kernel/linux.git/Documentation/powerpc, branch v6.1.168

powerpc/64s: update cpu selection options

2022-09-28T09:22:10+00:00

Update the 64s GENERIC_CPU option. POWER4 support has been dropped, so make that clear in the option name. The POWER5_CPU option is dropped because it's uncommon, and GENERIC_CPU covers it. -mtune= before power8 is dropped because the minimum gcc version supports power8, and tuning is made consistent between big and little endian. A 970 option is added for PowerPC 970 / G5 because they still have a user base, and -mtune=power8 does not generate good code for the 970. This also updates the ISA versions document to add Power4/Power4+ because I didn't realise Power4+ used 2.01. Signed-off-by: Nicholas Piggin Reviewed-by: Segher Boessenkool Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220921014103.587954-2-npiggin@gmail.com

powerpc: Update ISA versions to mention e5500/e6500

2022-08-26T01:02:20+00:00

Add the NXP (nee Freescale) e5500 and e6500 to the ISA versions documentation. Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220803063228.1250030-1-mpe@ellerman.id.au

docs: powerpc: add elf_hwcaps to table of contents

2022-07-28T06:19:47+00:00

elf_hwcaps documentation is missing from table of contents at index.rst, hence triggers Sphinx warning: Documentation/powerpc/elf_hwcaps.rst: WARNING: document isn't included in any toctree Add the documentation to the index to fix the warning. Fixes: 3df1ff42e69e91 ("powerpc: add documentation for HWCAPs") Reported-by: Stephen Rothwell Signed-off-by: Bagas Sanjaya Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/linuxppc-dev/20220727220050.549db613@canb.auug.org.au/ Link: https://lore.kernel.org/r/20220728033332.27836-4-bagasdotme@gmail.com

docs: powerpc: use different label name for elf_hwcaps.rst

2022-07-28T06:19:37+00:00

Sphinx reported duplicate label warning: WARNING: duplicate label elf_hwcaps_index, other instance in Documentation/arm64/elf_hwcaps.rst The warning is caused by elf_hwcaps_index label name is already used for arm64 documentation, whileas powerpc use the same name. Disambiguate the label name for powerpc. Fixes: 3df1ff42e69e91 ("powerpc: add documentation for HWCAPs") Reported-by: Stephen Rothwell Signed-off-by: Bagas Sanjaya Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/linuxppc-dev/20220727220050.549db613@canb.auug.org.au/ Link: https://lore.kernel.org/r/20220728033332.27836-3-bagasdotme@gmail.com

docs: powerpc: fix indentation warnings

2022-07-28T06:19:32+00:00

Sphinx reported unexpected indentation warnings: Documentation/powerpc/elf_hwcaps.rst:82: WARNING: Unexpected indentation. Documentation/powerpc/elf_hwcaps.rst:100: WARNING: Unexpected indentation. Documentation/powerpc/elf_hwcaps.rst:117: WARNING: Unexpected indentation. Documentation/powerpc/elf_hwcaps.rst:122: WARNING: Unexpected indentation. Documentation/powerpc/elf_hwcaps.rst:144: WARNING: Unexpected indentation. Fix these warnings by unindenting commit references and using literal code block for instructions list for PPC_FEATURE_ICACHE_SNOOP. Fixes: 3df1ff42e69e91 ("powerpc: add documentation for HWCAPs") Reported-by: Stephen Rothwell Signed-off-by: Bagas Sanjaya Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/linuxppc-dev/20220727220050.549db613@canb.auug.org.au/ Link: https://lore.kernel.org/r/20220728033332.27836-2-bagasdotme@gmail.com

powerpc: add documentation for HWCAPs

2022-07-27T11:36:04+00:00

Take the arm64 HWCAP documentation file and adjust it for powerpc. Signed-off-by: Nicholas Piggin Reviewed-by: Segher Boessenkool [mpe: Fix ARCH_2_05 comment, as noticed by Tulio.] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220715012636.165948-1-npiggin@gmail.com

