Difference between revisions of "Memory layout"
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* [[Virtual address mapping New3DS v9.0]] | * [[Virtual address mapping New3DS v9.0]] | ||
* [[Virtual address mapping New3DS v9.2]] | * [[Virtual address mapping New3DS v9.2]] | ||
+ | * [[Virtual address mapping New3DS v11.1]] | ||
=ARM11 Detailed physical memory map= | =ARM11 Detailed physical memory map= |
Revision as of 02:34, 26 September 2016
Physical Memory
ARM11
Old 3DS | Address | Size | Description |
---|---|---|---|
Yes | 0x00000000 | 0x00010000 | Bootrom (super secret code/data @ 0x8000) |
Yes | 0x00010000 | 0x00010000 | Bootrom mirror |
Yes | 0x10000000 | ? | IO memory |
Yes | 0x17E00000 | 0x00002000 | MPCore private memory region |
No | 0x17E10000 | 0x00001000 | L2C-310 Level 2 Cache Controller (2MB) |
Yes | 0x18000000 | 0x00600000 | VRAM (divided in two banks, VRAM and VRAMB) |
No | 0x1F000000 | 0x00400000 | New_3DS additional memory |
Yes | 0x1FF00000 | 0x00080000 | DSP memory |
Yes | 0x1FF80000 | 0x00080000 | AXI WRAM |
Yes | 0x20000000 | 0x08000000 | FCRAM |
No | 0x28000000 | 0x08000000 | New_3DS FCRAM extension |
Yes | 0xFFFF0000 | 0x00010000 | Bootrom mirror |
0x17E10000
The 32-bit register at 0x17E10000
+0x100
only has bit 0 set when, on New 3DS, PTMSYSM:ConfigureNew3DSCPU was used with bit 1 set for the input value (the L2 cache flag). All other bits in this register are normally all-zero. Therefore, bit 0 set = new cache hardware enabled, bit 0 clear = new cache hardware disabled. This bit is how the ARM11 kernel checks whether the additional cache hardware is enabled).
To enable the additional cache hardware, the following is used by the ARM11 kernel:
- Sets bit 0 in 32-bit register
0x17E10000
+0x100
.
To disable the additional cache hardware, the following is used by the ARM11 kernel:
- Writes value
0xFFFF
to 32-bit register0x17E10000
+0x77C
. - Waits for bit 0 in 32-bit register
0x17E10000
+0x730
to become clear. - Writes value
0x0
to 32-bit register
0x17E10000
+0x0
. - Clears bit 0 in 32-bit register
0x17E10000
+0x100
.
0x1F000000
(New 3DS only)
This area is used by QTM Services,starting at offset 0x200000
, size 0x180000
. This area is not accessible to the GPU on the old 3DS. The old 3DS and New 3DS GSP module has vaddr->physaddr
conversion code for this entire region. On the New 3DS, only the first 0x200000
bytes (half of this memory) are accessible to the GPU.
ARM9
Old 3DS
Address
Size
Description
Yes
0x00000000
0x08000000
Instruction TCM, repeating each 0x8000 bytes.
Yes
0x01FF8000
0x00008000
Instruction TCM (Accessed by the kernel and process by this address)
Yes
0x07FF8000
0x00008000
Instruction TCM (Accessed by bootrom by this address)
Yes
0x08000000
0x00100000
ARM9-only internal memory (ARM7's internal regions are mapped here as well)
No
0x08100000
0x00080000
New_3DS ARM9-only extension, only enabled when a certain CONFIG register is set.
Yes
0x10000000
0x08000000
IO memory
Yes
0x18000000
0x00600000
VRAM (divided in two banks, VRAM and VRAMB)
Yes
0x1FF00000
0x00080000
DSP memory
Yes
0x1FF80000
0x00080000
AXI WRAM
Yes
0x20000000
0x08000000
FCRAM
No
0x28000000
0x08000000
New_3DS FCRAM extension
Yes
0xFFF00000
0x00004000
Data TCM (Mapped during bootrom)
Yes
0xFFFF0000
0x00010000
Bootrom, the main region is at +0x8000, which is disabled during system boot.
ARM9 MPU Regions
For the below instruction permissions: RO = memory is executable, while None = not-executable.
