GitLab

In HandleServiceModeTranslation, make sure WsPtr is initialised
correctly before trying to use it. Fixes system heap corruption when
responding to Service_ModeTranslation (most likely overwriting part of
ChocolateMABlocks, and causing a crash when loading future modules)

Fixes issue reported on forums:
https://www.riscosopen.org/forum/forums/11/topics/15973

Version 6.47. Tagged as 'Kernel-6_47'

Detail:
RamFS now supports disc sizes up to 2GB-4KB, so raise the dynamic area limit from 508MB.

Admin:
Tested with a disc size up to 928MB

Version 6.46. Tagged as 'Kernel-6_46'

Changes in Kernel-6_44 left an undefined symbol in s.HAL in DebugTerminal_Rdch. These mods resolve that, and also add a note in s.Kernel to reflect this usage.

Version 6.45. Tagged as 'Kernel-6_45'

Previously both `RdchInkey` and `PageTest` enabled interrupts after
running callbacks before calling Portable_Idle with the result that
callback could be delayed until the next interrupt.

* Change `process_callback_chain` to leave interrupts disabled, and
  rename accordingly.
* Remove redundant check of CallBack_Flag.
* In `PageTest` move running calbacks into `CtrlShiftTest`, so that
  it is immediately before the test.
* Re-enable interrupts at appropriate locations.

Tested on StrongARM Risc PC.

Version 6.44. Tagged as 'Kernel-6_44'

Version 6.43. Not tagged

Multiple fixes, mostly related to error handling.

1. Ensure R1 is initialised correctly when generating BadPageNumber
errors (labels 94 & 95). Generally this involves setting it to zero to
indicate that no call to LogOp_MapOut is required. Failing to do this
would typically result in a crash.
2. When branching back to the start of the loop after calling
GetNonReservedPage, ensure R0 is reset to zero. Failing to do this would
have a performance impact on LogOp_MapOut, but shouldn't be fatal.
3. In the main routine, postpone writing back DANode_Size until after
the call to physical_to_ppn (because we may decide to abort the op
and return an error without moving a page).
4. Fix stack offset when accessing PMPLogOp_GlobalTBLFlushNeeded.
Getting this wrong could potentially result in some TLB maintenance
being skipped when moving uncacheable pages.
5. Fix stack imbalance at label 94

Version 6.43. Tagged as 'Kernel-6_43'

This ensures that on exit from OS_ReadC / INKEY either
a character is returned or the input buffer is empty,
and that Portable_Idle is only called when the input
buffer is empty.

This avoids a 10 microsecond delay and relying on timer
interrupts to make progress and allows reliably waiting
for input and another event by:

Disable Interrupts
Repeat
  Call INKEY(0), exit loop if key pressed
  Check other event, exit loop if key pressed
  Call Portable_Idle

Version 6.42. Tagged as 'Kernel-6_42'

The current OS_Memory 7 implementation uses an address range structure
returned by HAL_PhysInfo to decide which part of the physical address
arrangement table to overwrite with RAM information. I suspect the
original intention was for OS_Memory to use this address range to avoid
marking the VRAM as DRAM (HAL_PhysInfo is expected to fill in the VRAM
itself). But by overwriting everything between the start and the end
address, OS_Memory will also overwrite any non-RAM areas which are
sandwiched between RAM banks, e.g. the VideoCore-owned RAM on Pi models
with >1GB RAM. There's also the problem that the address range returned
by the HAL is using 32bit addresses, so it won't work as-is for RAM
located above the 4GB barrier.

Fix these issues by reworking the routine so that it ignores the address
range returned by the HAL and instead detects VRAM by checking the
IsVRAM flag in the PhysRamTable entry. And for detecting if the ROM is
running from RAM, instead of using the address range we can rely on the
flag available via OS_ReadSysInfo 8 (i.e. HAL_PlatformInfo), like
OS_Memory 8 does.

