Pull arm64 fixes from Will Deacon:
 "I'm safely chained back up to my desk, so please pull these arm64
  fixes for -rc1 that address some issues that cropped up during the
  merge window:

   - Prevent KASLR from mapping the top page of the virtual address
     space

   - Fix device-tree probing of SDEI driver

   - Fix incorrect register offset definition in Hisilicon DDRC PMU
     driver

   - Fix compilation issue with older binutils not liking unsigned
     immediates

   - Fix uapi headers so that libc can provide its own sigcontext
     definition

   - Fix handling of private compat syscalls

   - Hook up compat io_pgetevents() syscall for 32-bit tasks

   - Cleanup to arm64 Makefile (including now to avoid silly conflicts)"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: compat: Hook up io_pgetevents() for 32-bit tasks
  arm64: compat: Don't pull syscall number from regs in arm_compat_syscall
  arm64: compat: Avoid sending SIGILL for unallocated syscall numbers
  arm64/sve: Disentangle <uapi/asm/ptrace.h> from <uapi/asm/sigcontext.h>
  arm64/sve: ptrace: Fix SVE_PT_REGS_OFFSET definition
  drivers/perf: hisi: Fixup one DDRC PMU register offset
  arm64: replace arm64-obj-* in Makefile with obj-*
  arm64: kaslr: Reserve size of ARM64_MEMSTART_ALIGN in linear region
  firmware: arm_sdei: Fix DT platform device creation
  firmware: arm_sdei: fix wrong of_node_put() in init function
  arm64: entry: remove unused register aliases
  arm64: smp: Fix compilation error

The syscall number may have been changed by a tracer, so we should pass
the actual number in from the caller instead of pulling it from the
saved r7 value directly.

Cc: <stable@vger.kernel.org>
Cc: Pi-Hsun Shih <pihsun@chromium.org>
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

The ARM Linux kernel handles the EABI syscall numbers as follows:

  0           - NR_SYSCALLS-1	: Invoke syscall via syscall table
  NR_SYSCALLS - 0xeffff		: -ENOSYS (to be allocated in future)
  0xf0000     - 0xf07ff		: Private syscall or -ENOSYS if not allocated
  > 0xf07ff			: SIGILL

Our compat code gets this wrong and ends up sending SIGILL in response
to all syscalls greater than NR_SYSCALLS which have a value greater
than 0x7ff in the bottom 16 bits.

Fix this by defining the end of the ARM private syscall region and
checking the syscall number against that directly. Update the comment
while we're at it.

Cc: <stable@vger.kernel.org>
Cc: Dave Martin <Dave.Martin@arm.com>
Reported-by: Pi-Hsun Shih <pihsun@chromium.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

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 <torvalds@linux-foundation.org>

Instead of generating a struct siginfo before calling arm64_notify_die
pass the signal number, tne sicode and the fault address into
arm64_notify_die and have it call force_sig_fault instead of
force_sig_info to let the generic code generate the struct siginfo.

This keeps code passing just the needed information into
siginfo generating code, making it easier to see what
is happening and harder to get wrong.  Further by letting
the generic code handle the generation of struct siginfo
it reduces the number of sites generating struct siginfo
making it possible to review them and verify that all
of the fiddly details for a structure passed to userspace
are handled properly.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

Call clear_siginfo to ensure every stack allocated siginfo is properly
initialized before being passed to the signal sending functions.

Note: It is not safe to depend on C initializers to initialize struct
siginfo on the stack because C is allowed to skip holes when
initializing a structure.

The initialization of struct siginfo in tracehook_report_syscall_exit
was moved from the helper user_single_step_siginfo into
tracehook_report_syscall_exit itself, to make it clear that the local
variable siginfo gets fully initialized.

In a few cases the scope of struct siginfo has been reduced to make it
clear that siginfo siginfo is not used on other paths in the function
in which it is declared.

Instances of using memset to initialize siginfo have been replaced
with calls clear_siginfo for clarity.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

When the hardend usercopy support was added for arm64, it was
concluded that all cases of usercopy into and out of thread_struct
were statically sized and so didn't require explicit whitelisting
of the appropriate fields in thread_struct.

Testing with usercopy hardening enabled has revealed that this is
not the case for certain ptrace regset manipulation calls on arm64.
This occurs because the sizes of usercopies associated with the
regset API are dynamic by construction, and because arm64 does not
always stage such copies via the stack: indeed the regset API is
designed to avoid the need for that by adding some bounds checking.

This is currently believed to affect only the fpsimd and TLS
registers.

Because the whitelisted fields in thread_struct must be contiguous,
this patch groups them together in a nested struct.  It is also
necessary to be able to determine the location and size of that
struct, so rather than making the struct anonymous (which would
save on edits elsewhere) or adding an anonymous union containing
named and unnamed instances of the same struct (gross), this patch
gives the struct a name and makes the necessary edits to code that
references it (noisy but simple).

Care is needed to ensure that the new struct does not contain
padding (which the usercopy hardening would fail to protect).

For this reason, the presence of tp2_value is made unconditional,
since a padding field would be needed there in any case.  This pads
up to the 16-byte alignment required by struct user_fpsimd_state.

Acked-by: Kees Cook <keescook@chromium.org>
Reported-by: Mark Rutland <mark.rutland@arm.com>
Fixes: 9e8084d3f761 ("arm64: Implement thread_struct whitelist for hardened usercopy")
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Mirror arm behaviour for unimplemented syscalls: Below 2048 return
-ENOSYS, above 2048 raise SIGILL.

Signed-off-by: Michael Weiser <michael.weiser@gmx.de>
[will: Tweak die string to identify as compat syscall]
Signed-off-by: Will Deacon <will.deacon@arm.com>

In converting __range_ok() into a static inline, I inadvertently made
it more type-safe, but without considering the ordering of the relevant
conversions. This leads to quite a lot of Sparse noise about the fact
that we use __chk_user_ptr() after addr has already been converted from
a user pointer to an unsigned long.

Rather than just adding another cast for the sake of shutting Sparse up,
it seems reasonable to rework the types to make logical sense (although
the resulting codegen for __range_ok() remains identical). The only
callers this affects directly are our compat traps where the inferred
"user-pointer-ness" of a register value now warrants explicit casting.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Instead of including the full <linux/signal.h>, we are going to include the
types-only <linux/signal_types.h> header in <linux/sched.h>, to further
decouple the scheduler header from the signal headers.

This means that various files which relied on the full <linux/signal.h> need
to be updated to gain an explicit dependency on it.

Update the code that relies on sched.h's inclusion of the <linux/signal.h> header.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>