linux.git/arch/arm64/kernel/sleep.S, branch v5.9

Merge branch 'for-next/bti' into for-next/core

2020-05-28T17:00:51+00:00

Support for Branch Target Identification (BTI) in user and kernel
(Mark Brown and others)
* for-next/bti: (39 commits)
  arm64: vdso: Fix CFI directives in sigreturn trampoline
  arm64: vdso: Don't prefix sigreturn trampoline with a BTI C instruction
  arm64: bti: Fix support for userspace only BTI
  arm64: kconfig: Update and comment GCC version check for kernel BTI
  arm64: vdso: Map the vDSO text with guarded pages when built for BTI
  arm64: vdso: Force the vDSO to be linked as BTI when built for BTI
  arm64: vdso: Annotate for BTI
  arm64: asm: Provide a mechanism for generating ELF note for BTI
  arm64: bti: Provide Kconfig for kernel mode BTI
  arm64: mm: Mark executable text as guarded pages
  arm64: bpf: Annotate JITed code for BTI
  arm64: Set GP bit in kernel page tables to enable BTI for the kernel
  arm64: asm: Override SYM_FUNC_START when building the kernel with BTI
  arm64: bti: Support building kernel C code using BTI
  arm64: Document why we enable PAC support for leaf functions
  arm64: insn: Report PAC and BTI instructions as skippable
  arm64: insn: Don't assume unrecognized HINTs are skippable
  arm64: insn: Provide a better name for aarch64_insn_is_nop()
  arm64: insn: Add constants for new HINT instruction decode
  arm64: Disable old style assembly annotations
  ...

arm64: kernel: Convert to modern annotations for assembly functions

2020-05-04T11:46:03+00:00

In an effort to clarify and simplify the annotation of assembly functions
in the kernel new macros have been introduced. These replace ENTRY and
ENDPROC and also add a new annotation for static functions which previously
had no ENTRY equivalent. Update the annotations in the core kernel code to
the new macros.

Signed-off-by: Mark Brown 
Acked-by: Mark Rutland 
Link: https://lore.kernel.org/r/20200501115430.37315-3-broonie@kernel.org
Signed-off-by: Will Deacon

arm64: simplify ptrauth initialization

2020-04-28T10:23:21+00:00

Currently __cpu_setup conditionally initializes the address
authentication keys and enables them in SCTLR_EL1, doing so differently
for the primary CPU and secondary CPUs, and skipping this work for CPUs
returning from an idle state. For the latter case, cpu_do_resume
restores the keys and SCTLR_EL1 value after the MMU has been enabled.

This flow is rather difficult to follow, so instead let's move the
primary and secondary CPU initialization into their respective boot
paths. By following the example of cpu_do_resume and doing so once the
MMU is enabled, we can always initialize the keys from the values in
thread_struct, and avoid the machinery necessary to pass the keys in
secondary_data or open-coding initialization for the boot CPU.

This means we perform an additional RMW of SCTLR_EL1, but we already do
this in the cpu_do_resume path, and for other features in cpufeature.c,
so this isn't a major concern in a bringup path. Note that even while
the enable bits are clear, the key registers are accessible.

As this now renders the argument to __cpu_setup redundant, let's also
remove that entirely. Future extensions can follow a similar approach to
initialize values that differ for primary/secondary CPUs.

Signed-off-by: Mark Rutland 
Tested-by: Amit Daniel Kachhap 
Reviewed-by: Amit Daniel Kachhap 
Cc: Amit Daniel Kachhap 
Cc: Catalin Marinas 
Cc: James Morse 
Cc: Suzuki K Poulose 
Cc: Will Deacon 
Link: https://lore.kernel.org/r/20200423101606.37601-3-mark.rutland@arm.com
Signed-off-by: Will Deacon

arm64: ptrauth: Add bootup/runtime flags for __cpu_setup

2020-03-18T09:50:19+00:00

This patch allows __cpu_setup to be invoked with one of these flags,
ARM64_CPU_BOOT_PRIMARY, ARM64_CPU_BOOT_SECONDARY or ARM64_CPU_RUNTIME.
This is required as some cpufeatures need different handling during
different scenarios.

The input parameter in x0 is preserved till the end to be used inside
this function.

There should be no functional change with this patch and is useful
for the subsequent ptrauth patch which utilizes it. Some upcoming
arm cpufeatures can also utilize these flags.

Suggested-by: James Morse 
Signed-off-by: Amit Daniel Kachhap 
Reviewed-by: Vincenzo Frascino 
Reviewed-by: James Morse 
Reviewed-by: Suzuki K Poulose 
Signed-off-by: Catalin Marinas

arm64: kernel: use aff3 instead of aff2 in comment

2019-06-04T13:51:01+00:00

Should use aff3 instead of aff2 in comment.

Signed-off-by: Liu Song 
Signed-off-by: Catalin Marinas

arm64/mm: Pass ttbr1 as a parameter to __enable_mmu()

2018-09-25T14:10:54+00:00

In subsequent patches we'll use a transient pgd during the primary cpu's
boot process. To make this work while allowing secondary cpus to use the
swapper_pg_dir, we need to pass the relevant TTBR1 pgd as a parameter
to __enable_mmu().

This patch updates __enable__mmu() to take this as a parameter, updating
callsites to pass swapper_pg_dir for now.

There should be no functional change as a result of this patch.

