From e44e3482bdb4d0ebde2d8b41830ac2cdb07948fb Mon Sep 17 00:00:00 2001 From: Yang Zhang Date: Fri, 28 Aug 2015 09:58:54 +0800 Subject: Add qemu 2.4.0 Change-Id: Ic99cbad4b61f8b127b7dc74d04576c0bcbaaf4f5 Signed-off-by: Yang Zhang --- qemu/target-mips/TODO | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) create mode 100644 qemu/target-mips/TODO (limited to 'qemu/target-mips/TODO') diff --git a/qemu/target-mips/TODO b/qemu/target-mips/TODO new file mode 100644 index 000000000..1d782d802 --- /dev/null +++ b/qemu/target-mips/TODO @@ -0,0 +1,51 @@ +Unsolved issues/bugs in the mips/mipsel backend +----------------------------------------------- + +General +------- +- Unimplemented ASEs: + - MDMX + - SmartMIPS + - microMIPS DSP r1 & r2 encodings +- MT ASE only partially implemented and not functional +- Shadow register support only partially implemented, + lacks set switching on interrupt/exception. +- 34K ITC not implemented. +- A general lack of documentation, especially for technical internals. + Existing documentation is x86-centric. +- Reverse endianness bit not implemented +- The TLB emulation is very inefficient: + QEMU's softmmu implements a x86-style MMU, with separate entries + for read/write/execute, a TLB index which is just a modulo of the + virtual address, and a set of TLBs for each user/kernel/supervisor + MMU mode. + MIPS has a single entry for read/write/execute and only one MMU mode. + But it is fully associative with randomized entry indices, and uses + up to 256 ASID tags as additional matching criterion (which roughly + equates to 256 MMU modes). It also has a global flag which causes + entries to match regardless of ASID. + To cope with these differences, QEMU currently flushes the TLB at + each ASID change. Using the MMU modes to implement ASIDs hinges on + implementing the global bit efficiently. +- save/restore of the CPU state is not implemented (see machine.c). + +MIPS64 +------ +- Userland emulation (both n32 and n64) not functional. + +"Generic" 4Kc system emulation +------------------------------ +- Doesn't correspond to any real hardware. Should be removed some day, + U-Boot is the last remaining user. + +PICA 61 system emulation +------------------------ +- No framebuffer support yet. + +MALTA system emulation +---------------------- +- We fake firmware support instead of doing the real thing +- Real firmware (YAMON) falls over when trying to init RAM, presumably + due to lacking system controller emulation. +- Bonito system controller not implemented +- MSC1 system controller not implemented -- cgit 1.2.3-korg