| Message ID | 1480010543-25709-2-git-send-email-ard.biesheuvel@linaro.org |
|---|---|
| State | Accepted |
| Commit | 018edcfac4c3b140366ad51b0907f3becb5bb624 |
| Headers | show |
On Thu, 24 Nov, at 10:47:15PM, tip-bot for Ard Biesheuvel wrote: > Commit-ID: 018edcfac4c3b140366ad51b0907f3becb5bb624 > Gitweb: http://git.kernel.org/tip/018edcfac4c3b140366ad51b0907f3becb5bb624 > Author: Ard Biesheuvel <ard.biesheuvel@linaro.org> > AuthorDate: Thu, 24 Nov 2016 18:02:23 +0000 > Committer: Ingo Molnar <mingo@kernel.org> > CommitDate: Fri, 25 Nov 2016 07:15:23 +0100 > > efi/libstub: Make efi_random_alloc() allocate below 4 GB on 32-bit > > The UEFI stub executes in the context of the firmware, which identity > maps the available system RAM, which implies that only memory below > 4 GB can be used for allocations on 32-bit architectures, even on [L]PAE > capable hardware. > > So ignore any reported memory above 4 GB in efi_random_alloc(). This > also fixes a reported build problem on ARM under -Os, where the 64-bit > logical shift relies on a software routine that the ARM decompressor does > not provide. > > A second [minor] issue is also fixed, where the '+ 1' is moved out of > the shift, where it belongs: the reason for its presence is that a > memory region where start == end should count as a single slot, given > that 'end' takes the desired size and alignment of the allocation into > account. > > To clarify the code in this regard, rename start/end to 'first_slot' and > 'last_slot', respectively, and introduce 'region_end' to describe the > last usable address of the current region. > > Reported-by: Arnd Bergmann <arnd@arndb.de> > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> > Cc: Linus Torvalds <torvalds@linux-foundation.org> > Cc: Matt Fleming <matt@codeblueprint.co.uk> > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: linux-efi@vger.kernel.org > Link: http://lkml.kernel.org/r/1480010543-25709-2-git-send-email-ard.biesheuvel@linaro.org > Signed-off-by: Ingo Molnar <mingo@kernel.org> > --- > drivers/firmware/efi/libstub/random.c | 13 +++++++------ > 1 file changed, 7 insertions(+), 6 deletions(-) Ard, was this picked up for the correct tip branch? If it fixes a build failure it should have gone into tip/efi/urgent, right?
On 4 December 2016 at 14:17, Matt Fleming <matt@codeblueprint.co.uk> wrote: > On Thu, 24 Nov, at 10:47:15PM, tip-bot for Ard Biesheuvel wrote: >> Commit-ID: 018edcfac4c3b140366ad51b0907f3becb5bb624 >> Gitweb: http://git.kernel.org/tip/018edcfac4c3b140366ad51b0907f3becb5bb624 >> Author: Ard Biesheuvel <ard.biesheuvel@linaro.org> >> AuthorDate: Thu, 24 Nov 2016 18:02:23 +0000 >> Committer: Ingo Molnar <mingo@kernel.org> >> CommitDate: Fri, 25 Nov 2016 07:15:23 +0100 >> >> efi/libstub: Make efi_random_alloc() allocate below 4 GB on 32-bit >> >> The UEFI stub executes in the context of the firmware, which identity >> maps the available system RAM, which implies that only memory below >> 4 GB can be used for allocations on 32-bit architectures, even on [L]PAE >> capable hardware. >> >> So ignore any reported memory above 4 GB in efi_random_alloc(). This >> also fixes a reported build problem on ARM under -Os, where the 64-bit >> logical shift relies on a software routine that the ARM decompressor does >> not provide. >> >> A second [minor] issue is also fixed, where the '+ 1' is moved out of >> the shift, where it belongs: the reason for its presence is that a >> memory region where start == end should count as a single slot, given >> that 'end' takes the desired size and alignment of the allocation into >> account. >> >> To clarify the code in this regard, rename start/end to 'first_slot' and >> 'last_slot', respectively, and introduce 'region_end' to describe the >> last usable address of the current region. >> >> Reported-by: Arnd Bergmann <arnd@arndb.de> >> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> >> Cc: Linus Torvalds <torvalds@linux-foundation.org> >> Cc: Matt Fleming <matt@codeblueprint.co.uk> >> Cc: Peter Zijlstra <peterz@infradead.org> >> Cc: Thomas Gleixner <tglx@linutronix.de> >> Cc: linux-efi@vger.kernel.org >> Link: http://lkml.kernel.org/r/1480010543-25709-2-git-send-email-ard.biesheuvel@linaro.org >> Signed-off-by: Ingo Molnar <mingo@kernel.org> >> --- >> drivers/firmware/efi/libstub/random.c | 13 +++++++------ >> 1 file changed, 7 insertions(+), 6 deletions(-) > > Ard, was this picked up for the correct tip branch? If it fixes a > build failure it should have gone into tip/efi/urgent, right? The failure was in -next, with a patch queued up for v4.10, so that is where the fix went as well.
