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pmm: properly detect first available memory region #281

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Aug 22, 2023
Merged

pmm: properly detect first available memory region #281

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40 changes: 31 additions & 9 deletions mm/pmm.c
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Original file line number Diff line number Diff line change
Expand Up @@ -30,8 +30,6 @@
#include <mm/regions.h>
#include <mm/vmm.h>

#define PMM_FIRST_AVAIL_REGION 1

size_t total_phys_memory;

static list_head_t frames;
Expand Down Expand Up @@ -246,7 +244,27 @@ static inline unsigned int find_max_avail_order(size_t size) {
return PAGE_ORDER_4K;
}

static size_t process_memory_range(unsigned index) {
static unsigned find_first_avail_region(void) {
addr_range_t range;

for (unsigned int i = 0; i < regions_num; i++) {
if (get_avail_memory_range(i, &range) < 0)
continue;

if (_paddr(range.start) < _paddr(MB(1)))
continue;

if (_paddr(range.end) - _paddr(range.start) < MB(EARLY_VIRT_MEM))
continue;

return i;
}

panic("PMM: Cannot obtain first available physical memory address range\n");
UNREACHABLE();
}

static size_t process_memory_range(unsigned index, unsigned first_avail_region) {
paddr_t start, end, cur;
unsigned int max_order;
addr_range_t range;
Expand All @@ -267,7 +285,7 @@ static size_t process_memory_range(unsigned index) {

/* Add initial 4K frames and align to 2M. */
while ((cur < MB(EARLY_VIRT_MEM) || cur % PAGE_SIZE_2M) && cur + PAGE_SIZE <= end) {
if (index <= PMM_FIRST_AVAIL_REGION)
if (index <= first_avail_region)
add_early_frame(paddr_to_mfn(cur), PAGE_ORDER_4K);
else
add_frame(paddr_to_mfn(cur), PAGE_ORDER_4K);
Expand Down Expand Up @@ -320,11 +338,11 @@ void reclaim_frame(mfn_t mfn, unsigned int order) {
add_frame(mfn, order);
}

static inline void check_early_frames(void) {
static inline void check_early_frames(unsigned first_avail_region) {
unsigned early_frames_cnt;
addr_range_t range;

if (get_avail_memory_range(PMM_FIRST_AVAIL_REGION, &range) < 0)
if (get_avail_memory_range(first_avail_region, &range) < 0)
panic("PMM: Cannot obtain first available physical memory address range\n");

early_frames_cnt =
Expand All @@ -336,6 +354,8 @@ static inline void check_early_frames(void) {
}

void init_pmm(void) {
unsigned first_region_index;

printk("Initialize Physical Memory Manager\n");

BUILD_BUG_ON(sizeof(frames_array_t) > PAGE_SIZE);
Expand All @@ -348,13 +368,15 @@ void init_pmm(void) {
list_init(&busy_frames[order]);
}

first_region_index = find_first_avail_region();

/* Skip low memory range */
for (unsigned int i = PMM_FIRST_AVAIL_REGION; i < regions_num; i++)
total_phys_memory += process_memory_range(i);
for (unsigned int i = first_region_index; i < regions_num; i++)
total_phys_memory += process_memory_range(i, first_region_index);

display_frames_count();

check_early_frames();
check_early_frames(first_region_index);

if (opt_debug)
display_frames();
Expand Down