powerpc/4xx: Remove CONFIG_BOOKE_OR_40x

Now that 40x is gone, replace CONFIG_BOOKE_OR_40x by CONFIG_BOOKE.

Signed-off-by: Michael Ellerman <[email protected]>
Link: https://msgid.link/202406281212

powerpc/4xx: Remove CONFIG_BOOKE_OR_40x

Now that 40x is gone, replace CONFIG_BOOKE_OR_40x by CONFIG_BOOKE.

Signed-off-by: Michael Ellerman <[email protected]>
Link: https://msgid.link/[email protected]

show more ...

powerpc/dexcr: Add DEXCR prctl interface

Now that we track a DEXCR on a per-task basis, individual tasks are free
to configure it as they like.

The interface is a pair of getter/setter prctl's that

powerpc/dexcr: Add DEXCR prctl interface

Now that we track a DEXCR on a per-task basis, individual tasks are free
to configure it as they like.

The interface is a pair of getter/setter prctl's that work on a single
aspect at a time (multiple aspects at once is more difficult if there
are different rules applied for each aspect, now or in future). The
getter shows the current state of the process config, and the setter
allows setting/clearing the aspect.

Signed-off-by: Benjamin Gray <[email protected]>
[mpe: Account for PR_RISCV_SET_ICACHE_FLUSH_CTX, shrink some longs lines]
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://msgid.link/[email protected]

show more ...

powerpc/dexcr: Reset DEXCR value across exec

Inheriting the DEXCR across exec can have security and usability
concerns. If a program is compiled with hash instructions it generally
expects to run wi

powerpc/dexcr: Reset DEXCR value across exec

Inheriting the DEXCR across exec can have security and usability
concerns. If a program is compiled with hash instructions it generally
expects to run with NPHIE enabled. But if the parent process disables
NPHIE then if it's not careful it will be disabled for any children too
and the protection offered by hash checks is basically worthless.

This patch introduces a per-process reset value that new execs in a
particular process tree are initialized with. This enables fine grained
control over what DEXCR value child processes run with by default.
For example, containers running legacy binaries that expect hash
instructions to act as NOPs could configure the reset value of the
container root to control the default reset value for all members of
the container.

Signed-off-by: Benjamin Gray <[email protected]>
[mpe: Add missing SPDX tag on dexcr.c]
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://msgid.link/[email protected]

show more ...

powerpc/dexcr: Track the DEXCR per-process

Add capability to make the DEXCR act as a per-process SPR.

We do not yet have an interface for changing the values per task. We
also expect the kernel to

powerpc/dexcr: Track the DEXCR per-process

Add capability to make the DEXCR act as a per-process SPR.

We do not yet have an interface for changing the values per task. We
also expect the kernel to use a single DEXCR value across all tasks
while in privileged state, so there is no need to synchronize after
changing it (the userspace aspects will synchronize upon returning to
userspace).

Signed-off-by: Benjamin Gray <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://msgid.link/[email protected]

show more ...

powerpc/watchpoints: Track perf single step directly on the breakpoint

There is a bug in the current watchpoint tracking logic, where the
teardown in arch_unregister_hw_breakpoint() uses bp->ctx->ta

powerpc/watchpoints: Track perf single step directly on the breakpoint

There is a bug in the current watchpoint tracking logic, where the
teardown in arch_unregister_hw_breakpoint() uses bp->ctx->task, which it
does not have a reference of and parallel threads may be in the process
of destroying. This was partially addressed in commit fb822e6076d9
("powerpc/hw_breakpoint: Fix oops when destroying hw_breakpoint event"),
but the underlying issue of accessing a struct member in an unknown
state still remained. Syzkaller managed to trigger a null pointer
derefernce due to the race between the task destructor and checking the
pointer and dereferencing it in the loop.

While this null pointer dereference could be fixed by using READ_ONCE
to access the task up front, that just changes the error to manipulating
possbily freed memory.

Instead, the breakpoint logic needs to be reworked to remove any
dependency on a context or task struct during breakpoint removal.

The reason we have this currently is to clear thread.last_hit_ubp. This
member is used to differentiate the perf DAWR single-step sequence from
other causes of single-step, such as userspace just calling
ptrace(PTRACE_SINGLESTEP, ...). We need to differentiate them because,
when the single step interrupt is received, we need to know whether to
re-insert the DAWR breakpoint (perf) or not (ptrace / other).

arch_unregister_hw_breakpoint() needs to clear this information to
prevent dangling pointers to possibly freed memory. These pointers are
dereferenced in single_step_dabr_instruction() without a way to check
their validity.

This patch moves the tracking of this information to the breakpoint
itself. This means we no longer have to do anything special to clean up.

Signed-off-by: Benjamin Gray <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://msgid.link/[email protected]

show more ...

locking: remove spin_lock_prefetch

The only remaining consumer is new_inode, where it showed up in 2001 as
commit c37fa164f793 ("v2.4.9.9 -> v2.4.9.10") in a historical repo [1]
with a changelog whi

locking: remove spin_lock_prefetch

The only remaining consumer is new_inode, where it showed up in 2001 as
commit c37fa164f793 ("v2.4.9.9 -> v2.4.9.10") in a historical repo [1]
with a changelog which does not mention it.

Since then the line got only touched up to keep compiling.

While it may have been of benefit back in the day, it is guaranteed to
at best not get in the way in the multicore setting -- as the code
performs *a lot* of work between the prefetch and actual lock acquire,
any contention means the cacheline is already invalid by the time the
routine calls spin_lock(). It adds spurious traffic, for short.

On top of it prefetch is notoriously tricky to use for single-threaded
purposes, making it questionable from the get go.

As such, remove it.