NATIVE_FIRM/SAFE_MODE_FIRM ARM9 kernel
Region
Address
Size
Privileged-mode data permissions
User-mode data permissions
Privileged-mode instruction permissions
User-mode instruction permissions
0
0xFFFF0000
32KB/0x8000
RO
None
RO
None
1
0x01FF8000
32KB/0x8000
RW
RW
RO
RO
2
0x08000000
1MB/0x100000. >=8.0.0-X: 2MB/0x200000.
RW
RW
RO
RO
3
0x10000000
128KB/0x20000
RW
RW
None
None
4
0x10100000
512KB/0x80000
RW
RW
None
None
5
0x20000000
128MB/0x8000000. >=8.0.0-X: 256MB/0x10000000.
RW
RW
None
None
6
0x08000000
128KB/0x20000
RW
None
RO
None
7
0x08020000
<3.0.0-5: 64KB/0x10000. >=3.0.0-5: 32KB/0x8000.
RW
None
RO
None
The above is the MPU region settings setup by the ARM9-kernel in the crt0.
The New3DS ARM9-kernel MPU region settings are the same as the Old3DS MPU region settings for >=8.0.0-X.
At the start of the Process9 function executed in kernel-mode via svc7b during firm-launching, it changes some MPU region settings. At the end of that function, before it uses the ARM9/ARM11 entrypoint fields, it disables MPU.
New3DS ARM9-loader
Region
Address
Size
Privileged-mode data permissions
User-mode data permissions
Privileged-mode instruction permissions
User-mode instruction permissions
0
0xFFFF0000
32KB/0x8000
RO
None
RO
None
1
0x01FF8000
32KB/0x8000
RW
None
RO
None
2
0x08000000
2MB/0x200000
RW
None
RO
None
3
0x10000000
128KB/0x20000
RW
None
None
None
MPU regions 4-7 are disabled. Note that the entire ARM9-loader runs in SVC-mode.
TWL_FIRM/AGB_FIRM ARM9 kernel
Region
Address
Size
Privileged-mode data permissions
User-mode data permissions
Privileged-mode instruction permissions
User-mode instruction permissions
0
0xFFFF0000
32KB/0x8000
RO
None
RO
None
1
0x01FF8000
32KB/0x8000
RW
RW
RO
RO
2
0x08000000
1MB/0x100000. New3DS: 2MB/0x200000.
RW
RW
RO
RO
3
0x10000000
2MB/0x200000.
RW
RW
None
None
4
0x1FF00000
512KB/0x80000
RW
RW
None
None
5
0x20000000
128MB/0x8000000. New3DS: 256MB/0x10000000.
RW
RW
None
None
6
0x08000000
<3.0.0-X: 256KB/0x40000. >=3.0.0-X: 128KB/0x20000
RW
None
RO
None
7
0x08080000
128KB/0x20000
RW
RW
RO
RO
ARM9 ITCM
ITCM mirror address
ITCM bootrom mirror address
Offset
Size
Description
0x01FF8000
0x0
0x3700
Uninitialized memory.
0x01FFB700
0x07FFB700
0x3700
0x100
The unprotected ARM9-bootrom code copies code from unprotected bootrom to 0x07FFB700(ITCM mirror) size 0x100, then calls the code at 0x07FFB700. The code located here is the code used for disabling access to the bootroms.
0x01FFB800
0x3800
0x4
This is always 0xDEADB00F.
0x01FFB804
0x3804
0x4
This is the u32 DeviceId.
0x01FFB808
0x3808
0x10
This is the fall-back keyY used for movable.sed keyY when movable.sed doesn't exist in NAND(the last two words here are used on retail for generating console-unique TWL keydata/etc). This is also used for "LocalFriendCodeSeed", etc.
0x01FFB818
0x3818
0x1
?
0x01FFB819
0x3819
0x1
This is the CTCert issuer type: 0 = retail "Nintendo CA - G3_NintendoCTR2prod", non-zero = dev "Nintendo CA - G3_NintendoCTR2dev".
0x01FFB81A
0x381A
0x6
?
0x01FFB820
0x3820
0x4
This is the CTCert ECDSA exponent, this is byte-swapped when *((u8*)(0x01FFB800+0x18)) is >=5.
0x01FFB824
0x3824
0x2
?
0x01FFB826
0x3826
0x1E
This is the CTCert ECDSA privk.
0x01FFB844
0x3844
0x3C
This is the CTCert ECDSA signature.
0x01FFB880
0x3880
0x80
This is all-zero.
0x01FFB900
0x3900
0x200
This is the 0x200-bytes from NAND sector0.
