kernel/linux.git/include/asm-generic, branch v5.19.13

vmlinux.lds.h: CFI: Reduce alignment of jump-table to function alignment

2022-09-28T09:32:08+00:00

commit 13b0566962914e167cb3238fbe29ced618f07a27 upstream. Due to undocumented, hysterical raisins on x86, the CFI jump-table sections in .text are needlessly aligned to PMD_SIZE in the vmlinux linker script. When compiling a CFI-enabled arm64 kernel with a 64KiB page-size, a PMD maps 512MiB of virtual memory and so the .text section increases to a whopping 940MiB and blows the final Image up to 960MiB. Others report a link failure. Since the CFI jump-table requires only instruction alignment, reduce the alignment directives to function alignment for parity with other parts of the .text section. This reduces the size of the .text section for the aforementioned 64KiB page size arm64 kernel to 19MiB for a much more reasonable total Image size of 39MiB. Cc: Sami Tolvanen Cc: Mark Rutland Cc: "Mohan Rao .vanimina" Cc: Kees Cook Cc: Nathan Chancellor Cc: Link: https://lore.kernel.org/all/CAL_GTzigiNOMYkOPX1KDnagPhJtFNqSK=1USNbS0wUL4PW6-Uw@mail.gmail.com/ Fixes: cf68fffb66d6 ("add support for Clang CFI") Reviewed-by: Mark Rutland Tested-by: Mark Rutland Reviewed-by: Sami Tolvanen Reviewed-by: Kees Cook Link: https://lore.kernel.org/r/20220922215715.13345-1-will@kernel.org Signed-off-by: Will Deacon Signed-off-by: Greg Kroah-Hartman

asm-generic: sections: refactor memory_intersects

2022-08-31T15:18:14+00:00

commit 0c7d7cc2b4fe2e74ef8728f030f0f1674f9f6aee upstream. There are two problems with the current code of memory_intersects: First, it doesn't check whether the region (begin, end) falls inside the region (virt, vend), that is (virt < begin && vend > end). The second problem is if vend is equal to begin, it will return true but this is wrong since vend (virt + size) is not the last address of the memory region but (virt + size -1) is. The wrong determination will trigger the misreporting when the function check_for_illegal_area calls memory_intersects to check if the dma region intersects with stext region. The misreporting is as below (stext is at 0x80100000): WARNING: CPU: 0 PID: 77 at kernel/dma/debug.c:1073 check_for_illegal_area+0x130/0x168 DMA-API: chipidea-usb2 e0002000.usb: device driver maps memory from kernel text or rodata [addr=800f0000] [len=65536] Modules linked in: CPU: 1 PID: 77 Comm: usb-storage Not tainted 5.19.0-yocto-standard #5 Hardware name: Xilinx Zynq Platform unwind_backtrace from show_stack+0x18/0x1c show_stack from dump_stack_lvl+0x58/0x70 dump_stack_lvl from __warn+0xb0/0x198 __warn from warn_slowpath_fmt+0x80/0xb4 warn_slowpath_fmt from check_for_illegal_area+0x130/0x168 check_for_illegal_area from debug_dma_map_sg+0x94/0x368 debug_dma_map_sg from __dma_map_sg_attrs+0x114/0x128 __dma_map_sg_attrs from dma_map_sg_attrs+0x18/0x24 dma_map_sg_attrs from usb_hcd_map_urb_for_dma+0x250/0x3b4 usb_hcd_map_urb_for_dma from usb_hcd_submit_urb+0x194/0x214 usb_hcd_submit_urb from usb_sg_wait+0xa4/0x118 usb_sg_wait from usb_stor_bulk_transfer_sglist+0xa0/0xec usb_stor_bulk_transfer_sglist from usb_stor_bulk_srb+0x38/0x70 usb_stor_bulk_srb from usb_stor_Bulk_transport+0x150/0x360 usb_stor_Bulk_transport from usb_stor_invoke_transport+0x38/0x440 usb_stor_invoke_transport from usb_stor_control_thread+0x1e0/0x238 usb_stor_control_thread from kthread+0xf8/0x104 kthread from ret_from_fork+0x14/0x2c Refactor memory_intersects to fix the two problems above. Before the 1d7db834a027e ("dma-debug: use memory_intersects() directly"), memory_intersects is called only by printk_late_init: printk_late_init -> init_section_intersects ->memory_intersects. There were few places where memory_intersects was called. When commit 1d7db834a027e ("dma-debug: use memory_intersects() directly") was merged and CONFIG_DMA_API_DEBUG is enabled, the DMA subsystem uses it to check for an illegal area and the calltrace above is triggered. [akpm@linux-foundation.org: fix nearby comment typo] Link: https://lkml.kernel.org/r/20220819081145.948016-1-quanyang.wang@windriver.com Fixes: 979559362516 ("asm/sections: add helpers to check for section data") Signed-off-by: Quanyang Wang Cc: Ard Biesheuvel Cc: Arnd Bergmann Cc: Thierry Reding Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

