arm64 fixes:

- Restore previous SIGBUS behaviour for unhandled unaligned user accesses
 
 - Revert broken support for the contiguous bit in hugetlb (again...)
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Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 fixes from Will Deacon:
 "We've got a regression fix for the signal raised when userspace makes
  an unsupported unaligned access and a revert of the contiguous
  (hugepte) support for hugetlb, which has once again been found to be
  broken. One day, maybe, we'll get it right.

  Summary:

   - restore previous SIGBUS behaviour for unhandled unaligned user
     accesses

   - revert broken support for the contiguous bit in hugetlb (again...)"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  Revert "Revert "arm64: hugetlb: partial revert of 66b3923a1a0f""
  arm64: mm: unaligned access by user-land should be received as SIGBUS

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))
+	if (user_mode(regs)) {
-		__do_user_fault(tsk, addr, esr, SIGSEGV, SEGV_MAPERR, regs);
+		inf = esr_to_fault_info(esr);
-	else
+		__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 {
+static const struct fault_info fault_info[] = {
-	int	(*fn)(unsigned long addr, unsigned int esr, struct pt_regs *regs);
-	int	sig;
-	int	code;
-	const char *name;
-} 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))

arch/arm64/mm/hugetlbpage.c

@@ -294,10 +294,6 @@ static __init int setup_hugepagesz(char *opt)
 		hugetlb_add_hstate(PMD_SHIFT - PAGE_SHIFT);
 	} else if (ps == PUD_SIZE) {
 		hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
-	} else if (ps == (PAGE_SIZE * CONT_PTES)) {
-		hugetlb_add_hstate(CONT_PTE_SHIFT);
-	} else if (ps == (PMD_SIZE * CONT_PMDS)) {
-		hugetlb_add_hstate((PMD_SHIFT + CONT_PMD_SHIFT) - PAGE_SHIFT);
 	} else {
 		hugetlb_bad_size();
 		pr_err("hugepagesz: Unsupported page size %lu K\n", ps >> 10);
@@ -306,13 +302,3 @@ static __init int setup_hugepagesz(char *opt)
 	return 1;
 }
 __setup("hugepagesz=", setup_hugepagesz);
-
-#ifdef CONFIG_ARM64_64K_PAGES
-static __init int add_default_hugepagesz(void)
-{
-	if (size_to_hstate(CONT_PTES * PAGE_SIZE) == NULL)
-		hugetlb_add_hstate(CONT_PTE_SHIFT);
-	return 0;
-}
-arch_initcall(add_default_hugepagesz);
-#endif