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

Doug Berger
2017-03-24T14:47:57Z

From: Florian Fainelli <f.fainelli@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.fainelli@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