linux-stable.git/arch/arm/kernel, branch v4.9.321

ARM: 9197/1: spectre-bhb: fix loop8 sequence for Thumb2

2022-05-25T06:39:50+00:00

[ Upstream commit 3cfb3019979666bdf33a1010147363cf05e0f17b ]

In Thumb2, 'b . + 4' produces a branch instruction that uses a narrow
encoding, and so it does not jump to the following instruction as
expected. So use W(b) instead.

Fixes: 6c7cb60bff7a ("ARM: fix Thumb2 regression with Spectre BHB")
Signed-off-by: Ard Biesheuvel 
Signed-off-by: Russell King (Oracle) 
Signed-off-by: Sasha Levin

ARM: 9191/1: arm/stacktrace, kasan: Silence KASAN warnings in unwind_frame()

2022-05-25T06:39:48+00:00

[ Upstream commit 9be4c88bb7924f68f88cfd47d925c2d046f51a73 ]

The following KASAN warning is detected by QEMU.

==================================================================
BUG: KASAN: stack-out-of-bounds in unwind_frame+0x508/0x870
Read of size 4 at addr c36bba90 by task cat/163

CPU: 1 PID: 163 Comm: cat Not tainted 5.10.0-rc1 #40
Hardware name: ARM-Versatile Express
[] (unwind_backtrace) from [] (show_stack+0x10/0x14)
[] (show_stack) from [] (dump_stack+0x98/0xb0)
[] (dump_stack) from [] (print_address_description.constprop.0+0x58/0x4bc)
[] (print_address_description.constprop.0) from [] (kasan_report+0x154/0x170)
[] (kasan_report) from [] (unwind_frame+0x508/0x870)
[] (unwind_frame) from [] (__save_stack_trace+0x110/0x134)
[] (__save_stack_trace) from [] (stack_trace_save+0x8c/0xb4)
[] (stack_trace_save) from [] (kasan_set_track+0x38/0x60)
[] (kasan_set_track) from [] (kasan_set_free_info+0x20/0x2c)
[] (kasan_set_free_info) from [] (__kasan_slab_free+0xec/0x120)
[] (__kasan_slab_free) from [] (kmem_cache_free+0x7c/0x334)
[] (kmem_cache_free) from [] (rcu_core+0x390/0xccc)
[] (rcu_core) from [] (__do_softirq+0x180/0x518)
[] (__do_softirq) from [] (irq_exit+0x9c/0xe0)
[] (irq_exit) from [] (__handle_domain_irq+0xb0/0x110)
[] (__handle_domain_irq) from [] (gic_handle_irq+0xa0/0xb8)
[] (gic_handle_irq) from [] (__irq_svc+0x6c/0x94)
Exception stack(0xc36bb928 to 0xc36bb970)
b920:                   c36bb9c0 00000000 c0126919 c0101228 c36bb9c0 b76d7730
b940: c36b8000 c36bb9a0 c3335b00 c01ce0d8 00000003 c36bba3c c36bb940 c36bb978
b960: c010e298 c011373c 60000013 ffffffff
[] (__irq_svc) from [] (unwind_frame+0x0/0x870)
[] (unwind_frame) from [<00000000>] (0x0)

The buggy address belongs to the page:
page:(ptrval) refcount:0 mapcount:0 mapping:00000000 index:0x0 pfn:0x636bb
flags: 0x0()
raw: 00000000 00000000 ef867764 00000000 00000000 00000000 ffffffff 00000000
page dumped because: kasan: bad access detected

addr c36bba90 is located in stack of task cat/163 at offset 48 in frame:
 stack_trace_save+0x0/0xb4

this frame has 1 object:
 [32, 48) 'trace'

Memory state around the buggy address:
 c36bb980: f1 f1 f1 f1 00 04 f2 f2 00 00 f3 f3 00 00 00 00
 c36bba00: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
>c36bba80: 00 00 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
                 ^
 c36bbb00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 c36bbb80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================

There is a same issue on x86 and has been resolved by the commit f7d27c35ddff
("x86/mm, kasan: Silence KASAN warnings in get_wchan()").
The solution could be applied to arm architecture too.

Signed-off-by: Lin Yujun 
Reported-by: He Ying 
Signed-off-by: Russell King (Oracle) 
Signed-off-by: Sasha Levin

ARM: fix Thumb2 regression with Spectre BHB

2022-03-16T11:49:01+00:00

commit 6c7cb60bff7aec24b834343ff433125f469886a3 upstream.

