user/sven/linux.git/include/asm-generic, branch v5.4.289

asm-generic: qspinlock: fix queued_spin_value_unlocked() implementation

2023-12-20T14:41:22Z

[ Upstream commit 125b0bb95dd6bec81b806b997a4ccb026eeecf8f ] We really don't want to do atomic_read() or anything like that, since we already have the value, not the lock. The whole point of this is that we've loaded the lock from memory, and we want to check whether the value we loaded was a locked one or not. The main use of this is the lockref code, which loads both the lock and the reference count in one atomic operation, and then works on that combined value. With the atomic_read(), the compiler would pointlessly spill the value to the stack, in order to then be able to read it back "atomically". This is the qspinlock version of commit c6f4a9002252 ("asm-generic: ticket-lock: Optimize arch_spin_value_unlocked()") which fixed this same bug for ticket locks. Cc: Guo Ren Cc: Ingo Molnar Cc: Waiman Long Link: https://lore.kernel.org/all/CAHk-=whNRv0v6kQiV5QO6DJhjH4KEL36vWQ6Re8Csrnh4zbRkQ@mail.gmail.com/ Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

word-at-a-time: use the same return type for has_zero regardless of endianness

2023-08-11T09:53:54Z

[ Upstream commit 79e8328e5acbe691bbde029a52c89d70dcbc22f3 ] Compiling big-endian targets with Clang produces the diagnostic: fs/namei.c:2173:13: warning: use of bitwise '|' with boolean operands [-Wbitwise-instead-of-logical] } while (!(has_zero(a, &adata, &constants) | has_zero(b, &bdata, &constants))); ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ || fs/namei.c:2173:13: note: cast one or both operands to int to silence this warning It appears that when has_zero was introduced, two definitions were produced with different signatures (in particular different return types). Looking at the usage in hash_name() in fs/namei.c, I suspect that has_zero() is meant to be invoked twice per while loop iteration; using logical-or would not update `bdata` when `a` did not have zeros. So I think it's preferred to always return an unsigned long rather than a bool than update the while loop in hash_name() to use a logical-or rather than bitwise-or. [ Also changed powerpc version to do the same - Linus ] Link: https://github.com/ClangBuiltLinux/linux/issues/1832 Link: https://lore.kernel.org/lkml/20230801-bitwise-v1-1-799bec468dc4@google.com/ Fixes: 36126f8f2ed8 ("word-at-a-time: make the interfaces truly generic") Debugged-by: Nathan Chancellor Signed-off-by: Nick Desaulniers Acked-by: Heiko Carstens Cc: Arnd Bergmann Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

init: Remove check_bugs() leftovers

2023-08-08T17:56:34Z

commit 61235b24b9cb37c13fcad5b9596d59a1afdcec30 upstream Everything is converted over to arch_cpu_finalize_init(). Remove the check_bugs() leftovers including the empty stubs in asm-generic, alpha, parisc, powerpc and xtensa. Signed-off-by: Thomas Gleixner Reviewed-by: Richard Henderson Link: https://lore.kernel.org/r/20230613224545.553215951@linutronix.de Signed-off-by: Daniel Sneddon Signed-off-by: Greg Kroah-Hartman

asm-generic/io.h: suppress endianness warnings for readq() and writeq()

2023-05-17T09:35:32Z

[ Upstream commit d564fa1ff19e893e2971d66e5c8f49dc1cdc8ffc ] Commit c1d55d50139b ("asm-generic/io.h: Fix sparse warnings on big-endian architectures") missed fixing the 64-bit accessors. Arnd explains in the attached link why the casts are necessary, even if __raw_readq() and __raw_writeq() do not take endian-specific types. Link: https://lore.kernel.org/lkml/9105d6fc-880b-4734-857d-e3d30b87ccf6@app.fastmail.com/ Suggested-by: Arnd Bergmann Signed-off-by: Vladimir Oltean Reviewed-by: Jonathan Cameron Signed-off-by: Arnd Bergmann Signed-off-by: Sasha Levin

