GitLab

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'

Detail:
  Over the years the OS's substitute screen mode selection logic has grown to be a tangled mess, and the logic it does implement isn't always very useful. Additionally, the kernel is structured in such a way that it can be hard for modules to override it.
  This set of changes aims to fix the many of the problems, by doing the following:
  - Moving all substitute mode selection logic out of the core VDU driver code and into a Service_ModeTranslation handler. This means you now only have one place in the kernel to look instead of several, and modules can override the behaviour by claiming/blocking the service call as appropriate.
  - Moving handling of the built-in VIDC lists out of the core VDU driver code and into a Service_ModeExtension handler. This means programs can now inspect these VIDC lists by issuing the right service call (although you are essentially limited to lists which the GraphicsV driver is OK with)
  - Moving *TV interlace & offset adjustment logic into the Service_ModeExtension handler, since they're legacy things which can be handled more cleanly for MDF/EDID (and the old code was poking memory the kernel didn't own)
  - Adding a Service_EnumerateScreenModes implementation, so that if you end up in the desktop with ScreenModes non-functional, the display manager at least has something useful to show you
  - Enhancing the handling of the built-in numbered modes so that they are now available in any colour depth; the Service_ModeExtension handler (and related handlers) treat the builtin VIDC lists as a set of mode timings, not a discrete set of modes
  - Substitute mode selection logic is a complete re-write. Instead of trying a handful of numbered fallback modes, it now tries:
    - Same mode but at higher colour depths
    - Same mode but at lower colour depths
    - Alternate resolutions (half-width mode with no double-pixel if original request was for double-pixel, and default resolution for monitor type)
  - Combined with the logic to allow the builtin VIDC lists to be used at any colour depth, this means that the kernel should now be able to find substitute modes for machines which lack support for <=8bpp modes (e.g. OMAP5)
  - Additionally the mode substitution code will attempt to retain as many properties of the originally requested mode as possible (eigen values, gap mode type, etc.)
  Other improvements:
  - The kernel now actually vets the builtin VIDC lists instead of assuming that they'll work (which also means they'll have the correct ExtraBytes value, where applicable)
  - The kernel now uses GraphicsV 19 (VetMode2) to vet the mode during the mode switch process, using the result to detect where the framebuffer will be placed. This allows for GraphicsV drivers to switch between DA 2 and external framestores on a per-mode basis.
  - The kernel now supports mode selectors which specify LineLength values which are larger than necessary; this will get translated to a suitable ExtraBytes control list item (+ combined with whatever padding the driver indicates is necessary via the VetMode2 result)
  File changes:
  - hdr/KernelWS - Reserve space for a VIDC list, since the Service_ModeExtension implementation typically can't use the built-in list as-is
  - s/Arthur3 - Issue Service_ModeFileChanged when the configured monitor type is changed, so that DisplayManager + friends are aware that the set of available modes has changed
  - s/GetAll - Fiddle with GETs a bit
  - s/MemMap2 - Extra LTORG
  - s/NewIRQs - Small routine to install/uninstall false VSync routine (previously from PushModeInfo, which wasn't really the appropriate place for it)
  - s/Utility - Hook up the extra service call handlers
  - s/vdu/legacymodes - New file containing the new service call implementations, and some related code
  - s/vdu/vdudecl - Move mode workspace definition here, from vdumodes
  - s/vdu/vdudriver - Remove assorted bits of mode substitution code. Plug in new bits for calling GraphicsV 19 during mode set, and deal with ExtraBytes/LineLength during PushModeInfo
  - s/vdu/vdumodes - Move some workspace definitions to s/vdu/vdudecl. Tweak how the builtin VIDC lists are stored.
  - s/vdu/vduswis - Rip out more mode substitution code. Issue Service_ModeFileChanged when monitor type is changed by OS_ScreenMode.
Admin:
  Tested on Raspberry Pi 3, Iyonix, IGEPv5


Version 6.14. Tagged as 'Kernel-6_14'

Detail:
  s/vdu/vdudriver - When using mode selector blocks, don't allow the system to switch into double-vertical, double-pixel, or BBC-gap modes which are in colour depths unsupported by the kernel
Admin:
  Tested on BB-xM


