kernel/linux.git/include/asm-generic/io.h, branch v6.1.168

asm-generic/io.h: Skip trace helpers if rwmmio events are disabled

2025-10-19T14:23:22+00:00

[ Upstream commit 8327bd4fcb6c1dab01ce5c6ff00b42496836dcd2 ] With `CONFIG_TRACE_MMIO_ACCESS=y`, the `{read,write}{b,w,l,q}{_relaxed}()` mmio accessors unconditionally call `log_{post_}{read,write}_mmio()` helpers, which in turn call the ftrace ops for `rwmmio` trace events This adds a performance penalty per mmio accessor call, even when `rwmmio` events are disabled at runtime (~80% overhead on local measurement). Guard these with `tracepoint_enabled()`. Signed-off-by: Varad Gautam Fixes: 210031971cdd ("asm-generic/io: Add logging support for MMIO accessors") Cc: stable@vger.kernel.org Signed-off-by: Arnd Bergmann Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

asm-generic/io.h: suppress endianness warnings for relaxed accessors

2025-10-19T14:23:22+00:00

[ Upstream commit 05d3855b4d21ef3c2df26be1cbba9d2c68915fcb ] Copy the forced type casts from the normal MMIO accessors to suppress the sparse warnings that point out __raw_readl() returns a native endian word (just like readl()). Signed-off-by: Vladimir Oltean Signed-off-by: Arnd Bergmann Stable-dep-of: 8327bd4fcb6c ("asm-generic/io.h: Skip trace helpers if rwmmio events are disabled") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

asm-generic/io: Add _RET_IP_ to MMIO trace for more accurate debug info

2025-10-19T14:23:22+00:00

[ Upstream commit 5e5ff73c2e5863f93fc5fd78d178cd8f2af12464 ] Due to compiler optimizations like inlining, there are cases where MMIO traces using _THIS_IP_ for caller information might not be sufficient to provide accurate debug traces. 1) With optimizations (Seen with GCC): In this case, _THIS_IP_ works fine and prints the caller information since it will be inlined into the caller and we get the debug traces on who made the MMIO access, for ex: rwmmio_read: qcom_smmu_tlb_sync+0xe0/0x1b0 width=32 addr=0xffff8000087447f4 rwmmio_post_read: qcom_smmu_tlb_sync+0xe0/0x1b0 width=32 val=0x0 addr=0xffff8000087447f4 2) Without optimizations (Seen with Clang): _THIS_IP_ will not be sufficient in this case as it will print only the MMIO accessors itself which is of not much use since it is not inlined as below for example: rwmmio_read: readl+0x4/0x80 width=32 addr=0xffff8000087447f4 rwmmio_post_read: readl+0x48/0x80 width=32 val=0x4 addr=0xffff8000087447f4 So in order to handle this second case as well irrespective of the compiler optimizations, add _RET_IP_ to MMIO trace to make it provide more accurate debug information in all these scenarios. Before: rwmmio_read: readl+0x4/0x80 width=32 addr=0xffff8000087447f4 rwmmio_post_read: readl+0x48/0x80 width=32 val=0x4 addr=0xffff8000087447f4 After: rwmmio_read: qcom_smmu_tlb_sync+0xe0/0x1b0 -> readl+0x4/0x80 width=32 addr=0xffff8000087447f4 rwmmio_post_read: qcom_smmu_tlb_sync+0xe0/0x1b0 -> readl+0x4/0x80 width=32 val=0x0 addr=0xffff8000087447f4 Fixes: 210031971cdd ("asm-generic/io: Add logging support for MMIO accessors") Signed-off-by: Sai Prakash Ranjan Signed-off-by: Arnd Bergmann Stable-dep-of: 8327bd4fcb6c ("asm-generic/io.h: Skip trace helpers if rwmmio events are disabled") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

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

2023-05-11T14:02:58+00:00

[ 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

Merge tag 'asm-generic-6.0' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

2022-08-05T17:07:23+00:00

Pull asm-generic updates from Arnd Bergmann: "There are three independent sets of changes: - Sai Prakash Ranjan adds tracing support to the asm-generic version of the MMIO accessors, which is intended to help understand problems with device drivers and has been part of Qualcomm's vendor kernels for many years - A patch from Sebastian Siewior to rework the handling of IRQ stacks in softirqs across architectures, which is needed for enabling PREEMPT_RT - The last patch to remove the CONFIG_VIRT_TO_BUS option and some of the code behind that, after the last users of this old interface made it in through the netdev, scsi, media and staging trees" * tag 'asm-generic-6.0' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: uapi: asm-generic: fcntl: Fix typo 'the the' in comment arch/*/: remove CONFIG_VIRT_TO_BUS soc: qcom: geni: Disable MMIO tracing for GENI SE serial: qcom_geni_serial: Disable MMIO tracing for geni serial asm-generic/io: Add logging support for MMIO accessors KVM: arm64: Add a flag to disable MMIO trace for nVHE KVM lib: Add register read/write tracing support drm/meson: Fix overflow implicit truncation warnings irqchip/tegra: Fix overflow implicit truncation warnings coresight: etm4x: Use asm-generic IO memory barriers arm64: io: Use asm-generic high level MMIO accessors arch/*: Disable softirq stacks on PREEMPT_RT.

Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

2022-08-01T17:37:00+00:00

Pull arm64 updates from Will Deacon: "Highlights include a major rework of our kPTI page-table rewriting code (which makes it both more maintainable and considerably faster in the cases where it is required) as well as significant changes to our early boot code to reduce the need for data cache maintenance and greatly simplify the KASLR relocation dance. Summary: - Remove unused generic cpuidle support (replaced by PSCI version) - Fix documentation describing the kernel virtual address space - Handling of some new CPU errata in Arm implementations - Rework of our exception table code in preparation for handling machine checks (i.e. RAS errors) more gracefully - Switch over to the generic implementation of ioremap() - Fix lockdep tracking in NMI context - Instrument our memory barrier macros for KCSAN - Rework of the kPTI G->nG page-table repainting so that the MMU remains enabled and the boot time is no longer slowed to a crawl for systems which require the late remapping - Enable support for direct swapping of 2MiB transparent huge-pages on systems without MTE - Fix handling of MTE tags with allocating new pages with HW KASAN - Expose the SMIDR register to userspace via sysfs - Continued rework of the stack unwinder, particularly improving the behaviour under KASAN - More repainting of our system register definitions to match the architectural terminology - Improvements to the layout of the vDSO objects - Support for allocating additional bits of HWCAP2 and exposing FEAT_EBF16 to userspace on CPUs that support it - Considerable rework and optimisation of our early boot code to reduce the need for cache maintenance and avoid jumping in and out of the kernel when handling relocation under KASLR - Support for disabling SVE and SME support on the kernel command-line - Support for the Hisilicon HNS3 PMU - Miscellanous cleanups, trivial updates and minor fixes" * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (136 commits) arm64: Delay initialisation of cpuinfo_arm64::reg_{zcr,smcr} arm64: fix KASAN_INLINE arm64/hwcap: Support FEAT_EBF16 arm64/cpufeature: Store elf_hwcaps as a bitmap rather than unsigned long arm64/hwcap: Document allocation of upper bits of AT_HWCAP arm64: enable THP_SWAP for arm64 arm64/mm: use GENMASK_ULL for TTBR_BADDR_MASK_52 arm64: errata: Remove AES hwcap for COMPAT tasks arm64: numa: Don't check node against MAX_NUMNODES drivers/perf: arm_spe: Fix consistency of SYS_PMSCR_EL1.CX perf: RISC-V: Add of_node_put() when breaking out of for_each_of_cpu_node() docs: perf: Include hns3-pmu.rst in toctree to fix 'htmldocs' WARNING arm64: kasan: Revert "arm64: mte: reset the page tag in page->flags" mm: kasan: Skip page unpoisoning only if __GFP_SKIP_KASAN_UNPOISON mm: kasan: Skip unpoisoning of user pages mm: kasan: Ensure the tags are visible before the tag in page->flags drivers/perf: hisi: add driver for HNS3 PMU drivers/perf: hisi: Add description for HNS3 PMU driver drivers/perf: riscv_pmu_sbi: perf format perf/arm-cci: Use the bitmap API to allocate bitmaps ...

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

arch/*/: remove CONFIG_VIRT_TO_BUS

2022-06-28T11:20:21+00:00

All architecture-independent users of virt_to_bus() and bus_to_virt() have been fixed to use the dma mapping interfaces or have been removed now. This means the definitions on most architectures, and the CONFIG_VIRT_TO_BUS symbol are now obsolete and can be removed. The only exceptions to this are a few network and scsi drivers for m68k Amiga and VME machines and ppc32 Macintosh. These drivers work correctly with the old interfaces and are probably not worth changing. On alpha and parisc, virt_to_bus() were still used in asm/floppy.h. alpha can use isa_virt_to_bus() like x86 does, and parisc can just open-code the virt_to_phys() here, as this is architecture specific code. I tried updating the bus-virt-phys-mapping.rst documentation, which started as an email from Linus to explain some details of the Linux-2.0 driver interfaces. The bits about virt_to_bus() were declared obsolete backin 2000, and the rest is not all that relevant any more, so in the end I just decided to remove the file completely. Reviewed-by: Geert Uytterhoeven Acked-by: Geert Uytterhoeven Acked-by: Michael Ellerman (powerpc) Acked-by: Helge Deller # parisc Signed-off-by: Arnd Bergmann

mm: ioremap: Add ioremap/iounmap_allowed()

2022-06-27T11:22:31+00:00

Add special hook for architecture to verify addr, size or prot when ioremap() or iounmap(), which will make the generic ioremap more useful. ioremap_allowed() return a bool, - true means continue to remap - false means skip remap and return directly iounmap_allowed() return a bool, - true means continue to vunmap - false code means skip vunmap and return directly Meanwhile, only vunmap the address when it is in vmalloc area as the generic ioremap only returns vmalloc addresses. Acked-by: Andrew Morton Signed-off-by: Kefeng Wang Reviewed-by: Christoph Hellwig Reviewed-by: Baoquan He Link: https://lore.kernel.org/r/20220607125027.44946-5-wangkefeng.wang@huawei.com Signed-off-by: Will Deacon

mm: ioremap: Use more sensible name in ioremap_prot()

2022-06-27T11:21:29+00:00

Use more meaningful and sensible naming phys_addr instead addr in ioremap_prot(). Suggested-by: Andrew Morton Reviewed-by: Anshuman Khandual Signed-off-by: Kefeng Wang Reviewed-by: Baoquan He Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/20220610092255.32445-1-wangkefeng.wang@huawei.com Signed-off-by: Will Deacon