449 lines
14 KiB
C
449 lines
14 KiB
C
#include <printf.h>
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#include <stdint.h>
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#include <libc.h>
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#include <limits.h>
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#include <panic.h>
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#include <math.h>
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#include <addr.h>
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#include <stdbool.h>
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#include <cpuid.h>
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//just using char because c is a lil bitch and won't let us use void
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extern char _kernel_shared_zone_begin;
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// PAGE MAPPING
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#define PAGEMAP_LOCATION 0x10000
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#define MAX_BUDDY_ORDER 8
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#define PALLOC_AUTO_BLEVEL MAX_BUDDY_ORDER
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typedef struct phys_map {
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struct phys_map *next;
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unsigned int max_buddy;
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uint64_t bsize[MAX_BUDDY_ORDER];
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uint64_t *buddy[MAX_BUDDY_ORDER];
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} pmap_t;
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static pmap_t *first_pmap;
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#define MEM_AVAILABLE 1
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#define MEM_RESERVED 2
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#define MEM_APCI_RECLAIMABLE 3
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#define MEM_APCI_NVS 4
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#define MEM_BAD 5
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// ZONES
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#define ZONE_MAP_PLOC 0x7000
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#define ZONE_MAP PHYS_TO_VIRT(ZONE_MAP_PLOC)
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//reorganized (moved) from header
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typedef struct __attribute__((packed)) {
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unsigned int present : 1; // present, must be one when accessed.
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unsigned int read_write : 1; // if set to one, read and write is set
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unsigned int user : 1; // For seperating CPL 0-2 and 3+
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unsigned int writethrough_cache : 1; // honestly maybe I should look into caching
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unsigned int cachable : 1; // hardware chaching. 0 is enabled, whats the worst that could happen?
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unsigned int accessed : 1; // we'll never use any of these!
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unsigned int zg0 : 1; // needs to be (and will be) zero'd
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unsigned int size : 1; // if set to 1, this entry points to physical memory
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unsigned int zg1 : 1; // needs to be (and will be) zero'd
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unsigned int software_marks : 3; // available for our own use, I doubt we'll use it in such a simple thing
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uintptr_t base_ptr : 40;
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unsigned int avail:11;
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unsigned int no_exec:1;
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} page_table;
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struct memory_table {
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void *base;
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uint64_t length;
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uint32_t type;
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uint32_t ACPI;
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} __attribute__((packed));
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static bool NX_capable;
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static bool huge_page_capable;
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void get_mem_capabilities() {
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uint32_t unused, edx;
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__get_cpuid(0x80000001, &unused, &unused, &unused, &edx);
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huge_page_capable = (edx >> 26) & 1;
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NX_capable = (edx >> 20) & 1;
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}
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void fix_stack() {
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struct stack_frame *frame;
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asm("addq rsp, %0\n"
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"addq rbp, %0\n"
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"mov %0, rbp"
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:"=r"(frame)
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:"r"(PA_OFFSET));
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while(frame->next != 0) {
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printf("%p\n", frame->function_base);
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frame->next = PHYS_TO_VIRT((void *)frame->next);
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frame = frame->next;
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}
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}
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void unmap_lowmem() {
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//[future]
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//eventually, you should use the function that unmaps pages when you write it
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page_table *entry = (page_table *)PAGEMAP_LOCATION;
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entry[0].present = 0;
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}
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void debug_print_memory() {
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struct memory_table *memtable = (void *)ZONE_MAP;
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printf(" __________________________________________________________________________\n");
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printf("| type\tstart\t\t\tend\t\t\tsize\t\t |\n");
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printf("|--------------------------------------------------------------------------|\n");
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for(unsigned int i = 0; memtable[i].length > 0; i++) {
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printf("| %u %u\t0x%p\t0x%p\t0x%p |\n", memtable[i].type, memtable[i].ACPI, memtable[i].base, (memtable[i].base + memtable[i].length), memtable[i].length);
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}
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printf("----------------------------------------------------------------------------\n");
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}
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void ram_stresser() {
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struct memory_table *memtable = (void *)ZONE_MAP - PA_OFFSET;
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memtable[6].length = 0x10000;
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}
