ARM: 6356/1: hw-breakpoint: add ARM backend for the hw-breakpoint framework
authorWill Deacon <will.deacon@arm.com>
Fri, 3 Sep 2010 09:41:08 +0000 (10:41 +0100)
committerRussell King <rmk+kernel@arm.linux.org.uk>
Wed, 8 Sep 2010 09:05:00 +0000 (10:05 +0100)
commitf81ef4a920c8e1af75adf9f15042c2daa49d3cb3
tree48778ddf71477275bbe08c5e4394919061e27e12
parent3a4b5dca53aecb16db9e007d782b2d1e757e941a
ARM: 6356/1: hw-breakpoint: add ARM backend for the hw-breakpoint framework

The hw-breakpoint framework in the kernel requires architecture-specific
support in order to install, remove, validate and manage hardware
breakpoints.

This patch adds initial support for this framework to the ARM architecture,
but restricts the number of watchpoints to a single resource to get around
the fact that the Data Fault Address Register is unknown when a watchpoint
debug exception is taken.

On cores with v7 debug, the Kernel can handle breakpoint and watchpoint
exceptions occuring from userspace. Older cores require clients to handle
the exception themselves by registering an appropriate overflow handler
or, in the case of ptrace, handling the raised SIGTRAP.

The memory-mapped extended debug interface is unsupported due to its
unreliability in real implementations.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: S. Karthikeyan <informkarthik@gmail.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
arch/arm/include/asm/hw_breakpoint.h [new file with mode: 0644]
arch/arm/kernel/hw_breakpoint.c [new file with mode: 0644]