I admit upfront I did not see value in benchmarking this change, but I
can do it if that is deemed appropriate.

Removal from new_inode and of the entire thing are in the same patch as
requested by Linus, so whatever weird looks can be directed at that guy.

Link: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/fs/inode.c?id=c37fa164f793735b32aa3f53154ff1a7659e6442 [1]
Signed-off-by: Mateusz Guzik <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

powerpc/dexcr: Support userspace ROP protection

The ISA 3.1B hashst and hashchk instructions use a per-cpu SPR HASHKEYR
to hold a key used in the hash calculation. This key should be different
for e

powerpc/dexcr: Support userspace ROP protection

The ISA 3.1B hashst and hashchk instructions use a per-cpu SPR HASHKEYR
to hold a key used in the hash calculation. This key should be different
for each process to make it harder for a malicious process to recreate
valid hash values for a victim process.

Add support for storing a per-thread hash key, and setting/clearing
HASHKEYR appropriately.

Signed-off-by: Benjamin Gray <[email protected]>
Reviewed-by: Russell Currey <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://msgid.link/[email protected]

show more ...

powerpc: split validate_sp into two functions

Most callers just want to validate an arbitrary kernel stack pointer,
some need a particular size. Make the size case the exceptional one
with an extra

powerpc: split validate_sp into two functions

Most callers just want to validate an arbitrary kernel stack pointer,
some need a particular size. Make the size case the exceptional one
with an extra function.

Signed-off-by: Nicholas Piggin <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

show more ...

powerpc/64s: Make POWER10 and later use pause_short in cpu_relax loops

We want to move away from using SMT priority updates for cpu_relax, and
use a 'wait' instruction which is similar to x86. As we

powerpc/64s: Make POWER10 and later use pause_short in cpu_relax loops

We want to move away from using SMT priority updates for cpu_relax, and
use a 'wait' instruction which is similar to x86. As well as being a
much better fit for what everybody else uses and tests with, priority
nops are stateful which is nasty (interrupts have to consider they might
be taken at a different priority), and they're expensive to execute,
similar to a mtSPR which can effect other threads in the pipe.

This has shown to give results that are less affected by code alignment
on benchmarks that cause a lot of spin waiting (e.g., rwsem contention
on unixbench filesystem benchmarks) on POWER10.

QEMU TCG only supports this instruction correctly since v7.1, versions
without the fix may cause hangs whne running POWER10 CPUs.

Reviewed-by: Segher Boessenkool <[email protected]>
Signed-off-by: Nicholas Piggin <[email protected]>
[mpe: Fix checkpatch warnings RE the macros]
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

show more ...

kernel: exit: cleanup release_thread()

Only x86 has own release_thread(), introduce a new weak release_thread()
function to clean empty definitions in other ARCHs.

Link: https://lkml.kernel.org/r/2

kernel: exit: cleanup release_thread()

Only x86 has own release_thread(), introduce a new weak release_thread()
function to clean empty definitions in other ARCHs.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Kefeng Wang <[email protected]>
Acked-by: Guo Ren <[email protected]> [csky]
Acked-by: Russell King (Oracle) <[email protected]>
Acked-by: Geert Uytterhoeven <[email protected]>
Acked-by: Brian Cain <[email protected]>
Acked-by: Michael Ellerman <[email protected]> [powerpc]
Acked-by: Stafford Horne <[email protected]> [openrisc]
Acked-by: Catalin Marinas <[email protected]> [arm64]
Acked-by: Huacai Chen <[email protected]> [LoongArch]
Cc: Alexander Gordeev <[email protected]>
Cc: Anton Ivanov <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Chris Zankel <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Dinh Nguyen <[email protected]>
Cc: Guo Ren <[email protected]> [csky]
Cc: Heiko Carstens <[email protected]>
Cc: Helge Deller <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Ivan Kokshaysky <[email protected]>
Cc: James Bottomley <[email protected]>
Cc: Johannes Berg <[email protected]>
Cc: Jonas Bonn <[email protected]>
Cc: Matt Turner <[email protected]>
Cc: Max Filippov <[email protected]>
Cc: Michal Simek <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Richard Henderson <[email protected]>
Cc: Richard Weinberger <[email protected]>
Cc: Rich Felker <[email protected]>
Cc: Stefan Kristiansson <[email protected]>
Cc: Sven Schnelle <[email protected]>
Cc: Thomas Bogendoerfer <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Vineet Gupta <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Xuerui Wang <[email protected]>
Cc: Yoshinori Sato <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

powerpc/math-emu: Inhibit W=1 warnings

When building with W=1 you get:

arch/powerpc/math-emu/fre.c:6:5: error: no previous prototype for 'fre' [-Werror=missing-prototypes]
arch/powerpc/math-emu/f

powerpc/math-emu: Inhibit W=1 warnings

When building with W=1 you get:

