* Re: [PATCH v6 RESEND] x86/boot/KASLR: Restrict kernel to be randomized in mirror regions [not found] ` <20170728112603.GS24304@x1> @ 2017-08-04 11:23 ` Matt Fleming [not found] ` <20170804112325.GB8187-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org> 0 siblings, 1 reply; 4+ messages in thread From: Matt Fleming @ 2017-08-04 11:23 UTC (permalink / raw) To: Baoquan He Cc: Ingo Molnar, linux-kernel-u79uwXL29TY76Z2rM5mHXA, x86-DgEjT+Ai2ygdnm+yROfE0A, keescook-F7+t8E8rja9g9hUCZPvPmw, tglx-hfZtesqFncYOwBW4kG4KsQ, hpa-YMNOUZJC4hwAvxtiuMwx3w, izumi.taku-+CUm20s59erQFUHtdCDX3A, fanc.fnst-BthXqXjhjHXQFUHtdCDX3A, thgarnie-hpIqsD4AKlfQT0dZR+AlfA, n-horiguchi-PaJj6Psr51x8UrSeD/g0lQ, Ard Biesheuvel, linux-efi-u79uwXL29TY76Z2rM5mHXA On Fri, 28 Jul, at 07:26:03PM, Baoquan He wrote: > Hi Matt, > > On 07/28/17 at 11:55am, Ingo Molnar wrote: > > > > * Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org> wrote: > > > > > On Fri, 21 Jul, at 09:19:56PM, Baoquan He wrote: > > > > > > > > There are places where the efi map is getting and used like this. E.g > > > > in efi_high_alloc() of drivers/firmware/efi/libstub/efi-stub-helper.c. > > > > EFI developers worry the size of efi_memory_desc_t could not be the same > > > > as e->efi_memdesc_size? > > > > > > > > Hi Matt, > > > > > > > > Could you help have a look at this? > > > > > > You're exactly right. The code guards against the size of the > > > efi_memory_desc_t struct changing. The UEFI spec says to traverse the > > > memory map this way. > > > > This is not obvious and looks pretty ugly as well, and open coded in several > > places. > > > > At minimum we should have an efi_memdesc_ptr(efi, i) wrapper inline (or so) that > > gives us the entry pointer, plus a comment that points out that ->memdesc_size > > might not be equal to sizeof(efi_memory_memdesc_t). > > I can make a efi_memdesc_ptr(efi, i) wrapper as Ingo suggested and use > it here if you agree. Seems it might be not good to add another > for_each_efi_memory_desc_xxxx wrapper since there are different memmap > data structures in x86 boot and in general efi libstub. Or any other > idea? I think adding a wrapper is fine, but I'd suggest including the word "early" (or something similar) to explain that it should only be used during bootup -- we want everyone else to use the for_each_efi_memory_*() API. ^ permalink raw reply [flat|nested] 4+ messages in thread
[parent not found: <20170804112325.GB8187-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>]
* Re: [PATCH v6 RESEND] x86/boot/KASLR: Restrict kernel to be randomized in mirror regions [not found] ` <20170804112325.GB8187-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org> @ 2017-08-04 11:40 ` Baoquan He 2017-08-04 11:55 ` Matt Fleming 0 siblings, 1 reply; 4+ messages in thread From: Baoquan He @ 2017-08-04 11:40 UTC (permalink / raw) To: Matt Fleming Cc: Ingo Molnar, linux-kernel-u79uwXL29TY76Z2rM5mHXA, x86-DgEjT+Ai2ygdnm+yROfE0A, keescook-F7+t8E8rja9g9hUCZPvPmw, tglx-hfZtesqFncYOwBW4kG4KsQ, hpa-YMNOUZJC4hwAvxtiuMwx3w, izumi.taku-+CUm20s59erQFUHtdCDX3A, fanc.fnst-BthXqXjhjHXQFUHtdCDX3A, thgarnie-hpIqsD4AKlfQT0dZR+AlfA, n-horiguchi-PaJj6Psr51x8UrSeD/g0lQ, Ard Biesheuvel, linux-efi-u79uwXL29TY76Z2rM5mHXA On 08/04/17 at 12:23pm, Matt Fleming wrote: > On Fri, 28 Jul, at 07:26:03PM, Baoquan He wrote: > > Hi Matt, > > > > On 07/28/17 at 11:55am, Ingo Molnar wrote: > > > > > > * Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org> wrote: > > > > > > > On Fri, 21 Jul, at 09:19:56PM, Baoquan He wrote: > > > > > > > > > > There are places where the efi map is getting and used like this. E.g > > > > > in efi_high_alloc() of drivers/firmware/efi/libstub/efi-stub-helper.c. > > > > > EFI developers worry the size of efi_memory_desc_t could not be the same > > > > > as e->efi_memdesc_size? > > > > > > > > > > Hi Matt, > > > > > > > > > > Could you help have a look at this? > > > > > > > > You're exactly right. The code guards against the size of the > > > > efi_memory_desc_t struct changing. The UEFI spec says to traverse the > > > > memory map this way. > > > > > > This is not obvious and looks pretty ugly as well, and open coded in several > > > places. > > > > > > At minimum we should have an efi_memdesc_ptr(efi, i) wrapper inline (or so) that > > > gives us the entry pointer, plus a comment that points out that ->memdesc_size > > > might not be equal to sizeof(efi_memory_memdesc_t). > > > > I can make a efi_memdesc_ptr(efi, i) wrapper as Ingo suggested and use > > it here if you agree. Seems it might be not good to add another > > for_each_efi_memory_desc_xxxx wrapper since there are different memmap > > data structures in x86 boot and in general efi libstub. Or any other > > idea? > > I think adding a wrapper is fine, but I'd suggest including the word > "early" (or something similar) to explain that it should only be used > during bootup -- we want everyone else to use the > for_each_efi_memory_*() API. Thanks, Matt. I can do that. Do you think below helper definition is OK to you? If yes, I can upstate with it and post v9. #define efi_early_memdesc_ptr(map, desc_size, n) \ (efi_memory_desc_t *)((void *)(map) + ((n) * (desc_size))) ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v6 RESEND] x86/boot/KASLR: Restrict kernel to be randomized in mirror regions 2017-08-04 11:40 ` Baoquan He @ 2017-08-04 11:55 ` Matt Fleming 2017-08-04 12:02 ` Baoquan He 0 siblings, 1 reply; 4+ messages in thread From: Matt Fleming @ 2017-08-04 11:55 UTC (permalink / raw) To: Baoquan He Cc: Ingo Molnar, linux-kernel, x86, keescook, tglx, hpa, izumi.taku, fanc.fnst, thgarnie, n-horiguchi, Ard Biesheuvel, linux-efi On Fri, 04 Aug, at 07:40:05PM, Baoquan He wrote: > On 08/04/17 at 12:23pm, Matt Fleming wrote: > > On Fri, 28 Jul, at 07:26:03PM, Baoquan He wrote: > > > Hi Matt, > > > > > > On 07/28/17 at 11:55am, Ingo Molnar wrote: > > > > > > > > * Matt Fleming <matt@codeblueprint.co.uk> wrote: > > > > > > > > > On Fri, 21 Jul, at 09:19:56PM, Baoquan He wrote: > > > > > > > > > > > > There are places where the efi map is getting and used like this. E.g > > > > > > in efi_high_alloc() of drivers/firmware/efi/libstub/efi-stub-helper.c. > > > > > > EFI developers worry the size of efi_memory_desc_t could not be the same > > > > > > as e->efi_memdesc_size? > > > > > > > > > > > > Hi Matt, > > > > > > > > > > > > Could you help have a look at this? > > > > > > > > > > You're exactly right. The code guards against the size of the > > > > > efi_memory_desc_t struct changing. The UEFI spec says to traverse the > > > > > memory map this way. > > > > > > > > This is not obvious and looks pretty ugly as well, and open coded in several > > > > places. > > > > > > > > At minimum we should have an efi_memdesc_ptr(efi, i) wrapper inline (or so) that > > > > gives us the entry pointer, plus a comment that points out that ->memdesc_size > > > > might not be equal to sizeof(efi_memory_memdesc_t). > > > > > > I can make a efi_memdesc_ptr(efi, i) wrapper as Ingo suggested and use > > > it here if you agree. Seems it might be not good to add another > > > for_each_efi_memory_desc_xxxx wrapper since there are different memmap > > > data structures in x86 boot and in general