Imagelibrary/riscv-operating-system-mooc
1
0
Fork 0
mirror of https://github.com/plctlab/riscv-operating-system-mooc.git synced 2025-12-26 09:09:11 +00:00
Code Issues Packages Projects Releases Wiki Activity

Improve memory/page init

Browse Source 
Align heap start and caculate number of reserved pages
according to the length of ram available.

See
https://gitee.com/unicornx/riscv-operating-system-mooc/issues/I9LNCF.

Signed-off-by: Chen Wang <unicorn_wang@outlook.com>
This commit is contained in:
Chen Wang
2024-06-04 21:15:33 +08:00
parent 0e16685c97
commit eb61470e22
33 changed files with 428 additions and 64 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
code/os/06-interrupts/os.ld
View File

@@ -3,6 +3,8 @@
* Linker script for outputting to RVOS
*/
#include "platform.h"
/*
* https://sourceware.org/binutils/docs/ld/Miscellaneous-Commands.html
* OUTPUT_ARCH command specifies a particular output machine architecture.
@@ -47,7 +49,7 @@ ENTRY( _start )
*/
MEMORY
{
ram (wxa!ri) : ORIGIN = 0x80000000, LENGTH = 128M
ram (wxa!ri) : ORIGIN = 0x80000000, LENGTH = LENGTH_RAM
}
/*

40
code/os/06-interrupts/page.c
View File

@@ -76,22 +76,52 @@ static inline ptr_t _align_page(ptr_t address)
return (address + order) & (~order);
}
/*
* ______________________________HEAP_SIZE_______________________________
* / ___num_reserved_pages___ ______________num_pages______________ \
* / / \ / \ \
* |---|<--Page-->|<--Page-->|...|<--Page-->|<--Page-->|......|<--Page-->|---|
* A A A A A
* | | | | |
* | | | | _memory_end
* | | | |
* | _heap_start_aligned _alloc_start _alloc_end
* HEAP_START(BSS_END)
*
* Note: _alloc_end may equal to _memory_end.
*/
void page_init()
{
ptr_t _heap_start_aligned = _align_page(HEAP_START);
/*
* We reserved 8 Page (8 x 4096) to hold the Page structures.
* It should be enough to manage at most 128 MB (8 x 4096 x 4096)
* We reserved some Pages to hold the Page structures.
* The number of reserved pages depends on the LENGTH_RAM.
* For simplicity, the space we reserve here is just an approximation,
* assuming that it can accommodate the maximum LENGTH_RAM.
* We assume LENGTH_RAM should not be too small, ideally no less
* than 16M (i.e. PAGE_SIZE * PAGE_SIZE).
*/
_num_pages = (HEAP_SIZE / PAGE_SIZE) - 8;
printf("HEAP_START = %p, HEAP_SIZE = 0x%lx, num of pages = %d\n", HEAP_START, HEAP_SIZE, _num_pages);
uint32_t num_reserved_pages = LENGTH_RAM / (PAGE_SIZE * PAGE_SIZE);
_num_pages = (HEAP_SIZE - (_heap_start_aligned - HEAP_START))/ PAGE_SIZE - num_reserved_pages;
printf("HEAP_START = %p(aligned to %p), HEAP_SIZE = 0x%lx,\n"
"num of reserved pages = %d, num of pages to be allocated for heap = %d\n",
HEAP_START, _heap_start_aligned, HEAP_SIZE,
num_reserved_pages, _num_pages);
/*
* We use HEAP_START, not _heap_start_aligned as begin address for
* allocating struct Page, because we have no requirement of alignment
* for position of struct Page.
*/
struct Page *page = (struct Page *)HEAP_START;
for (int i = 0; i < _num_pages; i++) {
_clear(page);
page++;
}
_alloc_start = _align_page(HEAP_START + 8 * PAGE_SIZE);
_alloc_start = _heap_start_aligned + num_reserved_pages * PAGE_SIZE;
_alloc_end = _alloc_start + (PAGE_SIZE * _num_pages);
printf("TEXT: %p -> %p\n", TEXT_START, TEXT_END);

3
code/os/06-interrupts/platform.h
View File

@@ -12,6 +12,9 @@
*/
#define MAXNUM_CPU 8
/* used in os.ld */
#define LENGTH_RAM 128*1024*1024
/*
* MemoryMap
* see https://github.com/qemu/qemu/blob/master/hw/riscv/virt.c, virt_memmap[]