BMC/Intel-BMC/linux.git/arch/arm/kernel/signal.c, branch dev-5.0

Remove 'type' argument from access_ok() function

2019-01-04T02:57:57+00:00

Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument of the user address range verification function since we got rid of the old racy i386-only code to walk page tables by hand. It existed because the original 80386 would not honor the write protect bit when in kernel mode, so you had to do COW by hand before doing any user access. But we haven't supported that in a long time, and these days the 'type' argument is a purely historical artifact. A discussion about extending 'user_access_begin()' to do the range checking resulted this patch, because there is no way we're going to move the old VERIFY_xyz interface to that model. And it's best done at the end of the merge window when I've done most of my merges, so let's just get this done once and for all. This patch was mostly done with a sed-script, with manual fix-ups for the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form. There were a couple of notable cases: - csky still had the old "verify_area()" name as an alias. - the iter_iov code had magical hardcoded knowledge of the actual values of VERIFY_{READ,WRITE} (not that they mattered, since nothing really used it) - microblaze used the type argument for a debug printout but other than those oddities this should be a total no-op patch. I tried to fix up all architectures, did fairly extensive grepping for access_ok() uses, and the changes are trivial, but I may have missed something. Any missed conversion should be trivially fixable, though. Signed-off-by: Linus Torvalds

Merge branches 'fixes', 'misc' and 'spectre' into for-next

2018-10-10T12:53:33+00:00

ARM: 8793/1: signal: replace __put_user_error with __put_user

2018-10-05T09:51:15+00:00

With Spectre-v1.1 mitigations, __put_user_error is pointless. In an attempt to remove it, replace its references in frame setups with __put_user. Signed-off-by: Julien Thierry Signed-off-by: Russell King

ARM: 8791/1: vfp: use __copy_to_user() when saving VFP state

2018-10-05T09:51:15+00:00

Use __copy_to_user() rather than __put_user_error() for individual members when saving VFP state. This has the benefit of disabling/enabling PAN once per copied struct intead of once per write. Signed-off-by: Julien Thierry Signed-off-by: Russell King

ARM: 8790/1: signal: always use __copy_to_user to save iwmmxt context

2018-10-05T09:51:15+00:00

When setting a dummy iwmmxt context, create a local instance and use __copy_to_user both cases whether iwmmxt is being used or not. This has the benefit of disabling/enabling PAN once for the whole copy intead of once per write. Signed-off-by: Julien Thierry Signed-off-by: Russell King

ARM: 8789/1: signal: copy registers using __copy_to_user()

2018-10-05T09:51:15+00:00

When saving the ARM integer registers, use __copy_to_user() to copy them into user signal frame, rather than __put_user_error(). This has the benefit of disabling/enabling PAN once for the whole copy intead of once per write. Signed-off-by: Julien Thierry Signed-off-by: Russell King

Merge branch 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm

2018-08-14T02:13:38+00:00

Pull ARM updates from Russell King: - further Spectre variant 1 fixes for user accessors. - kbuild cleanups (Masahiro Yamada) - hook up sync core functionality (Will Deacon) - nommu updates for hypervisor mode booting (Vladimir Murzin) - use compiler built-ins for fls and ffs (Nicolas Pitre) * 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: ARM: spectre-v1: mitigate user accesses ARM: spectre-v1: use get_user() for __get_user() ARM: use __inttype() in get_user() ARM: oabi-compat: copy semops using __copy_from_user() ARM: vfp: use __copy_from_user() when restoring VFP state ARM: 8785/1: use compiler built-ins for ffs and fls ARM: 8784/1: NOMMU: Allow enter in Hyp mode ARM: 8783/1: NOMMU: Extend check for VBAR support ARM: 8782/1: vfp: clean up arch/arm/vfp/Makefile ARM: signal: copy registers using __copy_from_user() ARM: tcm: ensure inline stub functions are marked static ARM: 8779/1: add endianness option to LDFLAGS instead of LD ARM: 8777/1: Hook up SYNC_CORE functionality for sys_membarrier()

Merge branches 'fixes', 'misc' and 'spectre' into for-linus

2018-08-13T15:28:50+00:00

Conflicts: arch/arm/include/asm/uaccess.h Signed-off-by: Russell King

ARM: vfp: use __copy_from_user() when restoring VFP state

2018-08-02T16:41:37+00:00

__get_user_error() is used as a fast accessor to make copying structure members in the signal handling path as efficient as possible. However, with software PAN and the recent Spectre variant 1, the efficiency is reduced as these are no longer fast accessors. In the case of software PAN, it has to switch the domain register around each access, and with Spectre variant 1, it would have to repeat the access_ok() check for each access. Use __copy_from_user() rather than __get_user_err() for individual members when restoring VFP state. Acked-by: Mark Rutland Signed-off-by: Russell King

ARM: signal: copy registers using __copy_from_user()

2018-07-26T16:00:28+00:00

__get_user_error() is used as a fast accessor to make copying structure members in the signal handling path as efficient as possible. However, with software PAN and the recent Spectre variant 1, the efficiency is reduced as these are no longer fast accessors. In the case of software PAN, it has to switch the domain register around each access, and with Spectre variant 1, it would have to repeat the access_ok() check for each access. It becomes much more efficient to use __copy_from_user() instead, so let's use this for the ARM integer registers. Acked-by: Mark Rutland Signed-off-by: Russell King