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Homebrew PS2, PSP & PS3 Development Discussions
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IronPeter
Joined: 06 Aug 2007
Posts: 207
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 Posted: Sun Sep 21, 2008 7:09 am Post subject: linux kernel memory allocation. |
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That code allocates memory on PS3:
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**
* ps3_mm_region_create - create a memory region in the vas
* @r: pointer to a struct mem_region to accept initialized values
* @size: requested region size
*
* This implementation creates the region with the vas large page size.
* @size is rounded down to a multiple of the vas large page size.
*/
static int ps3_mm_region_create(struct mem_region *r, unsigned long size)
{
int result;
unsigned long muid;
r->size = _ALIGN_DOWN(size, 1 << PAGE_SHIFT_16M);
DBG("%s:%d requested %lxh\n", __func__, __LINE__, size);
DBG("%s:%d actual %lxh\n", __func__, __LINE__, r->size);
DBG("%s:%d difference %lxh (%luMB)\n", __func__, __LINE__,
(unsigned long)(size - r->size),
(size - r->size) / 1024 / 1024);
if (r->size == 0) {
DBG("%s:%d: size == 0\n", __func__, __LINE__);
result = -1;
goto zero_region;
}
result = lv1_allocate_memory(r->size, PAGE_SHIFT_16M, 0,
ALLOCATE_MEMORY_TRY_ALT_UNIT, &r->base, &muid);
....
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On my FW ( 1.9 ) that code works after main allocation:
result = lv1_allocate_memory( 6 * 1024 * 1024, 20,0,ALLOCATE_MEMORY_TRY_ALT_UNIT, &lpar, &muid);
ioremap ( and gpu_ioremap ) works for this lpar address.
So there are 6 free MiBs of memory, unused by Linux. Why? |
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ps2devman
Joined: 09 Oct 2006
Posts: 265
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| Posted: Sun Sep 21, 2008 7:19 pm Post subject: |
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Maybe a safety gap?
Allows future firmware update to have otheros bootstrap consumes a bit more? (for black listing or such...) |
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IronPeter
Joined: 06 Aug 2007
Posts: 207
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| Posted: Mon Sep 22, 2008 5:50 pm Post subject: |
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Anyhow, it is interesting to test this code ( giving 6+ free MiBs to Linux ):
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#define PAGE_SHIFT_1M 20
r->size = _ALIGN_DOWN(size, 1 << PAGE_SHIFT_1M);
result = lv1_allocate_memory(r->size, PAGE_SHIFT_1M, 0, ALLOCATE_MEMORY_TRY_ALT_UNIT, &r->base, &muid);
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Otherwise it is possible to write driver for additional memory allocation. |
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androvsky
Joined: 11 Nov 2007
Posts: 33
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| Posted: Tue Sep 23, 2008 2:33 am Post subject: |
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| IronPeter, this is probably off-topic, but I've been wondering if the PS3 you're testing on has some PS2 hardware in it. It might be interesting if you stumbled across that... ;) |
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IronPeter
Joined: 06 Aug 2007
Posts: 207
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| Posted: Wed Sep 24, 2008 2:51 am Post subject: |
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| I have no ideas about PS2 inside my PS3. Really no ideas :). |
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IronPeter
Joined: 06 Aug 2007
Posts: 207
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| Posted: Mon Oct 13, 2008 4:32 pm Post subject: alloc_memory - gpu_ioremap - release_memory cheat |
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I used memory chunk allocated by lv1_allocate_memory( 1 << 20, 20, 0, 0x04, &xdr_lpar, &muid );
The function lv1_gpu_context_iomap( context.handle, 0, xdr_lpar, 1 << 20, 0 ) returns 0. But RSX failed to write/read that memory. Why?
lv1_gpu_context_iomap( context.handle, 0, xdr_frame_buffer, 1 << 20, 0 ) works well for xdr frame buffer, it can be made visible both at GPU_IOIF and 0 addresses.
PS. I tried to test
1.) lv1_allocate_memory
2.) lv1_gpu_context_iomap
3.) lv1_release_memory
4.) some DMA transfers by GPU
I wanted to check GPU DMA protection (any access by CPU to released memory causes bus error ). But I failed at 2.) |
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