Version 6.13. Tagged as 'Kernel-6_13'

Detail:
  s/HAL - OS_Hardware 3 (remove HAL device) will now re-scan the device list for the device following the Service_Hardware call, so that the device list won't become corrupt if the service call triggers addition/removal of devices.
Admin:
  Tested on iMX6
  *HDMIOff now correctly removes the HDMI audio device and SoundDMA's software mixer device (SoundDMA removes mixer in response to the HDMI audio device vanishing, but re-entrancy bug meant that the HDMI device was left on the list)
  Note that this only covers re-entrancy via Service_Hardware. OS_Hardware 2/3/4/5 are not re-entrant from other locations (e.g. IRQ handlers or memory allocation service calls).


Version 6.12. Tagged as 'Kernel-6_12'

Detail:
  ECFIndex and PalIndex claim to be mode variables, but it's impossible for extension modes to specify their values.
  Since they're easy to calculate from the ModeFlags and Log2BPP values, drop them from the mode workspace (+ table of builtin modes) and calculate them on the fly instead.
  File changes:
  - hdr/KernelWS - Drop ECFIndex & PalIndex from workspace
  - s/vdu/vdumodes - Adjust workspace definition, drop ECFIndex & PalIndex values from VWSTAB
  - s/vdu/vdudriver - Remove now-redundant copy loop from ModeChangeSub. Remove code from GenerateModeSelectorVars that sets up the ECFIndex & PalIndex values on the stack
  - s/vdu/vdugrafl - Adjust copy loop in SwitchOutputToSprite/Mask
  - s/vdu/vdupalette, s/vdu/vdupalxx - Add GetPalIndex routine to generate PalIndex on the fly. Drop the obsolete 16bpp palette/gamma table and shuffle the other entries to simplify GetPalIndex a bit.
  - s/vdu/vduplot - Add GetECFIndex routine to generate ECFIndex on the fly. Also, fix things so that mode 0 isn't the only rectangular-pixel mode which uses the special rectangular-pixel ECF patterns (index 0 vs. index 4). Fiddle with ExportedHLine a bit to avoid an out-of-range ADR.
  - s/NewReset - Fix UAL warning for MOV R0, AppSpaceStart. Adjust memset to not assume 512KB is the correct amount
Admin:
  Tested on Raspberry Pi 3


Version 6.11. Tagged as 'Kernel-6_11'

Detail:
  s/MemInfo - The wrapper around OS_Memory 0 introduced in Kernel-5_35-4_79_2_311 was preserving the wrong PSR field on exit, causing any error generated by the core code to be lost.
Admin:
  Tested on Iyonix
  Fixes *screensave saving mostly white pixels (address translation for "external" VRAM should have failed and caused ADFS to fall back to a bounce buffer)
  Is also likely to be the cause of https://www.riscosopen.org/forum/forums/5/topics/11713 (address translation should have failed for soft ROM)


Version 6.10. Tagged as 'Kernel-6_10'

Detail:
  hdr/Options - The setting of the SMP switch can now be controlled by specifying the correct ASFLAGS, e.g. ASFLAGS="-PD \"SMP SETL {FALSE}\""
Admin:
  Untested


Version 6.08, 4.129.2.10. Tagged as 'Kernel-6_08-4_129_2_10'

Detail:
  As the application slot is now a normal dynamic area, there's no need to manipulate the CAM directly. Convert FudgeSomeAppSpace into a OS_ChangeDynamicArea SWI followed by memset().
  ChangeDyn.s: Offset by 32k to account for the -32k that dynamic area -1 has.
  NewReset.s: Delete FudgeSomeAppSpace and replace as above.
Admin:
  Submission from Timothy Baldwin.

Version 6.08. Tagged as 'Kernel-6_08'

Detail:
  NewReset.s: Remove warning about soft reset, this is not supported any longer
  MsgCode.s: Reload LR after potentially changing mode
  PMF/osinit.s: Delete vestiges of soft reset support
Admin:
  Submission from Timothy Baldwin.

Version 6.07. Tagged as 'Kernel-6_07'