Date: Thu, 28 May 2026 12:38:31 +0000 From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 67d61d18bb8d - main - amd64: extract uiomove_mem() from memrw() Message-ID: <6a183747.4556b.3070f025@gitrepo.freebsd.org>
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The branch main has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=67d61d18bb8debb4ffc51ef2248aa37ed0bfb8f5 commit 67d61d18bb8debb4ffc51ef2248aa37ed0bfb8f5 Author: Konstantin Belousov <kib@FreeBSD.org> AuthorDate: 2026-05-24 11:48:45 +0000 Commit: Konstantin Belousov <kib@FreeBSD.org> CommitDate: 2026-05-28 12:38:25 +0000 amd64: extract uiomove_mem() from memrw() Reviewed by: markj Tested by: aokblast Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D49566 --- sys/amd64/amd64/mem.c | 103 +++++------------------------------------- sys/amd64/amd64/uio_machdep.c | 96 +++++++++++++++++++++++++++++++++++++++ sys/amd64/include/md_var.h | 6 +++ 3 files changed, 113 insertions(+), 92 deletions(-) diff --git a/sys/amd64/amd64/mem.c b/sys/amd64/amd64/mem.c index ab1e6cde6cd5..7d1f0f42d01c 100644 --- a/sys/amd64/amd64/mem.c +++ b/sys/amd64/amd64/mem.c @@ -61,10 +61,6 @@ #include <machine/specialreg.h> #include <machine/vmparam.h> -#include <vm/vm.h> -#include <vm/pmap.h> -#include <vm/vm_extern.h> - #include <machine/memdev.h> /* @@ -72,99 +68,22 @@ */ MALLOC_DEFINE(M_MEMDESC, "memdesc", "memory range descriptors"); -/* ARGSUSED */ int memrw(struct cdev *dev, struct uio *uio, int flags) { - struct iovec *iov; - void *p, *vd; - ssize_t orig_resid; - vm_prot_t prot; - u_long v; - u_int c; - int error; - - error = 0; - orig_resid = uio->uio_resid; - while (uio->uio_resid > 0 && error == 0) { - iov = uio->uio_iov; - if (iov->iov_len == 0) { - uio->uio_iov++; - uio->uio_iovcnt--; - if (uio->uio_iovcnt < 0) - panic("memrw"); - continue; - } - v = uio->uio_offset; - c = ulmin(iov->iov_len, PAGE_SIZE - (u_int)(v & PAGE_MASK)); - - switch (dev2unit(dev)) { - case CDEV_MINOR_KMEM: - /* - * Since c is clamped to be less or equal than - * PAGE_SIZE, the uiomove() call does not - * access past the end of the direct map. - */ - if (v >= kva_layout.dmap_low && - v < kva_layout.dmap_high) { - error = uiomove((void *)v, c, uio); - break; - } - - switch (uio->uio_rw) { - case UIO_READ: - prot = VM_PROT_READ; - break; - case UIO_WRITE: - prot = VM_PROT_WRITE; - break; - } + enum uiomove_mem_req req; - if (!kernacc((void *)v, c, prot)) { - error = EFAULT; - break; - } - - /* - * If the extracted address is not accessible - * through the direct map, then we make a - * private (uncached) mapping because we can't - * depend on the existing kernel mapping - * remaining valid until the completion of - * uiomove(). - * - * XXX We cannot provide access to the - * physical page 0 mapped into KVA. - */ - v = pmap_extract(kernel_pmap, v); - if (v == 0) { - error = EFAULT; - break; - } - /* FALLTHROUGH */ - case CDEV_MINOR_MEM: - if (v < dmaplimit) { - vd = PHYS_TO_DMAP(v); - error = uiomove(vd, c, uio); - break; - } - if (v > cpu_getmaxphyaddr()) { - error = EFAULT; - break; - } - p = pmap_mapdev(v, PAGE_SIZE); - error = uiomove(p, c, uio); - pmap_unmapdev(p, PAGE_SIZE); - break; - } + switch (dev2unit(dev)) { + case CDEV_MINOR_KMEM: + req = UIO_MEM_KMEM; + break; + case CDEV_MINOR_MEM: + req = UIO_MEM_MEM; + break; + default: + __unreachable(); } - /* - * Don't return error if any byte was written. Read and write - * can return error only if no i/o was performed. - */ - if (uio->uio_resid != orig_resid) - error = 0; - return (error); + return (uiomove_mem(req, uio)); } /* diff --git a/sys/amd64/amd64/uio_machdep.c b/sys/amd64/amd64/uio_machdep.c index 16915bccf9f5..11e6ad2b1da9 100644 --- a/sys/amd64/amd64/uio_machdep.c +++ b/sys/amd64/amd64/uio_machdep.c @@ -44,9 +44,11 @@ #include <sys/uio.h> #include <vm/vm.h> +#include <vm/vm_extern.h> #include <vm/vm_page.h> #include <machine/vmparam.h> +#include <machine/md_var.h> /* * Implement uiomove(9) from physical memory using the direct map to @@ -141,3 +143,97 @@ out: td->td_pflags &= ~TDP_DEADLKTREAT; return (error); } + +int +uiomove_mem(enum uiomove_mem_req req, struct uio *uio) +{ + struct iovec *iov; + void *p, *vd; + ssize_t orig_resid; + vm_prot_t prot; + u_long v; + u_int c; + int error; + + error = 0; + orig_resid = uio->uio_resid; + while (uio->uio_resid > 0 && error == 0) { + iov = uio->uio_iov; + if (iov->iov_len == 0) { + uio->uio_iov++; + uio->uio_iovcnt--; + if (uio->uio_iovcnt < 0) + panic("memrw"); + continue; + } + v = uio->uio_offset; + c = ulmin(iov->iov_len, PAGE_SIZE - (u_int)(v & PAGE_MASK)); + + switch (req) { + case UIO_MEM_KMEM: + /* + * Since c is clamped to be less or equal than + * PAGE_SIZE, the uiomove() call does not + * access past the end of the direct map. + */ + if (v >= kva_layout.dmap_low && + v < kva_layout.dmap_high) { + error = uiomove((void *)v, c, uio); + break; + } + + switch (uio->uio_rw) { + case UIO_READ: + prot = VM_PROT_READ; + break; + case UIO_WRITE: + prot = VM_PROT_WRITE; + break; + } + + if (!kernacc((void *)v, c, prot)) { + error = EFAULT; + break; + } + + /* + * If the extracted address is not accessible + * through the direct map, then we make a + * private (uncached) mapping because we can't + * depend on the existing kernel mapping + * remaining valid until the completion of + * uiomove(). + * + * XXX We cannot provide access to the + * physical page 0 mapped into KVA. + */ + v = pmap_extract(kernel_pmap, v); + if (v == 0) { + error = EFAULT; + break; + } + /* FALLTHROUGH */ + case UIO_MEM_MEM: + if (v < dmaplimit) { + vd = PHYS_TO_DMAP(v); + error = uiomove(vd, c, uio); + break; + } + if (v > cpu_getmaxphyaddr()) { + error = EFAULT; + break; + } + p = pmap_mapdev(v, PAGE_SIZE); + error = uiomove(p, c, uio); + pmap_unmapdev(p, PAGE_SIZE); + break; + } + } + /* + * Don't return error if any byte was written. Read and write + * can return error only if no i/o was performed. + */ + if (uio->uio_resid != orig_resid) + error = 0; + return (error); +} diff --git a/sys/amd64/include/md_var.h b/sys/amd64/include/md_var.h index 4b98c5d8c418..0e8fe916490b 100644 --- a/sys/amd64/include/md_var.h +++ b/sys/amd64/include/md_var.h @@ -106,6 +106,12 @@ void wrmsr_early_safe_start(void); void wrmsr_early_safe_end(void); int wrmsr_early_safe(u_int msr, uint64_t data); +enum uiomove_mem_req { + UIO_MEM_KMEM = 101, + UIO_MEM_MEM, +}; +int uiomove_mem(enum uiomove_mem_req req, struct uio *uio); + #endif /* !_MACHINE_MD_VAR_H_ */ #endif /* __i386__ */home | help
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