Currently the Linux character device mmap handling only supports mmap
operations that map a single page that has an associated vm_page_t. This does not permit mapping larger regions (such as a PCI memory BAR) and it does not permit mapping addresses beyond the top of RAM (such as a 64-bit BAR located above the top of RAM). Instead of using a single OBJT_DEVICE object and passing the physaddr via the offset as a hack, create a new sglist and OBJT_SG object for each mmap request. The requested memory attribute is applied to the object thus affecting all pages mapped by the request. Reviewed by: hselasky, np MFC after: 1 week Sponsored by: Chelsio Differential Revision: https://reviews.freebsd.org/D3386
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parent
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188458ea7c
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=287440
@ -33,6 +33,7 @@
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#include <sys/kernel.h>
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#include <sys/sysctl.h>
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#include <sys/proc.h>
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#include <sys/sglist.h>
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#include <sys/sleepqueue.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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@ -415,16 +416,6 @@ linux_dev_poll(struct cdev *dev, int events, struct thread *td)
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return (revents);
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}
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static int
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linux_dev_mmap(struct cdev *dev, vm_ooffset_t offset, vm_paddr_t *paddr,
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int nprot, vm_memattr_t *memattr)
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{
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/* XXX memattr not honored. */
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*paddr = offset;
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return (0);
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}
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static int
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linux_dev_mmap_single(struct cdev *dev, vm_ooffset_t *offset,
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vm_size_t size, struct vm_object **object, int nprot)
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@ -433,36 +424,41 @@ linux_dev_mmap_single(struct cdev *dev, vm_ooffset_t *offset,
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struct linux_file *filp;
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struct file *file;
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struct vm_area_struct vma;
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vm_paddr_t paddr;
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vm_page_t m;
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int error;
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file = curthread->td_fpop;
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ldev = dev->si_drv1;
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if (ldev == NULL)
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return (ENODEV);
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if (size != PAGE_SIZE)
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return (EINVAL);
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if ((error = devfs_get_cdevpriv((void **)&filp)) != 0)
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return (error);
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filp->f_flags = file->f_flag;
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vma.vm_start = 0;
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vma.vm_end = PAGE_SIZE;
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vma.vm_end = size;
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vma.vm_pgoff = *offset / PAGE_SIZE;
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vma.vm_pfn = 0;
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vma.vm_page_prot = 0;
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if (filp->f_op->mmap) {
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error = -filp->f_op->mmap(filp, &vma);
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if (error == 0) {
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paddr = (vm_paddr_t)vma.vm_pfn << PAGE_SHIFT;
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*offset = paddr;
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m = PHYS_TO_VM_PAGE(paddr);
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*object = vm_pager_allocate(OBJT_DEVICE, dev,
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PAGE_SIZE, nprot, *offset, curthread->td_ucred);
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if (*object == NULL)
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return (EINVAL);
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if (vma.vm_page_prot != VM_MEMATTR_DEFAULT)
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pmap_page_set_memattr(m, vma.vm_page_prot);
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struct sglist *sg;
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sg = sglist_alloc(1, M_WAITOK);
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sglist_append_phys(sg,
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(vm_paddr_t)vma.vm_pfn << PAGE_SHIFT, vma.vm_len);
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*object = vm_pager_allocate(OBJT_SG, sg, vma.vm_len,
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nprot, 0, curthread->td_ucred);
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if (*object == NULL) {
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sglist_free(sg);
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return (EINVAL);
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}
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*offset = 0;
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if (vma.vm_page_prot != VM_MEMATTR_DEFAULT) {
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VM_OBJECT_WLOCK(*object);
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vm_object_set_memattr(*object,
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vma.vm_page_prot);
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VM_OBJECT_WUNLOCK(*object);
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}
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}
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} else
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error = ENODEV;
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@ -479,7 +475,6 @@ struct cdevsw linuxcdevsw = {
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.d_write = linux_dev_write,
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.d_ioctl = linux_dev_ioctl,
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.d_mmap_single = linux_dev_mmap_single,
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.d_mmap = linux_dev_mmap,
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.d_poll = linux_dev_poll,
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};
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@ -40,6 +40,7 @@ struct vm_area_struct {
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vm_offset_t vm_end;
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vm_offset_t vm_pgoff;
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vm_paddr_t vm_pfn; /* PFN For mmap. */
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vm_size_t vm_len; /* length for mmap. */
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vm_memattr_t vm_page_prot;
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};
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@ -78,6 +79,7 @@ io_remap_pfn_range(struct vm_area_struct *vma,
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{
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vma->vm_page_prot = prot;
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vma->vm_pfn = pfn;
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vma->vm_len = size;
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return (0);
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}
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