diff options
Diffstat (limited to 'sys/vm/vm_map.c')
| -rw-r--r-- | sys/vm/vm_map.c | 327 |
1 files changed, 327 insertions, 0 deletions
diff --git a/sys/vm/vm_map.c b/sys/vm/vm_map.c index 7b0656b..26effdb 100644 --- a/sys/vm/vm_map.c +++ b/sys/vm/vm_map.c @@ -30,9 +30,70 @@ #include <sys/param.h> #include <sys/types.h> #include <sys/errno.h> +#include <sys/proc.h> +#include <sys/systm.h> +#include <sys/syscall.h> +#include <sys/syslog.h> +#include <sys/mman.h> +#include <sys/filedesc.h> +#include <vm/dynalloc.h> +#include <vm/vm_pager.h> +#include <vm/vm_device.h> #include <vm/pmap.h> #include <vm/map.h> #include <vm/vm.h> +#include <assert.h> + +#define pr_trace(fmt, ...) kprintf("vm_map: " fmt, ##__VA_ARGS__) +#define pr_error(...) pr_trace(__VA_ARGS__) + +RBT_GENERATE(lgdr_entries, mmap_entry, hd, mmap_entrycmp); + +static inline void +mmap_dbg(void *addr, size_t len, int prot, int flags, int fildes, off_t off) +{ + pr_trace("addr=%p, len=%d, prot=%x\nflags=%x, fildes=%d, off=%d\n", + addr, len, prot, flags, fildes, off); +} + +/* + * Add a memory mapping to the mmap ledger. + * + * @td: Process to add mapping to. + * @ep: Memory map entry to add. + * @len: Length of memory mapping in bytes. + */ +static inline int +mmap_add(struct proc *td, struct mmap_entry *ep) +{ + struct mmap_entry *tmp; + struct mmap_lgdr *lp = td->mlgdr; + + if (ep->size == 0) { + return -EINVAL; + } + + tmp = RBT_INSERT(lgdr_entries, &lp->hd, ep); + __assert(tmp == NULL); + lp->nbytes += ep->size; + return 0; +} + +/* + * Remove memory mapping from mmap ledger + * + * @td: Process to remove mapping from. + * @ep: Memory map entry to remove. + */ +static inline void +mmap_remove(struct proc *td, struct mmap_entry *ep) +{ + struct mmap_lgdr *lp = td->mlgdr; + + RBT_REMOVE(lgdr_entries, &lp->hd, ep); + lp->nbytes -= ep->size; + dynfree(ep); +} /* * Create/destroy virtual memory mappings in a specific @@ -85,6 +146,263 @@ vm_map_modify(struct vas vas, vaddr_t va, paddr_t pa, vm_prot_t prot, bool unmap } /* + * Create a physical to virtual memory mapping. + * + * @addr: Virtual address to map (NULL to be any). + * @len: The amount of bytes to map (must be page aligned) + * @prot: Protection flags (PROT_*) + * @fildes: File descriptor. + * @off: Offset. + * + * TODO: Fields to use: `fildes' and `off' + * XXX: Must be called after pid 1 is up and running to avoid + * crashes. + */ +void * +mmap(void *addr, size_t len, int prot, int flags, int fildes, off_t off) +{ + struct vm_object *map_obj = NULL; + struct cdevsw *cdevp; + struct vm_page *pg; + struct mmap_entry *ep; + struct vnode *vp; + struct filedesc *fdp; + struct proc *td; + struct vas vas; + int error, npgs; + paddr_t pa; + vaddr_t va; + size_t misalign; + off_t page_off; + + misalign = len & (DEFAULT_PAGESIZE - 1); + len = ALIGN_UP(len + misalign, DEFAULT_PAGESIZE); + npgs = len / DEFAULT_PAGESIZE; + vas = pmap_read_vas(); + + /* Validate flags */ + if (ISSET(flags, MAP_FIXED)) { + pr_error("mmap: fixed mappings not yet supported\n"); + mmap_dbg(addr, len, prot, flags, fildes, off); + return NULL; + } + + /* + * Attempt to open the file if mapping + * is shared. + */ + if (ISSET(flags, MAP_SHARED)) { + fdp = fd_get(fildes); + if (fdp == NULL) { + pr_error("mmap: no such fd (fd=%d)\n", fildes); + return NULL; + } + + vp = fdp->vp; + if (vp->type != VCHR) { + /* TODO */ + pr_error("mmap: only device files supported\n"); + return NULL; + } + + map_obj = dv_attach(vp->major, vp->dev, prot); + if (map_obj == NULL) { + kprintf("mmap: dv_attach() failure\n"); + return NULL; + } + + cdevp = map_obj->data; + if ((pa = cdevp->mmap(vp->dev, len, off, 0)) == 0) { + kprintf("mmap: dev mmap() gave 0\n"); + return NULL; + } + + /* + * If the address passed is NULL, just identity + * map everything. + * + * XXX: This is why the bounds check done in the + * cdev mmap() *must* be correct. + * + * TODO: Use copy-on-write for this instead. Since mapping + * certain devices may required a lot of memory to + * be referenced anyways, we could use a buffered + * copy-on-write technique where