void pg_map(phys_bytes phys, vir_bytes vaddr, vir_bytes vaddr_end,
kinfo_t *cbi)
{
static int mapped_pde = -1;
static u32_t *pt = NULL;
int pde, pte;
assert(kernel_may_alloc);
if(phys == PG_ALLOCATEME) {
assert(!(vaddr % ARM_PAGE_SIZE));
} else {
assert((vaddr % ARM_PAGE_SIZE) == (phys % ARM_PAGE_SIZE));
vaddr = pg_rounddown(vaddr);
phys = pg_rounddown(phys);
}
assert(vaddr < kern_vir_start);
while(vaddr < vaddr_end) {
phys_bytes source = phys;
assert(!(vaddr % ARM_PAGE_SIZE));
if(phys == PG_ALLOCATEME) {
source = pg_alloc_page(cbi);
} else {
assert(!(phys % ARM_PAGE_SIZE));
}
assert(!(source % ARM_PAGE_SIZE));
pde = ARM_VM_PDE(vaddr);
pte = ARM_VM_PTE(vaddr);
if(mapped_pde < pde) {
phys_bytes ph;
pt = alloc_pagetable(&ph);
pagedir[pde] = (ph & ARM_VM_PDE_MASK)
| ARM_VM_PAGEDIR
| ARM_VM_PDE_DOMAIN;
mapped_pde = pde;
}
assert(pt);
pt[pte] = (source & ARM_VM_PTE_MASK)
| ARM_VM_PAGETABLE
| ARM_VM_PTE_WT
| ARM_VM_PTE_USER;
vaddr += ARM_PAGE_SIZE;
if(phys != PG_ALLOCATEME)
phys += ARM_PAGE_SIZE;
}
}
/*===========================================================================*
* vm_addrok *
*===========================================================================*/
int vm_addrok(void *vir, int writeflag)
{
pt_t *pt = &vmprocess->vm_pt;
int pde, pte;
vir_bytes v = (vir_bytes) vir;
#if defined(__i386__)
pde = I386_VM_PDE(v);
pte = I386_VM_PTE(v);
#elif defined(__arm__)
pde = ARM_VM_PDE(v);
pte = ARM_VM_PTE(v);
#endif
if(!(pt->pt_dir[pde] & ARCH_VM_PDE_PRESENT)) {
printf("addr not ok: missing pde %d\n", pde);
return 0;
}
#if defined(__i386__)
if(writeflag &&
!(pt->pt_dir[pde] & ARCH_VM_PTE_RW)) {
printf("addr not ok: pde %d present but pde unwritable\n", pde);
return 0;
}
#endif
if(!(pt->pt_pt[pde][pte] & ARCH_VM_PTE_PRESENT)) {
printf("addr not ok: missing pde %d / pte %d\n",
pde, pte);
return 0;
}
#if defined(__i386__)
if(writeflag &&
!(pt->pt_pt[pde][pte] & ARCH_VM_PTE_RW)) {
printf("addr not ok: pde %d / pte %d present but unwritable\n",
#elif defined(__arm__)
if(!writeflag &&
!(pt->pt_pt[pde][pte] & ARCH_VM_PTE_RO)) {
printf("addr not ok: pde %d / pte %d present but writable\n",
#endif
pde, pte);
return 0;
}
/* This function sets up a mapping from within the kernel's address
* space to any other area of memory, either straight physical
* memory (pr == NULL) or a process view of memory, in 1MB windows.
* I.e., it maps in 1MB chunks of virtual (or physical) address space
* to 1MB chunks of kernel virtual address space.
*
* It recognizes pr already being in memory as a special case (no
* mapping required).
*
* The target (i.e. in-kernel) mapping area is one of the freepdes[]
* VM has earlier already told the kernel about that is available. It is
* identified as the 'pde' parameter. This value can be chosen freely
* by the caller, as long as it is in range (i.e. 0 or higher and corresonds
* to a known freepde slot). It is up to the caller to keep track of which
* freepde's are in use, and to determine which ones are free to use.
*
* The logical number supplied by the caller is translated into an actual
* pde number to be used, and a pointer to it (linear address) is returned
* for actual use by phys_copy or memset.
*/
static phys_bytes createpde(
const struct proc *pr, /* Requested process, NULL for physical. */
const phys_bytes linaddr,/* Address after segment translation. */
phys_bytes *bytes, /* Size of chunk, function may truncate it. */
int free_pde_idx, /* index of the free slot to use */
int *changed /* If mapping is made, this is set to 1. */
)
{
u32_t pdeval;
phys_bytes offset;
int pde;
assert(free_pde_idx >= 0 && free_pde_idx < nfreepdes);
pde = freepdes[free_pde_idx];
assert(pde >= 0 && pde < 4096);
if(pr && ((pr == get_cpulocal_var(ptproc)) || iskernelp(pr))) {
/* Process memory is requested, and
* it's a process that is already in current page table, or
* the kernel, which is always there.
* Therefore linaddr is valid directly, with the requested
* size.
*/
return linaddr;
}
if(pr) {
/* Requested address is in a process that is not currently
* accessible directly. Grab the PDE entry of that process'
* page table that corresponds to the requested address.
