Merge branch 'arm64/vmap-stack' of git://git.kernel.org/pub/scm/linux/kernel/git/mark/linux into for-next/core

* 'arm64/vmap-stack' of git://git.kernel.org/pub/scm/linux/kernel/git/mark/linux:
  arm64: add VMAP_STACK overflow detection
  arm64: add on_accessible_stack()
  arm64: add basic VMAP_STACK support
  arm64: use an irq stack pointer
  arm64: assembler: allow adr_this_cpu to use the stack pointer
  arm64: factor out entry stack manipulation
  efi/arm64: add EFI_KIMG_ALIGN
  arm64: move SEGMENT_ALIGN to <asm/memory.h>
  arm64: clean up irq stack definitions
  arm64: clean up THREAD_* definitions
  arm64: factor out PAGE_* and CONT_* definitions
  arm64: kernel: remove {THREAD,IRQ_STACK}_START_SP
  fork: allow arch-override of VMAP stack alignment
  arm64: remove __die()'s stack dump

This patch adds stack overflow detection to arm64, usable when vmap'd stacks
are in use.

Overflow is detected in a small preamble executed for each exception entry,
which checks whether there is enough space on the current stack for the general
purpose registers to be saved. If there is not enough space, the overflow
handler is invoked on a per-cpu overflow stack. This approach preserves the
original exception information in ESR_EL1 (and where appropriate, FAR_EL1).

Task and IRQ stacks are aligned to double their size, enabling overflow to be
detected with a single bit test. For example, a 16K stack is aligned to 32K,
ensuring that bit 14 of the SP must be zero. On an overflow (or underflow),
this bit is flipped. Thus, overflow (of less than the size of the stack) can be
detected by testing whether this bit is set.

The overflow check is performed before any attempt is made to access the
stack, avoiding recursive faults (and the loss of exception information
these would entail). As logical operations cannot be performed on the SP
directly, the SP is temporarily swapped with a general purpose register
using arithmetic operations to enable the test to be performed.

This gives us a useful error message on stack overflow, as can be trigger with
the LKDTM overflow test:

