ARM: 9303/1: kprobes: avoid missing-declaration warnings

checker_stack_use_t32strd() and kprobe_handler() can be made static since
they are not used from other files, while coverage_start_registers()
and __kprobes_test_case() are used from assembler code, and just need
a declaration to avoid a warning with the global definition.

arch/arm/probes/kprobes/checkers-common.c:43:18: error: no previous prototype for 'checker_stack_use_t32strd'
arch/arm/probes/kprobes/core.c:236:16: error: no previous prototype for 'kprobe_handler'
arch/arm/probes/kprobes/test-core.c:723:10: error: no previous prototype for 'coverage_start_registers'
arch/arm/probes/kprobes/test-core.c:918:14: error: no previous prototype for '__kprobes_test_case_start'
arch/arm/probes/kprobes/test-core.c:952:14: error: no previous prototype for '__kprobes_test_case_end_16'
arch/arm/probes/kprobes/test-core.c:967:14: error: no previous prototype for '__kprobes_test_case_end_32'

Fixes: 6624cf651f1a ("ARM: kprobes: collects stack consumption for store instructions")
Fixes: 454f3e132d05 ("ARM/kprobes: Remove jprobe arm implementation")
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>

kprobes: treewide: Use 'kprobe_opcode_t *' for the code address in get_optimized_kprobe()

Since get_optimized_kprobe() is only used inside kprobes,
it doesn't need to use 'unsigned long' type for 'addr' parameter.
Make it use 'kprobe_opcode_t *' for the 'addr' parameter and
subsequent call of arch_within_optimized_kprobe() also should use
'kprobe_opcode_t *'.

Note that MAX_OPTIMIZED_LENGTH and RELATIVEJUMP_SIZE are defined
by byte-size, but the size of 'kprobe_opcode_t' depends on the
architecture. Therefore, we must be careful when calculating
addresses using those macros.

Link: https://lkml.kernel.org/r/163163040680.489837.12133032364499833736.stgit@devnote2

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

ARM: 9019/1: kprobes: Avoid fortify_panic() when copying optprobe template

Setting both CONFIG_KPROBES=y and CONFIG_FORTIFY_SOURCE=y on ARM leads
to a panic in memcpy() when injecting a kprobe despite the fixes found
in commit e46daee53bb5 ("ARM: 8806/1: kprobes: Fix false positive with
FORTIFY_SOURCE") and commit 0ac569bf6a79 ("ARM: 8834/1: Fix: kprobes:
optimized kprobes illegal instruction").

