From 7aa237973c36194ffc1d2ec89b97162fdb82b98f Mon Sep 17 00:00:00 2001 From: Gregory Nutt Date: Tue, 9 Feb 2016 11:25:29 -0600 Subject: [PATCH] Update TODO --- Documentation | 2 +- TODO | 27 +-------------------------- 2 files changed, 2 insertions(+), 27 deletions(-) diff --git a/Documentation b/Documentation index f1517cb0bb..0d2a964b20 160000 --- a/Documentation +++ b/Documentation @@ -1 +1 @@ -Subproject commit f1517cb0bb3fe10986030cd57b5bed1cf48e90b0 +Subproject commit 0d2a964b20c73ca7c67f6602345f903055c02623 diff --git a/TODO b/TODO index 31bd58e955..e8bf3a1a8b 100644 --- a/TODO +++ b/TODO @@ -26,7 +26,7 @@ nuttx/ (1) Pascal add-on (pcode/) (1) Build system / Toolchains (3) Linux/Cywgin simulation (arch/sim) - (5) ARM (arch/arm/) + (4) ARM (arch/arm/) apps/ @@ -1675,31 +1675,6 @@ o ARM (arch/arm/) If your design needs continuous interrupts like this, please try the above change and, please, submit a patch with the working fix. - Title: STACK ALIGNMENT IN INTERRUPT HANDLERS - Description: The EABI standard requires that the stack always have a 32-byte - alignment. There is no guarantee at present that the stack will be - so aligned in an interrupt handler. Therefore, I would expect some - issues if, for example, floating point or perhaps long long operations - were performed in an interrupt handler. - - This issue exists for ARM7, ARM9, and Cortex-M0 but has been - addressed for the Cortex-M3/4/7 and Cortex-A5/8. The fix - is really simple but cannot be incorporated without some - substantial testing. For ARM, the fix is the following logic - arround each call into C code from assembly: - - mov r4, sp /* Save the SP in a preserved register */ - bic sp, sp, #7 /* Force 8-byte alignment */ - bl cfunction /* Call the C function */ - mov sp, r4 /* Restore the possibly unaligned stack pointer */ - - This same issue applies to the interrupt stack which is, I think - improperly aligned in almost all cases (except Cortex-A5). - - Status: Open - Priority: Low for me because I never do floating point operations in - interrupt handlers. - Title: IMPROVED TASK START-UP AND SYSCALL RETURN Description: Couldn't up_start_task and up_start_pthread syscalls be eliminated. Wouldn't this work to get us from kernel-