1. 14 Jan, 2023 13 commits
  2. 05 Jan, 2023 1 commit
  3. 01 Jun, 2022 2 commits
  4. 07 Aug, 2021 4 commits
    • Jeffrey Lee's avatar
      Fix AbortTrap's handling of LDA instruction for emulated AP1 · 322fd3a6
      Jeffrey Lee authored
      When AP1 memory is being emulated (long descriptor page tables are in
      use), the AbortTrap machinery is used to emulate usermode read access.
      This provides coverage for all read instructions except those that
      AbortTrap handles via MemMap requests - LDREX, LDA, LDAEX, LDF & LFM.
      LDREX & LDAEX request both read & write access, so are fine (the MemMap
      request will get passed through to the registered AbortTrap handlers).
      LDF & LFM are irrelevant, since they only exist on ARM7500FE (on other
      machines FPEmulator will translate them to regular LDR/LDM, which are
      handled correctly)
      LDA however, will generate a plain "memmap with usermode read" request.
      When AbortTrap looks at the permissions of emulated AP1 it doesn't take
      into account the fact that the usermode read permission is being
      emulated, so it thinks that everything is fine and claims the memmap
      was successful, causing the abort handler to retry the instruction
      without making any changes, re...
    • Jeffrey Lee's avatar
      Add safety checks to s.CPUFeatures · e2e5a722
      Jeffrey Lee authored
      To avoid CallASWI's CPUFeatures implementation getting dangerously out
      of sync with the kernel, add extra asserts to both sets of sources to
      check try and make sure both sets of sources get updated when new flags
      are added.
    • Jeffrey Lee's avatar
      Allocate OS_PlatformFeatures 0 bit 22 · 305dc195
      Jeffrey Lee authored
      Pyromaniac doesn't allow low-level control or examination of the memory
      map; allocate an OS_PlatformFeatures bit to allow software to directly
      detect this limitation instead of having to rely on the affected SWIs
    • Jeffrey Lee's avatar
      Fix a couple of comment typos · e565ad40
      Jeffrey Lee authored
  5. 28 Jul, 2021 17 commits
    • Jeffrey Lee's avatar
      Make OS_Memory 24 report Abortable DAs · b98ccef2
      Jeffrey Lee authored
      Version 6.58. Tagged as 'Kernel-6_58'
    • Jeffrey Lee's avatar
      Add AP 1 emulation for long descriptor page tables · f93d930d
      Jeffrey Lee authored
      The long descriptor page table format doesn't support RISC OS access
      privilege 1 (user RX, privileged RWX). Previously we were downgrading
      this to AP 0 (user RWX, privielged RWX), which obviously weakens the
      security of the memory. However now that we have an AbortTrap
      implementation, we can map the memory as "user none, privileged RWX" and
      provide user read support via AbortTrap's instruction decode & execute
      There's no support for executing usermode code from the memory, but the
      compatibility issues caused by that are likely to be minimal.
    • Jeffrey Lee's avatar
      AbortTrap prefetch abort support · 84c73735
      Jeffrey Lee authored
      Also make lazy task swapping aborts to use IFAR where possible, to
      ensure any Thumb-2/Jazelle instructions which cross page boundaries are
      handled correctly.
    • Jeffrey Lee's avatar
      Fix OS_ReadSysInfo 7 to record prefetch abort details · 5266c864
      Jeffrey Lee authored
      OS_ReadSysInfo 7 is meant to record the details of the last data or
      prefetch abort that was passed to the environment handlers. This was
      implemented in Ursula, but the code for recording the prefetch abort
      details got lost somewhere during the 32 bit conversion process. Restore
    • Jeffrey Lee's avatar
      Add abortable DA support · fccd5e2f
      Jeffrey Lee authored
      This implementation should be compatible with RISCOS Ltd's
    • Jeffrey Lee's avatar
      Use decgen cache files · 5b6c1710
      Jeffrey Lee authored
      Sadly we need one file per combination of action files, but by adding
      these pre-generated cache files to git we can speed up building the
      kernel from clean by a significant amount.
    • Jeffrey Lee's avatar
      Add OS_AbortTrap implementation · c199c178
      Jeffrey Lee authored
      This supports all the load/store instructions, including FPA & VFP/NEON.
      Most instructions are handled directly via the base version of the
      AbortTrap API that was first implemented in RISC OS Select. However, to
      properly cope with LDREX/STREX, and future support for prefetch aborts,
      the API has been extended to allow the kernel to request that a block of
      memory is mapped in with certain permissions. For LDREX/STREX the kernel
      will then rewind the PC so that the instruction can be retried directly.
      Test code in Dev/AbortTrap exists in order to allow checking of all
      major functionality, along with code for building the code in a
      softloadable module for easier/quicker testing.
    • Jeffrey Lee's avatar
      OS_PlatformFeatures 34: Report presence of some CP15 regs · 3d5802b0
      Jeffrey Lee authored
      Report whether:
      * DFAR & DFSR are writable
      * IFAR, IFSR, AIFSR, ADFSR are implemented
    • Jeffrey Lee's avatar
      Add extra ops to hdr/Copro15ops · 994013b4
      Jeffrey Lee authored
      More data & prefetch abort registers
    • Jeffrey Lee's avatar
      Split AMB_LazyFixUp in two · de4dfa14
      Jeffrey Lee authored
      If lazy task swapping is active, but it isn't a lazy task swapping
      abort, AMB_LazyFixUp will force all of application space to be mapped
      in, in order to protect the data/prefetech abort environment handlers
      from triggering unexpected recursive aborts (which could easily happen
      if the handlers make use of application space in any way). Recursive
      aborts generally aren't tolerated by these handlers because they're
      entered in ABT32 mode and may rely on the DFSR/DFAR registers being
      To allow for more stages to be added to the abort handler inbetween lazy
      task swapping fixup & invoking the abort environment handler,
      AMB_LazyFixUp has now been split in two so that the code which maps in
      all of application space can be excuted at a more suitable time.
