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[76.210.143.223]) by smtp.gmail.com with ESMTPSA id bx18sm7168249pjb.49.2020.07.10.20.59.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 10 Jul 2020 20:59:19 -0700 (PDT) Subject: [PATCH 1/3] lib: Add a generic copy_oldmem_page() Date: Fri, 10 Jul 2020 20:55:42 -0700 Message-Id: <20200711035544.2832154-2-palmer@dabbelt.com> X-Mailer: git-send-email 2.27.0.383.g050319c2ae-goog In-Reply-To: <20200711035544.2832154-1-palmer@dabbelt.com> References: <20200711035544.2832154-1-palmer@dabbelt.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Cc: linux@armlinux.org.uk, catalin.marinas@arm.com, will@kernel.org, Arnd Bergmann , rppt@linux.ibm.com, akpm@linux-foundation.org, linus.walleij@linaro.org, mchehab+samsung@kernel.org, gregory.0xf0@gmail.com, masahiroy@kernel.org, Nick Desaulniers , bgolaszewski@baylibre.com, Palmer Dabbelt , mingo@kernel.org, ben-linux@fluff.org, peterz@infradead.org, broonie@kernel.org, davem@davemloft.net, rdunlap@infradead.org, uwe@kleine-koenig.org, dan.j.williams@intel.com, mhiramat@kernel.org, matti.vaittinen@fi.rohmeurope.com, zaslonko@linux.ibm.com, willy@infradead.org, krzk@kernel.org, paulmck@kernel.org, pmladek@suse.com, brendanhiggins@google.com, keescook@chromium.org, glider@google.com, elver@google.com, davidgow@google.com, mark.rutland@arm.com, ardb@kernel.org, takahiro.akashi@linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kernel-team@android.com From: Palmer Dabbelt To: mick@ics.forth.gr Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Palmer Dabbelt A version of this that is identical to the arm64 version was recently copied into the RISC-V port while adding kexec() support. Instead I'd like to put a shared copy in lib/ and use it from the various ports. Signed-off-by: Palmer Dabbelt --- lib/Kconfig | 3 +++ lib/Makefile | 2 ++ lib/copy_oldmem_page.c | 51 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 56 insertions(+) create mode 100644 lib/copy_oldmem_page.c diff --git a/lib/Kconfig b/lib/Kconfig index df3f3da95990..25544abc9547 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -676,3 +676,6 @@ config GENERIC_LIB_CMPDI2 config GENERIC_LIB_UCMPDI2 bool + +config GENERIC_LIB_COPY_OLDMEM_PAGE + bool diff --git a/lib/Makefile b/lib/Makefile index b1c42c10073b..30d57d8b32b1 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -318,3 +318,5 @@ obj-$(CONFIG_OBJAGG) += objagg.o # KUnit tests obj-$(CONFIG_LIST_KUNIT_TEST) += list-test.o obj-$(CONFIG_LINEAR_RANGES_TEST) += test_linear_ranges.o + +obj-$(CONFIG_GENERIC_LIB_COPY_OLDMEM_PAGE) += copy_oldmem_page.o diff --git a/lib/copy_oldmem_page.c b/lib/copy_oldmem_page.c new file mode 100644 index 000000000000..f0090027218a --- /dev/null +++ b/lib/copy_oldmem_page.c @@ -0,0 +1,51 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Routines for doing kexec-based kdump + * + * Originally part of arch/arm64/kernel/crash_dump.c + * Copyright (C) 2017 Linaro Limited + * Author: AKASHI Takahiro + */ + +#include +#include +#include + +/** + * copy_oldmem_page() - copy one page from old kernel memory + * @pfn: page frame number to be copied + * @buf: buffer where the copied page is placed + * @csize: number of bytes to copy + * @offset: offset in bytes into the page + * @userbuf: if set, @buf is in a user address space + * + * This function copies one page from old kernel memory into buffer pointed by + * @buf. If @buf is in userspace, set @userbuf to %1. Returns number of bytes + * copied or negative error in case of failure. + */ +ssize_t copy_oldmem_page(unsigned long pfn, char *buf, + size_t csize, unsigned long offset, + int userbuf) +{ + void *vaddr; + + if (!csize) + return 0; + + vaddr = memremap(__pfn_to_phys(pfn), PAGE_SIZE, MEMREMAP_WB); + if (!vaddr) + return -ENOMEM; + + if (userbuf) { + if (copy_to_user((char __user *)buf, vaddr + offset, csize)) { + memunmap(vaddr); + return -EFAULT; + } + } else { + memcpy(buf, vaddr + offset, csize); + } + + memunmap(vaddr); + + return csize; +} -- 2.27.0.383.g050319c2ae-goog