linux-toradex.git/arch/powerpc/lib, branch v5.17

powerpc/lib/sstep: fix 'ptesync' build error

2022-02-15T11:31:35+00:00

Building tinyconfig with gcc (Debian 11.2.0-16) and assembler (Debian
2.37.90.20220207) the following build error shows up:

  {standard input}: Assembler messages:
  {standard input}:2088: Error: unrecognized opcode: `ptesync'
  make[3]: *** [/builds/linux/scripts/Makefile.build:287: arch/powerpc/lib/sstep.o] Error 1

Add the 'ifdef CONFIG_PPC64' around the 'ptesync' in function
'emulate_update_regs()' to like it is in 'analyse_instr()'. Since it looks like
it got dropped inadvertently by commit 3cdfcbfd32b9 ("powerpc: Change
analyse_instr so it doesn't modify *regs").

A key detail is that analyse_instr() will never recognise lwsync or
ptesync on 32-bit (because of the existing ifdef), and as a result
emulate_update_regs() should never be called with an op specifying
either of those on 32-bit. So removing them from emulate_update_regs()
should be a nop in terms of runtime behaviour.

Fixes: 3cdfcbfd32b9 ("powerpc: Change analyse_instr so it doesn't modify *regs")
Cc: stable@vger.kernel.org # v4.14+
Suggested-by: Arnd Bergmann 
Signed-off-by: Anders Roxell 
[mpe: Add last paragraph of change log mentioning analyse_instr() details]
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20220211005113.1361436-1-anders.roxell@linaro.org

powerpc/32: Fix boot failure with GCC latent entropy plugin

2021-12-23T11:36:58+00:00

Boot fails with GCC latent entropy plugin enabled.

This is due to early boot functions trying to access 'latent_entropy'
global data while the kernel is not relocated at its final
destination yet.

As there is no way to tell GCC to use PTRRELOC() to access it,
disable latent entropy plugin in early_32.o and feature-fixups.o and
code-patching.o

Fixes: 38addce8b600 ("gcc-plugins: Add latent_entropy plugin")
Cc: stable@vger.kernel.org # v4.9+
Reported-by: Erhard Furtner 
Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215217
Link: https://lore.kernel.org/r/2bac55483b8daf5b1caa163a45fa5f9cdbe18be4.1640178426.git.christophe.leroy@csgroup.eu

powerpc/code-patching: Replace patch_instruction() by ppc_inst_write() in selftests

2021-12-23T11:36:58+00:00

The purpose of selftests is to check that instructions are
properly formed. Not to check that they properly run.

For that test it uses normal memory, not special test
memory.

In preparation of a future patch enforcing patch_instruction()
to be used only on valid text areas, implement a ppc_inst_write()
instruction which is the complement of ppc_inst_read(). This
new function writes the formated instruction in valid kernel
memory and doesn't bother about icache.

Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/7cf5335cc07ca9b6f8cdaa20ca9887fce4df3bea.1638446239.git.christophe.leroy@csgroup.eu

powerpc/code-patching: Move code patching selftests in its own file

2021-12-23T11:36:58+00:00

Code patching selftests are half of code-patching.c.
As they are guarded by CONFIG_CODE_PATCHING_SELFTESTS,
they'd be better in their own file.

Also add a missing __init for instr_is_branch_to_addr()

Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/c0c30504f04eb546a48ff77127a8bccd12a3d809.1638446239.git.christophe.leroy@csgroup.eu

powerpc/code-patching: Move instr_is_branch_{i/b}form() in code-patching.h

2021-12-23T11:36:58+00:00

To enable moving selftests in their own C file in following patch,
move instr_is_branch_iform() and instr_is_branch_bform()
to code-patching.h

Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/fca0f3b191211b3681020885a611bf73eef20563.1638446239.git.christophe.leroy@csgroup.eu

powerpc/code-patching: Move patch_exception() outside code-patching.c

2021-12-23T11:36:55+00:00

patch_exception() is dedicated to book3e/64 is nothing more than
a normal use of patch_branch(), so move it into a place dedicated
to book3e/64.

Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/0968622b98b1fb51838c35b844c42ad6609de62e.1638446239.git.christophe.leroy@csgroup.eu

powerpc/code-patching: Use test_trampoline for prefixed patch test

2021-12-23T11:35:25+00:00

Use the dedicated test_trampoline function for testing prefixed
patching like other tests and remove the hand coded assembly stuff.

Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/a450ef3f8653f75e1bd9aaf7a3889d379752f33b.1638446239.git.christophe.leroy@csgroup.eu

powerpc/code-patching: Fix patch_branch() return on out-of-range failure

2021-12-23T11:35:24+00:00

Do not silentely ignore a failure of create_branch() in
patch_branch(). Return -ERANGE.

Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/8540cb64b1f06710eaf41e3835c7ba3e21fa2b05.1638446239.git.christophe.leroy@csgroup.eu

powerpc/code-patching: Reorganise do_patch_instruction() to ease error handling

2021-12-23T11:35:24+00:00

Split do_patch_instruction() in two functions, the caller doing the
spin locking and the callee doing everything else.

And remove a few unnecessary initialisations and intermediate
variables.

This allows the callee to return from anywhere in the function.

Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/dbc85980a0d2a935731b272e8907e8bb1d8fc8c5.1638446239.git.christophe.leroy@csgroup.eu

powerpc/code-patching: Fix unmap_patch_area() error handling

2021-12-23T11:35:24+00:00

pXd_offset() doesn't return NULL. When the base is NULL, it
still adds the offset.

Use pXd_none() to check validity instead. It also improves
performance by folding out none existing levels as pXd_none()
always returns 0 in that case.

Such an error is unexpected, use WARN_ON() so that the caller
doesn't have to worry about it, and drop the returned value.

And now that unmap_patch_area() doesn't return error, we can
take into account the error returned by __patch_instruction().

While at it, remove the 'inline' property which is useless.

Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/299804b117fae35c786c827536c91f25352e279b.1638446239.git.christophe.leroy@csgroup.eu