linux-kernel - [PATCH 2/3] arm: Use the new generic copy_oldmem

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Message-Id: <20200711035544.2832154-3-palmer@dabbelt.com>
Date:   Fri, 10 Jul 2020 20:55:43 -0700
From:   Palmer Dabbelt <palmer@...belt.com>
To:     mick@....forth.gr
Cc:     linux@...linux.org.uk, catalin.marinas@....com, will@...nel.org,
        Arnd Bergmann <arnd@...db.de>, rppt@...ux.ibm.com,
        akpm@...ux-foundation.org, linus.walleij@...aro.org,
        mchehab+samsung@...nel.org, gregory.0xf0@...il.com,
        masahiroy@...nel.org, Nick Desaulniers <ndesaulniers@...gle.com>,
        bgolaszewski@...libre.com,
        Palmer Dabbelt <palmerdabbelt@...gle.com>, mingo@...nel.org,
        ben-linux@...ff.org, peterz@...radead.org, broonie@...nel.org,
        davem@...emloft.net, rdunlap@...radead.org, uwe@...ine-koenig.org,
        dan.j.williams@...el.com, mhiramat@...nel.org,
        matti.vaittinen@...rohmeurope.com, zaslonko@...ux.ibm.com,
        willy@...radead.org, krzk@...nel.org, paulmck@...nel.org,
        pmladek@...e.com, brendanhiggins@...gle.com, keescook@...omium.org,
        glider@...gle.com, elver@...gle.com, davidgow@...gle.com,
        mark.rutland@....com, ardb@...nel.org, takahiro.akashi@...aro.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        kernel-team@...roid.com
Subject: [PATCH 2/3] arm: Use the new generic copy_oldmem_page()

From: Palmer Dabbelt <palmerdabbelt@...gle.com>

This is exactly the same as the arm64 code, which I just into lib/ to
avoid copying it into the RISC-V port.  This builds with defconfig and with
CRASH_DUMP=y.

Signed-off-by: Palmer Dabbelt <palmerdabbelt@...gle.com>
---
 arch/arm/Kconfig             |  1 +
 arch/arm/kernel/Makefile     |  1 -
 arch/arm/kernel/crash_dump.c | 54 ------------------------------------
 3 files changed, 1 insertion(+), 55 deletions(-)
 delete mode 100644 arch/arm/kernel/crash_dump.c

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 2ac74904a3ce..dfbeb14e9673 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1933,6 +1933,7 @@ config ATAGS_PROC
 
 config CRASH_DUMP
 	bool "Build kdump crash kernel (EXPERIMENTAL)"
+	select GENERIC_LIB_COPY_OLDMEM_PAGE
 	help
 	  Generate crash dump after being started by kexec. This should
 	  be normally only set in special crash dump kernels which are
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index 89e5d864e923..b5310a90dfe4 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -65,7 +65,6 @@ obj-$(CONFIG_KGDB)		+= kgdb.o patch.o
 obj-$(CONFIG_ARM_UNWIND)	+= unwind.o
 obj-$(CONFIG_HAVE_TCM)		+= tcm.o
 obj-$(CONFIG_OF)		+= devtree.o
-obj-$(CONFIG_CRASH_DUMP)	+= crash_dump.o
 obj-$(CONFIG_SWP_EMULATE)	+= swp_emulate.o
 CFLAGS_swp_emulate.o		:= -Wa,-march=armv7-a
 obj-$(CONFIG_HAVE_HW_BREAKPOINT)	+= hw_breakpoint.o
diff --git a/arch/arm/kernel/crash_dump.c b/arch/arm/kernel/crash_dump.c
deleted file mode 100644
index 53cb92435392..000000000000
--- a/arch/arm/kernel/crash_dump.c
+++ /dev/null
@@ -1,54 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- * arch/arm/kernel/crash_dump.c
- *
- * Copyright (C) 2010 Nokia Corporation.
- * Author: Mika Westerberg
- *
- * This code is taken from arch/x86/kernel/crash_dump_64.c
- *   Created by: Hariprasad Nellitheertha (hari@...ibm.com)
- *   Copyright (C) IBM Corporation, 2004. All rights reserved
- */
-
-#include <linux/errno.h>
-#include <linux/crash_dump.h>
-#include <linux/uaccess.h>
-#include <linux/io.h>
-
-/**
- * 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 int he 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 = ioremap(__pfn_to_phys(pfn), PAGE_SIZE);
-	if (!vaddr)
-		return -ENOMEM;
-
-	if (userbuf) {
-		if (copy_to_user(buf, vaddr + offset, csize)) {
-			iounmap(vaddr);
-			return -EFAULT;
-		}
-	} else {
-		memcpy(buf, vaddr + offset, csize);
-	}
-
-	iounmap(vaddr);
-	return csize;
-}
-- 
2.27.0.383.g050319c2ae-goog