Also add a simple BASIC program (Dev.PhysInfo) to allow easy checking of
HAL & OS physical address arrangement tables.

Version 6.41. Tagged as 'Kernel-6_41'

Fix GrowFreePoolFromAppSpace (i.e. appspace shrink operation) to issue
UpCall_MemoryMoving / Service_Memory when attempting to shrink PMP-based
appspace (i.e. AMBControl nodes). This fixes (e.g.) BASIC getting stuck
in an abort loop if you try and use OS_ChangeDynamicArea to grow the
free pool.

Version 6.40. Tagged as 'Kernel-6_40'

Despite never being properly documented in the RISC OS PRMs, there's
evidence that Acorn were recommending that third-parties used OS_Byte
166 for locating the OS_Byte variables well into the mid-1990's:

https://www.riscosopen.org/forum/forums/5/topics/14676#posts-94080

Currently OS builds which use zero page relocation will only return the
low 16 bits of the address from OS_Byte 166, most likely breaking any
third-party software which is trying to use it. Attempt to restore
compatibility by having OS_Byte 166 add the missing high address bits
into the "next location" value returned in R2, and fix OS_Byte 167 in a
similar manner (adding into R1).

Additionally, make the values read-only, because the kernel is littered
with code that uses hard-coded OsbyteVars addresses and so is unlikely
to do anything sensible if someone was to modify the OsbyteVars address
that's stored in workspace.

Version 6.39. Tagged as 'Kernel-6_39'

* Create new header file defining symbolic name for OS_AMBControl
  reason codes and flags
* Implement OS_AMBControl 9 (used to determine required size of buffer
  passed to OS_AMBControl 8 - potential thread safety issue not addressed)
* Return allocated error numbers in various failure cases

Version 6.38. Tagged as 'Kernel-6_38'

Edits to the RISCOS header file should really have gone through the
allocations system. Fortunately, no harm was done in this case, but a
minor syntactical change is required in order to bring it in line with
the automatic redaction scripts used when exporting the header from the
allocations database.

Version 6.37. Not tagged

* Listen out for PointerV 9, which (RISC OS 5) mouse drivers use to
indicate scroll wheel updates + extra button status
* Changes in the state of the extra buttons are treated the same as
changes to normal mouse buttons: signalled via Event_Mouse, and stored
in the mouse buffer (for reading via OS_Mouse).
* Changes in the scroll wheel(s) are signalled via Event_Expansion,4. If
the event vector call is unclaimed, the kernel's wheel position
accumulators will be updated
* Wheel position accumulators can be read via OS_Pointer 2
* Wheel position accumulators implement "wrap to zero" logic on overflow

This matches RISCOS Ltd's implementation
(http://www.riscos.com/support/developers/riscos6/input/pointerdevices.html),
except that:

* The kernel currently doesn't call PointerV 4, so PointerV 9 is the
only way drivers can report wheel + extra button status
* Extra mouse buttons don't generate KeyV transitions
* Our implementation is in the kernel, not an OSPointer module

Version 6.37. Tagged as 'Kernel-6_37'

During ModHandReason_ClaimAligned care is taken to start on a multiple of 32 and end on a multiple of 32 + 16 (such that the next block in the heap would be at +20 same as plain ModHandReason_Claim would do). However, during a ModHandReason_ExtendBlock there's a possibility that those criteria can't be retained, due to having to move to a larger gap elsewhere, leaving the end at an inconvenient +36.
Similar allocation functions in other OS' don't guarantee to return an extended block with the same alignment, so take the position that for extends we always allocate a fresh block, copy the contents, and free the original. Shrinks are left in place.
Tested with a random allocator which juggles 16 aligned allocations 50,000 times.

Version 6.36. Tagged as 'Kernel-6_36'

OS_Module
=> R0=24
   R3=size in bytes
   R4=alignment in bytes (must be a power of 2)
<= R2=base of request
   or error
Tested with a handful of valid and invalid alignments, and with one grossly larger than the free RMA to trigger an RMA extend to occur.