When building for Thumb2, the vectors make use of a local label. Sadly,
the Spectre BHB code also uses a local label with the same number which
results in the Thumb2 reference pointing at the wrong place. Fix this
by changing the number used for the Spectre BHB local label.

Fixes: b9baf5c8c5c3 ("ARM: Spectre-BHB workaround")
Tested-by: Nathan Chancellor 
Signed-off-by: Russell King (Oracle) 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

ARM: Do not use NOCROSSREFS directive with ld.lld

2022-03-11T09:03:32+00:00

commit 36168e387fa7d0f1fe0cd5cf76c8cea7aee714fa upstream.

ld.lld does not support the NOCROSSREFS directive at the moment, which
breaks the build after commit b9baf5c8c5c3 ("ARM: Spectre-BHB
workaround"):

  ld.lld: error: ./arch/arm/kernel/vmlinux.lds:34: AT expected, but got NOCROSSREFS

Support for this directive will eventually be implemented, at which
point a version check can be added. To avoid breaking the build in the
meantime, just define NOCROSSREFS to nothing when using ld.lld, with a
link to the issue for tracking.

Cc: stable@vger.kernel.org
Fixes: b9baf5c8c5c3 ("ARM: Spectre-BHB workaround")
Link: https://github.com/ClangBuiltLinux/linux/issues/1609
Signed-off-by: Nathan Chancellor 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

ARM: fix build error when BPF_SYSCALL is disabled

2022-03-11T09:03:32+00:00

commit 330f4c53d3c2d8b11d86ec03a964b86dc81452f5 upstream.

It was missing a semicolon.

Signed-off-by: Emmanuel Gil Peyrot 
Reviewed-by: Nathan Chancellor 
Fixes: 25875aa71dfe ("ARM: include unprivileged BPF status in Spectre V2 reporting").
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

ARM: include unprivileged BPF status in Spectre V2 reporting

2022-03-11T09:03:32+00:00

commit 25875aa71dfefd1959f07e626c4d285b88b27ac2 upstream.

The mitigations for Spectre-BHB are only applied when an exception
is taken, but when unprivileged BPF is enabled, userspace can
load BPF programs that can be used to exploit the problem.

When unprivileged BPF is enabled, report the vulnerable status via
the spectre_v2 sysfs file.

Signed-off-by: Russell King (Oracle) 
Signed-off-by: Greg Kroah-Hartman

ARM: Spectre-BHB workaround

2022-03-11T09:03:31+00:00

commit b9baf5c8c5c356757f4f9d8180b5e9d234065bc3 upstream.

Workaround the Spectre BHB issues for Cortex-A15, Cortex-A57,
Cortex-A72, Cortex-A73 and Cortex-A75. We also include Brahma B15 as
well to be safe, which is affected by Spectre V2 in the same ways as
Cortex-A15.

Reviewed-by: Catalin Marinas 
Signed-off-by: Russell King (Oracle) 
[changes due to lack of SYSTEM_FREEING_INITMEM - gregkh]
Signed-off-by: Greg Kroah-Hartman

ARM: use LOADADDR() to get load address of sections

2022-03-11T09:03:31+00:00

commit 8d9d651ff2270a632e9dc497b142db31e8911315 upstream.

Use the linker's LOADADDR() macro to get the load address of the
sections, and provide a macro to set the start and end symbols.

Acked-by: Catalin Marinas 
Signed-off-by: Russell King (Oracle) 
Signed-off-by: Greg Kroah-Hartman

ARM: early traps initialisation

2022-03-11T09:03:31+00:00

commit 04e91b7324760a377a725e218b5ee783826d30f5 upstream.

Provide a couple of helpers to copy the vectors and stubs, and also
to flush the copied vectors and stubs.

Acked-by: Catalin Marinas 
Signed-off-by: Russell King (Oracle) 
Signed-off-by: Greg Kroah-Hartman

ARM: report Spectre v2 status through sysfs

2022-03-11T09:03:31+00:00

commit 9dd78194a3722fa6712192cdd4f7032d45112a9a upstream.

As per other architectures, add support for reporting the Spectre
vulnerability status via sysfs CPU.

Acked-by: Catalin Marinas 
Signed-off-by: Russell King (Oracle) 
[ preserve res variable and add SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED - gregkh ]
Signed-off-by: Greg Kroah-Hartman