Date: Thu, 11 Jun 2026 17:12:01 +0000 From: Mitchell Horne <mhorne@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: 6d526fa72b72 - stable/14 - linux/io: handle memtype_wc mapping for !DMAP range Message-ID: <6a2aec61.3b665.746993a5@gitrepo.freebsd.org>
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The branch stable/14 has been updated by mhorne: URL: https://cgit.FreeBSD.org/src/commit/?id=6d526fa72b723f28e72e0e8ff40029f0ae7db9b9 commit 6d526fa72b723f28e72e0e8ff40029f0ae7db9b9 Author: Mitchell Horne <mhorne@FreeBSD.org> AuthorDate: 2026-05-14 14:20:22 +0000 Commit: Mitchell Horne <mhorne@FreeBSD.org> CommitDate: 2026-06-11 17:11:40 +0000 linux/io: handle memtype_wc mapping for !DMAP range The amdgpu driver in drm-kmod will attempt to update/reserve certain GPU VRAM ranges as write-combining. Depending on the system, this address range may fall outside of FreeBSD's constructed DMAP. We cannot use pmap_change_attr() in this case. When INVARIANTS is enabled, this results in the following: panic: physical address 0x880000000 not covered by the DMAP Add a guard against triggering the KASSERT in PHYS_TO_DMAP(). This limitation in our implementation of arch_io_reserve_memtype_wc() is already known in drm-kmod's amdgpu_bo_init(), and errors are ignored there (see "BSDFIXME"). This change is only to eliminate the preventable assertion failure within this scheme. Tested by: kevans Reviewed by: kib, emaste MFC after: 3 days Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D56971 (cherry picked from commit 988c03980452a56fb0fbb15e18b0a644602d0ab3) --- sys/compat/linuxkpi/common/include/linux/io.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/sys/compat/linuxkpi/common/include/linux/io.h b/sys/compat/linuxkpi/common/include/linux/io.h index 164347dbc4e7..021add1153f7 100644 --- a/sys/compat/linuxkpi/common/include/linux/io.h +++ b/sys/compat/linuxkpi/common/include/linux/io.h @@ -547,6 +547,9 @@ arch_io_reserve_memtype_wc(resource_size_t start, resource_size_t size) #if defined(__amd64__) vm_offset_t va; + if (!PHYS_IN_DMAP(start) || !PHYS_IN_DMAP(start + size)) + return (-EINVAL); + va = PHYS_TO_DMAP(start); return (-pmap_change_attr(va, size, VM_MEMATTR_WRITE_COMBINING)); #else @@ -560,8 +563,10 @@ arch_io_free_memtype_wc(resource_size_t start, resource_size_t size) #if defined(__amd64__) vm_offset_t va; - va = PHYS_TO_DMAP(start); + if (!PHYS_IN_DMAP(start) || !PHYS_IN_DMAP(start + size)) + return; + va = PHYS_TO_DMAP(start); pmap_change_attr(va, size, VM_MEMATTR_WRITE_BACK); #endif }home | help
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