0x01FFBB00
0x3B00
0x200
This is the 0x200-bytes from the plaintext NAND firm partition FIRM header, read by bootrom.
0x01FFBD00
0x3D00
0x100
This is the RSA-2048 modulus for RSA-engine slot0 set by bootrom.
0x01FFBE00
0x3E00
0x100
This is the RSA-2048 modulus for RSA-engine slot1 set by bootrom.
0x01FFBF00
0x3F00
0x100
This is the RSA-2048 modulus for RSA-engine slot2.
0x01FFC000
0x4000
0x100
This is the RSA-2048 modulus for RSA-engine slot3.
0x01FFC100
0x4100
0x800
These are RSA-2048 keys: 4 slots, each slot is 0x200-bytes. Slot+0 is the modulus, slot+0x100 is the private exponent. This can be confirmed by RSA-decrypting a message into a signature, then RSA-encrypting the signature back into a message, and comparing the original message with the output from the last operation.
FIRM doesn't seem to ever use these. None of these are related to RSA-keyslot0 used for v6.0/v7.0 key generation. These moduli are separate from all other moduli used elsewhere.
0x01FFC900
0x07FFC900
0x4900
0x400
The unprotected ARM9-bootrom copies data to 0x07FFC900(mirror of 0x01FFC900) size 0x400. This data is copied from AXI WRAM, initialized by ARM11-bootrom(the addr used for the src is determined by REG_UNITINFO). These are RSA moduli: retailsrcptr = 0x1FFFD000, devsrvptr = 0x1FFFD400.
- The first 0x100-bytes here is the RSA-2048 modulus for the CFA NCCH header, and for the gamecard NCSD header.
- 0x01FFCA00 is the RSA-2048 modulus for the CXI accessdesc signature, written to rsaengine keyslot1 by NATIVE_FIRM.
- 0x01FFCB00 size 0x200 is unknown, probably RSA related, these aren't used by FIRM(these are not console-unique).
0x01FFCD00
0x4D00
0x80
Unknown, not used by FIRM. This isn't console-unique.
The first 0x10-bytes are checked by the v6.0/v7.0 NATIVE_FIRM keyinit function, when non-zero it clears this block and continues to do the key generation. Otherwise when this block was already all-zero, it immediately returns. This memclear was probably an attempt at destroying the RSA slot0 modulus, that missed (exactly 0x1000-bytes away). Even though they "failed" here, one would still need to derive the private exponent, which would require obtaining a ciphertext and plaintext.
0x01FFCD80
0x4D80
0x64
0x01FFCD84 size 0x10-bytes is the NAND CID(the 0x64-byte region at 0x01FFCD80 is initialized by Process9 + ARM9-bootrom). The u32 at 0x01FFCDC4 is the total number of NAND sectors, read from a MMC command.
0x01FFCDE4
0x4DE4
0x21C
Uninitialized memory.
0x01FFD000
0x07FFD000
0x5000
0x2470
The unprotected ARM9-bootrom copies 0x1FFFA000(AXIWRAM mem initialized by ARM11-bootrom) size 0x2470 to 0x07FFD000(mirror of 0x01FFD000). This block contains DSi keys.
- 0x01FFD000 is the RSA-1024 modulus for the retail System Menu
- 0x01FFD080 is the RSA-1024 modulus for DSi Wifi firmware and DSi Sound
- 0x01FFD100 is the RSA-1024 modulus for base DSi apps (Settings, Shop, etc.)
- 0x01FFD180 is the RSA-1024 modulus for DSiWare and RSA-signed cartridge headers
- 0x01FFD210 is the keyY for per-console-encrypted ES blocks
- 0x01FFD220 is the keyY for fixed-keyX ES blocks
- 0x01FFD300 is the DSi common (normal)key
- 0x01FFD350 is a normalkey set on keyslot 0x02, and is likely only used during boot
- 0x01FFD380 is the keyslot 0x00 keyX and the first half of the retail keyX for modcrypt crypto "Nintendo"
- 0x01FFD398 is the keyX used for 'Tad' crypto, usually in keyslot 0x02 "Nintendo DS", ..