arch/powerpc/math-emu/fre.c:6:5: error: no previous prototype for 'fre' [-Werror=missing-prototypes]
arch/powerpc/math-emu/fsqrt.c:11:1: error: no previous prototype for 'fsqrt' [-Werror=missing-prototypes]
arch/powerpc/math-emu/fsqrts.c:12:1: error: no previous prototype for 'fsqrts' [-Werror=missing-prototypes]
arch/powerpc/math-emu/frsqrtes.c:6:5: error: no previous prototype for 'frsqrtes' [-Werror=missing-prototypes]
arch/powerpc/math-emu/mtfsf.c:10:1: error: no previous prototype for 'mtfsf' [-Werror=missing-prototypes]
arch/powerpc/math-emu/mtfsfi.c:10:1: error: no previous prototype for 'mtfsfi' [-Werror=missing-prototypes]
arch/powerpc/math-emu/fabs.c:7:1: error: no previous prototype for 'fabs' [-Werror=missing-prototypes]
arch/powerpc/math-emu/fadd.c:11:1: error: no previous prototype for 'fadd' [-Werror=missing-prototypes]
arch/powerpc/math-emu/fadds.c:12:1: error: no previous prototype for 'fadds' [-Werror=missing-prototypes]
arch/powerpc/math-emu/fcmpo.c:11:1: error: no previous prototype for 'fcmpo' [-Werror=missing-prototypes]
arch/powerpc/math-emu/fcmpu.c:11:1: error: no previous prototype for 'fcmpu' [-Werror=missing-prototypes]
arch/powerpc/math-emu/fcmpu.c:14:19: error: variable 'B_c' set but not used [-Werror=unused-but-set-variable]
arch/powerpc/math-emu/fcmpu.c:13:19: error: variable 'A_c' set but not used [-Werror=unused-but-set-variable]
arch/powerpc/math-emu/fctiw.c:11:1: error: no previous prototype for 'fctiw' [-Werror=missing-prototypes]
arch/powerpc/math-emu/fctiwz.c:11:1: error: no previous prototype for 'fctiwz' [-Werror=missing-prototypes]
arch/powerpc/math-emu/fdiv.c:11:1: error: no previous prototype for 'fdiv' [-Werror=missing-prototypes]
arch/powerpc/math-emu/fdivs.c:12:1: error: no previous prototype for 'fdivs' [-Werror=missing-prototypes]
arch/powerpc/math-emu/fmadd.c:11:1: error: no previous prototype for 'fmadd' [-Werror=missing-prototypes]
arch/powerpc/math-emu/fmadds.c:12:1: error: no previous prototype for 'fmadds' [-Werror=missing-prototypes]
arch/powerpc/math-emu/fmsub.c:11:1: error: no previous prototype for 'fmsub' [-Werror=missing-prototypes]
arch/powerpc/math-emu/fmsubs.c:12:1: error: no previous prototype for 'fmsubs' [-Werror=missing-prototypes]
arch/powerpc/math-emu/fmul.c:11:1: error: no previous prototype for 'fmul' [-Werror=missing-prototypes]
arch/powerpc/math-emu/fmuls.c:12:1: error: no previous prototype for 'fmuls' [-Werror=missing-prototypes]
arch/powerpc/math-emu/fnabs.c:7:1: error: no previous prototype for 'fnabs' [-Werror=missing-prototypes]
arch/powerpc/math-emu/fneg.c:7:1: error: no previous prototype for 'fneg' [-Werror=missing-prototypes]
arch/powerpc/math-emu/fnmadd.c:11:1: error: no previous prototype for 'fnmadd' [-Werror=missing-prototypes]
arch/powerpc/math-emu/fnmadds.c:12:1: error: no previous prototype for 'fnmadds' [-Werror=missing-prototypes]
arch/powerpc/math-emu/fnmsub.c:11:1: error: no previous prototype for 'fnmsub' [-Werror=missing-prototypes]
arch/powerpc/math-emu/fnmsubs.c:12:1: error: no previous prototype for 'fnmsubs' [-Werror=missing-prototypes]
arch/powerpc/math-emu/fres.c:7:1: error: no previous prototype for 'fres' [-Werror=missing-prototypes]
arch/powerpc/math-emu/frsp.c:12:1: error: no previous prototype for 'frsp' [-Werror=missing-prototypes]
arch/powerpc/math-emu/fsel.c:11:1: error: no previous prototype for 'fsel' [-Werror=missing-prototypes]
arch/powerpc/math-emu/lfs.c:12:1: error: no previous prototype for 'lfs' [-Werror=missing-prototypes]
arch/powerpc/math-emu/frsqrte.c:7:1: error: no previous prototype for 'frsqrte' [-Werror=missing-prototypes]
arch/powerpc/math-emu/fsub.c:11:1: error: no previous prototype for 'fsub' [-Werror=missing-prototypes]
arch/powerpc/math-emu/fsubs.c:12:1: error: no previous prototype for 'fsubs' [-Werror=missing-prototypes]
arch/powerpc/math-emu/mcrfs.c:10:1: error: no previous prototype for 'mcrfs' [-Werror=missing-prototypes]
arch/powerpc/math-emu/mffs.c:10:1: error: no previous prototype for 'mffs' [-Werror=missing-prototypes]
arch/powerpc/math-emu/mtfsb0.c:10:1: error: no previous prototype for 'mtfsb0' [-Werror=missing-prototypes]
arch/powerpc/math-emu/mtfsb1.c:10:1: error: no previous prototype for 'mtfsb1' [-Werror=missing-prototypes]
arch/powerpc/math-emu/stfiwx.c:7:1: error: no previous prototype for 'stfiwx' [-Werror=missing-prototypes]
arch/powerpc/math-emu/stfs.c:12:1: error: no previous prototype for 'stfs' [-Werror=missing-prototypes]
arch/powerpc/math-emu/fmr.c:7:1: error: no previous prototype for 'fmr' [-Werror=missing-prototypes]
arch/powerpc/math-emu/lfd.c:10:1: error: no previous prototype for 'lfd' [-Werror=missing-prototypes]
arch/powerpc/math-emu/stfd.c:7:1: error: no previous prototype for 'stfd' [-Werror=missing-prototypes]
arch/powerpc/math-emu/math_efp.c:177:5: error: no previous prototype for 'do_spe_mathemu' [-Werror=missing-prototypes]
arch/powerpc/math-emu/math_efp.c:726:5: error: no previous prototype for 'speround_handler' [-Werror=missing-prototypes]
arch/powerpc/math-emu/math_efp.c:893:12: error: no previous prototype for 'spe_mathemu_init' [-Werror=missing-prototypes]

Fix the warnings in math_efp.c by adding prototypes of do_spe_mathemu()
and speround_handler() to asm/processor.h and declare spe_mathemu_init()
static.