[  305.388749] lkdtm: Performing direct entry OVERFLOW
[  305.395444] Insufficient stack space to handle exception!
[  305.395482] ESR: 0x96000047 -- DABT (current EL)
[  305.399890] FAR: 0xffff00000a5e7f30
[  305.401315] Task stack:     [0xffff00000a5e8000..0xffff00000a5ec000]
[  305.403815] IRQ stack:      [0xffff000008000000..0xffff000008004000]
[  305.407035] Overflow stack: [0xffff80003efce4e0..0xffff80003efcf4e0]
[  305.409622] CPU: 0 PID: 1219 Comm: sh Not tainted 4.13.0-rc3-00021-g9636aea #5
[  305.412785] Hardware name: linux,dummy-virt (DT)
[  305.415756] task: ffff80003d051c00 task.stack: ffff00000a5e8000
[  305.419221] PC is at recursive_loop+0x10/0x48
[  305.421637] LR is at recursive_loop+0x38/0x48
[  305.423768] pc : [<ffff00000859f330>] lr : [<ffff00000859f358>] pstate: 40000145
[  305.428020] sp : ffff00000a5e7f50
[  305.430469] x29: ffff00000a5e8350 x28: ffff80003d051c00
[  305.433191] x27: ffff000008981000 x26: ffff000008f80400
[  305.439012] x25: ffff00000a5ebeb8 x24: ffff00000a5ebeb8
[  305.440369] x23: ffff000008f80138 x22: 0000000000000009
[  305.442241] x21: ffff80003ce65000 x20: ffff000008f80188
[  305.444552] x19: 0000000000000013 x18: 0000000000000006
[  305.446032] x17: 0000ffffa2601280 x16: ffff0000081fe0b8
[  305.448252] x15: ffff000008ff546d x14: 000000000047a4c8
[  305.450246] x13: ffff000008ff7872 x12: 0000000005f5e0ff
[  305.452953] x11: ffff000008ed2548 x10: 000000000005ee8d
[  305.454824] x9 : ffff000008545380 x8 : ffff00000a5e8770
[  305.457105] x7 : 1313131313131313 x6 : 00000000000000e1
[  305.459285] x5 : 0000000000000000 x4 : 0000000000000000
[  305.461781] x3 : 0000000000000000 x2 : 0000000000000400
[  305.465119] x1 : 0000000000000013 x0 : 0000000000000012
[  305.467724] Kernel panic - not syncing: kernel stack overflow
[  305.470561] CPU: 0 PID: 1219 Comm: sh Not tainted 4.13.0-rc3-00021-g9636aea #5
[  305.473325] Hardware name: linux,dummy-virt (DT)
[  305.475070] Call trace:
[  305.476116] [<ffff000008088ad8>] dump_backtrace+0x0/0x378
[  305.478991] [<ffff000008088e64>] show_stack+0x14/0x20
[  305.481237] [<ffff00000895a178>] dump_stack+0x98/0xb8
[  305.483294] [<ffff0000080c3288>] panic+0x118/0x280
[  305.485673] [<ffff0000080c2e9c>] nmi_panic+0x6c/0x70
[  305.486216] [<ffff000008089710>] handle_bad_stack+0x118/0x128
[  305.486612] Exception stack(0xffff80003efcf3a0 to 0xffff80003efcf4e0)
[  305.487334] f3a0: 0000000000000012 0000000000000013 0000000000000400 0000000000000000
[  305.488025] f3c0: 0000000000000000 0000000000000000 00000000000000e1 1313131313131313
[  305.488908] f3e0: ffff00000a5e8770 ffff000008545380 000000000005ee8d ffff000008ed2548
[  305.489403] f400: 0000000005f5e0ff ffff000008ff7872 000000000047a4c8 ffff000008ff546d
[  305.489759] f420: ffff0000081fe0b8 0000ffffa2601280 0000000000000006 0000000000000013
[  305.490256] f440: ffff000008f80188 ffff80003ce65000 0000000000000009 ffff000008f80138
[  305.490683] f460: ffff00000a5ebeb8 ffff00000a5ebeb8 ffff000008f80400 ffff000008981000
[  305.491051] f480: ffff80003d051c00 ffff00000a5e8350 ffff00000859f358 ffff00000a5e7f50
[  305.491444] f4a0: ffff00000859f330 0000000040000145 0000000000000000 0000000000000000
[  305.492008] f4c0: 0001000000000000 0000000000000000 ffff00000a5e8350 ffff00000859f330
[  305.493063] [<ffff00000808205c>] __bad_stack+0x88/0x8c
[  305.493396] [<ffff00000859f330>] recursive_loop+0x10/0x48
[  305.493731] [<ffff00000859f358>] recursive_loop+0x38/0x48
[  305.494088] [<ffff00000859f358>] recursive_loop+0x38/0x48
[  305.494425] [<ffff00000859f358>] recursive_loop+0x38/0x48
[  305.494649] [<ffff00000859f358>] recursive_loop+0x38/0x48
[  305.494898] [<ffff00000859f358>] recursive_loop+0x38/0x48
[  305.495205] [<ffff00000859f358>] recursive_loop+0x38/0x48
[  305.495453] [<ffff00000859f358>] recursive_loop+0x38/0x48
[  305.495708] [<ffff00000859f358>] recursive_loop+0x38/0x48
[  305.496000] [<ffff00000859f358>] recursive_loop+0x38/0x48
[  305.496302] [<ffff00000859f358>] recursive_loop+0x38/0x48
[  305.496644] [<ffff00000859f358>] recursive_loop+0x38/0x48
[  305.496894] [<ffff00000859f358>] recursive_loop+0x38/0x48
[  305.497138] [<ffff00000859f358>] recursive_loop+0x38/0x48
[  305.497325] [<ffff00000859f3dc>] lkdtm_OVERFLOW+0x14/0x20
[  305.497506] [<ffff00000859f314>] lkdtm_do_action+0x1c/0x28
[  305.497786] [<ffff00000859f178>] direct_entry+0xe0/0x170
[  305.498095] [<ffff000008345568>] full_proxy_write+0x60/0xa8
[  305.498387] [<ffff0000081fb7f4>] __vfs_write+0x1c/0x128
[  305.498679] [<ffff0000081fcc68>] vfs_write+0xa0/0x1b0
[  305.498926] [<ffff0000081fe0fc>] SyS_write+0x44/0xa0
[  305.499182] Exception stack(0xffff00000a5ebec0 to 0xffff00000a5ec000)
[  305.499429] bec0: 0000000000000001 000000001c4cf5e0 0000000000000009 000000001c4cf5e0
[  305.499674] bee0: 574f4c465245564f 0000000000000000 0000000000000000 8000000080808080
[  305.499904] bf00: 0000000000000040 0000000000000038 fefefeff1b4bc2ff 7f7f7f7f7f7fff7f
[  305.500189] bf20: 0101010101010101 0000000000000000 000000000047a4c8 0000000000000038
[  305.500712] bf40: 0000000000000000 0000ffffa2601280 0000ffffc63f6068 00000000004b5000
[  305.501241] bf60: 0000000000000001 000000001c4cf5e0 0000000000000009 000000001c4cf5e0
[  305.501791] bf80: 0000000000000020 0000000000000000 00000000004b5000 000000001c4cc458
[  305.502314] bfa0: 0000000000000000 0000ffffc63f7950 000000000040a3c4 0000ffffc63f70e0
[  305.502762] bfc0: 0000ffffa2601268 0000000080000000 0000000000000001 0000000000000040
[  305.503207] bfe0: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
[  305.503680] [<ffff000008082fb0>] el0_svc_naked+0x24/0x28
[  305.504720] Kernel Offset: disabled
[  305.505189] CPU features: 0x002082
[  305.505473] Memory Limit: none
[  305.506181] ---[ end Kernel panic - not syncing: kernel stack overflow