- 0x01FFD3A8 is set as the middle two words of keyslot 0x03's keyX, before being overwritten "NINTENDO"
- 0x01FFD3BC is the keyY for keyslot 0x01, see below
- 0x01FFD3C8 is the fixed keyY used for eMMC partition crypto on retail DSi, see below (keyslot 0x03)
- 0x01FFD3E0 is the 0x1048-byte Blowfish data for DSi cart crypto
- 0x01FFE428 is the 0x1048-byte Blowfish data for DS cart crypto
On the 3DS, keyslots 0x01 and 0x03 have the last word set as 0xE1A00005 instead of the next word in ITCM. This is consistent with retail DSis.
0x01FFF470
0x7470
0xB90
Uninitialized memory.
0x01FFFC00 size 0x100-bytes starting with 9.5.0-X is the FIRM header used during FIRM-launching.
Memory map by firmware
- Virtual address mapping FW0B
- Virtual address mapping FW1F
- Virtual address mapping FW25
- Virtual address mapping FW2E
- Virtual address mapping FW37
- Virtual address mapping FW38
- Virtual address mapping FW3F
- FW49(9.6.0-X) and 10.0.0-X ARM11-kernel vmem mapping is identical to FW40(9.5.0-X).
ARM11 Detailed physical memory map
18000000 - 18600000: VRAM
1FF80000 - 1FFAB000: Kernel code
1FFAB000 - 1FFF0000: SlabHeap [temporarily contains boot processes]
1FFF0000 - 1FFF1000: ?
1FFF1000 - 1FFF2000: ?
1FFF2000 - 1FFF3000: ?
1FFF3000 - 1FFF4000: ?
1FFF4000 - 1FFF5000: Exception vectors
1FFF5000 - 1FFF5800: Unused?
1FFF5800 - 1FFF5C00: 256-entry L2 MMU table for VA FF4xx000
1FFF5C00 - 1FFF6000: 256-entry L2 MMU table for VA FF5xx000
1FFF6000 - 1FFF6400: 256-entry L2 MMU table for VA FF6xx000
1FFF6400 - 1FFF6800: 256-entry L2 MMU table for VA FF7xx000
1FFF6800 - 1FFF6C00: 256-entry L2 MMU table for VA FF8xx000
1FFF6C00 - 1FFF7000: 256-entry L2 MMU table for VA FF9xx000
1FFF7000 - 1FFF7400: 256-entry L2 MMU table for VA FFAxx000
1FFF7400 - 1FFF7800: 256-entry L2 MMU table for VA FFBxx000
1FFF7800 - 1FFF7C00: MMU table but unused?
1FFF7C00 - 1FFF8000: 256-entry L2 MMU table for VA FFFxx000
1FFF8000 - 1FFFC000: 4096-entry L1 MMU table for VA xxx00000 (CPU 0)
1FFFC000 - 20000000: 4096-entry L1 MMU table for VA xxx00000 (CPU 1)
20000000 - 28000000: Main memory
The entire FCRAM is cleared during NATIVE_FIRM boot. This is done by the ARM11 kernel in order by region as it initializes after loading FIRM launch parameters from FCRAM.
FCRAM memory-regions layout
FCRAM is partitioned into three regions of memory (APPLICATION, SYSTEM, and BASE). Most applications can only allocate memory from one of these regions (which is encoded in the process kernel flags). There is a fixed set of possible size of each memory region, determined by the APPMEMTYPE value in configuration memory (which in turn is set up according to the firmware launch parameters).
Support for APPMEMTYPEs 6 and 7 was implemented in NS with 8.0.0-18. These configurations are only supported in the New_3DS ARM11-kernel, and are in fact the only ones supported there at all. Applications only get access to the larger memory regions when this is specified in their extended header.
APPMEMTYPE
APPLICATION starting address (relative to FCRAM)
APPLICATION region size
SYSTEM starting address (relative to FCRAM)
SYSTEM region size
BASE starting address (relative to FCRAM)
BASE region size
0 (default with regular 3DS kernel, used when the type is not 2-5)
0x0
0x04000000(64MB)
0x04000000
0x02C00000
0x06C00000
0x01400000
2
0x0
0x06000000(96MB)
0x06000000
0x00C00000
0x06C00000
0x01400000
3
0x0
0x05000000(80MB)
0x05000000
0x01C00000
0x06C00000
0x01400000
4
0x0
0x04800000(72MB)
0x04800000
0x02400000
0x06C00000
0x01400000
5
0x0
0x02000000(32MB)
0x02000000
0x04C00000
0x06C00000
0x01400000
6 (This is the default on New3DS. With New_3DS kernel this is the type used when the value is not 7)
0x0
0x07C00000(124MB)
0x07C00000
0x06400000
0x0E000000
0x02000000
7
0x0
0x0B200000(178MB)
0x0B200000
0x02E00000
0x0E000000
0x02000000
The SYSTEM mem-region size is calculated with: size = FCRAMTOTALSIZE - (APPLICATION_MEMREGIONSIZE + BASE_MEMREGIONSIZE).