arch/arm/include/asm/kprobes.h effectively declares
the target type of the optprobe_template_entry assembly label as a u32
which leads memcpy()'s __builtin_object_size() call to determine that
the pointed-to object is of size four. However, the symbol is used as a handle
for the optimised probe assembly template that is at least 96 bytes in size.
The symbol's use despite its type blows up the memcpy() in ARM's
arch_prepare_optimized_kprobe() with a false-positive fortify_panic() when it
should instead copy the optimised probe template into place:

```
$ sudo perf probe -a aspeed_g6_pinctrl_probe
[ 158.457252] detected buffer overflow in memcpy
[ 158.458069] ------------[ cut here ]------------
[ 158.458283] kernel BUG at lib/string.c:1153!
[ 158.458436] Internal error: Oops - BUG: 0 [#1] SMP ARM
[ 158.458768] Modules linked in:
[ 158.459043] CPU: 1 PID: 99 Comm: perf Not tainted 5.9.0-rc7-00038-gc53ebf8167e9 #158
[ 158.459296] Hardware name: Generic DT based system
[ 158.459529] PC is at fortify_panic+0x18/0x20
[ 158.459658] LR is at __irq_work_queue_local+0x3c/0x74
[ 158.459831] pc : [<8047451c>] lr : [<8020ecd4>] psr: 60000013
[ 158.460032] sp : be2d1d50 ip : be2d1c58 fp : be2d1d5c
[ 158.460174] r10: 00000006 r9 : 00000000 r8 : 00000060
[ 158.460348] r7 : 8011e434 r6 : b9e0b800 r5 : 7f000000 r4 : b9fe4f0c
[ 158.460557] r3 : 80c04cc8 r2 : 00000000 r1 : be7c03cc r0 : 00000022
[ 158.460801] Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none
[ 158.461037] Control: 10c5387d Table: b9cd806a DAC: 00000051
[ 158.461251] Process perf (pid: 99, stack limit = 0x81c71a69)
[ 158.461472] Stack: (0xbe2d1d50 to 0xbe2d2000)
[ 158.461757] 1d40: be2d1d84 be2d1d60 8011e724 80474510
[ 158.462104] 1d60: b9e0b800 b9fe4f0c 00000000 b9fe4f14 80c8ec80 be235000 be2d1d9c be2d1d88
[ 158.462436] 1d80: 801cee44 8011e57c b9fe4f0c 00000000 be2d1dc4 be2d1da0 801d0ad0 801cedec
[ 158.462742] 1da0: 00000000 00000000 b9fe4f00 ffffffea 00000000 be235000 be2d1de4 be2d1dc8
[ 158.463087] 1dc0: 80204604 801d0738 00000000 00000000 b9fe4004 ffffffea be2d1e94 be2d1de8
[ 158.463428] 1de0: 80205434 80204570 00385c00 00000000 00000000 00000000 be2d1e14 be2d1e08
[ 158.463880] 1e00: 802ba014 b9fe4f00 b9e718c0 b9fe4f84 b9e71ec8 be2d1e24 00000000 00385c00
[ 158.464365] 1e20: 00000000 626f7270 00000065 802b905c be2d1e94 0000002e 00000000 802b9914
[ 158.464829] 1e40: be2d1e84 be2d1e50 802b9914 8028ff78 804629d0 b9e71ec0 0000002e b9e71ec0
[ 158.465141] 1e60: be2d1ea8 80c04cc8 00000cc0 b9e713c4 00000002 80205834 80205834 0000002e
[ 158.465488] 1e80: be235000 be235000 be2d1ea4 be2d1e98 80205854 80204e94 be2d1ecc be2d1ea8
[ 158.465806] 1ea0: 801ee4a0 80205840 00000002 80c04cc8 00000000 0000002e 0000002e 00000000
[ 158.466110] 1ec0: be2d1f0c be2d1ed0 801ee5c8 801ee428 00000000 be2d0000 006b1fd0 00000051
[ 158.466398] 1ee0: 00000000 b9eedf00 0000002e 80204410 006b1fd0 be2d1f60 00000000 00000004
[ 158.466763] 1f00: be2d1f24 be2d1f10 8020442c 801ee4c4 80205834 802c613c be2d1f5c be2d1f28
[ 158.467102] 1f20: 802c60ac 8020441c be2d1fac be2d1f38 8010c764 802e9888 be2d1f5c b9eedf00
[ 158.467447] 1f40: b9eedf00 006b1fd0 0000002e 00000000 be2d1f94 be2d1f60 802c634c 802c5fec
[ 158.467812] 1f60: 00000000 00000000 00000000 80c04cc8 006b1fd0 00000003 76f7a610 00000004
[ 158.468155] 1f80: 80100284 be2d0000 be2d1fa4 be2d1f98 802c63ec 802c62e8 00000000 be2d1fa8
[ 158.468508] 1fa0: 80100080 802c63e0 006b1fd0 00000003 00000003 006b1fd0 0000002e 00000000
[ 158.468858] 1fc0: 006b1fd0 00000003 76f7a610 00000004 006b1fb0 0026d348 00000017 7ef2738c
[ 158.469202] 1fe0: 76f3431c 7ef272d8 0014ec50 76f34338 60000010 00000003 00000000 00000000
[ 158.469461] Backtrace:
[ 158.469683] [<80474504>] (fortify_panic) from [<8011e724>] (arch_prepare_optimized_kprobe+0x1b4/0x1f8)
[ 158.470021] [<8011e570>] (arch_prepare_optimized_kprobe) from [<801cee44>] (alloc_aggr_kprobe+0x64/0x70)
[ 158.470287] r9:be235000 r8:80c8ec80 r7:b9fe4f14 r6:00000000 r5:b9fe4f0c r4:b9e0b800
[ 158.470478] [<801cede0>] (alloc_aggr_kprobe) from [<801d0ad0>] (register_kprobe+0x3a4/0x5a0)
