kernel.git/arch/powerpc/mm/pgtable_32.c, branch master

powerpc/32: Remove PAGE_KERNEL_TEXT to fix startup failure

2025-09-16T10:46:00Z

PAGE_KERNEL_TEXT is an old macro that is used to tell kernel whether kernel text has to be mapped read-only or read-write based on build time options. But nowadays, with functionnalities like jump_labels, static links, etc ... more only less all kernels need to be read-write at some point, and some combinations of configs failed to work due to innacurate setting of PAGE_KERNEL_TEXT. On the other hand, today we have CONFIG_STRICT_KERNEL_RWX which implements a more controlled access to kernel modifications. Instead of trying to keep PAGE_KERNEL_TEXT accurate with all possible options that may imply kernel text modification, always set kernel text read-write at startup and rely on CONFIG_STRICT_KERNEL_RWX to provide accurate protection. Do this by passing PAGE_KERNEL_X to map_kernel_page() in __maping_ram_chunk() instead of passing PAGE_KERNEL_TEXT. Once this is done, the only remaining user of PAGE_KERNEL_TEXT is mmu_mark_initmem_nx() which uses it in a call to setibat(). As setibat() ignores the RW/RO, we can seamlessly replace PAGE_KERNEL_TEXT by PAGE_KERNEL_X here as well and get rid of PAGE_KERNEL_TEXT completely. Reported-by: Erhard Furtner Closes: https://lore.kernel.org/all/342b4120-911c-4723-82ec-d8c9b03a8aef@mailbox.org/ Signed-off-by: Christophe Leroy Tested-by: Andrew Donnellan Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/8e2d793abf87ae3efb8f6dce10f974ac0eda61b8.1757412205.git.christophe.leroy@csgroup.eu

mm/memblock: add memblock_alloc_or_panic interface

2025-01-26T04:22:38Z

Before SLUB initialization, various subsystems used memblock_alloc to allocate memory. In most cases, when memory allocation fails, an immediate panic is required. To simplify this behavior and reduce repetitive checks, introduce `memblock_alloc_or_panic`. This function ensures that memory allocation failures result in a panic automatically, improving code readability and consistency across subsystems that require this behavior. [guoweikang.kernel@gmail.com: arch/s390: save_area_alloc default failure behavior changed to panic] Link: https://lkml.kernel.org/r/20250109033136.2845676-1-guoweikang.kernel@gmail.com Link: https://lore.kernel.org/lkml/Z2fknmnNtiZbCc7x@kernel.org/ Link: https://lkml.kernel.org/r/20250102072528.650926-1-guoweikang.kernel@gmail.com Signed-off-by: Guo Weikang Acked-by: Geert Uytterhoeven [m68k] Reviewed-by: Alexander Gordeev [s390] Acked-by: Mike Rapoport (Microsoft) Cc: Alexander Gordeev Signed-off-by: Andrew Morton

powerpc/8xx: rework support for 8M pages using contiguous PTE entries

2024-07-12T22:52:17Z

In order to fit better with standard Linux page tables layout, add support for 8M pages using contiguous PTE entries in a standard page table. Page tables will then be populated with 1024 similar entries and two PMD entries will point to that page table. The PMD entries also get a flag to tell it is addressing an 8M page, this is required for the HW tablewalk assistance. Link: https://lkml.kernel.org/r/8693d9a0408371043ca63bf9e4a9c140667af63e.1719928057.git.christophe.leroy@csgroup.eu Signed-off-by: Christophe Leroy Reviewed-by: Oscar Salvador Cc: Jason Gunthorpe Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Peter Xu Signed-off-by: Andrew Morton

powerpc: Handle error in mark_rodata_ro() and mark_initmem_nx()

2024-03-17T02:33:21Z

mark_rodata_ro() and mark_initmem_nx() use functions that can fail like set_memory_nx() and set_memory_ro(), leading to a not protected kernel. In case of failure, panic. Link: https://github.com/KSPP/linux/issues/7 Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://msgid.link/b16329611deb89e1af505d43f0e2a91310584d26.1710587887.git.christophe.leroy@csgroup.eu

Merge tag 'powerpc-6.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

2024-03-16T00:53:48Z

Pull powerpc updates from Michael Ellerman: - Add AT_HWCAP3 and AT_HWCAP4 aux vector entries for future use by glibc - Add support for recognising the Power11 architected and raw PVRs - Add support for nr_cpus=n on the command line where the boot CPU is >= n - Add ppcxx_allmodconfig targets for all 32-bit sub-arches - Other small features, cleanups and fixes Thanks to Akanksha J N, Brian King, Christophe Leroy, Dawei Li, Geoff Levand, Greg Kroah-Hartman, Jan-Benedict Glaw, Kajol Jain, Kunwu Chan, Li zeming, Madhavan Srinivasan, Masahiro Yamada, Nathan Chancellor, Nicholas Piggin, Peter Bergner, Qiheng Lin, Randy Dunlap, Ricardo B. Marliere, Rob Herring, Sathvika Vasireddy, Shrikanth Hegde, Uwe Kleine-König, Vaibhav Jain, and Wen Xiong. * tag 'powerpc-6.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (71 commits) powerpc/macio: Make remove callback of macio driver void returned powerpc/83xx: Fix build failure with FPU=n powerpc/64s: Fix get_hugepd_cache_index() build failure powerpc/4xx: Fix warp_gpio_leds build failure powerpc/amigaone: Make several functions static powerpc/embedded6xx: Fix no previous prototype for avr_uart_send() etc. macintosh/adb: make adb_dev_class constant powerpc: xor_vmx: Add '-mhard-float' to CFLAGS powerpc/fsl: Fix mfpmr() asm constraint error powerpc: Remove cpu-as-y completely powerpc/fsl: Modernise mt/mfpmr powerpc/fsl: Fix mfpmr build errors with newer binutils powerpc/64s: Use .machine power4 around dcbt powerpc/64s: Move dcbt/dcbtst sequence into a macro powerpc/mm: Code cleanup for __hash_page_thp powerpc/hv-gpci: Fix the H_GET_PERF_COUNTER_INFO hcall return value checks powerpc/irq: Allow softirq to hardirq stack transition powerpc: Stop using of_root powerpc/machdep: Define 'compatibles' property in ppc_md and use it of: Reimplement of_machine_is_compatible() using of_machine_compatible_match() ...