This patch was co-authored by Ard Biesheuvel and Mark Rutland.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>

Both unwind_frame() and dump_backtrace() try to check whether a stack
address is sane to access, with very similar logic. Both will need
updating in order to handle overflow stacks.

Factor out this logic into a helper, so that we can avoid further
duplication when we add overflow stacks.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>

This patch enables arm64 to be built with vmap'd task and IRQ stacks.

As vmap'd stacks are mapped at page granularity, stacks must be a multiple of
PAGE_SIZE. This means that a 64K page kernel must use stacks of at least 64K in
size.

To minimize the increase in Image size, IRQ stacks are dynamically allocated at
boot time, rather than embedding the boot CPU's IRQ stack in the kernel image.

This patch was co-authored by Ard Biesheuvel and Mark Rutland.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>

We allocate our IRQ stacks using a percpu array. This allows us to generate our
IRQ stack pointers with adr_this_cpu, but bloats the kernel Image with the boot
CPU's IRQ stack. Additionally, these are packed with other percpu variables,
and aren't guaranteed to have guard pages.

When we enable VMAP_STACK we'll want to vmap our IRQ stacks also, in order to
provide guard pages and to permit more stringent alignment requirements. Doing
so will require that we use a percpu pointer to each IRQ stack, rather than
allocating a percpu IRQ stack in the kernel image.

This patch updates our IRQ stack code to use a percpu pointer to the base of
each IRQ stack. This will allow us to change the way the stack is allocated
with minimal changes elsewhere. In some cases we may try to backtrace before
the IRQ stack pointers are initialised, so on_irq_stack() is updated to account
for this.