[ 158.470685] r5:00000000 r4:b9fe4f0c
[ 158.470790] [<801d072c>] (register_kprobe) from [<80204604>] (__register_trace_kprobe+0xa0/0xa4)
[ 158.471001] r9:be235000 r8:00000000 r7:ffffffea r6:b9fe4f00 r5:00000000 r4:00000000
[ 158.471188] [<80204564>] (__register_trace_kprobe) from [<80205434>] (trace_kprobe_create+0x5ac/0x9ac)
[ 158.471408] r7:ffffffea r6:b9fe4004 r5:00000000 r4:00000000
[ 158.471553] [<80204e88>] (trace_kprobe_create) from [<80205854>] (create_or_delete_trace_kprobe+0x20/0x3c)
[ 158.471766] r10:be235000 r9:be235000 r8:0000002e r7:80205834 r6:80205834 r5:00000002
[ 158.471949] r4:b9e713c4
[ 158.472027] [<80205834>] (create_or_delete_trace_kprobe) from [<801ee4a0>] (trace_run_command+0x84/0x9c)
[ 158.472255] [<801ee41c>] (trace_run_command) from [<801ee5c8>] (trace_parse_run_command+0x110/0x1f8)
[ 158.472471] r6:00000000 r5:0000002e r4:0000002e
[ 158.472594] [<801ee4b8>] (trace_parse_run_command) from [<8020442c>] (probes_write+0x1c/0x28)
[ 158.472800] r10:00000004 r9:00000000 r8:be2d1f60 r7:006b1fd0 r6:80204410 r5:0000002e
[ 158.472968] r4:b9eedf00
[ 158.473046] [<80204410>] (probes_write) from [<802c60ac>] (vfs_write+0xcc/0x1e8)
[ 158.473226] [<802c5fe0>] (vfs_write) from [<802c634c>] (ksys_write+0x70/0xf8)
[ 158.473400] r8:00000000 r7:0000002e r6:006b1fd0 r5:b9eedf00 r4:b9eedf00
[ 158.473567] [<802c62dc>] (ksys_write) from [<802c63ec>] (sys_write+0x18/0x1c)
[ 158.473745] r9:be2d0000 r8:80100284 r7:00000004 r6:76f7a610 r5:00000003 r4:006b1fd0
[ 158.473932] [<802c63d4>] (sys_write) from [<80100080>] (ret_fast_syscall+0x0/0x54)
[ 158.474126] Exception stack(0xbe2d1fa8 to 0xbe2d1ff0)
[ 158.474305] 1fa0: 006b1fd0 00000003 00000003 006b1fd0 0000002e 00000000
[ 158.474573] 1fc0: 006b1fd0 00000003 76f7a610 00000004 006b1fb0 0026d348 00000017 7ef2738c
[ 158.474811] 1fe0: 76f3431c 7ef272d8 0014ec50 76f34338
[ 158.475171] Code: e24cb004 e1a01000 e59f0004 ebf40dd3 (e7f001f2)
[ 158.475847] ---[ end trace 55a5b31c08a29f00 ]---
[ 158.476088] Kernel panic - not syncing: Fatal exception
[ 158.476375] CPU0: stopping
[ 158.476709] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G D 5.9.0-rc7-00038-gc53ebf8167e9 #158
[ 158.477176] Hardware name: Generic DT based system
[ 158.477411] Backtrace:
[ 158.477604] [<8010dd28>] (dump_backtrace) from [<8010dfd4>] (show_stack+0x20/0x24)
[ 158.477990] r7:00000000 r6:60000193 r5:00000000 r4:80c2f634
[ 158.478323] [<8010dfb4>] (show_stack) from [<8046390c>] (dump_stack+0xcc/0xe8)
[ 158.478686] [<80463840>] (dump_stack) from [<80110750>] (handle_IPI+0x334/0x3a0)
[ 158.479063] r7:00000000 r6:00000004 r5:80b65cc8 r4:80c78278
[ 158.479352] [<8011041c>] (handle_IPI) from [<801013f8>] (gic_handle_irq+0x88/0x94)
[ 158.479757] r10:10c5387d r9:80c01ed8 r8:00000000 r7:c0802000 r6:80c0537c r5:000003ff
[ 158.480146] r4:c080200c r3:fffffff4
[ 158.480364] [<80101370>] (gic_handle_irq) from [<80100b6c>] (__irq_svc+0x6c/0x90)
[ 158.480748] Exception stack(0x80c01ed8 to 0x80c01f20)
[ 158.481031] 1ec0: 000128bc 00000000
[ 158.481499] 1ee0: be7b8174 8011d3a0 80c00000 00000000 80c04cec 80c04d28 80c5d7c2 80a026d4
[ 158.482091] 1f00: 10c5387d 80c01f34 80c01f38 80c01f28 80109554 80109558 60000013 ffffffff
[ 158.482621] r9:80c00000 r8:80c5d7c2 r7:80c01f0c r6:ffffffff r5:60000013 r4:80109558
[ 158.482983] [<80109518>] (arch_cpu_idle) from [<80818780>] (default_idle_call+0x38/0x120)
[ 158.483360] [<80818748>] (default_idle_call) from [<801585a8>] (do_idle+0xd4/0x158)
[ 158.483945] r5:00000000 r4:80c00000
[ 158.484237] [<801584d4>] (do_idle) from [<801588f4>] (cpu_startup_entry+0x28/0x2c)
[ 158.484784] r9:80c78000 r8:00000000 r7:80c78000 r6:80c78040 r5:80c04cc0 r4:000000d6
[ 158.485328] [<801588cc>] (cpu_startup_entry) from [<80810a78>] (rest_init+0x9c/0xbc)
[ 158.485930] [<808109dc>] (rest_init) from [<80b00ae4>] (arch_call_rest_init+0x18/0x1c)
[ 158.486503] r5:80c04cc0 r4:00000001
[ 158.486857] [<80b00acc>] (arch_call_rest_init) from [<80b00fcc>] (start_kernel+0x46c/0x548)
[ 158.487589] [<80b00b60>] (start_kernel) from [<00000000>] (0x0)
```