locking/atomic: Make test_and_*_bit() ordered on failure

2022-08-25T09:45:06+00:00

commit 415d832497098030241605c52ea83d4e2cfa7879 upstream. These operations are documented as always ordered in include/asm-generic/bitops/instrumented-atomic.h, and producer-consumer type use cases where one side needs to ensure a flag is left pending after some shared data was updated rely on this ordering, even in the failure case. This is the case with the workqueue code, which currently suffers from a reproducible ordering violation on Apple M1 platforms (which are notoriously out-of-order) that ends up causing the TTY layer to fail to deliver data to userspace properly under the right conditions. This change fixes that bug. Change the documentation to restrict the "no order on failure" story to the _lock() variant (for which it makes sense), and remove the early-exit from the generic implementation, which is what causes the missing barrier semantics in that case. Without this, the remaining atomic op is fully ordered (including on ARM64 LSE, as of recent versions of the architecture spec). Suggested-by: Linus Torvalds Cc: stable@vger.kernel.org Fixes: e986a0d6cb36 ("locking/atomics, asm-generic/bitops/atomic.h: Rewrite using atomic_*() APIs") Fixes: 61e02392d3c7 ("locking/atomic/bitops: Document and clarify ordering semantics for failed test_and_{}_bit()") Signed-off-by: Hector Martin Acked-by: Will Deacon Reviewed-by: Arnd Bergmann Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

Merge tag 'asm-generic-fixes-5.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

2022-07-27T16:50:18+00:00

Pull asm-generic fixes from Arnd Bergmann: "Two more bug fixes for asm-generic, one addressing an incorrect Kconfig symbol reference and another one fixing a build failure for the perf tool on mips and possibly others" * tag 'asm-generic-fixes-5.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: asm-generic: remove a broken and needless ifdef conditional tools: Fixed MIPS builds due to struct flock re-definition

mmu_gather: fix the CONFIG_MMU_GATHER_NO_RANGE case

2022-07-22T16:28:34+00:00

Sudip reports that alpha doesn't build properly, with errors like include/asm-generic/tlb.h:401:1: error: redefinition of 'tlb_update_vma_flags' 401 | tlb_update_vma_flags(struct mmu_gather *tlb, struct vm_area_struct *vma) | ^~~~~~~~~~~~~~~~~~~~ include/asm-generic/tlb.h:372:1: note: previous definition of 'tlb_update_vma_flags' with type 'void(struct mmu_gather *, struct vm_area_struct *)' 372 | tlb_update_vma_flags(struct mmu_gather *tlb, struct vm_area_struct *vma) { } the cause being that We have this odd situation where some architectures were never converted to the newer TLB flushing interfaces that have a range for the flush. Instead people left them alone, and we have them select the MMU_GATHER_NO_RANGE config option to make the tlb header files account for this. Peter Zijlstra cleaned some of these nasty header file games up in commits 1e9fdf21a433 ("mmu_gather: Remove per arch tlb_{start,end}_vma()") 18ba064e42df ("mmu_gather: Let there be one tlb_{start,end}_vma() implementation") but tlb_update_vma_flags() was left alone, and then commit b67fbebd4cf9 ("mmu_gather: Force tlb-flush VM_PFNMAP vmas") ended up removing only _one_ of the two stale duplicate dummy inline functions. This removes the other stale one. Somebody braver than me should try to remove MMU_GATHER_NO_RANGE entirely, but it requires fixing up the oddball architectures that use it: alpha, m68k, microblaze, nios2 and openrisc. The fixups should be fairly straightforward ("fix the build errors it exposes by adding the appropriate range arguments"), but the reason this wasn't done in the first place is that so few people end up working on those architectures. But it could be done one architecture at a time, hint, hint. Reported-by: Sudip Mukherjee (Codethink) Fixes: b67fbebd4cf9 ("mmu_gather: Force tlb-flush VM_PFNMAP vmas") Link: https://lore.kernel.org/all/YtpXh0QHWwaEWVAY@debian/ Cc: Peter Zijlstra Cc: Will Deacon Cc: "Aneesh Kumar K.V" Cc: Andrew Morton Cc: Nick Piggin Cc: Arnd Bergmann Signed-off-by: Linus Torvalds

