Re: [PATCH v3 10/19] x86, 64bit: Set ident_mapping for kaslr

[Kees Cook]

On Mon, Mar 21, 2016 at 12:50 AM, Baoquan He <bhe@xxxxxxxxxx> wrote:
> On 03/07/16 at 03:34pm, Kees Cook wrote:
>> >  #ifdef CONFIG_EARLY_PRINTK
>> >  /* early_serial_console.c */
>> >  extern int early_serial_base;
>> > diff --git a/arch/x86/boot/compressed/misc_pgt.c b/arch/x86/boot/compressed/misc_pgt.c
>> > new file mode 100644
>> > index 0000000..954811e
>> > --- /dev/null
>> > +++ b/arch/x86/boot/compressed/misc_pgt.c
>> > @@ -0,0 +1,91 @@
>> > +#define __pa(x)  ((unsigned long)(x))
>> > +#define __va(x)  ((void *)((unsigned long)(x)))
>> > +
>> > +#include "misc.h"
>> > +
>> > +#include <asm/init.h>
>> > +#include <asm/pgtable.h>
>> > +
>> > +#include "../../mm/ident_map.c"
>> > +#include "../string.h"
>> > +
>> > +struct alloc_pgt_data {
>> > +       unsigned char *pgt_buf;
>> > +       unsigned long pgt_buf_size;
>> > +       unsigned long pgt_buf_offset;
>> > +};
>> > +
>> > +static void *alloc_pgt_page(void *context)
>> > +{
>> > +       struct alloc_pgt_data *d = (struct alloc_pgt_data *)context;
>> > +       unsigned char *p = (unsigned char *)d->pgt_buf;
>> > +
>> > +       if (d->pgt_buf_offset >= d->pgt_buf_size) {
>> > +               debug_putstr("out of pgt_buf in misc.c\n");
>>
>> This line probably isn't needed any more. Or, if it is, maybe it could
>> include more details from the context?
>
> I am trying to repost, found I missed this place.
>
> Is it OK to add more informatin in printing as below?
> if (d->pgt_buf_offset >= d->pgt_buf_size) {
>                 debug_putstr("out of pgt_buf in misc.c\n");
>                 debug_putaddr(d->pgt_buf_offset);
>                 debug_putaddr(d->pgt_buf_size);

Yeah, absolutely, that sounds perfect.

-Kees

-- 
Kees Cook
Chrome OS & Brillo Security