Fixes: e46daee53bb5 ("ARM: 8806/1: kprobes: Fix false positive with FORTIFY_SOURCE")
Fixes: 0ac569bf6a79 ("ARM: 8834/1: Fix: kprobes: optimized kprobes illegal instruction")
Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Tested-by: Luka Oreskovic <luka.oreskovic@sartura.hr>
Tested-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Luka Oreskovic <luka.oreskovic@sartura.hr>
Cc: Juraj Vijtiuk <juraj.vijtiuk@sartura.hr>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version this program is distributed in the
hope that it will be useful but without any warranty without even
the implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details you
should have received a copy of the gnu general public license along
with this program if not write to the free software foundation inc
59 temple place suite 330 boston ma 02111 1307 usa

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1334 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

ARM: 8834/1: Fix: kprobes: optimized kprobes illegal instruction

commit e46daee53bb5 ("ARM: 8806/1: kprobes: Fix false positive with
FORTIFY_SOURCE") introduced a regression in optimized kprobes. It
triggers "invalid instruction" oopses when using kprobes instrumentation
through lttng and perf. This commit was introduced in kernel v4.20, and
has been backported to stable kernels 4.19 and 4.14.

This crash was also reported by Hongzhi Song on the redhat bugzilla
where the patch was originally introduced.

Link: https://bugzilla.redhat.com/show_bug.cgi?id=1639397
Link: https://bugs.lttng.org/issues/1174
Link: https://lore.kernel.org/lkml/342740659.2887.1549307721609.JavaMail.zimbra@efficios.com

Fixes: e46daee53bb5 ("ARM: 8806/1: kprobes: Fix false positive with FORTIFY_SOURCE")
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reported-by: Robert Berger <Robert.Berger@ReliableEmbeddedSystems.com>
Tested-by: Robert Berger <Robert.Berger@ReliableEmbeddedSystems.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Robert Berger <Robert.Berger@ReliableEmbeddedSystems.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: William Cohen <wcohen@redhat.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: <stable@vger.kernel.org> # v4.14+
Cc: linux-arm-kernel@lists.infradead.org
Cc: patches@armlinux.org.uk
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

ARM: 8806/1: kprobes: Fix false positive with FORTIFY_SOURCE

The arm compiler internally interprets an inline assembly label
as an unsigned long value, not a pointer. As a result, under
CONFIG_FORTIFY_SOURCE, the address of a label has a size of 4 bytes,
which was tripping the runtime checks. Instead, we can just cast the label
(as done with the size calculations earlier).

