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#include "kernel/pmm.h"
#include "drivers/uart.h"
extern "C" char kernel_end[];
namespace PMM
{
struct Run
{
struct Run *next;
};
struct
{
struct Run *freelist;
} kmem;
inline uint64_t PGROUNDUP(uint64_t a)
{
return (a + PGSIZE - 1) & ~(PGSIZE - 1);
}
void init()
{
uint64_t start = PGROUNDUP((uint64_t)kernel_end);
Drivers::uart_puts("PMM: Initializing from");
for (uint64_t p = start; p + PGSIZE <= PHYSTOP; p += PGSIZE)
{
free_page((void *)p);
}
}
void free_page(void* pa)
{
struct Run *r;
if (((uint64_t)pa % PGSIZE) != 0 || (uint64_t)pa < (uint64_t)kernel_end || (uint64_t)pa >= PHYSTOP)
{
Drivers::uart_puts("PMM: Error - Invalid free address\n");
return;
}
r = (struct Run*)pa;
r->next = kmem.freelist;
kmem.freelist = r;
}
void* alloc_page()
{
struct Run* r;
r = kmem.freelist;
if (r)
{
kmem.freelist = r->next;
uint64_t *p = (uint64_t *)r;
for (int i = 0; i < PGSIZE / 8; i++)
{
p[i] = 0;
}
}
else
{
Drivers::uart_puts("PMM: Out of memory!\n");
}
return (void *)r;
}
}
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