asm-generic: remove a broken and needless ifdef conditional

2022-07-22T13:00:00+00:00

Commit 527701eda5f1 ("lib: Add a generic version of devmem_is_allowed()") introduces the config symbol GENERIC_LIB_DEVMEM_IS_ALLOWED, but then falsely refers to CONFIG_GENERIC_DEVMEM_IS_ALLOWED (note the missing LIB in the reference) in ./include/asm-generic/io.h. Luckily, ./scripts/checkkconfigsymbols.py warns on non-existing configs: GENERIC_DEVMEM_IS_ALLOWED Referencing files: include/asm-generic/io.h The actual fix, though, is simply to not to make this function declaration dependent on any kernel config. For architectures that intend to use the generic version, the arch's 'select GENERIC_LIB_DEVMEM_IS_ALLOWED' will lead to picking the function definition, and for other architectures, this function is simply defined elsewhere. The wrong '#ifndef' on a non-existing config symbol also always had the same effect (although more by mistake than by intent). So, there is no functional change. Remove this broken and needless ifdef conditional. Fixes: 527701eda5f1 ("lib: Add a generic version of devmem_is_allowed()") Signed-off-by: Lukas Bulwahn Signed-off-by: Arnd Bergmann

mmu_gather: Force tlb-flush VM_PFNMAP vmas

2022-07-21T17:50:13+00:00

Jann reported a race between munmap() and unmap_mapping_range(), where unmap_mapping_range() will no-op once unmap_vmas() has unlinked the VMA; however munmap() will not yet have invalidated the TLBs. Therefore unmap_mapping_range() will complete while there are still (stale) TLB entries for the specified range. Mitigate this by force flushing TLBs for VM_PFNMAP ranges. Signed-off-by: Peter Zijlstra (Intel) Acked-by: Will Deacon Signed-off-by: Linus Torvalds

mmu_gather: Let there be one tlb_{start,end}_vma() implementation

2022-07-21T17:50:13+00:00

Now that architectures are no longer allowed to override tlb_{start,end}_vma() re-arrange code so that there is only one implementation for each of these functions. This much simplifies trying to figure out what they actually do. Signed-off-by: Peter Zijlstra (Intel) Acked-by: Will Deacon Signed-off-by: Linus Torvalds

mmu_gather: Remove per arch tlb_{start,end}_vma()

2022-07-21T17:50:13+00:00

Scattered across the archs are 3 basic forms of tlb_{start,end}_vma(). Provide two new MMU_GATHER_knobs to enumerate them and remove the per arch tlb_{start,end}_vma() implementations. - MMU_GATHER_NO_FLUSH_CACHE indicates the arch has flush_cache_range() but does *NOT* want to call it for each VMA. - MMU_GATHER_MERGE_VMAS indicates the arch wants to merge the invalidate across multiple VMAs if possible. With these it is possible to capture the three forms: 1) empty stubs; select MMU_GATHER_NO_FLUSH_CACHE and MMU_GATHER_MERGE_VMAS 2) start: flush_cache_range(), end: empty; select MMU_GATHER_MERGE_VMAS 3) start: flush_cache_range(), end: flush_tlb_range(); default Obviously, if the architecture does not have flush_cache_range() then it also doesn't need to select MMU_GATHER_NO_FLUSH_CACHE. Signed-off-by: Peter Zijlstra (Intel) Acked-by: Will Deacon Cc: David Miller Signed-off-by: Linus Torvalds

kernel: add platform_has() infrastructure

2022-06-06T06:06:00+00:00

Add a simple infrastructure for setting, resetting and querying platform feature flags. Flags can be either global or architecture specific. Signed-off-by: Juergen Gross Reviewed-by: Oleksandr Tyshchenko Tested-by: Oleksandr Tyshchenko # Arm64 only Reviewed-by: Christoph Hellwig Acked-by: Borislav Petkov Signed-off-by: Juergen Gross