diff options
Diffstat (limited to 'nuttx')
| -rw-r--r-- | nuttx/Documentation/NuttXNxFlat.html | 2 | ||||
| -rw-r--r-- | nuttx/TODO | 42 | ||||
| -rw-r--r-- | nuttx/binfmt/libnxflat/gnu-nxflat-gotoff.ld | 5 |
3 files changed, 47 insertions, 2 deletions
diff --git a/nuttx/Documentation/NuttXNxFlat.html b/nuttx/Documentation/NuttXNxFlat.html index 4d70ed9c3..c51e3b6a1 100644 --- a/nuttx/Documentation/NuttXNxFlat.html +++ b/nuttx/Documentation/NuttXNxFlat.html @@ -522,7 +522,7 @@ cat ../syscall/syscall.csv ../lib/lib.csv | sort >tmp.csv </p> <p><b>NOTE:</b> - There are two linker scripts located at <code>binfmt/libnxflat/gnu-nxflat-gotoff.ld</code>. + There are two linker scripts located at <code>binfmt/libnxflat/</code>. </p> <ol> <li> diff --git a/nuttx/TODO b/nuttx/TODO index 30015ef50..90333c74c 100644 --- a/nuttx/TODO +++ b/nuttx/TODO @@ -12,7 +12,7 @@ nuttx/ (2) Signals (sched/, arch/) (2) pthreads (sched/) (2) C++ Support - (5) Binary loaders (binfmt/) + (6) Binary loaders (binfmt/) (17) Network (net/, drivers/net) (3) USB (drivers/usbdev, drivers/usbhost) (11) Libraries (lib/) @@ -395,6 +395,46 @@ o Binary loaders (binfmt/) Priority: There are too many references like the above. They will have to get fixed as needed for Windows native tool builds. + Title: TOOLCHAIN COMPATIBILITY PROBLEM + Descripton: The older 4.3.3 compiler generates GOTOFF relocations to the constant + strings, like: + + .L3: + .word .LC0(GOTOFF) + .word .LC1(GOTOFF) + .word .LC2(GOTOFF) + .word .LC3(GOTOFF) + .word .LC4(GOTOFF) + + Where .LC0, LC1, LC2, LC3, and .LC4 are the labels correponding to strings in + the .rodata.str1.1 section. One consequence of this is that .rodata must reside + in D-Space since it will addressed relative to the GOT (see the section entitled + "Read-Only Data in RAM" at + http://nuttx.org/Documentation/NuttXNxFlat.html#limitations). + + The newer 4.6.3compiler generated PC relative relocations to the strings: + + .L2: + .word .LC0-(.LPIC0+4) + .word .LC1-(.LPIC1+4) + .word .LC2-(.LPIC2+4) + .word .LC3-(.LPIC4+4) + .word .LC4-(.LPIC5+4) + + This is good and bad. This is good because it means that .rodata.str1.1 can not + reside in FLASH with .text and can be accessed using PC-relative addressing. + That can be accomplished by simply moving the .rodata from the .data section to + the .text section in the linker script. (The NXFLAT linker script is located at + nuttx/binfmt/libnxflat/gnu-nxflat.ld). + + This is bad because a lot of stuff may get broken an a lot of test will need to + be done. One question that I have is does this apply to all kinds of .rodata? + Or just to .rodata.str1.1? + + Status: Open. Many of the required changes are in place but, unfortunately, not enought + go be fully functional. + Priority: Medium. The workaround for now is to use the older, 4.3.3 OABI compiler. + o Network (net/, drivers/net) ^^^^^^^^^^^^^^^^^^^^^^^^^^^ diff --git a/nuttx/binfmt/libnxflat/gnu-nxflat-gotoff.ld b/nuttx/binfmt/libnxflat/gnu-nxflat-gotoff.ld index c0487212a..47debd663 100644 --- a/nuttx/binfmt/libnxflat/gnu-nxflat-gotoff.ld +++ b/nuttx/binfmt/libnxflat/gnu-nxflat-gotoff.ld @@ -107,11 +107,16 @@ SECTIONS .data 0x00000000 : { + /* In this model, .rodata is access using PC-relative addressing + * and, hence, must also reside in the .text section. + */ + __data_start = . ; *(.rodata) *(.rodata1) *(.rodata.*) *(.gnu.linkonce.r*) + *(.data) *(.data1) *(.data.*) |