linux.git/arch/powerpc/kernel/Makefile, branch vsnprintf

powerpc: Replace kretprobe code with rethook on powerpc

2024-09-05T12:25:36+00:00

This is an adaptation of commit f3a112c0c40d ("x86,rethook,kprobes:
Replace kretprobe with rethook on x86") to powerpc.

Rethook follows the existing kretprobe implementation, but separates
it from kprobes so that it can be used by fprobe (ftrace-based
function entry/exit probes). As such, this patch also enables fprobe
to work on powerpc. The only other change compared to the existing
kretprobe implementation is doing the return address fixup in
arch_rethook_fixup_return().

Reference to other archs:
commit b57c2f124098 ("riscv: add riscv rethook implementation")
commit 7b0a096436c2 ("LoongArch: Replace kretprobe with rethook")

Note:
=====

In future, rethook will be only for kretprobe, and kretprobe
will be replaced by fprobe.

https://lore.kernel.org/all/172000134410.63468.13742222887213469474.stgit@devnote2/

We will	adapt the above	implementation for powerpc once its upstream.
Until then, we can have	this implementation of rethook to serve
current	kretprobe usecases.

Reviewed-by: Naveen Rao 
Signed-off-by: Abhishek Dubey 
Signed-off-by: Michael Ellerman 
Link: https://msgid.link/20240830113131.7597-1-adubey@linux.ibm.com

powerpc: Remove core support for 40x

2024-06-28T12:28:47+00:00

Now that 40x platforms have gone, remove support
for 40x in the core of powerpc arch.

Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://msgid.link/20240628121201.130802-4-mpe@ellerman.id.au

powerpc/Makefile: Remove bits related to the previous use of -mcmodel=large

2024-05-07T13:48:45+00:00

All supported compilers today (gcc v5.1+ and clang v11+) have support for
-mcmodel=medium. As such, NO_MINIMAL_TOC is no longer being set. Remove
NO_MINIMAL_TOC as well as the fallback to -mminimal-toc.

Reviewed-by: Christophe Leroy 
Signed-off-by: Naveen N Rao 
Signed-off-by: Michael Ellerman 
Link: https://msgid.link/20240110141237.3179199-1-naveen@kernel.org

powerpc: remove unused *_syscall_64.o variables in Makefile

2024-05-07T12:46:23+00:00

Commit ab1a517d55b0 ("powerpc/syscall: Rename syscall_64.c into
interrupt.c") missed to update these three lines:

  GCOV_PROFILE_syscall_64.o := n
  KCOV_INSTRUMENT_syscall_64.o := n
  UBSAN_SANITIZE_syscall_64.o := n

To restore the original behavior, we could replace them with:

  GCOV_PROFILE_interrupt.o := n
  KCOV_INSTRUMENT_interrupt.o := n
  UBSAN_SANITIZE_interrupt.o := n

However, nobody has noticed the functional change in the past three
years, so they were unneeded.

Signed-off-by: Masahiro Yamada 
Signed-off-by: Michael Ellerman 
Link: https://msgid.link/20240216135517.2002749-1-masahiroy@kernel.org

powerpc/dexcr: Reset DEXCR value across exec

2024-05-03T10:46:51+00:00

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 
[mpe: Add missing SPDX tag on dexcr.c]
Signed-off-by: Michael Ellerman 
Link: https://msgid.link/20240417112325.728010-4-bgray@linux.ibm.com

powerpc: remove unused KCSAN_SANITIZE_early_64.o in Makefile

2024-02-19T05:16:58+00:00

Commit 2fb857bc9f9e ("powerpc/kcsan: Add exclusions from instrumentation")
added KCSAN_SANITIZE_early_64.o to arch/powerpc/kernel/Makefile, while
it does not compile early_64.o.

Signed-off-by: Masahiro Yamada 
Signed-off-by: Michael Ellerman 
Link: https://msgid.link/20240216135817.2003106-1-masahiroy@kernel.org

powerpc/64: Rename entry_64.S to prom_entry_64.S

2023-06-15T04:04:19+00:00

This file contains only the enter_prom implementation now.
Trim includes and update header comment while we're here.

Signed-off-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Link: https://msgid.link/20230606132447.315714-7-npiggin@gmail.com

powerpc: merge 32-bit and 64-bit _switch implementation

2023-06-15T04:03:55+00:00

The _switch stack frame setup are substantially the same, so are the
comments. The difference in how the stack and current are switched,
and other hardware and software housekeeping is done is moved into
macros.

Generated code should be unchanged.

Signed-off-by: Nicholas Piggin 
[mpe: Tweak include orer to fix compile errors on some configs]
Signed-off-by: Michael Ellerman 
Link: https://msgid.link/20230606132447.315714-6-npiggin@gmail.com

powerpc/kcsan: Add exclusions from instrumentation

2023-02-10T11:19:56+00:00

Exclude various incompatible compilation units from KCSAN
instrumentation.

Signed-off-by: Rohan McLure 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20230206021801.105268-2-rmclure@linux.ibm.com

powerpc/32: fix syscall wrappers with 64-bit arguments of unaligned register-pairs

2022-10-12T13:49:58+00:00

powerpc 32-bit system call (and function) calling convention for 64-bit
arguments requires the next available odd-pair (two sequential registers
with the first being odd-numbered) from the standard register argument
allocation.

The first argument register is r3, so a 64-bit argument that appears at
an even position in the argument list must skip a register (unless there
were preceding 64-bit arguments, which might throw things off). This
requires non-standard compat definitions to deal with the holes in the
argument register allocation.

With pt_regs syscall wrappers which use a standard mapper to map pt_regs
GPRs to function arguments, 32-bit kernels hit the same basic problem,
the standard definitions don't cope with the unused argument registers.

Fix this by having 32-bit kernels share those syscall definitions with
compat.

Thanks to Jason for spending a lot of time finding and bisecting this
and developing a trivial reproducer. The perfect bug report.

Reported-by: Jason A. Donenfeld 
Signed-off-by: Nicholas Piggin 
Fixes: 7e92e01b72452 ("powerpc: Provide syscall wrapper")
Reviewed-by: Arnd Bergmann 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20221012035335.866440-1-npiggin@gmail.com