On Sun, 04 Dec, at 02:31:23PM, Ard Biesheuvel wrote: > On 4 December 2016 at 14:17, Matt Fleming <matt@codeblueprint.co.uk> wrote: > > > > Ard, was this picked up for the correct tip branch? If it fixes a > > build failure it should have gone into tip/efi/urgent, right? > > The failure was in -next, with a patch queued up for v4.10, so that is > where the fix went as well. Oops, sorry I missed that. I was looking at the v4.11 queue and my brain suffered an off-by-one bug - I thought we'd already had the v4.10 release.
On 4 December 2016 at 21:38, Matt Fleming <matt@codeblueprint.co.uk> wrote: > On Sun, 04 Dec, at 02:31:23PM, Ard Biesheuvel wrote: >> On 4 December 2016 at 14:17, Matt Fleming <matt@codeblueprint.co.uk> wrote: >> > >> > Ard, was this picked up for the correct tip branch? If it fixes a >> > build failure it should have gone into tip/efi/urgent, right? >> >> The failure was in -next, with a patch queued up for v4.10, so that is >> where the fix went as well. > > Oops, sorry I missed that. I was looking at the v4.11 queue and my > brain suffered an off-by-one bug - I thought we'd already had the > v4.10 release. We haven't even had the v4.9 release :-)
diff --git a/drivers/firmware/efi/libstub/random.c b/drivers/firmware/efi/libstub/random.c index 3a3feacc329f..63cd3f262b6e 100644 --- a/drivers/firmware/efi/libstub/random.c +++ b/drivers/firmware/efi/libstub/random.c @@ -45,19 +45,21 @@ static unsigned long get_entry_num_slots(efi_memory_desc_t *md, unsigned long align_shift) { unsigned long align = 1UL << align_shift; - u64 start, end; + u64 first_slot, last_slot, region_end; if (md->type != EFI_CONVENTIONAL_MEMORY) return 0; - start = round_up(md->phys_addr, align); - end = round_down(md->phys_addr + md->num_pages * EFI_PAGE_SIZE - size, - align); + region_end = min((u64)ULONG_MAX, + md->phys_addr + md->num_pages * EFI_PAGE_SIZE - 1); - if (start > end) + first_slot = round_up(md->phys_addr, align); + last_slot = round_down(region_end - size + 1, align); + + if (first_slot > last_slot) return 0; - return (end - start + 1) >> align_shift; + return ((unsigned long)(last_slot - first_slot) >> align_shift) + 1; } /*
The UEFI stub executes in the context of the firmware, which identity maps the available system RAM, which implies that only memory below 4 GB can be used for allocations on 32-bit architectures, even on [L]PAE capable hardware. So ignore any reported memory above 4 GB in efi_random_alloc(). This also fixes a reported build problem on ARM under -Os, where the 64-bit logical shift relies on a software routine that the ARM decompressor does not provide. A second [minor] issue is also fixed, where the '+ 1' is moved out of the shift, where it belongs: the reason for its presence is that a memory region where start == end should count as a single slot, given that 'end' takes the desired size and alignment of the allocation into account. To clarify the code in this regard, rename start/end to 'first_slot' and 'last_slot', respectively, and introduce 'region_end' to describe the last usable address of the current region. Reported-by: Arnd Bergmann <arnd@arndb.de> Cc: Matt Fleming <matt@codeblueprint.co.uk> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> --- drivers/firmware/efi/libstub/random.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) -- 2.7.4