In testing with cyclictest, there was no measureable difference between using
adr_this_cpu (for irq_stack) and ldr_this_cpu (for irq_stack_ptr) in the IRQ
entry path.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>

Given that adr_this_cpu already requires a temp register in addition
to the destination register, tweak the instruction sequence so that sp
may be used as well.

This will simplify switching to per-cpu stacks in subsequent patches. While
this limits the range of adr_this_cpu, to +/-4GiB, we don't currently use
adr_this_cpu in modules, and this is not problematic for the main kernel image.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
[Mark: add more commit text]
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>

In subsequent patches, we will detect stack overflow in our exception
entry code, by verifying the SP after it has been decremented to make
space for the exception regs.

This verification code is small, and we can minimize its impact by
placing it directly in the vectors. To avoid redundant modification of
the SP, we also need to move the initial decrement of the SP into the
vectors.

As a preparatory step, this patch introduces kernel_ventry, which
performs this decrement, and updates the entry code accordingly.
Subsequent patches will fold SP verification into kernel_ventry.

There should be no functional change as a result of this patch.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
[Mark: turn into prep patch, expand commit msg]
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>

The EFI stub is intimately coupled with the kernel, and takes advantage
of this by relocating the kernel at a weaker alignment than the
documented boot protocol mandates.

However, it does so by assuming it can align the kernel to the segment
alignment, and assumes that this is 64K. In subsequent patches, we'll
have to consider other details to determine this de-facto alignment
constraint.

This patch adds a new EFI_KIMG_ALIGN definition that will track the
kernel's de-facto alignment requirements. Subsequent patches will modify
this as required.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>

Currently we define SEGMENT_ALIGN directly in our vmlinux.lds.S.

This is unfortunate, as the EFI stub currently open-codes the same
number, and in future we'll want to fiddle with this.

This patch moves the definition to our <asm/memory.h>, where it can be
used by both vmlinux.lds.S and the EFI stub code.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>

Before we add yet another stack to the kernel, it would be nice to
ensure that we consistently organise stack definitions and related
helper functions.

This patch moves the basic IRQ stack defintions to <asm/memory.h> to
live with their task stack counterparts. Helpers used for unwinding are
moved into <asm/stacktrace.h>, where subsequent patches will add helpers
for other stacks. Includes are fixed up accordingly.

This patch is a pure refactoring -- there should be no functional
changes as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>

Currently we define THREAD_SIZE and THREAD_SIZE_ORDER separately, with
the latter dependent on particular CONFIG_ARM64_*K_PAGES definitions.
This is somewhat opaque, and will get in the way of future modifications
to THREAD_SIZE.

This patch cleans this up, defining both in terms of a common
THREAD_SHIFT, and using PAGE_SHIFT to calculate THREAD_SIZE_ORDER,
rather than using a number of definitions dependent on config symbols.
Subsequent patches will make use of this to alter the stack size used in
some configurations.

At the same time, these are moved into <asm/memory.h>, which will avoid
circular include issues in subsequent patches. To ensure that existing
code isn't adversely affected, <asm/thread_info.h> is updated to
transitively include these definitions.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>

Some headers rely on PAGE_* definitions from <asm/page.h>, but cannot
include this due to potential circular includes. For example, a number
of definitions in <asm/memory.h> rely on PAGE_SHIFT, and <asm/page.h>
includes <asm/memory.h>.

This requires users of these definitions to include both headers, which
is fragile and error-prone.

This patch ameliorates matters by moving the basic definitions out to a
new header, <asm/page-def.h>. Both <asm/page.h> and <asm/memory.h> are
updated to include this, avoiding this fragility, and avoiding the
possibility of circular include dependencies.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>

For historical reasons, we leave the top 16 bytes of our task and IRQ
stacks unused, a practice used to ensure that the SP can always be
masked to find the base of the current stack (historically, where
thread_info could be found).