Version 6.35. Tagged as 'Kernel-6_35'

Detail:
  * various low-numbered dynamic areas used by RISC OS 6 and Pyromaniac
  * OS_ReadSysInfo 8 host platform classes for VirtualRPC, A9Home, Pyromaniac
  * OS_Byte 0,<not 0> MosVer values for various systems since the BBC micro
  * OS_Byte 129,0,255 (BASIC INKEY -256) values for various RISC OS systems

Admin:
  Discovered that these weren't really recorded anywhere during recent
  allocation request. Some information gleaned from http://beebwiki.mdfs.net

Version 6.34. Not tagged

Dynamic area PostGrow handlers aren't able to return errors, so the V
flag is likely undefined. Fix AreaGrow so that it ignores any V-set
condition returned by the call (especially since the CallPostGrow rapper
will have clobbered any error pointer).

Fixes issue reported on forums:
https://www.riscosopen.org/forum/forums/4/topics/14662

Version 6.34. Tagged as 'Kernel-6_34'

The XHCIDriver module adds 64k to get the register address. In an attempt to phase this out (so the registers are the true base address), assign a flag so that loading a suitable XHCIDriver on an old HAL still works.

Version 6.33. Not tagged

* Update OS_ScreenMode 11's handling of drivers which fail to
initialise. If there was no previous driver, then instead of trying to
restore that nonexistant driver, stick with the new one. This is mainly
to help with the case where the kernel's built in modes aren't accepted
by the driver, and valid modes only become available once an MDF is
loaded (this can happen with early OMAP3 chip revisions, which have very
tight sync & porch limits, causing 90% of the kernel's modes to be
rejected). If the kernel was to revert to the "no driver" state, then
loading the MDF would still leave you with no video output.
* Since we can now end up in a state where a driver is selected but
hasn't been programmed yet, update OS_Byte 19 to detect this (via the
magic ScreenBlankDPMSState value of 255) and avoid waiting for VSync
* Update RemovePages & InsertRemovePagesExit (screen DA handlers) to
avoid infinite loops if the screen DA gets shrunk to zero size (was seen
while attempting to complete the !Boot sequence while no driver was
active)

Version 6.33. Tagged as 'Kernel-6_33'

Special case for empty files was crashing, fix by removing
which also supports files which report a size of zero but
actually contain data such as Unix device nodes and
Linux procfs.

Error where start outside file adjusted to permit a start
exactly at the end of a file to permit (apparently) empty
files with no output. Doing likewise for non-empty files
is consistent.

Also fix closing file in case of error reading GS format
from CMOS.

Version 6.32. Tagged as 'Kernel-6_32'

OS_DynamicArea 21 was treating MaxCamEntry as if it was the exclusive
upper bound, when really it's the inclusive bound. The consequence of
this was that PMPs were unable to explicitly claim the highest-numbered
RAM page in the system.

Version 6.31. Tagged as 'Kernel-6_31'

OS_CLI permits commands to be prefixed with a temporary filing
system, for example "ADFS:Format"

It also passes commands unrecognised to FileSwitch to be executed,
so "ADFS::HardDisc4.$.!Boot" first sets the temporary filing to
ADFS then executes ":HardDisc4.$.!Boot".

This does not work if the path contains a special field,
currently this results in an error as the special filed
would be lost.

Unfortunately many programs, including the RISC OS source
fail because of this.

Instead if a filing system prefix with special field
is found switch to the Temporary filing system and
treat the whole command as a path to execute. For example
passing "IXFS#W:$.HardDisc4.!Boot" sets the temporary filing
system to "IXFS" then executes "IXFS#W:$.HardDisc4.!Boot".

Version 6.30. Tagged as 'Kernel-6_30'

OS_DynamicArea 27 is the same as OS_DynamicArea 5 ("return free
memory"), except the result is measured in pages instead of bytes,
allowing it to behave sensibly on machines with many gigabytes of RAM.

