The current interface copy_oldmem_page() passes user pointer without
__user annotation and hence does unnecessary user/kernel pointer
conversions during its implementation.
Use the interface copy_oldmem_page_buf() to avoid this issue.
Cc: Michael Ellerman <m...@ellerman.id.au>
CC: Benjamin Herrenschmidt <b...@kernel.crashing.org>
Cc: Paul Mackerras <pau...@samba.org>
Cc: linuxppc <linuxppc-dev@lists.ozlabs.org>
Signed-off-by: Amit Daniel Kachhap <amit.kach...@arm.com>
---
arch/powerpc/kernel/crash_dump.c | 33 ++++++++++++++++----------------
1 file changed, 17 insertions(+), 16 deletions(-)
diff --git a/arch/powerpc/kernel/crash_dump.c b/arch/powerpc/kernel/crash_dump.c
index 5693e1c67c2b..a1c8a3a11694 100644
--- a/arch/powerpc/kernel/crash_dump.c
+++ b/arch/powerpc/kernel/crash_dump.c
@@ -68,33 +68,34 @@ void __init setup_kdump_trampoline(void)
}
#endif /* CONFIG_NONSTATIC_KERNEL */
-static size_t copy_oldmem_vaddr(void *vaddr, char *buf, size_t csize,
- unsigned long offset, int userbuf)
+static size_t copy_oldmem_vaddr(void *vaddr, char __user *ubuf, char *kbuf,
+ size_t csize, unsigned long offset)
{
- if (userbuf) {
- if (copy_to_user((char __user *)buf, (vaddr + offset), csize))
+ if (ubuf) {
+ if (copy_to_user(ubuf, (vaddr + offset), csize))
return -EFAULT;
} else
- memcpy(buf, (vaddr + offset), csize);
+ memcpy(kbuf, (vaddr + offset), csize);
return csize;
}
/**
- * copy_oldmem_page - copy one page from "oldmem"
+ * copy_oldmem_page_buf - copy one page from "oldmem"
* @pfn: page frame number to be copied
- * @buf: target memory address for the copy; this can be in kernel address
- * space or user address space (see @userbuf)
+ * @ubuf: target user memory address for the copy; use copy_to_user() if this
+ * address is present
+ * @kbuf: target kernel memory address for the copy; use memcpy() if this
+ * address is present
* @csize: number of bytes to copy
* @offset: offset in bytes into the page (based on pfn) to begin the copy
- * @userbuf: if set, @buf is in user address space, use copy_to_user(),
- * otherwise @buf is in kernel address space, use memcpy().
*
- * Copy a page from "oldmem". For this page, there is no pte mapped
- * in the current kernel. We stitch up a pte, similar to kmap_atomic.
+ * Copy a page from "oldmem" into buffer pointed by either @ubuf or @kbuf. For
+ * this page, there is no pte mapped in the current kernel. We stitch up a pte,
+ * similar to kmap_atomic.
*/
-ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
- size_t csize, unsigned long offset, int userbuf)
+ssize_t copy_oldmem_page_buf(unsigned long pfn, char __user *ubuf, char *kbuf,
+ size_t csize, unsigned long offset)
{
void *vaddr;
phys_addr_t paddr;
@@ -107,10 +108,10 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
if (memblock_is_region_memory(paddr, csize)) {
vaddr = __va(paddr);
- csize = copy_oldmem_vaddr(vaddr, buf, csize, offset, userbuf);
+ csize = copy_oldmem_vaddr(vaddr, ubuf, kbuf, csize, offset);
} else {
vaddr = ioremap_cache(paddr, PAGE_SIZE);
- csize = copy_oldmem_vaddr(vaddr, buf, csize, offset, userbuf);
+ csize = copy_oldmem_vaddr(vaddr, ubuf, kbuf, csize, offset);
iounmap(vaddr);
}
--
2.17.1
