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Will Deacon authored
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>
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