The other warnings are benign and not worth the churn of fixing them,
expecially the 'unused-but-set-variable' which would impact the core
part of 'math-emu'.

So silence them by adding -Wno-missing-prototypes -Wno-unused-but-set-variable.

But then you get:

arch/powerpc/math-emu/fre.c:6:5: error: no previous declaration for 'fre' [-Werror=missing-declarations]
arch/powerpc/math-emu/fsqrt.c:11:1: error: no previous declaration for 'fsqrt' [-Werror=missing-declarations]
arch/powerpc/math-emu/fsqrts.c:12:1: error: no previous declaration for 'fsqrts' [-Werror=missing-declarations]
arch/powerpc/math-emu/frsqrtes.c:6:5: error: no previous declaration for 'frsqrtes' [-Werror=missing-declarations]
arch/powerpc/math-emu/mtfsf.c:10:1: error: no previous declaration for 'mtfsf' [-Werror=missing-declarations]
arch/powerpc/math-emu/mtfsfi.c:10:1: error: no previous declaration for 'mtfsfi' [-Werror=missing-declarations]
arch/powerpc/math-emu/fabs.c:7:1: error: no previous declaration for 'fabs' [-Werror=missing-declarations]
arch/powerpc/math-emu/fadd.c:11:1: error: no previous declaration for 'fadd' [-Werror=missing-declarations]
arch/powerpc/math-emu/fadds.c:12:1: error: no previous declaration for 'fadds' [-Werror=missing-declarations]
arch/powerpc/math-emu/fcmpo.c:11:1: error: no previous declaration for 'fcmpo' [-Werror=missing-declarations]
arch/powerpc/math-emu/fcmpu.c:11:1: error: no previous declaration for 'fcmpu' [-Werror=missing-declarations]
arch/powerpc/math-emu/fctiw.c:11:1: error: no previous declaration for 'fctiw' [-Werror=missing-declarations]
arch/powerpc/math-emu/fctiwz.c:11:1: error: no previous declaration for 'fctiwz' [-Werror=missing-declarations]
arch/powerpc/math-emu/fdiv.c:11:1: error: no previous declaration for 'fdiv' [-Werror=missing-declarations]
arch/powerpc/math-emu/fdivs.c:12:1: error: no previous declaration for 'fdivs' [-Werror=missing-declarations]
arch/powerpc/math-emu/fmadd.c:11:1: error: no previous declaration for 'fmadd' [-Werror=missing-declarations]
arch/powerpc/math-emu/fmadds.c:12:1: error: no previous declaration for 'fmadds' [-Werror=missing-declarations]
arch/powerpc/math-emu/fmsub.c:11:1: error: no previous declaration for 'fmsub' [-Werror=missing-declarations]
arch/powerpc/math-emu/fmsubs.c:12:1: error: no previous declaration for 'fmsubs' [-Werror=missing-declarations]
arch/powerpc/math-emu/fmul.c:11:1: error: no previous declaration for 'fmul' [-Werror=missing-declarations]
arch/powerpc/math-emu/fmuls.c:12:1: error: no previous declaration for 'fmuls' [-Werror=missing-declarations]
arch/powerpc/math-emu/fnabs.c:7:1: error: no previous declaration for 'fnabs' [-Werror=missing-declarations]
arch/powerpc/math-emu/fneg.c:7:1: error: no previous declaration for 'fneg' [-Werror=missing-declarations]
arch/powerpc/math-emu/fnmadd.c:11:1: error: no previous declaration for 'fnmadd' [-Werror=missing-declarations]
arch/powerpc/math-emu/fnmadds.c:12:1: error: no previous declaration for 'fnmadds' [-Werror=missing-declarations]
arch/powerpc/math-emu/fnmsub.c:11:1: error: no previous declaration for 'fnmsub' [-Werror=missing-declarations]
arch/powerpc/math-emu/fnmsubs.c:12:1: error: no previous declaration for 'fnmsubs' [-Werror=missing-declarations]
arch/powerpc/math-emu/fres.c:7:1: error: no previous declaration for 'fres' [-Werror=missing-declarations]
arch/powerpc/math-emu/frsp.c:12:1: error: no previous declaration for 'frsp' [-Werror=missing-declarations]
arch/powerpc/math-emu/fsel.c:11:1: error: no previous declaration for 'fsel' [-Werror=missing-declarations]
arch/powerpc/math-emu/lfs.c:12:1: error: no previous declaration for 'lfs' [-Werror=missing-declarations]
arch/powerpc/math-emu/frsqrte.c:7:1: error: no previous declaration for 'frsqrte' [-Werror=missing-declarations]
arch/powerpc/math-emu/fsub.c:11:1: error: no previous declaration for 'fsub' [-Werror=missing-declarations]
arch/powerpc/math-emu/fsubs.c:12:1: error: no previous declaration for 'fsubs' [-Werror=missing-declarations]
arch/powerpc/math-emu/mcrfs.c:10:1: error: no previous declaration for 'mcrfs' [-Werror=missing-declarations]
arch/powerpc/math-emu/mffs.c:10:1: error: no previous declaration for 'mffs' [-Werror=missing-declarations]
arch/powerpc/math-emu/mtfsb0.c:10:1: error: no previous declaration for 'mtfsb0' [-Werror=missing-declarations]
arch/powerpc/math-emu/mtfsb1.c:10:1: error: no previous declaration for 'mtfsb1' [-Werror=missing-declarations]
arch/powerpc/math-emu/stfiwx.c:7:1: error: no previous declaration for 'stfiwx' [-Werror=missing-declarations]
arch/powerpc/math-emu/stfs.c:12:1: error: no previous declaration for 'stfs' [-Werror=missing-declarations]
arch/powerpc/math-emu/fmr.c:7:1: error: no previous declaration for 'fmr' [-Werror=missing-declarations]
arch/powerpc/math-emu/lfd.c:10:1: error: no previous declaration for 'lfd' [-Werror=missing-declarations]
arch/powerpc/math-emu/stfd.c:7:1: error: no previous declaration for 'stfd' [-Werror=missing-declarations]

So also add -Wno-missing-declarations.

