kernel/linux.git/arch/arm64/include/asm/io.h, branch linux-7.0.y

arm64: io: Extract user memory type in ioremap_prot()

2026-02-25T19:49:52+00:00

The only caller of ioremap_prot() outside of the generic ioremap() implementation is generic_access_phys(), which passes a 'pgprot_t' value determined from the user mapping of the target 'pfn' being accessed by the kernel. On arm64, the 'pgprot_t' contains all of the non-address bits from the pte, including the permission controls, and so we end up returning a new user mapping from ioremap_prot() which faults when accessed from the kernel on systems with PAN: | Unable to handle kernel read from unreadable memory at virtual address ffff80008ea89000 | ... | Call trace: | __memcpy_fromio+0x80/0xf8 | generic_access_phys+0x20c/0x2b8 | __access_remote_vm+0x46c/0x5b8 | access_remote_vm+0x18/0x30 | environ_read+0x238/0x3e8 | vfs_read+0xe4/0x2b0 | ksys_read+0xcc/0x178 | __arm64_sys_read+0x4c/0x68 Extract only the memory type from the user 'pgprot_t' in ioremap_prot() and assert that we're being passed a user mapping, to protect us against any changes in future that may require additional handling. To avoid falsely flagging users of ioremap(), provide our own ioremap() macro which simply wraps __ioremap_prot(). Cc: Zeng Heng Cc: Jinjiang Tu Cc: Catalin Marinas Fixes: 893dea9ccd08 ("arm64: Add HAVE_IOREMAP_PROT support") Reported-by: Jinjiang Tu Reviewed-by: Catalin Marinas Signed-off-by: Will Deacon

arm64: io: Rename ioremap_prot() to __ioremap_prot()

2026-02-25T19:49:51+00:00

Rename our ioremap_prot() implementation to __ioremap_prot() and convert all arch-internal callers over to the new function. ioremap_prot() remains as a #define to __ioremap_prot() for generic_access_phys() and will be subsequently extended to handle user permissions in 'prot'. Cc: Zeng Heng Cc: Jinjiang Tu Cc: Catalin Marinas Reviewed-by: Catalin Marinas Signed-off-by: Will Deacon

arm64: Enable EFI secret area Securityfs support

2025-09-19T09:12:01+00:00

Enable EFI COCO secrets support. Provide the ioremap_encrypted() support required by the driver. Cc: Sami Mujawar Cc: Will Deacon Cc: Catalin Marinas Cc: Aneesh Kumar K.V Cc: Steven Price Reviewed-by: Gavin Shan Tested-by: Sami Mujawar Signed-off-by: Suzuki K Poulose Signed-off-by: Will Deacon

arm64: realm: ioremap: Allow mapping memory as encrypted

2025-09-19T09:12:01+00:00

For ioremap(), so far we only checked if it was a device (RIPAS_DEV) to choose an encrypted vs decrypted mapping. However, we may have firmware reserved memory regions exposed to the OS (e.g., EFI Coco Secret Securityfs, ACPI CCEL). We need to make sure that anything that is RIPAS_RAM (i.e., Guest protected memory with RMM guarantees) are also mapped as encrypted. Rephrasing the above, anything that is not RIPAS_EMPTY is guaranteed to be protected by the RMM. Thus we choose encrypted mapping for anything that is not RIPAS_EMPTY. While at it, rename the helper function __arm64_is_protected_mmio => arm64_rsi_is_protected to clearly indicate that this not an arm64 generic helper, but something to do with Realms. Cc: Sami Mujawar Cc: Will Deacon Cc: Catalin Marinas Cc: Aneesh Kumar K.V Cc: Steven Price Reviewed-by: Gavin Shan Reviewed-by: Steven Price Tested-by: Sami Mujawar Signed-off-by: Suzuki K Poulose Signed-off-by: Will Deacon

mm/ioremap: pass pgprot_t to ioremap_prot() instead of unsigned long

2025-03-17T05:06:23+00:00

ioremap_prot() currently accepts pgprot_val parameter as an unsigned long, thus implicitly assuming that pgprot_val and pgprot_t could never be bigger than unsigned long. But this assumption soon will not be true on arm64 when using D128 pgtables. In 128 bit page table configuration, unsigned long is 64 bit, but pgprot_t is 128 bit. Passing platform abstracted pgprot_t argument is better as compared to size based data types. Let's change the parameter to directly pass pgprot_t like another similar helper generic_ioremap_prot(). Without this change in place, D128 configuration does not work on arm64 as the top 64 bits gets silently stripped when passing the protection value to this function. Link: https://lkml.kernel.org/r/20250218101954.415331-1-anshuman.khandual@arm.com Signed-off-by: Ryan Roberts Co-developed-by: Anshuman Khandual Signed-off-by: Anshuman Khandual Acked-by: Catalin Marinas [arm64] Signed-off-by: Andrew Morton

Merge tag 'asm-generic-3.13' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