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void debug_pmap() {
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pmap_t *pmap = first_pmap;
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int pmap_i = 0, order;
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uint64_t blong_i, bbit_i, buddy_chunksize, omit_cnt;
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printf("Maximum buddy order: %u (up to %#x sized chunks)\n", MAX_BUDDY_ORDER, ((0x1000 << MAX_BUDDY_ORDER) - 1));
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for(; pmap != 0; pmap = pmap->next) {
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printf("Table %u:\n"
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"\tPhysical/pmap start:\t%#p\n"
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"\tTable Size:\t%u\n", pmap_i, pmap,
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(uint64_t)(pmap->buddy[MAX_BUDDY_ORDER - 1] + pmap->bsize[MAX_BUDDY_ORDER - 1]) - (uint64_t)pmap);
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for(order = 0; order <= MAX_BUDDY_ORDER - 1; order++) {
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buddy_chunksize = (0x1000 << order); //TODO just put it in the for loop
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printf("\tbuddy[%u]:\n"
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"\t\tAddress:\t%#p\n"
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"\t\tSize:\t\t%u\n"
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"\t\tBuddies:\t\t\n", order, pmap->buddy[order], pmap->bsize[order]);
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omit_cnt = 0;
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for(blong_i = 0; blong_i < pmap->bsize[order]; blong_i++) {
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for(bbit_i = 0; bbit_i < 64; bbit_i++) {
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if((pmap->buddy[order][blong_i]) & ((uint64_t)1 << bbit_i)) {
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if((omit_cnt < 20) || (blong_i == pmap->bsize[order] - 1)) {
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printf("address %#p\tbit %u: %p\t is free\n",
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pmap->buddy[order] + blong_i,
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bbit_i,
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((uint64_t)pmap - PA_OFFSET) + ((((blong_i * 64) + bbit_i) * buddy_chunksize)));
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}
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omit_cnt++;
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if(omit_cnt == 20) {
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printf("\t\t\t[more entries ommited]\n");
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}
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}
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}
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}
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}
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pmap_i++;
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}
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}
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//TODO I know you don't want to, but you need to thoroughly check this.
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void pfree(void *addr, size_t size) {
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int blevel = 0;
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uint64_t *onbyte; //the byte out buddy resides on in the current level
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uint64_t page_bitloc; // how many bits we are away from buddy[0]. Helps calculate bitshifts
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int bbitlen; //length of free'd area in current level
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int lshift; //lshift is how many bits we shift over, rightbit is what it sounds like dumbass
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pmap_t *pmap = first_pmap;
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/* note: there's no security check to see if the page is actually allocated,
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* or if we are freeing the table itself.
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* This should be okay, as only the kernel will be calling it.
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* If it gets too messy we can always come back.
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*/
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if(((uintptr_t)addr & 4095) || (size & 4095)) {
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PANIC(KERNEL_PANIC_INVALID_PFREE);
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return; //TODO [minor] some more specificity, not a huge deal
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}
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size /= 0x1000;
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for(; pmap != 0; pmap = pmap->next) {
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page_bitloc = (addr - (void *)pmap) / 0x1000;
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onbyte = pmap->buddy[0] + (page_bitloc / 64);
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if((addr >= (void *)pmap) && onbyte < pmap->buddy[1]) break;
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}
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while(blevel < MAX_BUDDY_ORDER) {
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lshift = (page_bitloc / (1 << blevel)) & 63;
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onbyte = pmap->buddy[blevel] + ((page_bitloc / 64) / (1 << blevel));
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bbitlen = size / (1 << blevel);
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//TODO clean up this part ------------------------------------------------------------- (below)
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if(bbitlen <= 1) {
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if(lshift & 1) {
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if((*onbyte >> (lshift - 1)) & 1) {
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*onbyte &= ~(((uint64_t)1 << (lshift - 1)) | ((uint64_t)1 << lshift));
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size += (1 << blevel);
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page_bitloc -= (1 << blevel);
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bbitlen = size / (1 << blevel);
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}
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}
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else if((*onbyte >> (lshift + 1)) & 1) {
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*onbyte &= ~(((uint64_t)1 << (lshift + 1)) | ((uint64_t)1 << lshift));
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size += (1 << blevel);
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bbitlen = size / (1 << blevel);
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}
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}
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else if(((lshift + bbitlen) & 1) && ((*onbyte >> (lshift + bbitlen)) & 1)) {
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*onbyte ^= ((uint64_t)1 << (lshift + bbitlen));
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size += (1 << blevel);
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bbitlen = size / (1 << blevel);
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}
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//TODO clean up this part ------------------------------------------------------------- (above)
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if((!((size - 1) & size)) && (bbitlen != 1)) {
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blevel = 63 - __builtin_clzl(size);
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}
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else {