Reported-by: kernel test robot <[email protected]>
Signed-off-by: Christophe Leroy <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/688084b40b5ac88f2905cb207d5dad947d8d34dc.1662531153.git.christophe.leroy@csgroup.eu

show more ...

powerpc/mm: Convert to default topdown mmap layout

Select CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT and
remove arch/powerpc/mm/mmap.c

This change reuses the generic framework added by
commit 67f

powerpc/mm: Convert to default topdown mmap layout

Select CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT and
remove arch/powerpc/mm/mmap.c

This change reuses the generic framework added by
commit 67f3977f805b ("arm64, mm: move generic mmap layout
functions to mm") without any functional change.

Comparison between powerpc implementation and the generic one:
- mmap_is_legacy() is identical.
- arch_mmap_rnd() does exactly the same allthough it's written
slightly differently.
- MIN_GAP and MAX_GAP are identical.
- mmap_base() does the same but uses STACK_RND_MASK which provides
the same values as stack_maxrandom_size().
- arch_pick_mmap_layout() is identical.

Signed-off-by: Christophe Leroy <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/518f9def87d3c889d5958103e7463cf45a2f673d.1649523076.git.christophe.leroy@csgroup.eu

show more ...

powerpc: Move C prototypes out of asm-prototypes.h

We originally added asm-prototypes.h in commit 42f5b4cacd78 ("powerpc:
Introduce asm-prototypes.h"). It's purpose was for prototypes of C
functions

powerpc: Move C prototypes out of asm-prototypes.h

We originally added asm-prototypes.h in commit 42f5b4cacd78 ("powerpc:
Introduce asm-prototypes.h"). It's purpose was for prototypes of C
functions that are only called from asm, in order to fix sparse
warnings about missing prototypes.

A few months later Nick added a different use case in
commit 4efca4ed05cb ("kbuild: modversions for EXPORT_SYMBOL() for asm")
for C prototypes for exported asm functions. This is basically the
inverse of our original usage.

Since then we've added various prototypes to asm-prototypes.h for both
reasons, meaning we now need to unstitch it all.

Dispatch prototypes of C functions into relevant headers and keep
only the prototypes for functions defined in assembly.

For the time being, leave prom_init() there because moving it
into asm/prom.h or asm/setup.h conflicts with
drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowrom.o
This will be fixed later by untaggling asm/pci.h and asm/prom.h
or by renaming the function in shadowrom.c

Signed-off-by: Christophe Leroy <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/62d46904eca74042097acf4cb12c175e3067f3d1.1646413435.git.christophe.leroy@csgroup.eu

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powerpc: Add KUAP support for BOOKE and 40x

On booke/40x we don't have segments like book3s/32.
On booke/40x we don't have access protection groups like 8xx.

Use the PID register to provide user ac

powerpc: Add KUAP support for BOOKE and 40x

On booke/40x we don't have segments like book3s/32.
On booke/40x we don't have access protection groups like 8xx.

Use the PID register to provide user access protection.
Kernel address space can be accessed with any PID.
User address space has to be accessed with the PID of the user.
User PID is always not null.

Everytime the kernel is entered, set PID register to 0 and
restore PID register when returning to user.

Everytime kernel needs to access user data, PID is restored
for the access.

In TLB miss handlers, check the PID and bail out to data storage
exception when PID is 0 and accessed address is in user space.

Note that also forbids execution of user text by kernel except
when user access is unlocked. But this shouldn't be a problem
as the kernel is not supposed to ever run user text.

This patch prepares the infrastructure but the real activation of KUAP
is done by following patches for each processor type one by one.

Signed-off-by: Christophe Leroy <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/5d65576a8e31e9480415785a180c92dd4e72306d.1634627931.git.christophe.leroy@csgroup.eu

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powerpc/32s: Save content of sr0 to avoid 'mfsr'

Calling 'mfsr' to get the content of segment registers is heavy,
in addition it requires clearing of the 'reserved' bits.

In order to avoid this ope

powerpc/32s: Save content of sr0 to avoid 'mfsr'

Calling 'mfsr' to get the content of segment registers is heavy,
in addition it requires clearing of the 'reserved' bits.

In order to avoid this operation, save it in mm context and in
thread struct.

The saved sr0 is the one used by kernel, this means that on
locking entry it can be used as is.

For unlocking, the only thing to do is to clear SR_NX.

This improves null_syscall selftest by 12 cycles, ie 4%.

Signed-off-by: Christophe Leroy <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/b02baf2ed8f09bad910dfaeeb7353b2ae6830525.1634627931.git.christophe.leroy@csgroup.eu

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powerpc/signal32: Use struct_group() to zero spe regs

In preparation for FORTIFY_SOURCE performing compile-time and run-time
field bounds checking for memset(), avoid intentionally writing across
ne

powerpc/signal32: Use struct_group() to zero spe regs

In preparation for FORTIFY_SOURCE performing compile-time and run-time
field bounds checking for memset(), avoid intentionally writing across
neighboring fields.