powerpc: Refactor __kernel_map_pages()

2024-03-03T11:18:45Z

__kernel_map_pages() is almost identical for PPC32 and RADIX. Refactor it. On PPC32 it is not needed for KFENCE, but to keep it simple just make it similar to PPC64. Move the prototype of hash__kernel_map_pages() into mmu_decl.h to allow IS_ENABLED() to work on 32-bit. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://msgid.link/3656d47c53bff577739dac536dbae31fff52f6d8.1708078640.git.christophe.leroy@csgroup.eu

arm64, powerpc, riscv, s390, x86: ptdump: refactor CONFIG_DEBUG_WX

2024-02-22T18:24:47Z

All architectures using the core ptdump functionality also implement CONFIG_DEBUG_WX, and they all do it more or less the same way, with a function called debug_checkwx() that is called by mark_rodata_ro(), which is a substitute to ptdump_check_wx() when CONFIG_DEBUG_WX is set and a no-op otherwise. Refactor by centrally defining debug_checkwx() in linux/ptdump.h and call debug_checkwx() immediately after calling mark_rodata_ro() instead of calling it at the end of every mark_rodata_ro(). On x86_32, mark_rodata_ro() first checks __supported_pte_mask has _PAGE_NX before calling debug_checkwx(). Now the check is inside the callee ptdump_walk_pgd_level_checkwx(). On powerpc_64, mark_rodata_ro() bails out early before calling ptdump_check_wx() when the MMU doesn't have KERNEL_RO feature. The check is now also done in ptdump_check_wx() as it is called outside mark_rodata_ro(). Link: https://lkml.kernel.org/r/a59b102d7964261d31ead0316a9f18628e4e7a8e.1706610398.git.christophe.leroy@csgroup.eu Signed-off-by: Christophe Leroy Reviewed-by: Alexandre Ghiti Cc: Albert Ou Cc: Alexander Gordeev Cc: Andy Lutomirski Cc: "Aneesh Kumar K.V (IBM)" Cc: Borislav Petkov (AMD) Cc: Catalin Marinas Cc: Christian Borntraeger Cc: Dave Hansen Cc: Gerald Schaefer Cc: Greg KH Cc: Heiko Carstens Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Kees Cook Cc: Mark Rutland Cc: Michael Ellerman Cc: "Naveen N. Rao" Cc: Nicholas Piggin Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Peter Zijlstra Cc: Phong Tran Cc: Russell King Cc: Steven Price Cc: Sven Schnelle Cc: Thomas Gleixner Cc: Vasily Gorbik Cc: Will Deacon Signed-off-by: Andrew Morton

powerpc: move __end_rodata to cover arch read-only sections

2022-09-26T10:58:16Z

powerpc has a number of read-only sections and tables that are put after RO_DATA(). Move the __end_rodata symbol to cover these as well. Setting memory to read-only at boot is done using __init_begin, change that to use __end_rodata. This makes is_kernel_rodata() exactly cover the read-only region, as well as other things using __end_rodata (e.g., kernel/dma/debug.c). Boot dmesg also prints the rodata size more accurately. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220916040755.2398112-2-npiggin@gmail.com

powerpc/32: Call mmu_mark_initmem_nx() regardless of data block mapping.

2022-07-27T11:36:05Z

mark_initmem_nx() calls either mmu_mark_initmem_nx() or set_memory_attr() based on return from v_block_mapped() of _sinittext. But we can now handle text and data independently, so that text may be mapped by block even when data is mapped by pages. On the 8xx for instance, at startup 32Mbytes of memory are pinned in TLB. So the pinned entries need to go away for sinittext. In next patch a BAT will be set to also covers sinittext on book3s/32. So it will also be needed to call mmu_mark_initmem_nx() even when data above sinittext is not mapped with BATs. As this is highly dependent on the platform, call mmu_mark_initmem_nx() regardless of data block mapping. Then the platform will know what to do. Modify 8xx mmu_mark_initmem_nx() so that inittext mapping is modified only when pagealloc debug and kfence are not active, otherwise inittext is mapped with standard pages. And don't do anything on kernel text which is already mapped with PAGE_KERNEL_TEXT. Fixes: da1adea07576 ("powerpc/8xx: Allow STRICT_KERNEL_RwX with pinned TLB") Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/db3fc14f3bfa6215b0786ef58a6e2bc1e1f964d7.1655202804.git.christophe.leroy@csgroup.eu

powerpc/32s: Enable STRICT_MODULE_RWX for the 603 core

2022-02-12T11:47:42Z

The book3s/32 MMU doesn't support per page execution protection and doesn't support RO protection for kernel pages. However, on the 603 which implements software loaded TLBs, execution protection is honored by the TLB Miss handler which doesn't load Instruction TLB for non executable pages. And RO protection is honored by clearing the C bit for RO pages, leading to DSI. So on the 603, STRICT_MODULE_RWX is possible without much effort. Don't disable STRICT_MODULE_RWX on book3s/32 and print a warning in case STRICT_MODULE_RWX has been selected and the platform has a Hardware HASH MMU. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/1e6162f334167e75f1140082932e3a354b16daba.1642413973.git.christophe.leroy@csgroup.eu