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if(bbitlen <= 1) {
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*onbyte |= ((uint64_t)1 << lshift);
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break;
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} else if(bbitlen & 1) { //check me
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size -= (1 << blevel);
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*onbyte |= ((uint64_t)1 << (bbitlen + lshift));
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}
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blevel++;
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}
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}
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}
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void *palloc(size_t size) {
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bool self_alloc;
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int min_blevel, blevel;
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uint64_t bbit, unshifted_entry, threshold, bloc; //TODO move when you've confirmed casting stuff
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uint64_t buddy_i, *ret, *bentry;
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int itercount;
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pmap_t *pmap = first_pmap;
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if(size == 0) return 0;
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if(size & 4095) {
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size = DIV_ROUND_UP(size, 0x1000);
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}
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else {
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size = size / 0x1000;
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}
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//checking if pmap has been initilized; if not we've been called to self allocate
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//the first buddy should never be allocated; that's where our pmap lives
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if(pmap->buddy[pmap->max_buddy][0] & 1) {
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self_alloc = true;
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min_blevel = pmap->max_buddy;
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}
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else {
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//log(size, 2)
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self_alloc = false;
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min_blevel = 63 - __builtin_clzl(size);
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if(size & (size - 1)) min_blevel++;
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if(min_blevel > MAX_BUDDY_ORDER - 1) return 0;
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}
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for(blevel = min_blevel; blevel < MAX_BUDDY_ORDER; blevel++) {
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for(pmap = first_pmap; pmap != 0; pmap = pmap->next) {
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for(buddy_i = 0; buddy_i < pmap->bsize[blevel]; buddy_i++) {
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if(pmap->buddy[blevel][buddy_i] > (uint64_t)0) {
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bentry = &pmap->buddy[blevel][buddy_i];
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bbit = __builtin_ctzl(*bentry);
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bloc = bbit;
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*bentry ^= (uint64_t)1 << bbit;
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ret = (((buddy_i * 64) + bbit) * (0x1000 << blevel)) + (void *)pmap;
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threshold = 0b11;
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itercount = 1;
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for(blevel--; blevel >= 0; blevel--) {
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bentry = pmap->buddy[blevel] + ((bentry - pmap->buddy[blevel + 1]) * 2);
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itercount++;
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if(bloc >= 32) bentry += 1;
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bloc = (bloc * 2) & 63; // will be the amount we need to shift
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bbit = ceil((float)size / (1 << blevel));
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unshifted_entry = ((uint64_t)1 << bbit) & threshold;
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if(unshifted_entry) {
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threshold = ((uint64_t)1 << (bbit * 2)) - 1;
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}
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else {
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threshold = (threshold << 2) | threshold;
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}
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*bentry |= (unshifted_entry << bloc);
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}
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if(!self_alloc) bzero(ret, size * 0x1000);
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return ret;
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}
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}
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}
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}
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return 0;
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}
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//returns size of pages needed
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size_t map_complete_physical() {
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uint64_t total_mem;
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unsigned int pdpe_cnt, pde_cnt, pde_max_i;
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int zone_i, entry_i;
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struct memory_table *zones = (void *)ZONE_MAP_PLOC;
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page_table *pml4 = (page_table *)PAGEMAP_LOCATION;
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page_table *pdpe = (page_table *)&_kernel_shared_zone_begin;
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page_table *pde;
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for(zone_i = 0; zones[zone_i].length > 0; zone_i++);
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total_mem = (uint64_t)zones[zone_i - 1].base + zones[zone_i - 1].length;
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pdpe_cnt = (total_mem + (0x40000000 - 1)) / 0x40000000;
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entry_i = (PA_OFFSET >> 39) & 0x1ff;
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pml4[entry_i].base_ptr = (uintptr_t)&_kernel_shared_zone_begin >> 12;
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pml4[entry_i].read_write = 1;
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pml4[entry_i].user = 0;
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pml4[entry_i].size = 0;
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pml4[entry_i].no_exec = 1;
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pml4[entry_i].present = 1;
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if(huge_page_capable) {
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for(int pdpe_i = 0; pdpe_i < pdpe_cnt; pdpe_i++) {
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pdpe[pdpe_i].base_ptr = pdpe_i << 18;
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pdpe[pdpe_i].read_write = 1;
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pdpe[pdpe_i].user = 0;
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pdpe[pdpe_i].size = 1;
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pdpe[pdpe_i].no_exec = NX_capable;
