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[MEMORY] Procmm page fault handler

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This commit is contained in:
Thomas Lovén 2016-12-19 14:16:20 +01:00
parent 0101440894
commit aa50bbcd0f
3 changed files with 38 additions and 0 deletions
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2
kernel/include/process.h
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@ -3,6 +3,7 @@ typedef struct process_st process_t;
#include <stdint.h> #include <stdint.h>
#include <thread.h> #include <thread.h>
#include <mem.h> #include <mem.h>
#include <int.h>
#include <cpu.h> #include <cpu.h>
#include <sync.h> #include <sync.h>
#include <mem.h> #include <mem.h>
@ -62,3 +63,4 @@ void procmm_print_map(procmm_mmap_t *map);
procmm_area_t *procmm_map(procmm_mmap_t *map, uintptr_t start, uintptr_t end, uint64_t flags); procmm_area_t *procmm_map(procmm_mmap_t *map, uintptr_t start, uintptr_t end, uint64_t flags);
void procmm_unmap(procmm_area_t *a); void procmm_unmap(procmm_area_t *a);
uintptr_t procmm_setup(process_t *proc); uintptr_t procmm_setup(process_t *proc);
registers_t *procmm_page_fault(registers_t *r);

8
kernel/mem/vmm.c
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@ -4,6 +4,7 @@
#include <int.h> #include <int.h>
#include <registers.h> #include <registers.h>
#include <thread.h> #include <thread.h>
#include <scheduler.h>
#define STRIP_FLAGS(addr) ((void *)(((uintptr_t)(addr)) & ~PAGE_FLAGS_MASK)) #define STRIP_FLAGS(addr) ((void *)(((uintptr_t)(addr)) & ~PAGE_FLAGS_MASK))
@ -169,6 +170,13 @@ size_t vmm_p4_memset(page_table *P4, void *s, int c, size_t n)
registers_t *page_fault_handler(registers_t *r) registers_t *page_fault_handler(registers_t *r)
{ {
if(get_current_process())
{
registers_t *ret = procmm_page_fault(r);
if(ret)
return ret;
}
debug("\n ===== PAGE FAULT =====\n"); debug("\n ===== PAGE FAULT =====\n");
debug("Instruction at:%x tried to", r->rip); debug("Instruction at:%x tried to", r->rip);
if(r->err_code & 0x2) if(r->err_code & 0x2)

28
kernel/proc/procmm.c
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@ -1,6 +1,9 @@
#include <scheduler.h> #include <scheduler.h>
#include <list.h> #include <list.h>
#include <debug.h> #include <debug.h>
#include <int.h>
#include <cpu.h>
#include <registers.h>
procmm_mmap_t *procmm_new_map(process_t *proc, procmm_mmap_t *src) procmm_mmap_t *procmm_new_map(process_t *proc, procmm_mmap_t *src)
{ {
@ -112,3 +115,28 @@ uintptr_t procmm_setup(process_t *proc)
return brk_start; return brk_start;
} }
registers_t *procmm_page_fault(registers_t *r)
{
procmm_mmap_t *map = get_current_process()->mmap;
uintptr_t addr = read_cr2();
// We don't want to handle stuff in the kernel
if(addr >= KERNEL_OFFSET)
return 0;
// Check if we're close to the stack
if(map->stack)
{
if(map->stack->start <= addr + PAGE_SIZE)
{
debug("Increase user stack\n");
map->stack->start = map->stack->start - PAGE_SIZE;
vmm_set_page(map->P4, map->stack->start, pmm_alloc(), PAGE_PRESENT | PAGE_WRITE | PAGE_USER);
return r;
}
}
// If we reach this point, procmm couldn't handle the page fault
return 0;
}