2024-11-20T23:13:02+00:00

Pull asm-generic updates from Arnd Bergmann: "These are a number of unrelated cleanups, generally simplifying the architecture specific header files: - A series from Al Viro simplifies asm/vga.h, after it turns out that most of it can be generalized. - A series from Julian Vetter adds a common version of memcpy_{to,from}io() and memset_io() and changes most architectures to use that instead of their own implementation - A series from Niklas Schnelle concludes his work to make PC style inb()/outb() optional - Nicolas Pitre contributes improvements for the generic do_div() helper - Christoph Hellwig adds a generic version of page_to_phys() and phys_to_page(), replacing the slightly different architecture specific definitions. - Uwe Kleine-Koenig has a minor cleanup for ioctl definitions" * tag 'asm-generic-3.13' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: (24 commits) empty include/asm-generic/vga.h sparc: get rid of asm/vga.h asm/vga.h: don't bother with scr_mem{cpy,move}v() unless we need to vt_buffer.h: get rid of dead code in default scr_...() instances tty: serial: export serial_8250_warn_need_ioport lib/iomem_copy: fix kerneldoc format style hexagon: simplify asm/io.h for !HAS_IOPORT loongarch: Use new fallback IO memcpy/memset csky: Use new fallback IO memcpy/memset arm64: Use new fallback IO memcpy/memset New implementation for IO memcpy and IO memset watchdog: Add HAS_IOPORT dependency for SBC8360 and SBC7240 __arch_xprod64(): make __always_inline when optimizing for performance ARM: div64: improve __arch_xprod_64() asm-generic/div64: optimize/simplify __div64_const32() lib/math/test_div64: add some edge cases relevant to __div64_const32() asm-generic: add an optional pfn_valid check to page_to_phys asm-generic: provide generic page_to_phys and phys_to_page implementations asm-generic/io.h: Remove I/O port accessors for HAS_IOPORT=n tty: serial: handle HAS_IOPORT dependencies ...

arm64: Use new fallback IO memcpy/memset

2024-10-28T21:44:29+00:00

Use the new fallback memcpy_{from,to}io and memset_io functions from lib/iomem_copy.c on the arm64 processor architecture. Reviewed-by: Catalin Marinas Reviewed-by: Yann Sionneau Signed-off-by: Julian Vetter Signed-off-by: Arnd Bergmann

arm64: rsi: Add support for checking whether an MMIO is protected

2024-10-23T09:19:32+00:00

On Arm CCA, with RMM-v1.0, all MMIO regions are shared. However, in the future, an Arm CCA-v1.0 compliant guest may be run in a lesser privileged partition in the Realm World (with Arm CCA-v1.1 Planes feature). In this case, some of the MMIO regions may be emulated by a higher privileged component in the Realm world, i.e, protected. Thus the guest must decide today, whether a given MMIO region is shared vs Protected and create the stage1 mapping accordingly. On Arm CCA, this detection is based on the "IPA State" (RIPAS == RIPAS_IO). Provide a helper to run this check on a given range of MMIO. Also, provide a arm64 helper which may be hooked in by other solutions. Reviewed-by: Catalin Marinas Reviewed-by: Gavin Shan Signed-off-by: Suzuki K Poulose Signed-off-by: Steven Price Link: https://lore.kernel.org/r/20241017131434.40935-5-steven.price@arm.com Signed-off-by: Catalin Marinas

arm64: mm: Add confidential computing hook to ioremap_prot()

2024-08-30T15:30:41+00:00

Confidential Computing environments such as pKVM and Arm's CCA distinguish between shared (i.e. emulated) and private (i.e. assigned) MMIO regions. Introduce a hook into our implementation of ioremap_prot() so that MMIO regions can be shared if necessary. Reviewed-by: Catalin Marinas Reviewed-by: Steven Price Acked-by: Marc Zyngier Link: https://lore.kernel.org/r/20240830130150.8568-6-will@kernel.org Signed-off-by: Will Deacon

arm64/io: add constant-argument check

2024-06-05T12:30:58+00:00

In some configurations __const_iowrite32_copy() does not get inlined and gcc runs into the BUILD_BUG(): In file included from : In function '__const_memcpy_toio_aligned32', inlined from '__const_iowrite32_copy' at arch/arm64/include/asm/io.h:203:3, inlined from '__const_iowrite32_copy' at arch/arm64/include/asm/io.h:199:20: include/linux/compiler_types.h:487:45: error: call to '__compiletime_assert_538' declared with attribute error: BUILD_BUG failed 487 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__) | ^ include/linux/compiler_types.h:468:25: note: in definition of macro '__compiletime_assert' 468 | prefix ## suffix(); \ | ^~~~~~ include/linux/compiler_types.h:487:9: note: in expansion of macro '_compiletime_assert' 487 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__) | ^~~~~~~~~~~~~~~~~~~ include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert' 39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg) | ^~~~~~~~~~~~~~~~~~ include/linux/build_bug.h:59:21: note: in expansion of macro 'BUILD_BUG_ON_MSG' 59 | #define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed") | ^~~~~~~~~~~~~~~~ arch/arm64/include/asm/io.h:193:17: note: in expansion of macro 'BUILD_BUG' 193 | BUILD_BUG(); | ^~~~~~~~~ Move the check for constant arguments into the inline function to ensure it is still constant if the compiler decides against inlining it, and mark them as __always_inline to override the logic that sometimes leads to the compiler not producing the simplified output. Note that either the __always_inline annotation or the check for a constant value are sufficient here, but combining the two looks cleaner as it also avoids the macro. With clang-8 and older, the macro was still needed, but all versions of gcc and clang can reliably perform constant folding here. Fixes: ead79118dae6 ("arm64/io: Provide a WC friendly __iowriteXX_copy()") Signed-off-by: Arnd Bergmann Reviewed-by: Mark Rutland Reviewed-by: Jason Gunthorpe Link: https://lore.kernel.org/r/20240604210006.668912-1-arnd@kernel.org Signed-off-by: Will Deacon