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1639397

Reported-by: William Cohen <wcohen@redhat.com>
Fixes: 6974f0c4555e ("include/linux/string.h: add the option of fortified string.h functions")
Cc: stable@vger.kernel.org
Acked-by: Laura Abbott <labbott@redhat.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: William Cohen <wcohen@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

ARM: 8770/1: kprobes: Prohibit probing on optimized_callback

Prohibit probing on optimized_callback() because
it is called from kprobes itself. If we put a kprobes
on it, that will cause a recursive call loop.
Mark it NOKPROBE_SYMBOL.

Fixes: 0dc016dbd820 ("ARM: kprobes: enable OPTPROBES for ARM 32")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

ARM: 8769/1: kprobes: Fix to use get_kprobe_ctlblk after irq-disabed

Since get_kprobe_ctlblk() uses smp_processor_id() to access
per-cpu variable, it hits smp_processor_id sanity check as below.

[ 7.006928] BUG: using smp_processor_id() in preemptible [00000000] code: swapper/0/1
[ 7.007859] caller is debug_smp_processor_id+0x20/0x24
[ 7.008438] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.16.0-rc1-00192-g4eb17253e4b5 #1
[ 7.008890] Hardware name: Generic DT based system
[ 7.009917] [<c0313f0c>] (unwind_backtrace) from [<c030e6d8>] (show_stack+0x20/0x24)
[ 7.010473] [<c030e6d8>] (show_stack) from [<c0c64694>] (dump_stack+0x84/0x98)
[ 7.010990] [<c0c64694>] (dump_stack) from [<c071ca5c>] (check_preemption_disabled+0x138/0x13c)
[ 7.011592] [<c071ca5c>] (check_preemption_disabled) from [<c071ca80>] (debug_smp_processor_id+0x20/0x24)
[ 7.012214] [<c071ca80>] (debug_smp_processor_id) from [<c03335e0>] (optimized_callback+0x2c/0xe4)
[ 7.013077] [<c03335e0>] (optimized_callback) from [<bf0021b0>] (0xbf0021b0)

To fix this issue, call get_kprobe_ctlblk() right after
irq-disabled since that disables preemption.

Fixes: 0dc016dbd820 ("ARM: kprobes: enable OPTPROBES for ARM 32")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

ARM: optprobes: execute instruction during restoring if possible.

This patch removes software emulation or simulation for most of probed
instructions. If the instruction doesn't use PC relative addressing,
it will be translated into following instructions in the restore code
in code template:

ldmia {r0 - r14} // restore all instruction except PC
<instruction> // direct execute the probed instruction
b next_insn // branch to next instruction.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Jon Medhurst <tixy@linaro.org>

ARM: kprobes: enable OPTPROBES for ARM 32

This patch introduce kprobeopt for ARM 32.

Limitations:
- Currently only kernel compiled with ARM ISA is supported.

- Offset between probe point and optinsn slot must not larger than
32MiB. Masami Hiramatsu suggests replacing 2 words, it will make
things complex. Futher patch can make such optimization.

Kprobe opt on ARM is relatively simpler than kprobe opt on x86 because
ARM instruction is always 4 bytes aligned and 4 bytes long. This patch
replace probed instruction by a 'b', branch to trampoline code and then
calls optimized_callback(). optimized_callback() calls opt_pre_handler()
to execute kprobe handler. It also emulate/simulate replaced instruction.

When unregistering kprobe, the deferred manner of unoptimizer may leave
branch instruction before optimizer is called. Different from x86_64,
which only copy the probed insn after optprobe_template_end and
reexecute them, this patch call singlestep to emulate/simulate the insn
directly. Futher patch can optimize this behavior.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Will Deacon <will.deacon@arm.com>
Reviewed-by: Jon Medhurst (Tixy) <tixy@linaro.org>
Signed-off-by: Jon Medhurst <tixy@linaro.org>