hw-breakpoints: Get the number of available registers on boot dynamically
authorFrederic Weisbecker <fweisbec@gmail.com>
Fri, 23 Apr 2010 03:59:55 +0000 (05:59 +0200)
committerFrederic Weisbecker <fweisbec@gmail.com>
Sat, 1 May 2010 02:32:14 +0000 (04:32 +0200)
commitfeef47d0cb530e8419dfa0b48141b538b89b1b1a
treead40b07e8b240eca134770120b5c644ec0062ce2
parentf93a20541134fa767e8dc4eb32e956d30b9f6b92
hw-breakpoints: Get the number of available registers on boot dynamically

The breakpoint generic layer assumes that archs always know in advance
the static number of address registers available to host breakpoints
through the HBP_NUM macro.

However this is not true for every archs. For example Arm needs to get
this information dynamically to handle the compatiblity between
different versions.

To solve this, this patch proposes to drop the static HBP_NUM macro
and let the arch provide the number of available slots through a
new hw_breakpoint_slots() function. For archs that have
CONFIG_HAVE_MIXED_BREAKPOINTS_REGS selected, it will be called once
as the number of registers fits for instruction and data breakpoints
together.
For the others it will be called first to get the number of
instruction breakpoint registers and another time to get the
data breakpoint registers, the targeted type is given as a
parameter of hw_breakpoint_slots().

Reported-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Cc: K. Prasad <prasad@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Ingo Molnar <mingo@elte.hu>
arch/sh/include/asm/hw_breakpoint.h
arch/x86/include/asm/hw_breakpoint.h
include/linux/hw_breakpoint.h
kernel/hw_breakpoint.c
kernel/trace/trace_ksym.c