventry __invalid // Error 64-bit EL1
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ventry __invalid // Synchronous 32-bit EL1
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ventry __invalid // IRQ 32-bit EL1
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ventry __invalid // FIQ 32-bit EL1
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ventry __invalid // Error 32-bit EL1
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__invalid:
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b .
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/*
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* x0: HYP pgd
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* x1: HYP stack
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* x2: HYP vectors
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*/
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__do_hyp_init:
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/* Check for a stub HVC call */
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cmp x0, #HVC_STUB_HCALL_NR
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b.lo __kvm_handle_stub_hvc
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msr ttbr0_el2, x0
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mrs x4, tcr_el1
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ldr x5, =TCR_EL2_MASK
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and x4, x4, x5
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mov x5, #TCR_EL2_RES1
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orr x4, x4, x5
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#ifndef CONFIG_ARM64_VA_BITS_48
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/*
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* If we are running with VA_BITS < 48, we may be running with an extra
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* level of translation in the ID map. This is only the case if system
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* RAM is out of range for the currently configured page size and number
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* of translation levels, in which case we will also need the extra
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* level for the HYP ID map, or we won't be able to enable the EL2 MMU.
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*
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* However, at EL2, there is only one TTBR register, and we can't switch
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* between translation tables *and* update TCR_EL2.T0SZ at the same
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* time. Bottom line: we need the extra level in *both* our translation
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* tables.
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*
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* So use the same T0SZ value we use for the ID map.
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*/
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ldr_l x5, idmap_t0sz
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bfi x4, x5, TCR_T0SZ_OFFSET, TCR_TxSZ_WIDTH
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#endif
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/*
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* Read the PARange bits from ID_AA64MMFR0_EL1 and set the PS bits in
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* TCR_EL2.
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*/
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mrs x5, ID_AA64MMFR0_EL1
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bfi x4, x5, #16, #3
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msr tcr_el2, x4
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mrs x4, mair_el1
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msr mair_el2, x4
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isb
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/* Invalidate the stale TLBs from Bootloader */
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tlbi alle2
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dsb sy
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/*
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* Preserve all the RES1 bits while setting the default flags,
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* as well as the EE bit on BE. Drop the A flag since the compiler
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* is allowed to generate unaligned accesses.
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*/
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ldr x4, =(SCTLR_EL2_RES1 | (SCTLR_ELx_FLAGS & ~SCTLR_ELx_A))
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CPU_BE( orr x4, x4, #SCTLR_ELx_EE)
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msr sctlr_el2, x4
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isb
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/* Set the stack and new vectors */
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kern_hyp_va x1
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mov sp, x1
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kern_hyp_va x2
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msr vbar_el2, x2
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/* Hello, World! */
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eret
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ENDPROC(__kvm_hyp_init)
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ENTRY(__kvm_handle_stub_hvc)
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cmp x0, #HVC_SOFT_RESTART
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b.ne 1f
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/* This is where we're about to jump, staying at EL2 */
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msr elr_el2, x1
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mov x0, #(PSR_F_BIT | PSR_I_BIT | PSR_A_BIT | PSR_D_BIT | PSR_MODE_EL2h)
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msr spsr_el2, x0
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/* Shuffle the arguments, and don't come back */
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mov x0, x2
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mov x1, x3
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mov x2, x4
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b reset
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1: cmp x0, #HVC_RESET_VECTORS
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b.ne 1f
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reset:
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/*
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* Reset kvm back to the hyp stub. Do not clobber x0-x4 in
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* case we coming via HVC_SOFT_RESTART.
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*/
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mrs x5, sctlr_el2
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ldr x6, =SCTLR_ELx_FLAGS
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bic x5, x5, x6 // Clear SCTL_M and etc
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msr sctlr_el2, x5
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isb
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/* Install stub vectors */
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adr_l x5, __hyp_stub_vectors
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msr vbar_el2, x5
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mov x0, xzr
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eret
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1: /* Bad stub call */
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ldr x0, =HVC_STUB_ERR
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eret
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ENDPROC(__kvm_handle_stub_hvc)
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.ltorg
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.popsection
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