arm64: make _TIF_WORK_MASK bits contiguous
authorMark Rutland <mark.rutland@arm.com>
Wed, 16 Dec 2020 21:32:48 +0000 (21:32 +0000)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 16 Dec 2020 22:08:47 +0000 (14:08 -0800)
commit870d16757ba8918c3f8cac162b9ca7669556dbab
treec047c19cbfeed18571b3d63c20466903e10e3bda
parent19778dd504b5ff5c3c1283aa3da7a56f34c2c3b0
arm64: make _TIF_WORK_MASK bits contiguous

We need the bits of _TIF_WORK_MASK to be contiguous in order to to use
this as an immediate argument to an AND instruction in entry.S.

We happened to change these bits in commits:

  b5a5a01d8e9a ("arm64: uaccess: remove addr_limit_user_check()")
  192caabd4dd9 ("arm64: add support for TIF_NOTIFY_SIGNAL")

which each worked in isolation, but the merge resolution in commit:

  005b2a9dc819 ("Merge tag 'tif-task_work.arch-2020-12-14' of git://git.kernel.dk/linux-block")

happened to make the bits non-contiguous.

Fix this by moving TIF_NOTIFY_SIGNAL to be bit 6, which is contiguous
with the rest of _TIF_WORK_MASK.

Otherwise, we'll get a build-time failure as below:

   arch/arm64/kernel/entry.S: Assembler messages:
   arch/arm64/kernel/entry.S:733: Error: immediate out of range at operand 3 -- `and x2,x19,#((1<<1)|(1<<0)|(1<<2)|(1<<3)|(1<<4)|(1<<5)|(1<<7))'
   scripts/Makefile.build:360: recipe for target 'arch/arm64/kernel/entry.o' failed

Fixes: 005b2a9dc819a126 ("Merge tag 'tif-task_work.arch-2020-12-14' of git://git.kernel.dk/linux-block")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
arch/arm64/include/asm/thread_info.h