*/
assert(pr->p_seg.p_ttbr_v);
pdeval = pr->p_seg.p_ttbr_v[ARM_VM_PDE(linaddr)];
} else {
/* Requested address is physical. Make up the PDE entry. */
pdeval = (linaddr & ARM_VM_SECTION_MASK)
| ARM_VM_SECTION
| ARM_VM_SECTION_DOMAIN
| ARM_VM_SECTION_DEVICE
| ARM_VM_SECTION_USER;
}
/* Write the pde value that we need into a pde that the kernel
* can access, into the currently loaded page table so it becomes
* visible.
*/
assert(get_cpulocal_var(ptproc)->p_seg.p_ttbr_v);
if(get_cpulocal_var(ptproc)->p_seg.p_ttbr_v[pde] != pdeval) {
get_cpulocal_var(ptproc)->p_seg.p_ttbr_v[pde] = pdeval;
*changed = 1;
}
/* Memory is now available, but only the 1MB window of virtual
* address space that we have mapped; calculate how much of
* the requested range is visible and return that in *bytes,
* if that is less than the requested range.
*/
offset = linaddr & ARM_VM_OFFSET_MASK_1MB; /* Offset in 1MB window. */
*bytes = MIN(*bytes, ARM_SECTION_SIZE - offset);
/* Return the linear address of the start of the new mapping. */
return ARM_SECTION_SIZE*pde + offset;
}
/*===========================================================================*
* findhole *
*===========================================================================*/
static u32_t findhole(int pages)
{
/* Find a space in the virtual address space of VM. */
u32_t curv;
int pde = 0, try_restart;
static u32_t lastv = 0;
pt_t *pt = &vmprocess->vm_pt;
vir_bytes vmin, vmax;
#if defined(__arm__)
u32_t holev;
#endif
vmin = (vir_bytes) (&_end); /* marks end of VM BSS */
vmin += 1024*1024*1024; /* reserve 1GB virtual address space for VM heap */
vmin &= ARCH_VM_ADDR_MASK;
vmax = VM_STACKTOP;
/* Input sanity check. */
assert(vmin + VM_PAGE_SIZE >= vmin);
assert(vmax >= vmin + VM_PAGE_SIZE);
assert((vmin % VM_PAGE_SIZE) == 0);
assert((vmax % VM_PAGE_SIZE) == 0);
#if defined(__arm__)
assert(pages > 0);
#endif
#if SANITYCHECKS
curv = ((u32_t) random()) % ((vmax - vmin)/VM_PAGE_SIZE);
curv *= VM_PAGE_SIZE;
curv += vmin;
#else
curv = lastv;
if(curv < vmin || curv >= vmax)
curv = vmin;
#endif
try_restart = 1;
/* Start looking for a free page starting at vmin. */
while(curv < vmax) {
int pte;
#if defined(__arm__)
int i, nohole;
#endif
assert(curv >= vmin);
assert(curv < vmax);
#if defined(__i386__)
pde = I386_VM_PDE(curv);
pte = I386_VM_PTE(curv);
#elif defined(__arm__)
holev = curv; /* the candidate hole */
nohole = 0;
for (i = 0; i < pages && !nohole; ++i) {
if(curv >= vmax) {
break;
}
#endif
#if defined(__i386__)
if(!(pt->pt_dir[pde] & ARCH_VM_PDE_PRESENT) ||
!(pt->pt_pt[pde][pte] & ARCH_VM_PAGE_PRESENT)) {
#elif defined(__arm__)
pde = ARM_VM_PDE(curv);
pte = ARM_VM_PTE(curv);
/* if page present, no hole */
if((pt->pt_dir[pde] & ARCH_VM_PDE_PRESENT) &&
(pt->pt_pt[pde][pte] & ARCH_VM_PTE_PRESENT))
nohole = 1;
/* if not contiguous, no hole */
if (curv != holev + i * VM_PAGE_SIZE)
nohole = 1;
curv+=VM_PAGE_SIZE;
}
/* there's a large enough hole */
if (!nohole && i == pages) {
#endif
lastv = curv;
#if defined(__i386__)
return curv;
#elif defined(__arm__)
return holev;
#endif
}
#if defined(__i386__)
curv+=VM_PAGE_SIZE;
#elif defined(__arm__)
/* Reset curv */
#endif
if(curv >= vmax && try_restart) {
curv = vmin;
try_restart = 0;
}
}
printf("VM: out of virtual address space in vm\n");
return NO_MEM;
}
/*===========================================================================*
* vm_freepages *
*===========================================================================*/
void vm_freepages(vir_bytes vir, int pages)
{
assert(!(vir % VM_PAGE_SIZE));
if(is_staticaddr(vir)) {
printf("VM: not freeing static page\n");
return;
}
if(pt_writemap(vmprocess, &vmprocess->vm_pt, vir,
MAP_NONE, pages*VM_PAGE_SIZE, 0,
WMF_OVERWRITE | WMF_FREE) != OK)
panic("vm_freepages: pt_writemap failed");
vm_self_pages--;
#if SANITYCHECKS
/* If SANITYCHECKS are on, flush tlb so accessing freed pages is
* always trapped, also if not in tlb.
*/
if((sys_vmctl(SELF, VMCTL_FLUSHTLB, 0)) != OK) {
panic("VMCTL_FLUSHTLB failed");
}
#endif
}
