| From | Vivek Goyal <> | Subject | [PATCH 05/13] kexec: Make kexec_segment user buffer pointer a union | Date | Tue, 3 Jun 2014 09:06:54 -0400 |
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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> --- include/linux/kexec.h | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/include/linux/kexec.h b/include/linux/kexec.h index a756419..d0285cc 100644 --- a/include/linux/kexec.h +++ b/include/linux/kexec.h @@ -69,7 +69,18 @@ typedef unsigned long kimage_entry_t; #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; -- 1.9.0
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