All memory allocated by the kernel itself for kernel use is located under BASE. Most system-modules run under the BASE memregion too.
Free/used memory on 4.5.0-10 with Home Menu / Internet Browser, with the default APPMEMTYPE on retail:
Region
Base address relative to FCRAM+0
Region size
Used memory once Home Menu finishes loading for system boot, on 4.5.0-10
Used memory with Internet Browser running instead of Home Menu, on 4.5.0-10
Free memory once Home Menu finishes loading for system boot, on 4.5.0-10
Free memory with Internet Browser running instead of Home Menu, on 4.5.0-10
APPLICATION
0x0
0x04000000
0x0
0x04000000
SYSTEM
0x04000000
0x02C00000
0x01488000
0x02A50000
0x01778000
0x001B0000
BASE
0x06C00000
0x01400000
0x01202000
0x01236000
0x001FE000
0x001CA000
ARM11 Detailed virtual memory map
(valid only for FW0B, see Memory map by firmware for subsequent versions)
E8000000 - E8600000: mapped VRAM (18000000 - 18600000)
EFF00000 - F0000000: mapped Internal memory (1FF00000 - 20000000)
F0000000 - F8000000: mapped Main memory
FF401000 - FF402000: mapped ? (27FC7000 - 27FC8000)
FF403000 - FF404000: mapped ? (27FC2000 - 27FC3000)
FF405000 - FF406000: mapped ? (27FBB000 - 27FBC000)
FF407000 - FF408000: mapped ? (27FB3000 - 27FB4000)
FF409000 - FF40A000: mapped ? (27F8E000 - 27F8F000)
FFF00000 - FFF45000: mapped SlabHeap
FFF60000 - FFF8B000: mapped Kernel code
FFFCC000 - FFFCD000: mapped IO I2C second bus (10144000 - 10145000)
FFFCE000 - FFFCF000: mapped IO PDC(LCD) (10400000 - 10401000)
FFFD0000 - FFFD1000: mapped IO PDN (10141000 - 10142000)
FFFD2000 - FFFD3000: mapped IO PXI (10163000 - 10164000)
FFFD4000 - FFFD5000: mapped IO PAD (10146000 - 10147000)
FFFD6000 - FFFD7000: mapped IO LCD (10202000 - 10203000)
FFFD8000 - FFFD9000: mapped IO DSP (10140000 - 10141000)
FFFDA000 - FFFDB000: mapped IO XDMA (10200000 - 10201000)
FFFDC000 - FFFE0000: mapped ? (1FFF8000 - 1FFFC000)
FFFE1000 - FFFE2000: mapped ? (1FFF0000 - 1FFF1000)
FFFE3000 - FFFE4000: mapped ? (1FFF2000 - 1FFF3000)
FFFE5000 - FFFE9000: mapped L1 MMU table for VA xxx00000
FFFEA000 - FFFEB000: mapped ? (1FFF1000 - 1FFF2000)
FFFEC000 - FFFED000: mapped ? (1FFF3000 - 1FFF4000)
FFFEE000 - FFFF0000: mapped IO IRQ (17E00000 - 17E02000)
FFFF0000 - FFFF1000: mapped Exception vectors
FFFF2000 - FFFF6000: mapped L1 MMU table for VA xxx00000
FFFF7000 - FFFF8000: mapped ? (1FFF1000 - 1FFF2000)
FFFF9000 - FFFFA000: mapped ? (1FFF3000 - 1FFF4000)
FFFFB000 - FFFFE000: mapped L2 MMU tables (1FFF5000 - 1FFF8000)
0xFF4XX000
Each thread is allocated a 0x1000-byte page in this region for the thread context: the first page at 0xFF401000 is for the first created thread, 0xFF403000 for the second thread. This region is used to store the SVC-mode stack for the thread, and thread context data used for context switching. When the IRQ handler, prefetch/data abort handlers, and undefined instruction handler are entered where the SPSR-mode=user, these handlers then store LR+SPSR for the current mode on the SVC-mode stack, then these handlers switch to SVC-mode.
