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 --- doc/openocd.texi | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'doc/openocd.texi') diff --git a/doc/openocd.texi b/doc/openocd.texi index 2ddcd041..e84f4c8b 100644 --- a/doc/openocd.texi +++ b/doc/openocd.texi @@ -3185,13 +3185,18 @@ since performing a backup slows down operations. For example, the beginning of an SRAM block is likely to be used by most build systems, but the end is often unused. -@item @code{-work-area-size} @var{size} -- specify/set the work area +@item @code{-work-area-size} @var{size} -- specify work are size, +in bytes. The same size applies regardless of whether its physical +or virtual address is being used. @item @code{-work-area-phys} @var{address} -- set the work area base @var{address} to be used when no MMU is active. @item @code{-work-area-virt} @var{address} -- set the work area base @var{address} to be used when an MMU is active. +@emph{Do not specify a value for this except on targets with an MMU.} +The value should normally correspond to a static mapping for the +@code{-work-area-phys} address, set up by the current operating system. @end itemize @end deffn -- cgit v1.2.3