    • Jeffrey Lee's avatar
      Improve LibKern · 85f92e4f
      Jeffrey Lee authored
      Add kalloc (malloc with an error pointer), free, _kernel_irqs_disabled,
      _kernel_irqs_off, _kernel_irqs_on, and a simple memcpy implementation.
      Export the symbols so they're actually usable from other object files.
    • Jeffrey Lee's avatar
    • Jeffrey Lee's avatar
      Add extra LTORG to s.HAL · e7152ebd
      Jeffrey Lee authored
      Needed to resolve some literal pool range issues when long descriptor
      page table support is enabled
    • Jeffrey Lee's avatar
      Tidy up data abort handling · 876079a4
      Jeffrey Lee authored
      There was some redundant code needlessly pushing & popping various
      registers to the stack, left behind from when we removed the code that
      dealt with 26-bit processor vector reads on StrongARM & processed the
      proto-OS_AbortTrap "abort indirection nodes".
    • Jeffrey Lee's avatar
      Allow RW/ZI sections to be used · 2b665896
      Jeffrey Lee authored
      * Instruct the linker to place any RW/ZI data sections in the last ~16MB
      of the memory map, starting from &ff000000 (with the current toolchain,
      giving it a fixed base address is much easier than giving it a variable
      base address)
      * The RW/ZI section is mapped as completely inaccessible to user mode
      * The initial content of the RW section is copied over shortly after MMU
      startup (in Continue_after_HALInit)
      * Since link's -bin option produces a file containing a copy of the
      (zero-initialised) ZI section, the kernel binary is now produced from a
      "binary with AIF header" AIF with the help of the new 'kstrip' tool.
      kstrip extracts just the RO and RW sections, ensuring the ROM doesn't
      contain a redundant block of zeros for the ZI section.
      This should make it easier to use C code & arbitrary libraries within
      the kernel, providing they're compiled with suitable settings (e.g.
      non-module, no FP, no stack checking, like HALs typically use)
    • Timothy E Baldwin's avatar
      Support multiple source files · 9bc4a580
      Timothy E Baldwin authored
    • Timothy E Baldwin's avatar
      Build kernel using relocatable AOF · 5835d7b0
      Timothy E Baldwin authored
      * Add KernelBaseA absolute symbol.
      * Use KernelBase - KernelBaseA to convert some expressions
        to/from AREA relative form.
      * Link to correct address.
      * Remove ORG directive
      * Move EndOfKernel to separate AREA
  6. 30 Apr, 2021 1 commit
    • Jeffrey Lee's avatar
      Fix compressed ROM support · 2a3ad40a
      Jeffrey Lee authored
      When PhysRamTable was updated to store addresses in page units instead
      of byte units (commit df4efb68), the code which allocates the ROM
      decompression workspace didn't get updated, causing it to break. Add a
      few extra shifts to the code in order to account for the changes.
      Fixes issue reported on forums with (compressed) OMAP3 ROM failing to
      boot: https://www.riscosopen.org/forum/forums/5/topics/16446
      Version 6.57. Tagged as 'Kernel-6_57'
  7. 28 Apr, 2021 2 commits
    • Jeffrey Lee's avatar
      Log -> phys conversion improvements · 46081bca
      Jeffrey Lee authored
      * RISCOS_LogToPhys upgraded to allow it to cope with all page types
      (added support for 64KB "large" pages and lazily-mapped pages)
      * Added OS_Memory 65, which calls through to RISCOS_LogToPhys, to allow
      regular software to do logical-to-physical conversions for all page
      types (other calls, like OS_Memory 0/64, typically only work with 4KB
      * LoadAndDecodeL2Entry updated to always return a page/entry size, like
      Version 6.56. Tagged as 'Kernel-6_56'
    • Jeffrey Lee's avatar
      Support runtime selection of pagetable format · ba993cb5
      Jeffrey Lee authored
      Runtime selection between long descriptor and short descriptor page
      table format is now possible (with the decision based on whether the HAL
      registers any high RAM or not). The main source changes are as follows:
      * LongDesc and ShortDesc switches are in hdr.Options to control what
      kernel variant is built
      * PTOp and PTWhich macros introduced in hdr.ARMops to allow for
      invocation of functions / code blocks which are specific to the page
      table format. If the kernel is being built with only one page table
      format enabled, PTOp is just a BL instruction, ensuring there's no
      performance loss compared to the old code.
      * _LongDesc and _ShortDesc suffixes added to various function names, to
      allow both versions of the function to be included at once if runtime
      selection is enabled
      * Most of the kernel / MMU initialisation code in s.HAL is now encased
      in a big WHILE loop, allowing it to be duplicated if runtime switching
      is enabled (easier than adding dynamic branches all over the place, and
      only costs a few KB of ROM/RAM)
      * Some more functions (notably AccessPhysicalAddress,
      ReleasePhysicalAddress, and MapInIO) have been moved to s.ShortDesc /
      s.LongDesc since they were already 90% specific to page table format