This page does not contain a dedicated block for storing R0-PC(etc). For user-mode, the user-mode regs are instead saved on the SVC-mode stack when IRQs such as timers for context switching are triggered.
For NATIVE_FIRM the memory pages for this region are located in FCRAM, however for TWL_FIRM these are located in AXI WRAM. For TWL_FIRM v6704 the first thread's page for this region is located at physical address 0x1FF93000, the next one at 0x1FF92000, etc.
IO Process virtual addressing equivalence
It seems an IO register's process virtual address can be calculated by adding 0xEB00000 to its physical address. However for kernel mappings there is no fixed address equivalence.
ARM11 User-land memory regions
NATIVE_FIRM/SAFE_MODE_FIRM Userland Memory
Virtual Address Base
Physical Address Base
Region Max Size
Address-range available for svcMapMemoryBlock
Description
0x00100000 / 0x14000000
0x03F00000
No
The ExeFS:/.code is loaded here, executables must be loaded to the 0x00100000 region when the exheader "special memory" flag is clear. The 0x03F00000-byte size restriction only applies when this flag is clear. Executables are usually loaded to 0x14000000 when the exheader "special memory" flag is set, however this address can be arbitrary.
0x04000000
?
?
No
Used for mapping buffers during IPC, see IPC Command Structure.
0x08000000
Main stack physaddr - <heap size for the allocated vaddr 0x08000000 memory>
0x08000000
Yes
Heap mapped by ControlMemory
0x10000000-StackSize
.bss physical address - total stack pages
StackSize from process exheader
Stack for the main-thread, initialized by the ARM11 kernel. The StackSize from the exheader is usually 0x4000, therefore the stack-bottom is usually 0x0FFFC000. The stack for the other threads is normally located in the process .data section however this can be arbitrary.
0x10000000
0x04000000
Yes
Shared memory
0x14000000
FCRAM+0
0x08000000
No
Can be mapped by ControlMemory, this is used for processes' LINEAR/GSP heap.
0x1E800000
0x1F000000
0x00400000
No
New_3DS additional memory, access to this is specified by the exheader. Added with 8.0.0-18, see above section regarding this memory.
0x1EC00000
0x10100000
0x00400000
No
IO registers, the mapped IO pages which each process can access is specified in the exheader. (Applications normally don't have access to registers in this range)
0x1F000000
0x18000000
0x00600000
No
VRAM, access to this is specified by the exheader.
0x1FF00000
0x1FF00000
0x00080000
No
DSP memory, access to this is specified by the exheader.
0x1FF80000
FCRAM memory page allocated by the ARM11 kernel.
0x1000
No
Configuration Memory, all processes have read-only access to this.
0x1FF81000
FCRAM memory page allocated by the ARM11 kernel.
0x1000
No
Shared page, all processes have read-access to this. Write access to this is specified by the exheader "Shared page writing" kernel flag.
0x1FF82000
Dynamically taken from the BASE region of FCRAM
Number of threads * 0x1000 / 8
No
Thread Local Storage
0x30000000
FCRAM+0
0x08000000(Old3DS) / 0x10000000(New_3DS)
No
This LINEAR memory mapping was added with 8.0.0-18, see here. This replaces the original 0x14000000 mapping, for system(memory-region=BASE)/newer titles. The Old3DS kernel uses size 0x08000000 for LINEAR-memory address range checks, while the New3DS kernel uses size 0x10000000 for those range checks. Old3DS/New3DS system-module code doing vaddr->phys-addr conversion uses size 0x10000000.
0x20000000 / 0x40000000
This is the end-address of userland memory, memory under this address is process-unique. Memory starting at this address is only accessible in privileged-mode. This address was changed from 0x20000000 to 0x40000000 with 8.0.0-18.
All executable pages are read-only, and data pages have the execute-never permission set. Normally .text from the loaded ExeFS:/.code is the only mapped executable memory. Executable CROs can be loaded into memory, once loaded the CRO .text section memory page permissions are changed via ControlProcessMemory from RW- to R-X. The address and size of each ExeFS:/.code section is stored in the exheader, the permissions for each section is: .text R-X, .rodata R--, .data RW-, and .bss RW-. The loaded .code is mapped to the addresses specified in the exheader by the ARM11 kernel. The stack permissions is initialized by the ARM11 kernel: RW-. The heap permissions is normally RW-.
