linux-stable.git/arch/powerpc, branch v6.2.7

powerpc/kcsan: Exclude udelay to prevent recursive instrumentation

2023-03-17T07:58:02+00:00

[ Upstream commit 2a7ce82dc46c591c9244057d89a6591c9639b9b9 ]

In order for KCSAN to increase its likelihood of observing a data race,
it sets a watchpoint on memory accesses and stalls, allowing for
detection of conflicting accesses by other kernel threads or interrupts.

Stalls are implemented by injecting a call to udelay in instrumented code.
To prevent recursive instrumentation, exclude udelay from being instrumented.

Signed-off-by: Rohan McLure 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20230206021801.105268-3-rmclure@linux.ibm.com
Signed-off-by: Sasha Levin

powerpc/64: Move paca allocation to early_setup()

2023-03-17T07:58:02+00:00

[ Upstream commit dc222fa7737212fe0da513e5b8937c156d02225d ]

The early paca and boot cpuid dance is complicated and currently does
not quite work as expected for boot cpuid != 0 cases.

early_init_devtree() currently allocates the paca_ptrs and boot cpuid
paca, but until that returns and early_setup() calls setup_paca(), this
thread is currently still executing with smp_processor_id() == 0.

One problem this causes is the paca_ptrs[smp_processor_id()] pointer is
poisoned, so valid_emergency_stack() (any backtrace) and any similar
users will crash.

Another is that the hardware id which is set here will not be returned
by get_hard_smp_processor_id(smp_processor_id()), but it would work
correctly for boot_cpuid == 0, which could lead to difficult to
reproduce or find bugs. The hard id does not seem to be used by the rest
of early_init_devtree(), it just looks like all this code might have
been put here to allocate somewhere to store boot CPU hardware id while
scanning the devtree.

Rearrange things so the hwid is put in a global variable like
boot_cpuid, and do all the paca allocation and boot paca setup in the
64-bit early_setup() after we have everything ready to go.

The paca_ptrs[0] re-poisoning code in early_setup does not seem to have
ever worked, because paca_ptrs[0] was never not-poisoned when boot_cpuid
is not 0.

Signed-off-by: Nicholas Piggin 
[mpe: Fix build error on 32-bit]
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20221216115930.2667772-4-npiggin@gmail.com
Signed-off-by: Sasha Levin

powerpc/64: Fix task_cpu in early boot when booting non-zero cpuid

2023-03-17T07:58:01+00:00

[ Upstream commit 9fa24404f5044967753a6cd3e5e36f57686bec6e ]

powerpc/64 can boot on a non-zero SMP processor id. Initially, the boot
CPU is said to be "assumed to be 0" until early_init_devtree() discovers
the id from the device tree. That is not a good description because the
assumption can be wrong and that has to be handled, the better
description is that 0 is used as a placeholder, and things are fixed
after the real id is discovered.

smp_processor_id() is set to the boot cpuid, but task_cpu(current) is
not, which causes the smp_processor_id() == task_cpu(current) invariant
to be broken until init_idle() in sched_init().

This is quite fragile and could lead to subtle bugs in future. One bug
is that validate_sp_size uses task_cpu() to get the process stack, so
any stack trace from the booting CPU between early_init_devtree()
and sched_init() will have problems. Early on paca_ptrs[0] will be
poisoned, so that can cause machine checks dereferencing that memory
in real mode. Later, validating the current stack pointer against the
idle task of a different secondary will probably cause no stack trace
to be printed.

Fix this by setting thread_info->cpu right after smp_processor_id() is
set to the boot cpuid.

Signed-off-by: Nicholas Piggin 
[mpe: Fix SMP=n build as reported by sfr]
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20221216115930.2667772-3-npiggin@gmail.com
Signed-off-by: Sasha Levin

powerpc/bpf/32: Only set a stack frame when necessary

2023-03-17T07:58:01+00:00

[ Upstream commit d084dcf256bc4565b4b1af9b00297ac7b51c7049 ]

Until now a stack frame was set at all time due to the need
to keep tail call counter in the stack.

But since commit 89d21e259a94 ("powerpc/bpf/32: Fix Oops on tail call
tests") the tail call counter is passed via register r4. It is therefore
not necessary anymore to have a stack frame for that.

Just like PPC64, implement bpf_has_stack_frame() and only sets the frame
when needed.

The difference with PPC64 is that PPC32 doesn't have a redzone, so
the stack is required as soon as non volatile registers are used or
when tail call count is set up.

Signed-off-by: Christophe Leroy 
[mpe: Fix commit reference in change log]
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/62d7b654a3cfe73d998697cb29bbc5ffd89bfdb1.1675245773.git.christophe.leroy@csgroup.eu
Signed-off-by: Sasha Levin

powerpc: Remove __kernel_text_address() in show_instructions()

2023-03-17T07:58:01+00:00

[ Upstream commit d9ab6da64fd15608c9feb20d769d8df1a32fe212 ]

That test was introducted in 2006 by
commit 00ae36de49cc ("[POWERPC] Better check in show_instructions").
At that time, there was no BPF progs.

As seen in message of commit 89d21e259a94 ("powerpc/bpf/32: Fix Oops
on tail call tests"), when a page fault occurs in test_bpf.ko for
instance, the code is dumped as XXXXXXXXs. Allthough
__kernel_text_address() checks is_bpf_text_address(), it seems it is
not enough.

Today, show_instructions() uses get_kernel_nofault() to read the code,
so there is no real need for additional verifications.

ARM64 and x86 don't do any additional check before dumping
instructions. Do the same and remove __kernel_text_address()
in show_instructions().

Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/4fd69ef7945518c3e27f96b95046a5c1468d35bf.1675245773.git.christophe.leroy@csgroup.eu
Signed-off-by: Sasha Levin

powerpc/iommu: fix memory leak with using debugfs_lookup()

2023-03-17T07:58:01+00:00

[ Upstream commit b505063910c134778202dfad9332dfcecb76bab3 ]

When calling debugfs_lookup() the result must have dput() called on it,
otherwise the memory will leak over time.  To make things simpler, just
call debugfs_lookup_and_remove() instead which handles all of the logic
at once.

Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20230202141919.2298821-1-gregkh@linuxfoundation.org
Signed-off-by: Sasha Levin

powerpc/64: Don't recurse irq replay

2023-03-17T07:58:01+00:00

[ Upstream commit 5746ca131e2496ccd5bb4d7a0244d6c38070cbf5 ]

Interrupt handlers called by soft-pending irq replay code can run
softirqs, softirq replay enables and disables local irqs, which allows
interrupts to come in including soft-masked interrupts, and it can
cause pending irqs to be replayed again. That makes the soft irq replay
state machine and possible races more complicated and fragile than it
needs to be.

Use irq_enter/irq_exit around irq replay to prevent softirqs running
while interrupts are being replayed. Softirqs will now be run at the
irq_exit() call after all the irq replaying is done. This prevents irqs
being replayed while irqs are being replayed, and should hopefully make
things simpler and easier to think about and debug.

A new PACA_IRQ_REPLAYING is added to prevent asynchronous interrupt
handlers hard-enabling EE while pending irqs are being replayed, because
that causes new pending irqs to arrive which is also a complexity. This
means pending irqs won't be profiled quite so well because perf irqs
can't be taken.

Signed-off-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20230121102618.2824429-1-npiggin@gmail.com
Signed-off-by: Sasha Levin

powerpc: dts: t1040rdb: fix compatible string for Rev A boards

2023-03-17T07:57:52+00:00

[ Upstream commit ae44f1c9d1fc54aeceb335fedb1e73b2c3ee4561 ]

It looks like U-Boot fails to start the kernel properly when the
compatible string of the board isn't fsl,T1040RDB, so stop overriding it
from the rev-a.dts.

Fixes: 5ebb74749202 ("powerpc: dts: t1040rdb: fix ports names for Seville Ethernet switch")
Signed-off-by: Vladimir Oltean 
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

eth: fealnx: bring back this old driver

2023-03-11T12:50:46+00:00

commit 8f14820801042c221bb9fe51643a2585cac5dec2 upstream.

This reverts commit d5e2d038dbece821f1af57acbeded3aa9a1832c1.

We have a report of this chip being used on a

  SURECOM EP-320X-S 100/10M Ethernet PCI Adapter

which could still have been purchased in some parts
of the world 3 years ago.

Cc: stable@vger.kernel.org
Link: https://bugzilla.kernel.org/show_bug.cgi?id=217151
Fixes: d5e2d038dbec ("eth: fealnx: delete the driver for Myson MTD-800")
Link: https://lore.kernel.org/r/20230307171930.4008454-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

powerpc: Remove linker flag from KBUILD_AFLAGS

2023-03-10T08:29:00+00:00

[ Upstream commit 31f48f16264bc70962fb3e7ec62da64d0a2ba04a ]

When clang's -Qunused-arguments is dropped from KBUILD_CPPFLAGS, it
points out that KBUILD_AFLAGS contains a linker flag, which will be
unused:

  clang: error: -Wl,-a32: 'linker' input unused [-Werror,-Wunused-command-line-argument]

This was likely supposed to be '-Wa,-a$(BITS)'. However, this change is
unnecessary, as all supported versions of clang and gcc will pass '-a64'
or '-a32' to GNU as based on the value of '-m'; the behavior of the
latest stable release of the oldest supported major version of each
compiler is shown below and each compiler's latest release exhibits the
same behavior (GCC 12.2.0 and Clang 15.0.6).

  $ powerpc64-linux-gcc --version | head -1
  powerpc64-linux-gcc (GCC) 5.5.0

  $ powerpc64-linux-gcc -m64 -### -x assembler-with-cpp -c -o /dev/null /dev/null &| grep 'as '
  .../as -a64 -mppc64 -many -mbig -o /dev/null /tmp/cctwuBzZ.s

  $ powerpc64-linux-gcc -m32 -### -x assembler-with-cpp -c -o /dev/null /dev/null &| grep 'as '
  .../as -a32 -mppc -many -mbig -o /dev/null /tmp/ccaZP4mF.sg

  $ clang --version | head -1
  Ubuntu clang version 11.1.0-++20211011094159+1fdec59bffc1-1~exp1~20211011214622.5

  $ clang --target=powerpc64-linux-gnu -fno-integrated-as -m64 -### \
    -x assembler-with-cpp -c -o /dev/null /dev/null &| grep gnu-as
   "/usr/bin/powerpc64-linux-gnu-as" "-a64" "-mppc64" "-many" "-o" "/dev/null" "/tmp/null-80267c.s"

  $ clang --target=powerpc64-linux-gnu -fno-integrated-as -m64 -### \
    -x assembler-with-cpp -c -o /dev/null /dev/null &| grep gnu-as
   "/usr/bin/powerpc64-linux-gnu-as" "-a32" "-mppc" "-many" "-o" "/dev/null" "/tmp/null-ab8f8d.s"

Remove this flag altogether to avoid future issues.

Fixes: 1421dc6d4829 ("powerpc/kbuild: Use flags variables rather than overriding LD/CC/AS")
Signed-off-by: Nathan Chancellor 
Reviewed-by: Nick Desaulniers 
Tested-by: Linux Kernel Functional Testing 
Tested-by: Anders Roxell 
Acked-by: Michael Ellerman 
Signed-off-by: Masahiro Yamada 
Signed-off-by: Sasha Levin