kexec: make kexec_segment user buffer pointer a union
So far kexec_segment->buf was always a user space pointer as user space
passed the array of kexec_segment structures and kernel copied it.
But with new system call, list of kexec segments will be prepared by
kernel and kexec_segment->buf will point to a kernel memory.
So while I was adding code where I made assumption that ->buf is pointing
to kernel memory, sparse started giving warning.
Make ->buf a union. And where a user space pointer is expected, access it
using ->buf and where a kernel space pointer is expected, access it using
->kbuf. That takes care of sparse warnings.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: WANG Chao <chaowang@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index d9bb0a5..66d56ac 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -69,7 +69,18 @@
#define IND_SOURCE 0x8
struct kexec_segment {
- void __user *buf;
+ /*
+ * This pointer can point to user memory if kexec_load() system
+ * call is used or will point to kernel memory if
+ * kexec_file_load() system call is used.
+ *
+ * Use ->buf when expecting to deal with user memory and use ->kbuf
+ * when expecting to deal with kernel memory.
+ */
+ union {
+ void __user *buf;
+ void *kbuf;
+ };
size_t bufsz;
unsigned long mem;
size_t memsz;