Signed-off-by: Jun Yao 
Reviewed-by: James Morse 
[Mark: simplify assembly, clarify commit message]
Signed-off-by: Mark Rutland 
Signed-off-by: Catalin Marinas

arm64: idmap: Use "awx" flags for .idmap.text .pushsection directives

2018-02-06T22:53:27+00:00

The identity map is mapped as both writeable and executable by the
SWAPPER_MM_MMUFLAGS and this is relied upon by the kpti code to manage
a synchronisation flag. Update the .pushsection flags to reflect the
actual mapping attributes.

Reported-by: Marc Zyngier 
Signed-off-by: Will Deacon 
Signed-off-by: Catalin Marinas

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

2017-11-02T10:10:55+00:00

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart 
Reviewed-by: Philippe Ombredanne 
Reviewed-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

arm64: move sp_el0 and tpidr_el1 into cpu_suspend_ctx

2016-11-11T18:25:44+00:00

When returning from idle, we rely on the fact that thread_info lives at
the end of the kernel stack, and restore this by masking the saved stack
pointer. Subsequent patches will sever the relationship between the
stack and thread_info, and to cater for this we must save/restore sp_el0
explicitly, storing it in cpu_suspend_ctx.

As cpu_suspend_ctx must be doubleword aligned, this leaves us with an
extra slot in cpu_suspend_ctx. We can use this to save/restore tpidr_el1
in the same way, which simplifies the code, avoiding pointer chasing on
the restore path (as we no longer need to load thread_info::cpu followed
by the relevant slot in __per_cpu_offset based on this).

This patch stashes both registers in cpu_suspend_ctx.

Signed-off-by: Mark Rutland 
Tested-by: Laura Abbott 
Cc: James Morse 
Cc: Lorenzo Pieralisi 
Cc: Will Deacon 
Signed-off-by: Catalin Marinas

kprobes: Unpoison stack in jprobe_return() for KASAN

2016-10-16T09:02:31+00:00

I observed false KSAN positives in the sctp code, when
sctp uses jprobe_return() in jsctp_sf_eat_sack().

The stray 0xf4 in shadow memory are stack redzones:

[     ] ==================================================================
[     ] BUG: KASAN: stack-out-of-bounds in memcmp+0xe9/0x150 at addr ffff88005e48f480
[     ] Read of size 1 by task syz-executor/18535
[     ] page:ffffea00017923c0 count:0 mapcount:0 mapping:          (null) index:0x0
[     ] flags: 0x1fffc0000000000()
[     ] page dumped because: kasan: bad access detected
[     ] CPU: 1 PID: 18535 Comm: syz-executor Not tainted 4.8.0+ #28
[     ] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[     ]  ffff88005e48f2d0 ffffffff82d2b849 ffffffff0bc91e90 fffffbfff10971e8
[     ]  ffffed000bc91e90 ffffed000bc91e90 0000000000000001 0000000000000000
[     ]  ffff88005e48f480 ffff88005e48f350 ffffffff817d3169 ffff88005e48f370
[     ] Call Trace:
[     ]  [] dump_stack+0x12e/0x185
[     ]  [] kasan_report+0x489/0x4b0
[     ]  [] __asan_report_load1_noabort+0x19/0x20
[     ]  [] memcmp+0xe9/0x150
[     ]  [] depot_save_stack+0x176/0x5c0
[     ]  [] save_stack+0xb1/0xd0
[     ]  [] kasan_slab_free+0x72/0xc0
[     ]  [] kfree+0xc8/0x2a0
[     ]  [] skb_free_head+0x79/0xb0
[     ]  [] skb_release_data+0x37a/0x420
[     ]  [] skb_release_all+0x4f/0x60
[     ]  [] consume_skb+0x138/0x370
[     ]  [] sctp_chunk_put+0xcb/0x180
[     ]  [] sctp_chunk_free+0x58/0x70
[     ]  [] sctp_inq_pop+0x68f/0xef0
[     ]  [] sctp_assoc_bh_rcv+0xd6/0x4b0
[     ]  [] sctp_inq_push+0x131/0x190
[     ]  [] sctp_backlog_rcv+0xe9/0xa20
[ ... ]
[     ] Memory state around the buggy address:
[     ]  ffff88005e48f380: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[     ]  ffff88005e48f400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[     ] >ffff88005e48f480: f4 f4 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[     ]                    ^
[     ]  ffff88005e48f500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[     ]  ffff88005e48f580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[     ] ==================================================================

KASAN stack instrumentation poisons stack redzones on function entry
and unpoisons them on function exit. If a function exits abnormally
(e.g. with a longjmp like jprobe_return()), stack redzones are left
poisoned. Later this leads to random KASAN false reports.

Unpoison stack redzones in the frames we are going to jump over
before doing actual longjmp in jprobe_return().

Signed-off-by: Dmitry Vyukov 
Acked-by: Masami Hiramatsu 
Reviewed-by: Mark Rutland 
Cc: Mark Rutland 
Cc: Catalin Marinas 
Cc: Andrey Ryabinin 
Cc: Lorenzo Pieralisi 
Cc: Alexander Potapenko 
Cc: Will Deacon 
Cc: Andrew Morton 
Cc: Ananth N Mavinakayanahalli 
Cc: Anil S Keshavamurthy 
Cc: "David S. Miller" 
Cc: Masami Hiramatsu 
Cc: kasan-dev@googlegroups.com
Cc: surovegin@google.com
Cc: rostedt@goodmis.org
Link: http://lkml.kernel.org/r/1476454043-101898-1-git-send-email-dvyukov@google.com
Signed-off-by: Ingo Molnar