[PATCH 1/9] arm64: mm: Allow installation of memory abort handlers

[Doug Berger]

From: Florian Fainelli <f.faine...@gmail.com>

Similarly to what the ARM/Linux kernel provides, add a hook_fault_code()
function which allows drivers or other parts of the kernel to install
custom memory abort handlers. This is useful when a given SoC's busing
does not propagate the exact faulting physical address, but there is a
way to read it through e.g: a special arbiter driver.

Signed-off-by: Florian Fainelli <f.faine...@gmail.com>
---
 arch/arm64/include/asm/system_misc.h |  3 +++
 arch/arm64/mm/fault.c                | 15 ++++++++++++++-
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/system_misc.h 
b/arch/arm64/include/asm/system_misc.h
index bc812435bc76..e05f5b8c7c1c 100644
--- a/arch/arm64/include/asm/system_misc.h
+++ b/arch/arm64/include/asm/system_misc.h
@@ -38,6 +38,9 @@ void arm64_notify_die(const char *str, struct pt_regs *regs,
 void hook_debug_fault_code(int nr, int (*fn)(unsigned long, unsigned int,
                                             struct pt_regs *),
                           int sig, int code, const char *name);
+void hook_fault_code(int nr, int (*fn)(unsigned long, unsigned int,
+                                      struct pt_regs *),
+                    int sig, int code, const char *name);
 
 struct mm_struct;
 extern void show_pte(struct mm_struct *mm, unsigned long addr);
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 4bf899fb451b..cdf1260f1005 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -488,7 +488,7 @@ static int do_bad(unsigned long addr, unsigned int esr, 
struct pt_regs *regs)
        return 1;
 }
 
-static const struct fault_info {
+static struct fault_info {
        int     (*fn)(unsigned long addr, unsigned int esr, struct pt_regs 
*regs);
        int     sig;
        int     code;
@@ -560,6 +560,19 @@ static const struct fault_info {
        { do_bad,               SIGBUS,  0,             "unknown 63"            
        },
 };
 
+void __init hook_fault_code(int nr,
+                           int (*fn)(unsigned long, unsigned int, struct 
pt_regs *),
+                           int sig, int code, const char *name)
+{
+       BUG_ON(nr < 0 || nr >= ARRAY_SIZE(fault_info));
+
+       fault_info[nr].fn       = fn;
+       fault_info[nr].sig      = sig;
+       fault_info[nr].code     = code;
+       fault_info[nr].name     = name;
+}
+
+
 static const char *fault_name(unsigned int esr)
 {
        const struct fault_info *inf = fault_info + (esr & 63);
-- 
2.12.0