powerpc: Enable the DAWR on POWER9 DD2.3 and above

2022-05-22T05:59:53+00:00

The hardware bug in POWER9 preventing use of the DAWR was fixed in DD2.3. Set the CPU_FTR_DAWR feature bit on these newer systems to start using it again, and update the documentation accordingly. The CPU features for DD2.3 are currently determined by "DD2.2 or later" logic. In adding DD2.3 as a discrete case for the first time here, I'm carrying the quirks of DD2.2 forward to keep all behavior outside of this DAWR change the same. This leaves the assessment and potential removal of those quirks on DD2.3 for later. Signed-off-by: Reza Arbab Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220503170152.23412-1-arbab@linux.ibm.com

powerpc: Book3S 64-bit outline-only KASAN support

2022-05-22T05:58:29+00:00

Implement a limited form of KASAN for Book3S 64-bit machines running under the Radix MMU, supporting only outline mode. - Enable the compiler instrumentation to check addresses and maintain the shadow region. (This is the guts of KASAN which we can easily reuse.) - Require kasan-vmalloc support to handle modules and anything else in vmalloc space. - KASAN needs to be able to validate all pointer accesses, but we can't instrument all kernel addresses - only linear map and vmalloc. On boot, set up a single page of read-only shadow that marks all iomap and vmemmap accesses as valid. - Document KASAN in powerpc docs. Background ---------- KASAN support on Book3S is a bit tricky to get right: - It would be good to support inline instrumentation so as to be able to catch stack issues that cannot be caught with outline mode. - Inline instrumentation requires a fixed offset. - Book3S runs code with translations off ("real mode") during boot, including a lot of generic device-tree parsing code which is used to determine MMU features. [ppc64 mm note: The kernel installs a linear mapping at effective address c000...-c008.... This is a one-to-one mapping with physical memory from 0000... onward. Because of how memory accesses work on powerpc 64-bit Book3S, a kernel pointer in the linear map accesses the same memory both with translations on (accessing as an 'effective address'), and with translations off (accessing as a 'real address'). This works in both guests and the hypervisor. For more details, see s5.7 of Book III of version 3 of the ISA, in particular the Storage Control Overview, s5.7.3, and s5.7.5 - noting that this KASAN implementation currently only supports Radix.] - Some code - most notably a lot of KVM code - also runs with translations off after boot. - Therefore any offset has to point to memory that is valid with translations on or off. One approach is just to give up on inline instrumentation. This way boot-time checks can be delayed until after the MMU is set is up, and we can just not instrument any code that runs with translations off after booting. Take this approach for now and require outline instrumentation. Previous attempts allowed inline instrumentation. However, they came with some unfortunate restrictions: only physically contiguous memory could be used and it had to be specified at compile time. Maybe we can do better in the future. [paulus@ozlabs.org - Rebased onto 5.17. Note that a kernel with CONFIG_KASAN=y will crash during boot on a machine using HPT translation because not all the entry points to the generic KASAN code are protected with a call to kasan_arch_is_ready().] Originally-by: Balbir Singh # ppc64 out-of-line radix version Signed-off-by: Daniel Axtens Signed-off-by: Paul Mackerras [mpe: Update copyright year and comment formatting] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/YoTE69OQwiG7z+Gu@cleo

kasan: Document support on 32-bit powerpc

2022-05-22T05:58:29+00:00

KASAN is supported on 32-bit powerpc and the docs should reflect this. Suggested-by: Christophe Leroy Signed-off-by: Daniel Axtens Signed-off-by: Paul Mackerras Reviewed-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/YoTEnMLrnd64j0w5@cleo

powerpc/doc: Fix htmldocs errors

2021-08-26T14:56:34+00:00

Fix make htmldocs related errors with the newly added associativity.rst doc file. Reported-by: Stephen Rothwell Tested-by: Stephen Rothwell # build test Signed-off-by: Aneesh Kumar K.V Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20210825042447.106219-1-aneesh.kumar@linux.ibm.com