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authorVictor Kamensky <kamensky@cisco.com>2017-04-03 22:51:01 -0700
committerWill Deacon <will.deacon@arm.com>2017-04-04 12:13:36 +0100
commit09a6adf53d42ca3088fa3fb41f40b768efc711ed (patch)
treeb453a6b17322576ddad32ef6dfdeb26e7b880e16 /arch/arm64/mm/fault.c
parenta71c9a1c779f2499fb2afc0553e543f18aff6edf (diff)
downloadlwn-09a6adf53d42ca3088fa3fb41f40b768efc711ed.tar.gz
lwn-09a6adf53d42ca3088fa3fb41f40b768efc711ed.zip
arm64: mm: unaligned access by user-land should be received as SIGBUS
After 52d7523 (arm64: mm: allow the kernel to handle alignment faults on user accesses) commit user-land accesses that produce unaligned exceptions like in case of aarch32 ldm/stm/ldrd/strd instructions operating on unaligned memory received by user-land as SIGSEGV. It is wrong, it should be reported as SIGBUS as it was before 52d7523 commit. Changed do_bad_area function to take signal and code parameters out of esr value using fault_info table, so in case of do_alignment_fault fault user-land will receive SIGBUS. Wrapped access to fault_info table into esr_to_fault_info function. Cc: <stable@vger.kernel.org> Fixes: 52d7523 (arm64: mm: allow the kernel to handle alignment faults on user accesses) Signed-off-by: Victor Kamensky <kamensky@cisco.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm64/mm/fault.c')
-rw-r--r--arch/arm64/mm/fault.c42
1 files changed, 24 insertions, 18 deletions
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 4bf899fb451b..1b35b8bddbfb 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -42,7 +42,20 @@
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
-static const char *fault_name(unsigned int esr);
+struct fault_info {
+ int (*fn)(unsigned long addr, unsigned int esr,
+ struct pt_regs *regs);
+ int sig;
+ int code;
+ const char *name;
+};
+
+static const struct fault_info fault_info[];
+
+static inline const struct fault_info *esr_to_fault_info(unsigned int esr)
+{
+ return fault_info + (esr & 63);
+}
#ifdef CONFIG_KPROBES
static inline int notify_page_fault(struct pt_regs *regs, unsigned int esr)
@@ -197,10 +210,12 @@ static void __do_user_fault(struct task_struct *tsk, unsigned long addr,
struct pt_regs *regs)
{
struct siginfo si;
+ const struct fault_info *inf;
if (unhandled_signal(tsk, sig) && show_unhandled_signals_ratelimited()) {
+ inf = esr_to_fault_info(esr);
pr_info("%s[%d]: unhandled %s (%d) at 0x%08lx, esr 0x%03x\n",
- tsk->comm, task_pid_nr(tsk), fault_name(esr), sig,
+ tsk->comm, task_pid_nr(tsk), inf->name, sig,
addr, esr);
show_pte(tsk->mm, addr);
show_regs(regs);
@@ -219,14 +234,16 @@ static void do_bad_area(unsigned long addr, unsigned int esr, struct pt_regs *re
{
struct task_struct *tsk = current;
struct mm_struct *mm = tsk->active_mm;
+ const struct fault_info *inf;
/*
* If we are in kernel mode at this point, we have no context to
* handle this fault with.
*/
- if (user_mode(regs))
- __do_user_fault(tsk, addr, esr, SIGSEGV, SEGV_MAPERR, regs);
- else
+ if (user_mode(regs)) {
+ inf = esr_to_fault_info(esr);
+ __do_user_fault(tsk, addr, esr, inf->sig, inf->code, regs);
+ } else
__do_kernel_fault(mm, addr, esr, regs);
}
@@ -488,12 +505,7 @@ static int do_bad(unsigned long addr, unsigned int esr, struct pt_regs *regs)
return 1;
}
-static const struct fault_info {
- int (*fn)(unsigned long addr, unsigned int esr, struct pt_regs *regs);
- int sig;
- int code;
- const char *name;
-} fault_info[] = {
+static const struct fault_info fault_info[] = {
{ do_bad, SIGBUS, 0, "ttbr address size fault" },
{ do_bad, SIGBUS, 0, "level 1 address size fault" },
{ do_bad, SIGBUS, 0, "level 2 address size fault" },
@@ -560,19 +572,13 @@ static const struct fault_info {
{ do_bad, SIGBUS, 0, "unknown 63" },
};
-static const char *fault_name(unsigned int esr)
-{
- const struct fault_info *inf = fault_info + (esr & 63);
- return inf->name;
-}
-
/*
* Dispatch a data abort to the relevant handler.
*/
asmlinkage void __exception do_mem_abort(unsigned long addr, unsigned int esr,
struct pt_regs *regs)
{
- const struct fault_info *inf = fault_info + (esr & 63);
+ const struct fault_info *inf = esr_to_fault_info(esr);
struct siginfo info;
if (!inf->fn(addr, esr, regs))