arch: fix broken BuildID for arm64 and riscv

2023-03-17T07:32:53Z

commit 99cb0d917ffa1ab628bb67364ca9b162c07699b1 upstream. Dennis Gilmore reports that the BuildID is missing in the arm64 vmlinux since commit 994b7ac1697b ("arm64: remove special treatment for the link order of head.o"). The issue is that the type of .notes section, which contains the BuildID, changed from NOTES to PROGBITS. Ard Biesheuvel figured out that whichever object gets linked first gets to decide the type of a section. The PROGBITS type is the result of the compiler emitting .note.GNU-stack as PROGBITS rather than NOTE. While Ard provided a fix for arm64, I want to fix this globally because the same issue is happening on riscv since commit 2348e6bf4421 ("riscv: remove special treatment for the link order of head.o"). This problem will happen in general for other architectures if they start to drop unneeded entries from scripts/head-object-list.txt. Discard .note.GNU-stack in include/asm-generic/vmlinux.lds.h. Link: https://lore.kernel.org/lkml/CAABkxwuQoz1CTbyb57n0ZX65eSYiTonFCU8-LCQc=74D=xE=rA@mail.gmail.com/ Fixes: 994b7ac1697b ("arm64: remove special treatment for the link order of head.o") Fixes: 2348e6bf4421 ("riscv: remove special treatment for the link order of head.o") Reported-by: Dennis Gilmore Suggested-by: Ard Biesheuvel Signed-off-by: Masahiro Yamada Acked-by: Palmer Dabbelt [Tom: stable backport 5.15.y, 5.10.y, 5.4.y] Though the above "Fixes:" commits are not in this kernel, the conditions which lead to a missing Build ID in arm64 vmlinux are similar. Evidence points to these conditions: 1. ld version > 2.36 (exact binutils commit documented in a494398bde27) 2. first object which gets linked (head.o) has a PROGBITS .note.GNU-stack segment These conditions can be observed when: - 5.15.60+ OR 5.10.136+ OR 5.4.210+ - AND ld version > 2.36 - AND arch=arm64 - AND CONFIG_MODVERSIONS=y There are notable differences in the vmlinux elf files produced before(bad) and after(good) applying this series. Good: p_type:PT_NOTE segment exists. Bad: p_type:PT_NOTE segment is missing. Good: sh_name_str:.notes section has sh_type:SHT_NOTE Bad: sh_name_str:.notes section has sh_type:SHT_PROGBITS `readelf -n` (as of v2.40) searches for Build Id by processing only the very first note in sh_type:SHT_NOTE sections. This was previously bisected to the stable backport of 0d362be5b142. Follow-up experiments were discussed here: https://lore.kernel.org/all/20221221235413.xaisboqmr7dkqwn6@oracle.com/ which strongly hints at condition 2. Signed-off-by: Tom Saeger Signed-off-by: Greg Kroah-Hartman

x86, vmlinux.lds: Add RUNTIME_DISCARD_EXIT to generic DISCARDS

2023-03-17T07:32:53Z

commit 84d5f77fc2ee4e010c2c037750e32f06e55224b0 upstream. In the x86 kernel, .exit.text and .exit.data sections are discarded at runtime, not by the linker. Add RUNTIME_DISCARD_EXIT to generic DISCARDS and define it in the x86 kernel linker script to keep them. The sections are added before the DISCARD directive so document here only the situation explicitly as this change doesn't have any effect on the generated kernel. Also, other architectures like ARM64 will use it too so generalize the approach with the RUNTIME_DISCARD_EXIT define. [ bp: Massage and extend commit message. ] Signed-off-by: H.J. Lu Signed-off-by: Borislav Petkov Reviewed-by: Kees Cook Link: https://lkml.kernel.org/r/20200326193021.255002-1-hjl.tools@gmail.com Signed-off-by: Tom Saeger

mm/khugepaged: fix GUP-fast interaction by sending IPI

2022-12-14T10:30:42Z

commit 2ba99c5e08812494bc57f319fb562f527d9bacd8 upstream. Since commit 70cbc3cc78a99 ("mm: gup: fix the fast GUP race against THP collapse"), the lockless_pages_from_mm() fastpath rechecks the pmd_t to ensure that the page table was not removed by khugepaged in between. However, lockless_pages_from_mm() still requires that the page table is not concurrently freed. Fix it by sending IPIs (if the architecture uses semi-RCU-style page table freeing) before freeing/reusing page tables. Link: https://lkml.kernel.org/r/20221129154730.2274278-2-jannh@google.com Link: https://lkml.kernel.org/r/20221128180252.1684965-2-jannh@google.com Link: https://lkml.kernel.org/r/20221125213714.4115729-2-jannh@google.com Fixes: ba76149f47d8 ("thp: khugepaged") Signed-off-by: Jann Horn Reviewed-by: Yang Shi Acked-by: David Hildenbrand Cc: John Hubbard Cc: Peter Xu Cc: Signed-off-by: Andrew Morton [manual backport: two of the three places in khugepaged that can free ptes were refactored into a common helper between 5.15 and 6.0; TLB flushing was refactored between 5.4 and 5.10] Signed-off-by: Jann Horn Signed-off-by: Sasha Levin

vmlinux.lds.h: Fix placement of '.data..decrypted' section

2022-11-25T16:42:09Z

commit 000f8870a47bdc36730357883b6aef42bced91ee upstream. Commit d4c639990036 ("vmlinux.lds.h: Avoid orphan section with !SMP") fixed an orphan section warning by adding the '.data..decrypted' section to the linker script under the PERCPU_DECRYPTED_SECTION define but that placement introduced a panic with !SMP, as the percpu sections are not instantiated with that configuration so attempting to access variables defined with DEFINE_PER_CPU_DECRYPTED() will result in a page fault. Move the '.data..decrypted' section to the DATA_MAIN define so that the variables in it are properly instantiated at boot time with CONFIG_SMP=n. Cc: stable@vger.kernel.org Fixes: d4c639990036 ("vmlinux.lds.h: Avoid orphan section with !SMP") Link: https://lore.kernel.org/cbbd3548-880c-d2ca-1b67-5bb93b291d5f@huawei.com/ Debugged-by: Ard Biesheuvel Reported-by: Zhao Wenhui Tested-by: xiafukun Signed-off-by: Nathan Chancellor Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20221108174934.3384275-1-nathan@kernel.org Signed-off-by: Greg Kroah-Hartman

asm-generic: sections: refactor memory_intersects

2022-09-05T08:27:43Z

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

2022-08-25T09:18:31Z

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