Similarly, OS_DynamicArea 28 is the same as OS_DynamicArea 7 (internal
DA enumeration call used by TaskManager), except the returned size
values are measured in pages instead of bytes. A flags word has also
been added to allow for more expansion in the future.

Hdr:OSMem now also contains some more definitions which external code
will find useful.

Version 6.29. Tagged as 'Kernel-6_29'

Version 6.28. Not tagged

This change adds a new OS_Memory reason code, 23, for reserving memory
without actually assigning it to a dynamic area. Other dynamic areas can
still use the memory, but only the code that reserved it will be allowed
to claim exclusive use over it (i.e. PageFlags_Unavailable).

This is useful for systems such as the PCI heap, where physically
contiguous memory is required, but the memory isn't needed all of the
time. By reserving the pages, it allows other regular DAs to make use of
the memory when the PCI heap is small. But when the PCI heap needs to
grow, it guarantees that (if there's enough free memory in the system)
the previously reserved pages can be allocated to the PCI heap.

Notes:

* Reservations are handled on an honour system; there's no checking that
the program that reserved the memory is the one attempting to map it in.

* For regular NeedsSpecificPages DAs, reserved pages can only be used if
the special "RESV" R0 return value is used.

* For PMP DAs, reserved pages can only be made Unavailable if the entry
in the page block also specifies the Reserved page flag. The actual
state of the Reserved flag can't be modified via PMP DA ops, the flag is
only used to indicate the caller's permission/intent to make the page
Unavailable.

* If a PMP DA tries to make a Reserved page Unavailable without
specifying the Reserved flag, the kernel will try to swap it out for a
replacement page taken from the free pool (preserving the contents and
generating Service_PagesUnsafe / Service_PagesSafe, as if another DA
had claimed the page)

Version 6.28. Tagged as 'Kernel-6_28'

 * MinAplWork isn't used.
 * SuperMode isn't used and is less well known than "SWI OS_EnterOS".
 * MEMCADR is now only a magic value returned by OS_UpdateMEMC,
   so it is clearer to include it literally with comment.

Added a comment to explain the baffling combination of
the MEMC1 control register's address with it's value.


Version 6.27. Not tagged

This makes SVLK and NVECTORS available.

Version 6.27. Tagged as 'Kernel-6_27'

Version 6.26. Tagged as 'Kernel-6_26'

Version 6.25. Tagged as 'Kernel-6_25'

Between RISC OS 3.6 and 3.7 the directory was renamed from
Doc to Docs and was duplicated during CVS import.

Fix by deleting Doc. Identical files remain in Docs.


Version 6.24. Not tagged

Detail:
This adds a new OS_DynamicArea reason code, 26, for adjusting
AplWorkMaxSize at runtime. This allows compatibility tools such as
Aemulor to adjust the limit without resorting to patching the kernel.
Any adjustment made to the value will affect the upper limit of
application space, and the lower limit of dynamic area placement.
Attempting to adjust beyond the compile-time upper/default limit, or
such that it will interfere with existing dynamic areas / wimpslots,
will result in an error.

Relevant forum thread:
https://www.riscosopen.org/forum/forums/11/topics/14734

Admin:
Tested on BB-xM, desktop active & inactive

Version 6.24. Tagged as 'Kernel-6_24'

Detail:

- s/HAL - Fix ADD v. SUB muddle that could prevent addresses from being rounded down correctly. Fix incorrect logical address being returned to caller on pre-ARMv6 machines due to PageTableSync corrupting a1.
- s/NewReset - Initialising the CMOS RAM cache while in the middle of setting up the processor vectors feels a bit silly. Move the code to just afterwards so that it feels a bit safer, and so that early crashes are easier to debug (processor vectors in stable state)

Admin:

Tested on Iyonix.
Fixes ROM softload failure reported on forums:
https://www.riscosopen.org/forum/forums/11/topics/14749

Version 6.23. Tagged as 'Kernel-6_23'

To achieve this:
* DecodeL1Entry and DecodeL2Entry return 64-bit physical addresses in
  r0 and r1, with additional return values shuffled up to r2 and r3
* DecodeL1Entry now returns the section size, so callers can distinguish
  section- from supersection-mapped memory
* PhysAddrToPageNo now accepts a 64-bit address (though since the physical
  RAM table is currently still all 32-bit, it will report any top-word-set
  addresses as being not in RAM)

Version 6.22. Tagged as 'Kernel-6_22'

ControlList_Interlaced is taken to have meant "output interlaced sync on H/V" and "configure DMA to show alternate lines in the framestore on alternate fields", therefore SyncPol flags mean:
b43
 00 = 'normal' progressive scan
 01 = interlaced sync, but both fields show the same image
 10 = (invalid)
 11 = interlaced sync, fields use alternate lines from the image

Version 6.21. Tagged as 'Kernel-6_21'

Without this, some CPUs (including Cortex-A72) take the undefined instruction
trap when encountering any CP15-encoded barrier instructions.

Requires RiscOS/Sources/Programmer/HdrSrc!1

Version 6.20. Tagged as 'Kernel-6_20'

Detail:
  s/vdu/vdudriver - When mapping external framestores, only double-map them if the driver supports hardware scrolling. Avoids wasting IO address space, and reduces IO space fragmentation if the framestore address changes
Admin:
  Tested on Raspberry Pi 3


Version 6.19. Tagged as 'Kernel-6_19'

Detail:
  s/vdu/vdupalxx:
  - Fix conditional code sequence in PV_BulkWrite which meant that the greyscale palette flag was being recalculated when the border or pointer colour was changed.
  - Change PV_1stFlashState / PV_2ndFlashState to act as NOPs in true colour modes, which helps to avoid regular redundant gamma table updates (due to the flashing colour logic in the VSync handler).
Admin:
  Tested on Raspberry Pi 3


Version 6.18. Tagged as 'Kernel-6_18'

Detail:
  s/vdu/legacymodes - Make the Service_ModeExtension implementation automatically use ExtraBytes to request that the row length is a multiple of a word (since things fail with non-word aligned rows)
  hdr/VIDCList - Un-deprecate SyncPol bits 2 & 3 and improve the comments to indicate the difference between SyncPol interlace and control list interlace
Admin:
  Tested on BB-xM


Version 6.17. Tagged as 'Kernel-6_17'

Detail:
  s/vdu/vduswis - Fix 18 year old register corruption bug in FindOKMode which would prevent it from falling back to Service_ModeTranslation if Service_ModeExtension returned a VIDC list but the VIDC list was rejected by the GraphicsV driver
  s/vdu/vdudriver - Also, change a couple of error cases in ModeChangeSub so that they use the "Screen mode not available" error instead of the incorrect "Not enough screen memory" error.
Admin:
  Tested on Raspberry Pi 3
  Fixes issue reported on forums where if AnyMode is loaded, numbered modes in unsupported colour depths weren't being replaced with substitutes (although note that there are still some AnyMode-related issues to resolve)
  https://www.riscosopen.org/forum/forums/4/topics/12773


Version 6.16. Tagged as 'Kernel-6_16'

Detail:
  s/ARMops - If the ICacheInvalidate macro was told to pull a2, it would pull it before invoking ICache_InvalidateRange, causing the end address of the range to be lost. Avoid this by only pulling the registers after the ranged call.
  Also optimise MMU_ChangingEntry to go straight to ICache_InvalidateRange instead of doing a redundant range size check.
Admin:
  Tested on OMAP5
  Potentially fixes lockup/long stall seen when using PhotoDesk, reported by Willi Theiss


Version 6.15. Tagged as 'Kernel-6_15'