From 3e6f9e8d1e65c4da505ff78481d54a115520d3d1 Mon Sep 17 00:00:00 2001 From: David Brownell Date: Sun, 8 Nov 2009 08:52:40 -0800 Subject: target.cfg: remove "-work-area-virt 0" The semantics of "-work-area-virt 0" (or phys) changed with the patch to require specifying physical or virtrual work area addresses. Specifying zero was previously a NOP. Now it means that address zero is valid. This patch addresses three related issues: - MMU-less processors should never specify work-area-virt; remove those specifications. Such processors include ARM7TDMI, Cortex-M3, and ARM966. - MMU-equipped processors *can* specify work-area-virt... but zero won't be appropriate, except in mischievous contexts (which hide null pointer exceptions). Remove those specs from those processors too. If any of those mappings is valid, someone will need to submit a patch adding it ... along with a comment saying what OS provides the mapping, and in which context. Example, say "works with Linux 2.6.30+, in kernel mode". (Note that ARM Linux doesn't map kernel memory to zero ...) - Clarify docs on that "-virt" and other work area stuff. Seems to me work-area-virt is quite problematic; not every operating system provides such static mappings; if they do, they're not in every MMU context... Signed-off-by: David Brownell --- tcl/target/imx27.cfg | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'tcl/target/imx27.cfg') diff --git a/tcl/target/imx27.cfg b/tcl/target/imx27.cfg index 837ea614..4a93a675 100644 --- a/tcl/target/imx27.cfg +++ b/tcl/target/imx27.cfg @@ -40,7 +40,9 @@ jtag newtap $_CHIPNAME cpu -irlen 4 -ircapture 0x1 -irmask 0xf -expected-id $_C # Create the GDB Target. set _TARGETNAME $_CHIPNAME.cpu target create $_TARGETNAME arm926ejs -endian $_ENDIAN -chain-position $_TARGETNAME -variant arm926ejs -$_TARGETNAME configure -work-area-virt 0xffff4c00 -work-area-phys 0xffff4c00 -work-area-size 0x8000 -work-area-backup 1 +# REVISIT what operating environment sets up this virtual address mapping? +$_TARGETNAME configure -work-area-virt 0xffff4c00 -work-area-phys 0xffff4c00 \ + -work-area-size 0x8000 -work-area-backup 1 # Internal to the chip, there is 45K of SRAM # -- cgit v1.2.3