Add a struct_group() for the spe registers so that memset() can correctly reason
about the size:

In function 'fortify_memset_chk',
inlined from 'restore_user_regs.part.0' at arch/powerpc/kernel/signal_32.c:539:3:
>> include/linux/fortify-string.h:195:4: error: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Werror=attribute-warning]
195 | __write_overflow_field();
| ^~~~~~~~~~~~~~~~~~~~~~~~

Reported-by: kernel test robot <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Reviewed-by: Christophe Leroy <[email protected]>
Acked-by: Michael Ellerman <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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sched: Add wrapper for get_wchan() to keep task blocked

Having a stable wchan means the process must be blocked and for it to
stay that way while performing stack unwinding.

Suggested-by: Peter Zij

sched: Add wrapper for get_wchan() to keep task blocked

Having a stable wchan means the process must be blocked and for it to
stay that way while performing stack unwinding.

Suggested-by: Peter Zijlstra <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Acked-by: Geert Uytterhoeven <[email protected]>
Acked-by: Russell King (Oracle) <[email protected]> [arm]
Tested-by: Mark Rutland <[email protected]> [arm64]
Link: https://lkml.kernel.org/r/[email protected]

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powerpc/64: drop redundant defination of spin_until_cond

linux/processor.h has exactly same defination for spin_until_cond.
Drop the redundant defination in asm/processor.h

Signed-off-by: Sudeep Ho

powerpc/64: drop redundant defination of spin_until_cond

linux/processor.h has exactly same defination for spin_until_cond.
Drop the redundant defination in asm/processor.h

Signed-off-by: Sudeep Holla <[email protected]>
Signed-off-by: Christophe Leroy <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/1fff2054e5dfc00329804dbd3f2a91667c9a8aff.1623438544.git.christophe.leroy@csgroup.eu

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powerpc/32s: Rework Kernel Userspace Access Protection

On book3s/32, KUAP is provided by toggling Ks bit in segment registers.
One segment register addresses 256M of virtual memory.

At the time bei

powerpc/32s: Rework Kernel Userspace Access Protection

On book3s/32, KUAP is provided by toggling Ks bit in segment registers.
One segment register addresses 256M of virtual memory.

At the time being, KUAP implements a complex logic to apply the
unlock/lock on the exact number of segments covering the user range
to access, with saving the boundaries of the range of segments in
a member of thread struct.

But most if not all user accesses are within a single segment.

Rework KUAP with a different approach:
- Open only one segment, the one corresponding to the starting
address of the range to be accessed.
- If a second segment is involved, it will generate a page fault. The
segment will then be open by the page fault handler.

The kuap member of thread struct will now contain:
- The start address of the current on going user access, that will be
used to know which segment to lock at the end of the user access.
- ~0 when no user access is open
- ~1 when additionnal segments are opened by a page fault.

Then, at lock time
- When only one segment is open, close it.
- When several segments are open, close all user segments.

Almost 100% of the time, only one segment will be involved.

In interrupts, inline the function that unlock/lock all segments,
because not inlining them implies a lot of register save/restore.

With the patch, writing value 128 in userspace in perf_copy_attr() is
done with 16 instructions:

3890: 93 82 04 dc stw r28,1244(r2)
3894: 7d 20 e5 26 mfsrin r9,r28
3898: 55 29 00 80 rlwinm r9,r9,0,2,0
389c: 7d 20 e1 e4 mtsrin r9,r28
38a0: 4c 00 01 2c isync

38a4: 39 20 00 80 li r9,128
38a8: 91 3c 00 00 stw r9,0(r28)

38ac: 81 42 04 dc lwz r10,1244(r2)
38b0: 39 00 ff ff li r8,-1
38b4: 91 02 04 dc stw r8,1244(r2)
38b8: 2c 0a ff fe cmpwi r10,-2
38bc: 41 82 00 88 beq 3944 <perf_copy_attr+0x36c>
38c0: 7d 20 55 26 mfsrin r9,r10
38c4: 65 29 40 00 oris r9,r9,16384
38c8: 7d 20 51 e4 mtsrin r9,r10
38cc: 4c 00 01 2c isync
...
3944: 48 00 00 01 bl 3944 <perf_copy_attr+0x36c>
3944: R_PPC_REL24 kuap_lock_all_ool

Before the patch it was 118 instructions. In reality only 42 are
executed in most cases, but GCC is not able to see that a properly
aligned user access cannot involve more than one segment.

5060: 39 1d 00 04 addi r8,r29,4
5064: 3d 20 b0 00 lis r9,-20480
5068: 7c 08 48 40 cmplw r8,r9
506c: 40 81 00 08 ble 5074 <perf_copy_attr+0x2cc>
5070: 3d 00 b0 00 lis r8,-20480
5074: 39 28 ff ff addi r9,r8,-1
5078: 57 aa 00 06 rlwinm r10,r29,0,0,3
507c: 55 29 27 3e rlwinm r9,r9,4,28,31
5080: 39 29 00 01 addi r9,r9,1
5084: 7d 29 53 78 or r9,r9,r10
5088: 91 22 04 dc stw r9,1244(r2)
508c: 7d 20 ed 26 mfsrin r9,r29
5090: 55 29 00 80 rlwinm r9,r9,0,2,0
5094: 7c 08 50 40 cmplw r8,r10
5098: 40 81 00 c0 ble 5158 <perf_copy_attr+0x3b0>
509c: 7d 46 50 f8 not r6,r10
50a0: 7c c6 42 14 add r6,r6,r8
50a4: 54 c6 27 be rlwinm r6,r6,4,30,31
50a8: 7d 20 51 e4 mtsrin r9,r10
50ac: 3c ea 10 00 addis r7,r10,4096
50b0: 39 29 01 11 addi r9,r9,273
50b4: 7f 88 38 40 cmplw cr7,r8,r7
50b8: 55 29 02 06 rlwinm r9,r9,0,8,3
50bc: 40 9d 00 9c ble cr7,5158 <perf_copy_attr+0x3b0>

