Messages in this thread | | | Date | Mon, 26 Sep 2005 12:49:13 +0200 | From | Pavel Machek <> | Subject | Re: [PATCH][Fix] Prevent swsusp from corrupting page translation tables during resume on x86-64 |
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Hi!
> > > The following patch fixes Bug #4959. It creates temporary page translation > > > tables located in the page frames that are not overwritten by swsusp while copying > > > the image. > > > > > > The temporary page translation tables are generally based on the existing ones > > > with the exception that the mappings using 4KB pages are replaced with the > > > equivalent mappings that use 2MB pages only. The temporary page tables are > > > only used for copying the image. > > > > Would not it be simpler to create them from scratch? mm/init.c has > > some handy functions, they should be applicable. [init_memory_mapping, > > phys_pud_init]. Perhaps even initialize only simple direct mapping, > > and place virt_to_phys() at strategic places? > > Perhaps, but the outcome would be very much the same. The problem is to what > extent we can use the existing constructs, because I'd rather like to avoid the situation > in which any future changes to the initialization code would have to be replicated > in the swsusp code. I'll have a look at that, but I'm not sure. Also I don't really know > what the Andi's preferences are with this respect. > > Anyway do you think that creating temporary page tables at the beginning of > swsusp_arch_resume() is a good idea? If not, where do you think should they be > created?
For i386, I simply let bootup code create them, and create "backup copy" that is not damaged by any page splits... Result is in mm/init.c:
#ifdef CONFIG_SOFTWARE_SUSPEND /* * Swap suspend & friends need this for resume because things like the intel-agp * driver might have split up a kernel 4MB mapping. */ char __nosavedata swsusp_pg_dir[PAGE_SIZE] __attribute__ ((aligned (PAGE_SIZE)));
static inline void save_pg_dir(void) { memcpy(swsusp_pg_dir, swapper_pg_dir, PAGE_SIZE); } #else static inline void save_pg_dir(void) { } #endif
It is probably not as simple for x86-64 case, but some bootup code reusal still should be neccessary... Pavel -- if you have sharp zaurus hardware you don't need... you know my address - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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