However, this is not necessary, as:

* When an exception is taken from a task stack, we decrement the SP by
  S_FRAME_SIZE and stash the exception registers before we compare the
  SP against the task stack. In such cases, the SP must be at least
  S_FRAME_SIZE below the limit, and can be safely masked to determine
  whether the task stack is in use.

* When transitioning to an IRQ stack, we'll place a dummy frame onto the
  IRQ stack before enabling asynchronous exceptions, or executing code
  we expect to trigger faults. Thus, if an exception is taken from the
  IRQ stack, the SP must be at least 16 bytes below the limit.

* We no longer mask the SP to find the thread_info, which is now found
  via sp_el0. Note that historically, the offset was critical to ensure
  that cpu_switch_to() found the correct stack for new threads that
  hadn't yet executed ret_from_fork().

Given that, this initial offset serves no purpose, and can be removed.
This brings us in-line with other architectures (e.g. x86) which do not
rely on this masking.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
[Mark: rebase, kill THREAD_START_SP, commit msg additions]
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>

In some cases, an architecture might wish its stacks to be aligned to a
boundary larger than THREAD_SIZE. For example, using an alignment of
double THREAD_SIZE can allow for stack overflows smaller than
THREAD_SIZE to be detected by checking a single bit of the stack
pointer.

This patch allows architectures to override the alignment of VMAP'd
stacks, by defining THREAD_ALIGN. Where not defined, this defaults to
THREAD_SIZE, as is the case today.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: linux-kernel@vger.kernel.org

Our __die() implementation tries to dump the stack memory, in addition
to a backtrace, which is problematic.

For contemporary 16K stacks, this can be a lot of data, which can take a
long time to dump, and can push other useful context out of the kernel's
printk ringbuffer (and/or a user's scrollback buffer on an attached
console).

Additionally, the code implicitly assumes that the SP is on the task's
stack, and tries to dump everything between the SP and the highest task
stack address. When the SP points at an IRQ stack (or is corrupted),
this makes the kernel attempt to dump vast amounts of VA space. With
vmap'd stacks, this may result in erroneous accesses to peripherals.

This patch removes the memory dump, leaving us to rely on the backtrace,
and other means of dumping stack memory such as kdump.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>

Commit a7be6e5a ("mm: drop useless local parameters of
__register_one_node()") removes the last user of parent_node().

The parent_node() macro in ARM64 platform is unnecessary.

Remove it for cleanup.
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Commit a1d5ebaf ("arm64: big-endian: don't treat code as data when
copying sigret code") moved the 32-bit sigreturn trampoline code from
the aarch32_sigret_code array to kuser32.S. The commit removed the
array definition from signal32.c, but not its declaration in
signal32.h. Remove the leftover declaration.
Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Signed-off-by: Mark Salyzyn <salyzyn@android.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

A recent change reintroduced a bug that had previously been
fixed by commit d49f2ded ("ACPI/IORT: Fix CONFIG_IOMMU_API
dependency"):

drivers/acpi/arm64/iort.c: In function 'iort_iommu_configure':
drivers/acpi/arm64/iort.c:829:26: error: 'struct iommu_fwspec' has no member named 'ops'

Replace a direct reference to iommu_fwspec->ops with a helper function
call to fix the issue.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Defining the two functions as 'static inline' and exporting them
leads to the interesting case where we can use the interface
from loadable modules, but not from built-in drivers, as shown
in this link failure:

vers/nvdimm/claim.o: In function `nsio_rw_bytes':
claim.c:(.text+0x1b8): undefined reference to `arch_invalidate_pmem'
drivers/nvdimm/pmem.o: In function `pmem_dax_flush':
pmem.c:(.text+0x11c): undefined reference to `arch_wb_cache_pmem'
drivers/nvdimm/pmem.o: In function `pmem_make_request':
pmem.c:(.text+0x5a4): undefined reference to `arch_invalidate_pmem'
pmem.c:(.text+0x650): undefined reference to `arch_invalidate_pmem'
pmem.c:(.text+0x6d4): undefined reference to `arch_invalidate_pmem'

This removes the bogus 'static inline'.

