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

[Palmer Dabbelt]

From: Palmer Dabbelt <palmerdabb...@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 <palmerdabb...@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