linux/arch
Linus Torvalds 1423e2660c Fixes and improvements for FPU handling on x86:
- Prevent sigaltstack out of bounds writes. The kernel unconditionally
     writes the FPU state to the alternate stack without checking whether
     the stack is large enough to accomodate it.
 
     Check the alternate stack size before doing so and in case it's too
     small force a SIGSEGV instead of silently corrupting user space data.
 
   - MINSIGSTKZ and SIGSTKSZ are constants in signal.h and have never been
     updated despite the fact that the FPU state which is stored on the
     signal stack has grown over time which causes trouble in the field
     when AVX512 is available on a CPU. The kernel does not expose the
     minimum requirements for the alternate stack size depending on the
     available and enabled CPU features.
 
     ARM already added an aux vector AT_MINSIGSTKSZ for the same reason.
     Add it to x86 as well
 
   - A major cleanup of the x86 FPU code. The recent discoveries of XSTATE
     related issues unearthed quite some inconsistencies, duplicated code
     and other issues.
 
     The fine granular overhaul addresses this, makes the code more robust
     and maintainable, which allows to integrate upcoming XSTATE related
     features in sane ways.
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Merge tag 'x86-fpu-2021-07-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fpu updates from Thomas Gleixner:
 "Fixes and improvements for FPU handling on x86:

   - Prevent sigaltstack out of bounds writes.

     The kernel unconditionally writes the FPU state to the alternate
     stack without checking whether the stack is large enough to
     accomodate it.

     Check the alternate stack size before doing so and in case it's too
     small force a SIGSEGV instead of silently corrupting user space
     data.

   - MINSIGSTKZ and SIGSTKSZ are constants in signal.h and have never
     been updated despite the fact that the FPU state which is stored on
     the signal stack has grown over time which causes trouble in the
     field when AVX512 is available on a CPU. The kernel does not expose
     the minimum requirements for the alternate stack size depending on
     the available and enabled CPU features.

     ARM already added an aux vector AT_MINSIGSTKSZ for the same reason.
     Add it to x86 as well.

   - A major cleanup of the x86 FPU code. The recent discoveries of
     XSTATE related issues unearthed quite some inconsistencies,
     duplicated code and other issues.

     The fine granular overhaul addresses this, makes the code more
     robust and maintainable, which allows to integrate upcoming XSTATE
     related features in sane ways"

* tag 'x86-fpu-2021-07-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (74 commits)
  x86/fpu/xstate: Clear xstate header in copy_xstate_to_uabi_buf() again
  x86/fpu/signal: Let xrstor handle the features to init
  x86/fpu/signal: Handle #PF in the direct restore path
  x86/fpu: Return proper error codes from user access functions
  x86/fpu/signal: Split out the direct restore code
  x86/fpu/signal: Sanitize copy_user_to_fpregs_zeroing()
  x86/fpu/signal: Sanitize the xstate check on sigframe
  x86/fpu/signal: Remove the legacy alignment check
  x86/fpu/signal: Move initial checks into fpu__restore_sig()
  x86/fpu: Mark init_fpstate __ro_after_init
  x86/pkru: Remove xstate fiddling from write_pkru()
  x86/fpu: Don't store PKRU in xstate in fpu_reset_fpstate()
  x86/fpu: Remove PKRU handling from switch_fpu_finish()
  x86/fpu: Mask PKRU from kernel XRSTOR[S] operations
  x86/fpu: Hook up PKRU into ptrace()
  x86/fpu: Add PKRU storage outside of task XSAVE buffer
  x86/fpu: Dont restore PKRU in fpregs_restore_userspace()
  x86/fpu: Rename xfeatures_mask_user() to xfeatures_mask_uabi()
  x86/fpu: Move FXSAVE_LEAK quirk info __copy_kernel_to_fpregs()
  x86/fpu: Rename __fpregs_load_activate() to fpregs_restore_userregs()
  ...
2021-07-07 11:12:01 -07:00
..
alpha TTY / Serial patches for 5.14-rc1 2021-07-05 14:08:24 -07:00
arc Merge branch 'akpm' (patches from Andrew) 2021-07-02 12:08:10 -07:00
arm ARM development updates for 5.14-rc1: 2021-07-06 11:52:58 -07:00
arm64 ARM development updates for 5.14-rc1: 2021-07-06 11:52:58 -07:00
csky arch/csky patches for 5.14-rc1 2021-07-04 12:07:54 -07:00
h8300 Merge branch 'akpm' (patches from Andrew) 2021-06-29 17:29:11 -07:00
hexagon Merge branch 'akpm' (patches from Andrew) 2021-07-02 12:08:10 -07:00
ia64 asm-generic/unaligned: Unify asm/unaligned.h around struct helper 2021-07-02 12:43:40 -07:00
m68k TTY / Serial patches for 5.14-rc1 2021-07-05 14:08:24 -07:00
microblaze asm-generic/unaligned: Unify asm/unaligned.h around struct helper 2021-07-02 12:43:40 -07:00
mips TTY / Serial patches for 5.14-rc1 2021-07-05 14:08:24 -07:00
nds32 Merge branch 'akpm' (patches from Andrew) 2021-07-02 12:08:10 -07:00
nios2 Merge branch 'akpm' (patches from Andrew) 2021-07-02 12:08:10 -07:00
openrisc asm-generic/unaligned: Unify asm/unaligned.h around struct helper 2021-07-02 12:43:40 -07:00
parisc TTY / Serial patches for 5.14-rc1 2021-07-05 14:08:24 -07:00
powerpc TTY / Serial patches for 5.14-rc1 2021-07-05 14:08:24 -07:00
riscv Merge branch 'akpm' (patches from Andrew) 2021-07-02 12:08:10 -07:00
s390 s390 updates for the 5.14 merge window 2021-07-04 12:17:38 -07:00
sh asm-generic/unaligned: Unify asm/unaligned.h around struct helper 2021-07-02 12:43:40 -07:00
sparc Char / Misc driver updates for 5.14-rc1 2021-07-05 13:42:16 -07:00
um TTY / Serial patches for 5.14-rc1 2021-07-05 14:08:24 -07:00
x86 Fixes and improvements for FPU handling on x86: 2021-07-07 11:12:01 -07:00
xtensa TTY / Serial patches for 5.14-rc1 2021-07-05 14:08:24 -07:00
.gitignore
Kconfig Kconfig: Introduce ARCH_WANTS_NO_INSTR and CC_HAS_NO_PROFILE_FN_ATTR 2021-06-22 11:07:18 -07:00