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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Minios-devel] [UNIKRAFT PATCHv5 21/46] plat/common: Add cache maintenance support for arm64
Hi, On 10/08/18 08:08, Wei Chen wrote: When MMU is disabled, when we modify some data, for example, write page-table, we will write with Device nGnRnE attributes. So the cache will be bypassed. But the cache may still contain stall data that we will hit when enabling MMU and cache. To prevent such issue, we need to clean the cache potentially before and after updating the page-table area. So we introduce the cache maintenance functions in this patch. Signed-off-by: Wei Chen <wei.chen@xxxxxxx> --- plat/common/arm/cache64.S | 98 ++++++++++++++++++++++++ plat/common/include/arm/arm64/cpu_defs.h | 60 +++++++++++++++ plat/common/include/arm/cpu_defs.h | 44 +++++++++++ plat/kvm/Makefile.uk | 1 + 4 files changed, 203 insertions(+) create mode 100644 plat/common/arm/cache64.S create mode 100644 plat/common/include/arm/arm64/cpu_defs.h create mode 100644 plat/common/include/arm/cpu_defs.h diff --git a/plat/common/arm/cache64.S b/plat/common/arm/cache64.S new file mode 100644 index 0000000..0f20e11 --- /dev/null +++ b/plat/common/arm/cache64.S @@ -0,0 +1,98 @@ +/* SPDX-License-Identifier: BSD-2-Clause */ So here you say BSD-2-Clause but ... +/* + * This code is taken from: + * /arm-trusted-firmware/lib/aarch64/cache_helpers.S + * + * Copyright (c) 2013-2014, ARM Limited and Contributors. All rights reserved. + * + * SPDX-License-Identifier: BSD-3-Clause .... here you say BSD-3-Clause. Which one apply? + */ +#include <asm.h> +#include <arm/cpu_defs.h> +/* --------------------------------------------------------------- + * Data cache operations by set/way to the level specified TL;DR: Set/Way *should* not be used in Unikraft. Now the long answer:I am afraid this is not going to work very well in virtualized environment and/or with system caches present on the platform. ARMv8 platform can have system caches but they cannot be managed via set/way instructions. They can only be managed with PoC instructions. Furthermore, Set/Way are very difficult to virtualized because they only apply to a given physical CPU. So if a vCPU moving between CPU, you also have to propagate the changes in the cache. What KVM (and soon Xen) does is going through the page-tables and cleaning page mapped one by one. I let you imagine how expensive this is... The right way to go is using Cache maintenance by VA/PA for each region you modify. Cheers, + * + * The main function, do_dcsw_op requires: + * x0: The operation type (0-2), as defined in cpu_defs.h + * x3: The last cache level to operate on + * x9: clidr_el1 + * x10: The cache level to begin operation from + * and will carry out the operation on each data cache from level 0 + * to the level in x3 in sequence + * + * The dcsw_op macro sets up the x3 and x9 parameters based on + * clidr_el1 cache information before invoking the main function + * --------------------------------------------------------------- + */ + +.macro dcsw_op shift, fw, ls + mrs x9, clidr_el1 + ubfx x3, x9, \shift, \fw + lsl x3, x3, \ls + mov x10, xzr + b do_dcsw_op +.endm + +ENTRY(do_dcsw_op) + cbz x3, exit + adr x14, dcsw_loop_table // compute inner loop address + add x14, x14, x0, lsl #5 // inner loop is 8x32-bit instructions + mov x0, x9 + mov w8, #1 +loop1: + add x2, x10, x10, lsr #1 // work out 3x current cache level + lsr x1, x0, x2 // extract cache type bits from clidr + and x1, x1, #7 // mask the bits for current cache only + cmp x1, #2 // see what cache we have at this level + b.lo level_done // nothing to do if no cache or icache + + msr csselr_el1, x10 // select current cache level in csselr + isb // isb to sych the new cssr&csidr + mrs x1, ccsidr_el1 // read the new ccsidr + and x2, x1, #7 // extract the length of the cache lines + add x2, x2, #4 // add 4 (line length offset) + ubfx x4, x1, #3, #10 // maximum way number + clz w5, w4 // bit position of way size increment + lsl w9, w4, w5 // w9 = aligned max way number + lsl w16, w8, w5 // w16 = way number loop decrement + orr w9, w10, w9 // w9 = combine way and cache number + ubfx w6, w1, #13, #15 // w6 = max set number + lsl w17, w8, w2 // w17 = set number loop decrement + dsb sy // barrier before we start this level + br x14 // jump to DC operation specific loop + +.macro dcsw_loop _op +loop2_\_op: + lsl w7, w6, w2 // w7 = aligned max set number + +loop3_\_op: + orr w11, w9, w7 // combine cache, way and set number + dc \_op, x11 + subs w7, w7, w17 // decrement set number + b.hs loop3_\_op + + subs x9, x9, x16 // decrement way number + b.hs loop2_\_op + + b level_done +.endm + +level_done: + add x10, x10, #2 // increment cache number + cmp x3, x10 + b.hi loop1 + msr csselr_el1, xzr // select cache level 0 in csselr + dsb sy // barrier to complete final cache operation + isb +exit: + ret +END(do_dcsw_op) + +dcsw_loop_table: + dcsw_loop isw + dcsw_loop cisw + dcsw_loop csw + +ENTRY(dcsw_op_all) + dcsw_op #CLIDR_LOC_SHIFT, #CLIDR_FIELD_WIDTH, #CSSELR_LEVEL_SHIFT +END(dcsw_op_all) diff --git a/plat/common/include/arm/arm64/cpu_defs.h b/plat/common/include/arm/arm64/cpu_defs.h new file mode 100644 index 0000000..56082e3 --- /dev/null +++ b/plat/common/include/arm/arm64/cpu_defs.h @@ -0,0 +1,60 @@ +/* SPDX-License-Identifier: BSD-3-Clause */ +/* + * Authors: Wei Chen <wei.chen@xxxxxxx> + * + * Copyright (c) 2018, Arm Ltd. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of the copyright holder nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + * + * THIS HEADER MAY NOT BE EXTRACTED OR MODIFIED IN ANY WAY. + */ +#ifndef __CPU_ARM_64_DEFS_H__ +#define __CPU_ARM_64_DEFS_H__ + +/* + * CLIDR_EL1, Cache Level ID Register + * Identifies the type of cache, or caches, that are implemented at each + * level and can be managed using the architected cache maintenance + * instructions that operate by set/way, up to a maximum of seven + * levels. Also identifies the Level of Coherence (LoC) and Level of + * Unification (LoU) for the cache hierarchy. + */ +#define CLIDR_ICB_SHIFT 30 +#define CLIDR_LOUU_SHIFT 27 +#define CLIDR_LOC_SHIFT 24 +#define CLIDR_LOUIS_SHIFT 21 +#define CLIDR_FIELD_WIDTH 3 +#define CLIDR_FIELD_MASK 0x7 + +/* CSSELR_EL1, Cache Size Selection Register definitions */ +#define CSSELR_LEVEL_SHIFT 1 + +/* Data cache set/way op type defines */ +#define DCISW 0x0 +#define DCCISW 0x1 +#define DCCSW 0x2 + +#endif /* __CPU_ARM_64_DEFS_H__ */ diff --git a/plat/common/include/arm/cpu_defs.h b/plat/common/include/arm/cpu_defs.h new file mode 100644 index 0000000..7502f03 --- /dev/null +++ b/plat/common/include/arm/cpu_defs.h @@ -0,0 +1,44 @@ +/* SPDX-License-Identifier: BSD-3-Clause */ +/* + * Authors: Wei Chen <wei.chen@xxxxxxx> + * + * Copyright (c) 2018, Arm Ltd. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of the copyright holder nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + * + * THIS HEADER MAY NOT BE EXTRACTED OR MODIFIED IN ANY WAY. + */ + +#ifndef __PLAT_CMN_ARM_CPU_DEFS_H__ +#define __PLAT_CMN_ARM_CPU_DEFS_H__ + +#if defined(__ARM_64__) +#include "arm64/cpu_defs.h" +#else +#error "Add cpu_defs.h for current architecture." +#endif + +#endif /* __PLAT_CMN_ARM_CPU_DEFS_H__ */ diff --git a/plat/kvm/Makefile.uk b/plat/kvm/Makefile.uk index 4ec90f3..2b4c813 100644 --- a/plat/kvm/Makefile.uk +++ b/plat/kvm/Makefile.uk @@ -52,6 +52,7 @@ ifeq ($(CONFIG_ARCH_ARM_64),y) ifeq ($(findstring y,$(CONFIG_KVM_KERNEL_SERIAL_CONSOLE) $(CONFIG_KVM_DEBUG_SERIAL_CONSOLE)),y) LIBKVMPLAT_SRCS-$(CONFIG_ARCH_ARM_64) += $(UK_PLAT_COMMON_BASE)/arm/console.c|common endif +LIBKVMPLAT_SRCS-$(CONFIG_ARCH_ARM_64) += $(UK_PLAT_COMMON_BASE)/arm/cache64.S|common LIBKVMPLAT_SRCS-$(CONFIG_ARCH_ARM_64) += $(LIBKVMPLAT_BASE)/arm/entry64.S LIBKVMPLAT_SRCS-$(CONFIG_ARCH_ARM_64) += $(LIBKVMPLAT_BASE)/arm/setup.c endif -- Julien Grall _______________________________________________ Minios-devel mailing list Minios-devel@xxxxxxxxxxxxxxxxxxxx https://lists.xenproject.org/mailman/listinfo/minios-devel
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