efi libstub. Or any other > > > idea? > > > > I think adding a wrapper is fine, but I'd suggest including the word > > "early" (or something similar) to explain that it should only be used > > during bootup -- we want everyone else to use the > > for_each_efi_memory_*() API. > > Thanks, Matt. I can do that. Do you think below helper definition is OK > to you? If yes, I can upstate with it and post v9. > > #define efi_early_memdesc_ptr(map, desc_size, n) \ > (efi_memory_desc_t *)((void *)(map) + ((n) * (desc_size))) Looks fine to me, but I'd wait for Ingo's OK before resending. ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v6 RESEND] x86/boot/KASLR: Restrict kernel to be randomized in mirror regions 2017-08-04 11:55 ` Matt Fleming @ 2017-08-04 12:02 ` Baoquan He 0 siblings, 0 replies; 4+ messages in thread From: Baoquan He @ 2017-08-04 12:02 UTC (permalink / raw) To: Matt Fleming Cc: Ingo Molnar, linux-kernel, x86, keescook, tglx, hpa, izumi.taku, fanc.fnst, thgarnie, n-horiguchi, Ard Biesheuvel, linux-efi On 08/04/17 at 12:55pm, Matt Fleming wrote: > On Fri, 04 Aug, at 07:40:05PM, Baoquan He wrote: > > On 08/04/17 at 12:23pm, Matt Fleming wrote: > > > On Fri, 28 Jul, at 07:26:03PM, Baoquan He wrote: > > > > Hi Matt, > > > > > > > > On 07/28/17 at 11:55am, Ingo Molnar wrote: > > > > > > > > > > * Matt Fleming <matt@codeblueprint.co.uk> wrote: > > > > > > > > > > > On Fri, 21 Jul, at 09:19:56PM, Baoquan He wrote: > > > > > > > > > > > > > > There are places where the efi map is getting and used like this. E.g > > > > > > > in efi_high_alloc() of drivers/firmware/efi/libstub/efi-stub-helper.c. > > > > > > > EFI developers worry the size of efi_memory_desc_t could not be the same > > > > > > > as e->efi_memdesc_size? > > > > > > > > > > > > > > Hi Matt, > > > > > > > > > > > > > > Could you help have a look at this? > > > > > > > > > > > > You're exactly right. The code guards against the size of the > > > > > > efi_memory_desc_t struct changing. The UEFI spec says to traverse the > > > > > > memory map this way. > > > > > > > > > > This is not obvious and looks pretty ugly as well, and open coded in several > > > > > places. > > > > > > > > > > At minimum we should have an efi_memdesc_ptr(efi, i) wrapper inline (or so) that > > > > > gives us the entry pointer, plus a comment that points out that ->memdesc_size > > > > > might not be equal to sizeof(efi_memory_memdesc_t). > > > > > > > > I can make a efi_memdesc_ptr(efi, i) wrapper as Ingo suggested and use > > > > it here if you agree. Seems it might be not good to add another > > > > for_each_efi_memory_desc_xxxx wrapper since there are different memmap > > > > data structures in x86 boot and in general efi libstub. Or any other > > > > idea? > > > > > > I think adding a wrapper is fine, but I'd suggest including the word > > > "early" (or something similar) to explain that it should only be used > > > during bootup -- we want everyone else to use the > > > for_each_efi_memory_*() API. > > > > Thanks, Matt. I can do that. Do you think if below helper definition is OK > > to you? If yes, I can update with it and post v9. > > > > #define efi_early_memdesc_ptr(map, desc_size, n) \ > > (efi_memory_desc_t *)((void *)(map) + ((n) * (desc_size))) > > Looks fine to me, but I'd wait for Ingo's OK before resending. Sure, thanks! ^ permalink raw reply [flat|nested] 4+ messages in thread
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2017-08-04 11:23 ` [PATCH v6 RESEND] x86/boot/KASLR: Restrict kernel to be randomized in mirror regions Matt Fleming
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