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reserve at boot time a region for the heap

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=> no race between stack und heap creation
This commit is contained in:
Stefan Lankes 2016-11-27 23:21:47 +01:00 • committed by Daniel Krebs
parent 9d6375b8fb
commit cadacc24ae
4 changed files with 31 additions and 6 deletions
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3
include/hermit/config.h
View file

@ -42,7 +42,8 @@ extern "C" {
#define CACHE_LINE 64
#define KERNEL_STACK_SIZE (8*1024)
#define DEFAULT_STACK_SIZE (256*1024)
#define HEAP_START (1ULL << 34)
#define HEAP_START (PAGE_2M_FLOOR((size_t)&kernel_end) + 4*PAGE_SIZE)
#define HEAP_SIZE (1ULL << 32)
#define KMSG_SIZE (4*1024)
#define INT_SYSCALL 0x80
#define MAILBOX_SIZE 128

5
kernel/main.c
View file

@ -392,7 +392,9 @@ static int initd(void* arg)
curr_task->heap->start = PAGE_FLOOR(heap);
curr_task->heap->end = PAGE_FLOOR(heap);
// reserve VMA region
// region is already reserved for the heap, we have to change the
// property of the first page
vma_free(curr_task->heap->start, curr_task->heap->start+PAGE_SIZE);
vma_add(curr_task->heap->start, curr_task->heap->start+PAGE_SIZE, VMA_HEAP|VMA_USER);
//create_kernel_task(NULL, foo, "foo1", NORMAL_PRIO);
@ -595,6 +597,7 @@ int hermit_main(void)
PAUSE;
print_status();
//vma_dump();
create_kernel_task_on_core(NULL, initd, NULL, NORMAL_PRIO, boot_processor);

23
kernel/syscall.c
View file

@ -43,6 +43,13 @@
#include <lwip/err.h>
#include <lwip/stats.h>
/*
* Note that linker symbols are not variables, they have no memory allocated for
* maintaining a value, rather their address is their value.
*/
extern const void kernel_start;
extern const void kernel_end;
//TODO: don't use one big kernel lock to comminicate with all proxies
static spinlock_irqsave_t lwip_lock = SPINLOCK_IRQSAVE_INIT;
@ -244,11 +251,19 @@ ssize_t sys_sbrk(ssize_t incr)
spinlock_lock(&heap_lock);
ret = heap->end;
heap->end += incr;
// reserve VMA regions
if (PAGE_CEIL(heap->end) > PAGE_CEIL(ret))
vma_add(PAGE_CEIL(ret), PAGE_FLOOR(heap->end), VMA_HEAP|VMA_USER);
// check heapp boundaries
if ((heap->end >= HEAP_START) && (heap->end+incr < HEAP_START + HEAP_SIZE)) {
heap->end += incr;
// reserve VMA regions
if (PAGE_CEIL(heap->end) > PAGE_CEIL(ret)) {
// region is already reserved for the heap, we have to change the
// property
vma_free(PAGE_CEIL(ret), PAGE_FLOOR(heap->end));
vma_add(PAGE_CEIL(ret), PAGE_FLOOR(heap->end), VMA_HEAP|VMA_USER);
}
} else ret = -ENOMEM;
// allocation and mapping of new pages for the heap
// is catched by the pagefault handler

6
mm/vma.c
View file

@ -68,6 +68,11 @@ int vma_init(void)
if (BUILTIN_EXPECT(ret, 0))
goto out;
// reserve space for the heap
ret = vma_add(HEAP_START, HEAP_START+HEAP_SIZE, VMA_NO_ACCESS);
if (BUILTIN_EXPECT(ret, 0))
goto out;
#ifdef CONFIG_VGA
// add VGA video memory
ret = vma_add(VIDEO_MEM_ADDR, VIDEO_MEM_ADDR + PAGE_SIZE, VMA_READ|VMA_WRITE);
@ -141,6 +146,7 @@ found:
new->flags = flags;
new->next = succ;
new->prev = pred;
LOG_DEBUG("vma_alloc: create new vma, new->start 0x%zx, new->end 0x%zx\n", new->start, new->end);
if (succ)
succ->prev = new;