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Functions for copying stuff between kernel and user space

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This commit is contained in:
Thomas Lovén 2018-02-28 22:02:20 +01:00
parent ace36fe919
commit 19d58ec71d
3 changed files with 50 additions and 3 deletions
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5
src/kernel/boot/kmain.c
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@ -29,9 +29,8 @@ void kmain(uint64_t multiboot_magic, void *multiboot_data)
cpu_init();
struct process *p1 = new_process((void (*)(void))0x10000);
uint64_t page = pmm_alloc();
vmm_set_page(p1->P4, 0x10000, page, PAGE_WRITE | PAGE_PRESENT | PAGE_USER);
memcpy(P2V(page), (void *)(uintptr_t)thread_function, PAGE_SIZE);
vmm_set_page(p1->P4, 0x10000, pmm_calloc(), PAGE_WRITE | PAGE_PRESENT | PAGE_USER);
memcpy_k2u(p1->P4, (void *)0x10000, (void *)(uintptr_t)thread_function, 100);
ready(p1);

2
src/kernel/include/memory.h
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@ -45,6 +45,8 @@ uint64_t vmm_get_page(uint64_t P4, uint64_t addr);
#define PAGE_EXIST(p) ((p) != (uint64_t)-1)
int vmm_set_page(uint64_t P4, uint64_t addr, uint64_t page, uint16_t flags);
void vmm_clear_page(uint64_t P4, uint64_t addr, int free);
size_t memcpy_k2u(uint64_t P4, void *dst, void *src, size_t n);
size_t memcpy_u2k(void *dst, uint64_t P4, void *src, size_t n);
extern union PTE BootP4;
extern int kernel_start, kernel_end;

46
src/kernel/memory/vmm.c
View File

@ -1,4 +1,5 @@
#include <memory.h>
#include <debug.h>
#define FLAGS_MASK (PAGE_SIZE-1)
#define MASK_FLAGS(addr) ((uint64_t)addr & ~FLAGS_MASK)
@ -101,3 +102,48 @@ void vmm_clear_page(uint64_t P4, uint64_t addr, int free)
pmm_free(MASK_FLAGS(P4E));
P4E = 0;
}
#define min(a,b) (((a) < (b))?(a):(b))
#define offset(p) ((uintptr_t)(p) % PAGE_SIZE)
#define remaining(p) (PAGE_SIZE - offset(p))
size_t memcpy_k2u(uint64_t P4, void *dst, void *src, size_t n)
{
size_t copied = 0;
while(n)
{
size_t bytes = min(remaining(dst), n);
uintptr_t page = vmm_get_page(P4, (uintptr_t)dst);
if(!PAGE_EXIST(page))
return copied;
void *to = P2V(MASK_FLAGS(page) + offset(dst));
memcpy(to, src, bytes);
copied += bytes;
n -= bytes;
dst = incptr(dst, bytes);
src = incptr(src, bytes);
}
return copied;
}
size_t memcpy_u2k(void *dst, uint64_t P4, void *src, size_t n)
{
size_t copied = 0;
while(n)
{
size_t bytes = min(remaining(src), n);
uintptr_t page = vmm_get_page(P4, (uintptr_t)src);
if(!PAGE_EXIST(page))
return copied;
void *from = P2V(MASK_FLAGS(page) + offset(src));
memcpy(dst, from, bytes);
copied += bytes;
n -= bytes;
dst = incptr(dst, bytes);
src = incptr(src, bytes);
}
return copied;
}