[PATCH 3/3] arm64: Use the new generic copy_oldmem_page()

[Palmer Dabbelt]

From: Palmer Dabbelt <palmerdabbelt at google.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.

Signed-off-by: Palmer Dabbelt <palmerdabbelt at google.com>
---
 arch/arm64/Kconfig             |  1 +
 arch/arm64/kernel/crash_dump.c | 39 ----------------------------------
 2 files changed, 1 insertion(+), 39 deletions(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 66dc41fd49f2..55b27d56b163 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -1109,6 +1109,7 @@ comment "Support for PE file signature verification disabled"
 
 config CRASH_DUMP
 	bool "Build kdump crash kernel"
+	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/arm64/kernel/crash_dump.c b/arch/arm64/kernel/crash_dump.c
index e6e284265f19..197b92c249ba 100644
--- a/arch/arm64/kernel/crash_dump.c
+++ b/arch/arm64/kernel/crash_dump.c
@@ -13,45 +13,6 @@
 #include <linux/uaccess.h>
 #include <asm/memory.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 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;
-}
-
 /**
  * elfcorehdr_read - read from ELF core header
  * @buf: buffer where the data is placed
-- 
2.27.0.383.g050319c2ae-goog