Fixes: d50e071f ("arm64: Implement pmem API support")
Acked-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

The uaccess_flushcache.c file was inadvertently dropped by the
maintainer in a previous commit. Add it back.

Fixes: 5d7bdeb1 ("arm64: uaccess: Implement *_flushcache variants")
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Provide a NEON accelerated implementation of the recovery algorithm,
which supersedes the default byte-by-byte one.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

The P/Q left side optimization in the delta syndrome simply involves
repeatedly multiplying a value by polynomial 'x' in GF(2^8). Given
that 'x * x * x * x' equals 'x^4' even in the polynomial world, we
can accelerate this substantially by performing up to 4 such operations
at once, using the NEON instructions for polynomial multiplication.

Results on a Cortex-A57 running in 64-bit mode:

  Before:
  -------
  raid6: neonx1   xor()  1680 MB/s
  raid6: neonx2   xor()  2286 MB/s
  raid6: neonx4   xor()  3162 MB/s
  raid6: neonx8   xor()  3389 MB/s

  After:
  ------
  raid6: neonx1   xor()  2281 MB/s
  raid6: neonx2   xor()  3362 MB/s
  raid6: neonx4   xor()  3787 MB/s
  raid6: neonx8   xor()  4239 MB/s

While we're at it, simplify MASK() by using a signed shift rather than
a vector compare involving a temp register.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Merge tag 'arm64-iort-for-v4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/lpieralisi/linux into for-next/core

Two patches for the 4.14 release merge window:

- IORT PCI aliases detection improvement to cater for systems with
  complex PCI topologies that current code mishandles (R.Murphy)
- IORT SMMUv3 proximity domain (ie NUMA) handling (respective ACPICA
  changes will be merged separately) (G. Kulkarni)

* tag 'arm64-iort-for-v4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/lpieralisi/linux:
  ACPI/IORT: numa: Add numa node mapping for smmuv3 devices
  ACPI/IORT: Handle PCI aliases properly for IOMMUs

Merge branch 'arm64/exception-stack' of git://git.kernel.org/pub/scm/linux/kernel/git/mark/linux into for-next/core

* 'arm64/exception-stack' of git://git.kernel.org/pub/scm/linux/kernel/git/mark/linux:
  arm64: unwind: remove sp from struct stackframe
  arm64: unwind: reference pt_regs via embedded stack frame
  arm64: unwind: disregard frame.sp when validating frame pointer
  arm64: unwind: avoid percpu indirection for irq stack
  arm64: move non-entry code out of .entry.text
  arm64: consistently use bl for C exception entry
  arm64: Add ASM_BUG()

The unwind code sets the sp member of struct stackframe to
'frame pointer + 0x10' unconditionally, without regard for whether
doing so produces a legal value. So let's simply remove it now that
we have stopped using it anyway.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will.deacon@arm.com>

As it turns out, the unwind code is slightly broken, and probably has
been for a while. The problem is in the dumping of the exception stack,
which is intended to dump the contents of the pt_regs struct at each
level in the call stack where an exception was taken and routed to a
routine marked as __exception (which means its stack frame is right
below the pt_regs struct on the stack).

'Right below the pt_regs struct' is ill defined, though: the unwind
code assigns 'frame pointer + 0x10' to the .sp member of the stackframe
struct at each level, and dump_backtrace() happily dereferences that as
the pt_regs pointer when encountering an __exception routine. However,
the actual size of the stack frame created by this routine (which could
be one of many __exception routines we have in the kernel) is not known,
and so frame.sp is pretty useless to figure out where struct pt_regs
really is.