All userland memory is mapped with RW permissions for privileged-mode. However, normally the ARM11 kernel only uses userland read/write instructions(or checks that the memory can be written from userland first) for accessing memory specified by SVCs.
Processes can't directly access memory for other processes. When service commands are used, the kernel maps memory in the destination process for input/output buffers, where the addresses in the command received by the process is replaced by this mapped memory. When this is an input buffer, the buffer data is copied to the mapped memory. When this is an output buffer, the data stored in the mapped memory is copied to the destination buffer specified in the command.
The physical address which memory for the application memory-type is mapped to begins at FCRAM+0, the total memory allocated for this memory-type is stored in Configuration_Memory. Applications' .text + .rodata + .data under the application memory-type is mapped at FCRAM + APPMEMALLOC - (aligned page-size for .text + .rodata + .data). The application .bss is mapped at CODEADDR - .bss size aligned down to the page size.
TWL_FIRM Userland Memory
Virtual Address Base
Physical Address Base
Size
Description
0x00100000
0x1FFAB000 (with newer TWL_FIRM such as v6704 this is located at 0x1FFAC000)
0x00055000
Code + .(ro)data copied from the process 0x00300000 region is located here(.bss is located here as well).
0x00155000
0x18555000
0x000AB000
0x00200000
0x18500000
0x00100000
0x00300000
0x24000000
0x04000000
The beginning of the ARM11 process .text is located here.
0x08000000
0x20000000
0x07E00000
0x1EC00000
0x10100000
0x00400000
IO
0x1F000000
0x18000000
0x00600000
VRAM
0x1FF00000
0x1FF00000
0x00080000
This is mapped to the DSP memory.
The above regions are mapped by the ARM11 kernel. Later when the ARM11 process uses svcKernelSetState with type4, the kernel unmaps(?) the following regions: 0x00300000..0x04300000, 0x08000000..0x0FE00000, and 0x10000000..0xF8000000.
Detailed TWL_FIRM ARM11 Memory
Process Virtual Address
Physical Address
Size
Description
0x08000000
0x20000000
0x01000000*4
DS(i) 0x02000000 RAM. Vaddr = (DSRAMOffset*4) + 0x08000000, where DSRAMOffset is DSRAMAddr-0x02000000.
0x0FC00000
0x27C00000
Loaded SRL binary, initially the dev DSi launcher SRL is located here(copied here by the ARM11 process).
0x0FD00000
0x27D00000
The data located here is copied to here by the ARM11 process. The data located here is a TWL NAND bootloader image, using the same format+encryption/verification methods as the DSi NAND bootloader(stage2). The keyX for this bootloader keyslot is initially set to the retail DSi key-data, however when TWL_FIRM is launched this keyX key-data is replaced with a separate keyX. TWL_FIRM can use either the retail DSi bootloader RSA-1024 modulus, or a seperate modulus: normally only the latter is used(the former is only used when loading the image from FS instead of FCRAM). When using the image from FCRAM(default code-path), TWL_FIRM will not calculate+check the hashes for the bootloader code binaries(this is done when loading from FS however).
0x0FDF7000
0x27DF7000
0x1000
SRL header
System memory details
0xFFFF9000 Pointer to the current KThread instance
0xFFFF9004 Pointer to the current KProcess instance
0xFFFF9008 Pointer to the current KScheduler instance
0xFFFF9010 Pointer to the last KThread to encounter an exception
0x8000040 Pointer to the current KThread instance on the ARM9
0x8000044 Pointer to the current KProcess instance on the ARM9
0x8000048 Pointer to the current KScheduler instance on the ARM9
VRAM Map While Running System Applets
- 0x1E6000-0x22C500 -- top screen 3D left framebuffer 0(240x400x3) (The "3D right first-framebuf" addr stored in the LCD register is set to this, when the 3D is set to "off")
- 0x22C800-0x272D00 -- top screen 3D right framebuffer 0(240x400x3)
- 0x273000-0x2B9500 -- top screen 3D left framebuffer 1(240x400x3)
- 0x2B9800-0x2FFD00 -- top screen 3D right framebuffer 1(240x400x3)
- 0x48F000-0x4C7400 -- bottom screen framebuffer 0(240x320x3)
- 0x4C7800-0x4FF800 -- bottom screen framebuffer 1(240x320x3)
These LCD framebuffer addresses are not changed by the system when launching regular applications, the application itself handles that if needed. These VRAM framebuffers are cleared when launching regular applications.