50c0: 2f 86 00 00 cmpwi cr7,r6,0
50c4: 41 9e 00 4c beq cr7,5110 <perf_copy_attr+0x368>
50c8: 2f 86 00 01 cmpwi cr7,r6,1
50cc: 41 9e 00 2c beq cr7,50f8 <perf_copy_attr+0x350>
50d0: 2f 86 00 02 cmpwi cr7,r6,2
50d4: 41 9e 00 14 beq cr7,50e8 <perf_copy_attr+0x340>
50d8: 7d 20 39 e4 mtsrin r9,r7
50dc: 39 29 01 11 addi r9,r9,273
50e0: 3c e7 10 00 addis r7,r7,4096
50e4: 55 29 02 06 rlwinm r9,r9,0,8,3
50e8: 7d 20 39 e4 mtsrin r9,r7
50ec: 39 29 01 11 addi r9,r9,273
50f0: 3c e7 10 00 addis r7,r7,4096
50f4: 55 29 02 06 rlwinm r9,r9,0,8,3
50f8: 7d 20 39 e4 mtsrin r9,r7
50fc: 3c e7 10 00 addis r7,r7,4096
5100: 39 29 01 11 addi r9,r9,273
5104: 7f 88 38 40 cmplw cr7,r8,r7
5108: 55 29 02 06 rlwinm r9,r9,0,8,3
510c: 40 9d 00 4c ble cr7,5158 <perf_copy_attr+0x3b0>
5110: 7d 20 39 e4 mtsrin r9,r7
5114: 39 29 01 11 addi r9,r9,273
5118: 3c c7 10 00 addis r6,r7,4096
511c: 55 29 02 06 rlwinm r9,r9,0,8,3
5120: 7d 20 31 e4 mtsrin r9,r6
5124: 39 29 01 11 addi r9,r9,273
5128: 3c c6 10 00 addis r6,r6,4096
512c: 55 29 02 06 rlwinm r9,r9,0,8,3
5130: 7d 20 31 e4 mtsrin r9,r6
5134: 39 29 01 11 addi r9,r9,273
5138: 3c c7 30 00 addis r6,r7,12288
513c: 55 29 02 06 rlwinm r9,r9,0,8,3
5140: 7d 20 31 e4 mtsrin r9,r6
5144: 3c e7 40 00 addis r7,r7,16384
5148: 39 29 01 11 addi r9,r9,273
514c: 7f 88 38 40 cmplw cr7,r8,r7
5150: 55 29 02 06 rlwinm r9,r9,0,8,3
5154: 41 9d ff bc bgt cr7,5110 <perf_copy_attr+0x368>

5158: 4c 00 01 2c isync
515c: 39 20 00 80 li r9,128
5160: 91 3d 00 00 stw r9,0(r29)

5164: 38 e0 00 00 li r7,0
5168: 90 e2 04 dc stw r7,1244(r2)
516c: 7d 20 ed 26 mfsrin r9,r29
5170: 65 29 40 00 oris r9,r9,16384
5174: 40 81 00 c0 ble 5234 <perf_copy_attr+0x48c>
5178: 7d 47 50 f8 not r7,r10
517c: 7c e7 42 14 add r7,r7,r8
5180: 54 e7 27 be rlwinm r7,r7,4,30,31
5184: 7d 20 51 e4 mtsrin r9,r10
5188: 3d 4a 10 00 addis r10,r10,4096
518c: 39 29 01 11 addi r9,r9,273
5190: 7c 08 50 40 cmplw r8,r10
5194: 55 29 02 06 rlwinm r9,r9,0,8,3
5198: 40 81 00 9c ble 5234 <perf_copy_attr+0x48c>

519c: 2c 07 00 00 cmpwi r7,0
51a0: 41 82 00 4c beq 51ec <perf_copy_attr+0x444>
51a4: 2c 07 00 01 cmpwi r7,1
51a8: 41 82 00 2c beq 51d4 <perf_copy_attr+0x42c>
51ac: 2c 07 00 02 cmpwi r7,2
51b0: 41 82 00 14 beq 51c4 <perf_copy_attr+0x41c>
51b4: 7d 20 51 e4 mtsrin r9,r10
51b8: 39 29 01 11 addi r9,r9,273
51bc: 3d 4a 10 00 addis r10,r10,4096
51c0: 55 29 02 06 rlwinm r9,r9,0,8,3
51c4: 7d 20 51 e4 mtsrin r9,r10
51c8: 39 29 01 11 addi r9,r9,273
51cc: 3d 4a 10 00 addis r10,r10,4096
51d0: 55 29 02 06 rlwinm r9,r9,0,8,3
51d4: 7d 20 51 e4 mtsrin r9,r10
51d8: 3d 4a 10 00 addis r10,r10,4096
51dc: 39 29 01 11 addi r9,r9,273
51e0: 7c 08 50 40 cmplw r8,r10
51e4: 55 29 02 06 rlwinm r9,r9,0,8,3
51e8: 40 81 00 4c ble 5234 <perf_copy_attr+0x48c>
51ec: 7d 20 51 e4 mtsrin r9,r10
51f0: 39 29 01 11 addi r9,r9,273
51f4: 3c ea 10 00 addis r7,r10,4096
51f8: 55 29 02 06 rlwinm r9,r9,0,8,3
51fc: 7d 20 39 e4 mtsrin r9,r7
5200: 39 29 01 11 addi r9,r9,273
5204: 3c e7 10 00 addis r7,r7,4096
5208: 55 29 02 06 rlwinm r9,r9,0,8,3
520c: 7d 20 39 e4 mtsrin r9,r7
5210: 39 29 01 11 addi r9,r9,273
5214: 3c ea 30 00 addis r7,r10,12288
5218: 55 29 02 06 rlwinm r9,r9,0,8,3
521c: 7d 20 39 e4 mtsrin r9,r7
5220: 3d 4a 40 00 addis r10,r10,16384
5224: 39 29 01 11 addi r9,r9,273
5228: 7c 08 50 40 cmplw r8,r10
522c: 55 29 02 06 rlwinm r9,r9,0,8,3
5230: 41 81 ff bc bgt 51ec <perf_copy_attr+0x444>