So it seems the only way to ensure that we can find our struct pt_regs
when walking the stack frames is to put it at a known fixed offset of
the stack frame pointer that is passed to such __exception routines.
The simplest way to do that is to put it inside pt_regs itself, which is
the main change implemented by this patch. As a bonus, doing this allows
us to get rid of a fair amount of cruft related to walking from one stack
to the other, which is especially nice since we intend to introduce yet
another stack for overflow handling once we add support for vmapped
stacks. It also fixes an inconsistency where we only add a stack frame
pointing to ELR_EL1 if we are executing from the IRQ stack but not when
we are executing from the task stack.

To consistly identify exceptions regs even in the presence of exceptions
taken from entry code, we must check whether the next frame was created
by entry text, rather than whether the current frame was crated by
exception text.

To avoid backtracing using PCs that fall in the idmap, or are controlled
by userspace, we must explcitly zero the FP and LR in startup paths, and
must ensure that the frame embedded in pt_regs is zeroed upon entry from
EL0. To avoid these NULL entries showin in the backtrace, unwind_frame()
is updated to avoid them.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
[Mark: compare current frame against .entry.text, avoid bogus PCs]
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will.deacon@arm.com>

vDSO VMA address is saved in mm_context for the purpose of using
restorer from vDSO page to return to userspace after signal handling.

In Checkpoint Restore in Userspace (CRIU) project we place vDSO VMA
on restore back to the place where it was on the dump.
With the exception for x86 (where there is API to map vDSO with
arch_prctl()), we move vDSO inherited from CRIU task to restoree
position by mremap().

CRIU does support arm64 architecture, but kernel doesn't update
context.vdso pointer after mremap(). Which results in translation
fault after signal handling on restored application:
https://github.com/xemul/criu/issues/288

Make vDSO code track the VMA address by supplying .mremap() fops
the same way it's done for x86 and arm32 by:
commit b059a453 ("x86/vdso: Add mremap hook to vm_special_mapping")
commit 280e87e9 ("ARM: 8683/1: ARM32: Support mremap() for sigpage/vDSO").

Cc: Russell King <rmk+kernel@armlinux.org.uk>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Cc: Christopher Covington <cov@codeaurora.org>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Implement the set of copy functions with guarantees of a clean cache
upon completion necessary to support the pmem driver.
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Add a clean-to-point-of-persistence cache maintenance helper, and wire
up the basic architectural support for the pmem driver based on it.
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
[catalin.marinas@arm.com: move arch_*_pmem() functions to arch/arm64/mm/flush.c]
[catalin.marinas@arm.com: change dmb(sy) to dmb(osh)]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Cache clean to PoP is subject to the same access controls as to PoC, so
if we are trapping userspace cache maintenance with SCTLR_EL1.UCI, we
need to be prepared to handle it. To avoid getting into complicated
fights with binutils about ARMv8.2 options, we'll just cheat and use the
raw SYS instruction rather than the 'proper' DC alias.
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

The ARMv8.2-DCPoP feature introduces persistent memory support to the
architecture, by defining a point of persistence in the memory
hierarchy, and a corresponding cache maintenance operation, DC CVAP.
Expose the support via HWCAP and MRS emulation.
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

__inval_cache_range() is already the odd one out among our data cache
maintenance routines as the only remaining range-based one; as we're
going to want an invalidation routine to call from C code for the pmem
API, let's tweak the prototype and name to bring it in line with the
clean operations, and to make its relationship with __dma_inv_area()
neatly mirror that of __clean_dcache_area_poc() and __dma_clean_area().
The loop clearing the early page tables gets mildly massaged in the
process for the sake of consistency.
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Clearly, set_memory_valid() has never been seen in the same room as its
declaration... Whilst the type mismatch is such that kexec probably
wasn't broken in practice, fix it to match the definition as it should.

