From: Will Deacon <will.deacon@arm.com>
Date: Fri, 3 Sep 2010 09:39:59 +0000 (+0100)
Subject: ARM: 6355/1: hw-breakpoint: add mechanism for hooking into prefetch aborts
X-Git-Tag: v2.6.37-rc1~122^2~9^4~3
X-Git-Url: http://git.cascardo.eti.br/?a=commitdiff_plain;h=3a4b5dca53aecb16db9e007d782b2d1e757e941a;p=cascardo%2Flinux.git

ARM: 6355/1: hw-breakpoint: add mechanism for hooking into prefetch aborts

On ARM processors with hardware breakpoint and watchpoint support,
triggering these events results in a debug exception. These manifest
as prefetch and data aborts respectively.

arch/arm/mm/fault.c already provides hook_fault_code for hooking
into data aborts dependent on the DFSR. This patch adds a new function,
hook_ifault_code for hooking into prefetch aborts in the same manner.

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>
---

diff --git a/arch/arm/include/asm/system.h b/arch/arm/include/asm/system.h
index 8ba1ccf82a02..b516cdea5ae2 100644
--- a/arch/arm/include/asm/system.h
+++ b/arch/arm/include/asm/system.h
@@ -85,6 +85,10 @@ void hook_fault_code(int nr, int (*fn)(unsigned long, unsigned int,
 				       struct pt_regs *),
 		     int sig, int code, const char *name);
 
+void hook_ifault_code(int nr, int (*fn)(unsigned long, unsigned int,
+				       struct pt_regs *),
+		     int sig, int code, const char *name);
+
 #define xchg(ptr,x) \
 	((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
 
diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
index 23b0b03af5ea..1e21e125fe3a 100644
--- a/arch/arm/mm/fault.c
+++ b/arch/arm/mm/fault.c
@@ -581,6 +581,19 @@ static struct fsr_info ifsr_info[] = {
 	{ do_bad,		SIGBUS,  0,		"unknown 31"			   },
 };
 
+void __init
+hook_ifault_code(int nr, int (*fn)(unsigned long, unsigned int, struct pt_regs *),
+		 int sig, int code, const char *name)
+{
+	if (nr < 0 || nr >= ARRAY_SIZE(ifsr_info))
+		BUG();
+
+	ifsr_info[nr].fn   = fn;
+	ifsr_info[nr].sig  = sig;
+	ifsr_info[nr].code = code;
+	ifsr_info[nr].name = name;
+}
+
 asmlinkage void __exception
 do_PrefetchAbort(unsigned long addr, unsigned int ifsr, struct pt_regs *regs)
 {