5234: 4c 00 01 2c isync

Signed-off-by: Christophe Leroy <[email protected]>
[mpe: Export the ool handlers to fix build errors]
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/d9121f96a7c4302946839a0771f5d1daeeb6968c.1622708530.git.christophe.leroy@csgroup.eu

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powerpc/64s: power4 nap fixup in C

There is no need for this to be in asm, use the new intrrupt entry wrapper.

Signed-off-by: Nicholas Piggin <[email protected]>
Tested-by: Andreas Schwab <schwab@l

powerpc/64s: power4 nap fixup in C

There is no need for this to be in asm, use the new intrrupt entry wrapper.

Signed-off-by: Nicholas Piggin <[email protected]>
Tested-by: Andreas Schwab <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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powerpc/math: Fix missing __user qualifier for get_user() and other sparse warnings

Sparse reports the following problems:

arch/powerpc/math-emu/math.c:228:21: warning: Using plain integer as NULL

powerpc/math: Fix missing __user qualifier for get_user() and other sparse warnings

Sparse reports the following problems:

arch/powerpc/math-emu/math.c:228:21: warning: Using plain integer as NULL pointer
arch/powerpc/math-emu/math.c:228:31: warning: Using plain integer as NULL pointer
arch/powerpc/math-emu/math.c:228:41: warning: Using plain integer as NULL pointer
arch/powerpc/math-emu/math.c:228:51: warning: Using plain integer as NULL pointer
arch/powerpc/math-emu/math.c:237:13: warning: incorrect type in initializer (different address spaces)
arch/powerpc/math-emu/math.c:237:13: expected unsigned int [noderef] __user *_gu_addr
arch/powerpc/math-emu/math.c:237:13: got unsigned int [usertype] *
arch/powerpc/math-emu/math.c:226:1: warning: symbol 'do_mathemu' was not declared. Should it be static?

Add missing __user qualifier when casting pointer used in get_user()

Use NULL instead of 0 to initialise opX local variables.

Add a prototype for do_mathemu() (Added in processor.h like sparc)

Reported-by: kernel test robot <[email protected]>
Signed-off-by: Christophe Leroy <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/e4d1aae7604d89c98a52dfd8ce8443462e595670.1615809591.git.christophe.leroy@csgroup.eu

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powerpc/32: Always enable data translation in exception prolog

If the code can use a stack in vm area, it can also use a
stack in linear space.

Simplify code by removing old non VMAP stack code on

powerpc/32: Always enable data translation in exception prolog

If the code can use a stack in vm area, it can also use a
stack in linear space.

Simplify code by removing old non VMAP stack code on PPC32.

That means the data translation is now re-enabled early in
exception prolog in all cases, not only when using VMAP stacks.

While we are touching EXCEPTION_PROLOG macros, remove the
unused for_rtas parameter in EXCEPTION_PROLOG_1.

Signed-off-by: Christophe Leroy <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/7cd6440c60a7e8f4f035b245c57720f51e225aae.1615552866.git.christophe.leroy@csgroup.eu

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powerpc/32: Remove ksp_limit

ksp_limit is there to help detect stack overflows.
That is specific to ppc32 as it was removed from ppc64 in
commit cbc9565ee826 ("powerpc: Remove ksp_limit on ppc64").

powerpc/32: Remove ksp_limit

ksp_limit is there to help detect stack overflows.
That is specific to ppc32 as it was removed from ppc64 in
commit cbc9565ee826 ("powerpc: Remove ksp_limit on ppc64").

There are other means for detecting stack overflows.

As ppc64 has proven to not need it, ppc32 should be able to do
without it too.

Lets remove it and simplify exception handling.

Signed-off-by: Christophe Leroy <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/d789c3385b22e07bedc997613c0d26074cb513e7.1615552866.git.christophe.leroy@csgroup.eu

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powerpc/book3s64/pkeys: Don't update SPRN_AMR when in kernel mode.

Now that kernel correctly store/restore userspace AMR/IAMR values, avoid
manipulating AMR and IAMR from the kernel on behalf of use

powerpc/book3s64/pkeys: Don't update SPRN_AMR when in kernel mode.

Now that kernel correctly store/restore userspace AMR/IAMR values, avoid
manipulating AMR and IAMR from the kernel on behalf of userspace.

Signed-off-by: Aneesh Kumar K.V <[email protected]>
Reviewed-by: Sandipan Das <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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powerpc/signal: Remove get_clean_sp()

get_clean_sp() is only used once in kernel/signal.c .

GCC is smart enough to see that x & 0xffffffff is a nop
calculation on PPC32, no need of a special PPC32

powerpc/signal: Remove get_clean_sp()

get_clean_sp() is only used once in kernel/signal.c .

GCC is smart enough to see that x & 0xffffffff is a nop
calculation on PPC32, no need of a special PPC32 trivial version.

Include the logic from the PPC64 version of get_clean_sp() directly
in get_sigframe().

Signed-off-by: Christophe Leroy <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/13ef6510ce30a4867e043157b93af5bb8c67fb3b.1597770847.git.christophe.leroy@csgroup.eu

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