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pdpe[pdpe_i].present = 1;
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}
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return pdpe_cnt * 0x1000;
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}
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else {
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pde_cnt = (total_mem + 0x100000) / 0x200000;
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for(int pdpe_i = 0; pdpe_i < pdpe_cnt; pdpe_i++) {
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pde = (page_table *)(&_kernel_shared_zone_begin + (pdpe_cnt * 0x1000) + (pdpe_i * 0x1000));
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if((pdpe_i < pdpe_cnt - 1) || (!(pde_cnt & 511))) {
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pde_max_i = 512;
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}
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else {
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pde_max_i = pde_cnt & 511;
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}
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pdpe[pdpe_i].base_ptr = (uintptr_t)pde >> 12;
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pdpe[pdpe_i].read_write = 1;
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pdpe[pdpe_i].user = 0;
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pdpe[pdpe_i].size = 0;
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pdpe[pdpe_i].no_exec = NX_capable;
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pdpe[pdpe_i].present = 1;
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for(int pde_i = 0; pde_i < pde_max_i; pde_i++) {
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pde[pde_i].base_ptr = ((pdpe_i << 9) + pde_i) << 9;
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pde[pde_i].read_write = 1;
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pde[pde_i].user = 0;
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pde[pde_i].size = 1;
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pde[pde_i].no_exec = NX_capable;
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pde[pde_i].present = 1;
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}
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}
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return (pdpe_cnt * 2) * 0x1000;
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}
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}
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pmap_t *init_pmap(size_t pagetable_size) {
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pmap_t *pmap, *last_pmap;
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struct memory_table *zones = (void *)ZONE_MAP;
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int budorder, zone_i;
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uint64_t pmap_size, pmap_bbitsize, zone_size;
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bool first_pmap_i = true;
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for(zone_i = 0; zones[zone_i].length > 0; zone_i++) {
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if((zones[zone_i].type == MEM_AVAILABLE) && (zones[zone_i].ACPI & 1) &&
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zones[zone_i].length >= (0x2000)) {
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printf("found allocatable map at %p\n", zones[zone_i].base);
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last_pmap = pmap;
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if(zones[zone_i].base == (void *)0x100000) {
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zone_size = zones[zone_i].length - (((uint64_t)&_kernel_shared_zone_begin - 0x100000) + pagetable_size);
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pmap = PHYS_TO_VIRT((void *)&_kernel_shared_zone_begin + pagetable_size);
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}
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else {
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zone_size = zones[zone_i].length;
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pmap = PHYS_TO_VIRT(zones[zone_i].base);
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}
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if(first_pmap_i) {
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pmap->next = NULL;
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first_pmap_i = false;
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}
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else {
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pmap->next = last_pmap;
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}
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for(budorder = 0; budorder < MAX_BUDDY_ORDER; budorder++) {
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pmap_bbitsize = zone_size / (0x1000 << budorder);
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pmap->bsize[budorder] = DIV_ROUND_UP(pmap_bbitsize , 64);
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if(budorder) {
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pmap->buddy[budorder] = pmap->buddy[budorder - 1] + pmap->bsize[budorder - 1];
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}
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else {
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pmap->buddy[0] = (void *)pmap + sizeof(*pmap);
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}
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if(budorder < MAX_BUDDY_ORDER - 1) {
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bzero(pmap->buddy[budorder], pmap->bsize[budorder] * 8);
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if(pmap_bbitsize & 1) {
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pmap->buddy[budorder][pmap->bsize[budorder] - 1] =
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((uint64_t)1 << ((pmap_bbitsize - 1) & 63));
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}
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if(pmap_bbitsize == 1) {
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pmap->max_buddy = budorder;
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for(budorder++; budorder < MAX_BUDDY_ORDER; budorder++) {
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pmap->buddy[budorder] = 0;
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pmap->bsize[budorder] = 0;
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}
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break;
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}
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}
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else {
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pmap->max_buddy = MAX_BUDDY_ORDER - 1;
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memset(pmap->buddy[budorder], UINT8_MAX, pmap->bsize[budorder] * 8);
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if((pmap_bbitsize / 64) != (pmap->bsize[budorder])) {
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pmap->buddy[budorder][pmap->bsize[budorder] - 1] =
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(((uint64_t)1 << (pmap_bbitsize & 63)) - 1);
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}
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}
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}
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pmap_size = (uint64_t)(pmap->buddy[pmap->max_buddy] + pmap->bsize[pmap->max_buddy]) - (uint64_t)pmap;
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first_pmap = pmap; //we spoof palloc into allocating from the specific required pmap.
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palloc(pmap_size);
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}
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}
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return pmap;
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}
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