Author: alfredo Date: Fri Mar 20 11:51:08 2020 New Revision: 359160 URL: https://svnweb.freebsd.org/changeset/base/359160
Log: [PowerPC] fix panic reading /dev/kmem on !DMAP machines This fixes /dev/kmem causing panic on machines not using DMAP. Found when running libkvm Kyua test case on QEMU VM with no Huge Pages support. Reviewed by: jhibbits, luporl Approved by: jhibbits (mentor) Sponsored by: Eldorado Research Institute (eldorado.org.br) Differential Revision: https://reviews.freebsd.org/D23776 Modified: head/sys/powerpc/powerpc/mem.c Modified: head/sys/powerpc/powerpc/mem.c ============================================================================== --- head/sys/powerpc/powerpc/mem.c Fri Mar 20 05:12:16 2020 (r359159) +++ head/sys/powerpc/powerpc/mem.c Fri Mar 20 11:51:08 2020 (r359160) @@ -98,9 +98,11 @@ memrw(struct cdev *dev, struct uio *uio, int flags) struct vm_page m; vm_page_t marr; vm_size_t cnt; + ssize_t orig_resid; cnt = 0; error = 0; + orig_resid = uio->uio_resid; while (uio->uio_resid > 0 && !error) { iov = uio->uio_iov; @@ -137,7 +139,8 @@ kmem_direct_mapped: off = v & PAGE_MASK; else if (dev2unit(dev) == CDEV_MINOR_KMEM) { va = uio->uio_offset; - if ((va < VM_MIN_KERNEL_ADDRESS) || (va > virtual_end)) { + if (hw_direct_map && + ((va < VM_MIN_KERNEL_ADDRESS) || (va > virtual_end))) { v = DMAP_TO_PHYS(va); goto kmem_direct_mapped; } @@ -151,24 +154,34 @@ kmem_direct_mapped: off = v & PAGE_MASK; * so that we don't create any zero-fill pages. */ - for (; va < eva; va += PAGE_SIZE) - if (pmap_extract(kernel_pmap, va) == 0) - return (EFAULT); + for (; va < eva; va += PAGE_SIZE) { + if (pmap_extract(kernel_pmap, va) == 0) { + error = EFAULT; + break; + } + } + if (error != 0) + break; prot = (uio->uio_rw == UIO_READ) ? VM_PROT_READ : VM_PROT_WRITE; va = uio->uio_offset; - if (kernacc((void *) va, iov->iov_len, prot) - == FALSE) - return (EFAULT); + if (((va >= VM_MIN_KERNEL_ADDRESS) && (va <= virtual_end)) && + !kernacc((void *) va, iov->iov_len, prot)) { + error = EFAULT; + break; + } error = uiomove((void *)va, iov->iov_len, uio); - - continue; } } - + /* + * 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); } _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