only a window of + * pages can be mapped on-demand and other pages + * freed when that window is exceeded. + */ + if (addr == NULL) { + addr = (void *)pa; + } + + va = ALIGN_DOWN((vaddr_t)addr, DEFAULT_PAGESIZE); + error = vm_map(vas, va, pa, prot, len); + if (error != 0) { + kprintf("mmap: map failed (error=%d)\n", error); + return NULL; + } + + goto done; + } + + /* Only allocate new obj if needed */ + if (map_obj == NULL) { + map_obj = dynalloc(sizeof(*map_obj)); + if (map_obj == NULL) { + kprintf("mmap: failed to allocate map object\n"); + return NULL; + } + error = vm_obj_init(map_obj, &vm_anonops, 1); + if (error < 0) { + kprintf("mmap: vm_obj_init() returned %d\n", error); + kprintf("mmap: failed to init object\n"); + return NULL; + } + } + + /* XXX: Assuming private */ + va = ALIGN_DOWN((vaddr_t)addr, DEFAULT_PAGESIZE); + + for (int i = 0; i < npgs; ++i) { + pg = vm_pagealloc(map_obj, PALLOC_ZERO); + page_off = i * DEFAULT_PAGESIZE; + + if (pg == NULL) { + /* TODO */ + pr_error("mmap: failed to allocate page %d\n"); + return NULL; + } + + /* TODO: copy-on-write */ + if (addr == NULL) { + va = pg->phys_addr; + addr = (void *)va; + } + + pa = pg->phys_addr; + error = vm_map(vas, va + page_off, pa, prot, len); + if (error < 0) { + pr_error("mmap: failed to map page (retval=%x)\n", error); + return NULL; + } + } + +done: + /* Add entry to ledger */ + td = this_td(); + ep = dynalloc(sizeof(*ep)); + if (ep == NULL) { + pr_error("mmap: failed to allocate mmap ledger entry\n"); + return NULL; + } + + ep->va_start = va; + ep->obj = map_obj; + ep->size = len; + mmap_add(td, ep); + return addr; +} + +/* + * Remove mappings for entire pages that + * belong to the current process. + * + * XXX: POSIX munmap(3) requires `addr' to be page-aligned + * and will return -EINVAL if otherwise. However, with + * OUSI munmap(3), `addr' is rounded down to the nearest + * multiple of the machine page size. + */ +int +munmap(void *addr, size_t len) +{ + int pgno; + vaddr_t va; + struct proc *td; + struct mmap_lgdr *lp; + struct mmap_entry find, *res; + struct vas vas; + + if (addr == NULL || len == 0) { + return -EINVAL; + } + + /* Apply machine specific addr/len adjustments */ + va = ALIGN_DOWN((vaddr_t)addr, DEFAULT_PAGESIZE); + len = ALIGN_UP(len, DEFAULT_PAGESIZE); + pgno = va >> 12; + + td = this_td(); + __assert(td != NULL && "no pid 1"); + vas = pmap_read_vas(); + + /* + * Try to get the mmap ledger, should not run into + * any issues as long as the PCB isn't borked. However, + * if it somehow is, just segfault ourselves. + */ + if ((lp = td->mlgdr) == NULL) { + __sigraise(SIGSEGV); + return -EFAULT; /* Unreachable */ + } + + /* Lookup entry in ledger with virtual address */ + find.va_start = va; + res = RBT_FIND(lgdr_entries, &lp->hd, &find); + if (res == NULL) { + pr_error("munmap: page %d not in ledger\n", pgno); + return -EINVAL; + } + + vm_unmap(vas, va, len); + mmap_remove(td, res); + return 0; +} + +/* + * mmap() syscall + * + * arg0 -> addr + * arg1 -> len + * arg2 -> prot + * arg3 -> flags + * arg4 -> fildes + * arg5 -> off + */ +scret_t +sys_mmap(struct syscall_args *scargs) +{ + void *addr; + size_t len; + int prot, flags; + int fildes, off; + + addr = (void *)scargs->arg0; + len = scargs->arg1; + prot = scargs->arg2 | PROT_USER; + flags = scargs->arg3; + fildes = scargs->arg4; + off = scargs->arg5; + return (scret_t)mmap(addr, len, prot, flags, fildes, off); +} + +/* + * munmap() syscall + * + * arg0 -> addr + * arg1 -> len + */ +scret_t +sys_munmap(struct syscall_args *scargs) +{ + void *addr; + size_t len; + + addr = (void *)scargs->arg0; + len = scargs->arg1; + return (scret_t)munmap(addr, len); +} + +/* * Create a virtual memory mapping in a specific * address space. * @@ -130,3 +448,12 @@ vm_unmap(struct vas vas, vaddr_t va, size_t count) { return vm_map_modify(vas, va, 0, 0, true, count); } + +/* + * Helper for tree(3) and the mmap ledger. + */ +int +mmap_entrycmp(const struct mmap_entry *a, const struct mmap_entry *b) +{ + return (a->va_start < b->va_start) ? -1 : a->va_start > b->va_start; +} |