linux-toradex.git/arch/powerpc/kernel/paca.c, branch v6.7

docs: move powerpc under arch

2023-10-10T19:35:55+00:00

and fix all in-tree references.

Architecture-specific documentation is being moved into Documentation/arch/
as a way of cleaning up the top-level documentation directory and making
the docs hierarchy more closely match the source hierarchy.

Signed-off-by: Costa Shulyupin 
Acked-by: Michael Ellerman 
Signed-off-by: Jonathan Corbet 
Link: https://lore.kernel.org/r/20230826165737.2101199-1-costa.shul@redhat.com

powerpc/64: vmlinux support building with PCREL addresing

2023-04-20T02:59:21+00:00

PC-Relative or PCREL addressing is an extension to the ELF ABI which
uses Power ISA v3.1 PC-relative instructions to calculate addresses,
rather than the traditional TOC scheme.

Add an option to build vmlinux using pcrel addressing. Modules continue
to use TOC addressing.

- TOC address helpers and r2 are poisoned with -1 when running vmlinux.
  r2 could be used for something useful once things are ironed out.

- Assembly must call C functions with @notoc annotation, or the linker
  complains aobut a missing nop after the call. This is done with the
  CFUNC macro introduced earlier.

- Boot: with the exception of prom_init, the execution branches to the
  kernel virtual address early in boot, before any addresses are
  generated, which ensures 34-bit pcrel addressing does not miss the
  high PAGE_OFFSET bits. TOC relative addressing has a similar
  requirement. prom_init does not go to the virtual address and its
  addresses should not carry over to the post-prom kernel.

- Ftrace trampolines are converted from TOC addressing to pcrel
  addressing, including module ftrace trampolines that currently use the
  kernel TOC to find ftrace target functions.

- BPF function prologue and function calling generation are converted
  from TOC to pcrel.

- copypage_64.S has an interesting problem, prefixed instructions have
  alignment restrictions so the linker can add padding, which makes the
  assembler treat the difference between two local labels as
  non-constant even if alignment is arranged so padding is not required.
  This may need toolchain help to solve nicely, for now move the prefix
  instruction out of the alternate patch section to work around it.

This reduces kernel text size by about 6%.

Signed-off-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Link: https://msgid.link/20230408021752.862660-6-npiggin@gmail.com

powerpc: Remove CONFIG_PPC_BOOK3E

2022-09-26T13:00:13+00:00

CONFIG_PPC_BOOK3E is redundant with CONFIG_PPC_BOOK3E_64.

The later is more explicit about the fact that it's a 64 bits target.

Remove CONFIG_PPC_BOOK3E.

Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/5d0891490813c19cdcfc04678f512ea68cba3e64.1663606876.git.christophe.leroy@csgroup.eu

Revert "powerpc/rtas: Implement reentrant rtas call"

2022-09-14T12:43:13+00:00

At the time this was submitted by Leonardo, I confirmed -- or thought
I had confirmed -- with PowerVM partition firmware development that
the following RTAS functions:

- ibm,get-xive
- ibm,int-off
- ibm,int-on
- ibm,set-xive

were safe to call on multiple CPUs simultaneously, not only with
respect to themselves as indicated by PAPR, but with arbitrary other
RTAS calls:

https://lore.kernel.org/linuxppc-dev/875zcy2v8o.fsf@linux.ibm.com/

Recent discussion with firmware development makes it clear that this
is not true, and that the code in commit b664db8e3f97 ("powerpc/rtas:
Implement reentrant rtas call") is unsafe, likely explaining several
strange bugs we've seen in internal testing involving DLPAR and
LPM. These scenarios use ibm,configure-connector, whose internal state
can be corrupted by the concurrent use of the "reentrant" functions,
leading to symptoms like endless busy statuses from RTAS.

Fixes: b664db8e3f97 ("powerpc/rtas: Implement reentrant rtas call")
Cc: stable@vger.kernel.org # v5.8+
Signed-off-by: Nathan Lynch 
Reviewed-by: Laurent Dufour 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20220907220111.223267-1-nathanl@linux.ibm.com

powerpc/mm: Remove CONFIG_PPC_MM_SLICES

2022-05-05T12:11:57+00:00

CONFIG_PPC_MM_SLICES is always selected by hash book3s/64.
CONFIG_PPC_MM_SLICES is never selected by other platforms.

Remove it.

Signed-off-by: Christophe Leroy 
Reviewed-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/dc2cdc204de8978574bf7c02329b6cfc4db0bce7.1649523076.git.christophe.leroy@csgroup.eu

powerpc/64s: Move hash MMU support code under CONFIG_PPC_64S_HASH_MMU

2021-12-09T11:41:13+00:00

Compiling out hash support code when CONFIG_PPC_64S_HASH_MMU=n saves
128kB kernel image size (90kB text) on powernv_defconfig minus KVM,
350kB on pseries_defconfig minus KVM, 40kB on a tiny config.

Signed-off-by: Nicholas Piggin 
[mpe: Fixup defined(ARCH_HAS_MEMREMAP_COMPAT_ALIGN), which needs CONFIG.
      Fix radix_enabled() use in setup_initial_memory_limit(). Add some
      stubs to reduce number of ifdefs.]
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20211201144153.2456614-18-npiggin@gmail.com

memblock: rename memblock_free to memblock_phys_free

2021-11-06T20:30:41+00:00

Since memblock_free() operates on a physical range, make its name
reflect it and rename it to memblock_phys_free(), so it will be a
logical counterpart to memblock_phys_alloc().

The callers are updated with the below semantic patch:

    @@
    expression addr;
    expression size;
    @@
    - memblock_free(addr, size);
    + memblock_phys_free(addr, size);

Link: https://lkml.kernel.org/r/20210930185031.18648-6-rppt@kernel.org
Signed-off-by: Mike Rapoport 
Cc: Christophe Leroy 
Cc: Juergen Gross 
Cc: Shahab Vahedi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

powerpc/paca: Remove mm_ctx_id and mm_ctx_slb_addr_limit

2021-05-17T05:27:15+00:00

mm_ctx_id and mm_ctx_slb_addr_limit are not used anymore.

Remove them.

Signed-off-by: Christophe Leroy 
Reviewed-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/6e1813953da38c452c131fe3e2a2761a0fddb975.1620223303.git.christophe.leroy@csgroup.eu

powerpc: Avoid broken GCC attribute((optimize))

2020-11-19T03:50:14+00:00

Commit 7053f80d9696 ("powerpc/64: Prevent stack protection in early
boot") introduced a couple of uses of __attribute__((optimize)) with
function scope, to disable the stack protector in some early boot
code.

Unfortunately, and this is documented in the GCC man pages [0],
overriding function attributes for optimization is broken, and is only
supported for debug scenarios, not for production: the problem appears
to be that setting GCC -f flags using this method will cause it to
forget about some or all other optimization settings that have been
applied.

So the only safe way to disable the stack protector is to disable it
for the entire source file.

[0] https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html

Fixes: 7053f80d9696 ("powerpc/64: Prevent stack protection in early boot")
Signed-off-by: Ard Biesheuvel 
[mpe: Drop one remaining use of __nostackprotector, reported by snowpatch]
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20201028080433.26799-1-ardb@kernel.org

Merge branch 'fixes' into next

2020-07-18T12:43:55+00:00

Merge our fixes branch, primarily to bring in the ebb selftests build
fix and the pkey fix, which is a dependency for some future work.