Fixes: 9b0aa14e ("arm64: mm: add set_memory_valid()")
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

ARM IORT specification(rev. C) has added  provision to define proximity
domain in SMMUv3 IORT table. Adding required code to parse Proximity
domain and set numa_node of smmv3 platform devices.
Signed-off-by: Ganapatrao Kulkarni <ganapatrao.kulkarni@cavium.com>
[lorenzo.pieralisi@arm.com: update pr_info()/commit log]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Currently, when unwinding the call stack, we validate the frame pointer
of each frame against frame.sp, whose value is not clearly defined, and
which makes it more difficult to link stack frames together across
different stacks. It is far better to simply check whether the frame
pointer itself points into a valid stack.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will.deacon@arm.com>

Our IRQ_STACK_PTR() and on_irq_stack() helpers both take a cpu argument,
used to generate a percpu address. In all cases, they are passed
{raw_,}smp_processor_id(), so this parameter is redundant.

Since {raw_,}smp_processor_id() use a percpu variable internally, this
approach means we generate a percpu offset to find the current cpu, then
use this to index an array of percpu offsets, which we then use to find
the current CPU's IRQ stack pointer. Thus, most of the work is
redundant.

Instead, we can consistently use raw_cpu_ptr() to generate the CPU's
irq_stack pointer by simply adding the percpu offset to the irq_stack
address, which is simpler in both respects.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will.deacon@arm.com>

Currently, cpu_switch_to and ret_from_fork both live in .entry.text,
though neither form the critical path for an exception entry.

In subsequent patches, we will require that code in .entry.text is part
of the critical path for exception entry, for which we can assume
certain properties (e.g. the presence of exception regs on the stack).

Neither cpu_switch_to nor ret_from_fork will meet these requirements, so
we must move them out of .entry.text. To ensure that neither are kprobed
after being moved out of .entry.text, we must explicitly blacklist them,
requiring a new NOKPROBE() asm helper.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will.deacon@arm.com>

In most cases, our exception entry assembly branches to C handlers with
a BL instruction, but in cases where we do not expect to return, we use
B instead.

While this is correct today, it means that backtraces for fatal
exceptions miss the entry assembly (as the LR is stale at the point we
call C code), while non-fatal exceptions have the entry assembly in the
LR. In subsequent patches, we will need the LR to be set in these cases
in order to backtrace reliably.

This patch updates these sites to use a BL, ensuring consistency, and
preparing for backtrace rework. An ASM_BUG() is added after each of
these new BLs, which both catches unexpected returns, and ensures that
the LR value doesn't point to another function label.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will.deacon@arm.com>

Currently. we can only use BUG() from C code, though there are
situations where we would like an equivalent mechanism in assembly code.

This patch refactors our BUG() definition such that it can be used in
either C or assembly, in the form of a new ASM_BUG().

The refactoring requires the removal of escape sequences, such as '\n'
and '\t', but these aren't strictly necessary as we can use ';' to
terminate assembler statements.

The low-level assembly is factored out into <asm/asm-bug.h>, with
<asm/bug.h> retained as the C wrapper.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Martin <dave.martin@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will.deacon@arm.com>

When a PCI device has DMA quirks, we need to ensure that an upstream
IOMMU knows about all possible aliases, since the presence of a DMA
quirk does not preclude the device still also emitting transactions
(e.g. MSIs) on its 'real' RID. Similarly, the rules for bridge aliasing
are relatively complex, and some bridges may only take ownership of
transactions under particular transient circumstances, leading again to
multiple RIDs potentially being seen at the IOMMU for the given device.

Take all this into account in iort_iommu_configure() by mapping every
RID produced by the alias walk, not just whichever one comes out last.
Since adding any more internal PTR_ERR() juggling would have confused me
no end, a bit of refactoring happens in the process - we know where to
find the ops if everything succeeded, so we're free to just pass regular
error codes around up until then.

CC: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
CC: Hanjun Guo <hanjun.guo@linaro.org>
CC: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
[lorenzo.pieralisi@arm.com: tagged __get_pci_rid __maybe_unused]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>