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Michael Neuling ed596114fd powerpc: Fix undetected data corruption with P9N DD2.1 VSX CI load emulation
commit 1da4a0272c upstream.

__get_user_atomic_128_aligned() stores to kaddr using stvx which is a
VMX store instruction, hence kaddr must be 16 byte aligned otherwise
the store won't occur as expected.

Unfortunately when we call __get_user_atomic_128_aligned() in
p9_hmi_special_emu(), the buffer we pass as kaddr (ie. vbuf) isn't
guaranteed to be 16B aligned. This means that the write to vbuf in
__get_user_atomic_128_aligned() has the bottom bits of the address
truncated. This results in other local variables being
overwritten. Also vbuf will not contain the correct data which results
in the userspace emulation being wrong and hence undetected user data
corruption.

In the past we've been mostly lucky as vbuf has ended up aligned but
this is fragile and isn't always true. CONFIG_STACKPROTECTOR in
particular can change the stack arrangement enough that our luck runs
out.

This issue only occurs on POWER9 Nimbus <= DD2.1 bare metal.

The fix is to align vbuf to a 16 byte boundary.

Fixes: 5080332c2c ("powerpc/64s: Add workaround for P9 vector CI load issue")
Cc: stable@vger.kernel.org # v4.15+
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201013043741.743413-1-mikey@neuling.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-11-05 11:08:51 +01:00
arch powerpc: Fix undetected data corruption with P9N DD2.1 VSX CI load emulation 2020-11-05 11:08:51 +01:00
block Revert "block: ratelimit handle_bad_sector() message" 2020-11-05 11:08:35 +01:00
certs
crypto crypto: algif_skcipher - EBUSY on aio should be an error 2020-10-29 09:55:01 +01:00
Documentation media: videodev2.h: RGB BT2020 and HSV are always full range 2020-11-05 11:08:40 +01:00
drivers iio:gyro:itg3200: Fix timestamp alignment and prevent data leak. 2020-11-05 11:08:51 +01:00
firmware
fs udf: Fix memory leak when mounting 2020-11-05 11:08:50 +01:00
include usb: typec: tcpm: During PR_SWAP, source caps should be sent only after tSwapSourceStart 2020-11-05 11:08:40 +01:00
init printk: reduce LOG_BUF_SHIFT range for H8300 2020-11-05 11:08:41 +01:00
ipc ipc/util.c: sysvipc_find_ipc() incorrectly updates position index 2020-05-20 08:18:40 +02:00
kernel kgdb: Make "kgdbcon" work properly with "kgdb_earlycon" 2020-11-05 11:08:41 +01:00
lib sgl_alloc_order: fix memory leak 2020-11-05 11:08:45 +01:00
LICENSES
mm mm, oom_adj: don't loop through tasks in __set_oom_adj when not necessary 2020-10-29 09:55:15 +01:00
net net: 9p: initialize sun_server.sun_path to have addr's value only when addr is valid 2020-11-05 11:08:44 +01:00
samples misc: vop: add round_up(x,4) for vring_size to avoid kernel panic 2020-10-30 10:38:29 +01:00
scripts scripts/setlocalversion: make git describe output more reliable 2020-11-05 11:08:31 +01:00
security evm: Check size of security.evm before using it 2020-11-05 11:08:34 +01:00
sound ALSA: seq: oss: Avoid mutex lock for a long-time ioctl 2020-10-29 09:55:11 +01:00
tools bpf: Fix comment for helper bpf_current_task_under_cgroup() 2020-11-05 11:08:34 +01:00
usr initramfs: restore default compression behavior 2020-04-13 10:44:59 +02:00
virt KVM: arm64: Assume write fault on S1PTW permission fault on instruction fetch 2020-10-01 13:14:54 +02:00
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Kbuild
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MAINTAINERS Documentation/llvm: add documentation on building w/ Clang/LLVM 2020-09-26 18:01:31 +02:00
Makefile Linux 4.19.154 2020-10-30 10:38:33 +01:00
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