ARM: suspend: fix CPU suspend code for !CONFIG_MMU configurations

The ARM CPU suspend code can be selected even for a !CONFIG_MMU
configuration. The resulting kernel will not compile and, even if it did,
would access undefined co-processor registers when executing.

This patch fixes the v6 and v7 CPU suspend code for the nommu case.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Tested-by: Jonathan Austin <jonathan.austin@arm.com>
CC: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> (commit_signer:1/3=33%)
CC: Santosh Shilimkar <santosh.shilimkar@ti.com> (commit_signer:1/3=33%)
CC: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

1 files changed, 36 insertions, 28 deletions

diff --git a/arch/arm/kernel/suspend.c b/arch/arm/kernel/suspend.c
index c59c97ea8268..38a50676213b 100644
--- a/arch/arm/kernel/suspend.c
+++ b/arch/arm/kernel/suspend.c
@@ -10,6 +10,42 @@
 extern int __cpu_suspend(unsigned long, int (*)(unsigned long));
 extern void cpu_resume_mmu(void);
 
+#ifdef CONFIG_MMU
+/*
+ * Hide the first two arguments to __cpu_suspend - these are an implementation
+ * detail which platform code shouldn't have to know about.
+ */
+int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
+{
+	struct mm_struct *mm = current->active_mm;
+	int ret;
+
+	if (!idmap_pgd)
+		return -EINVAL;
+
+	/*
+	 * Provide a temporary page table with an identity mapping for
+	 * the MMU-enable code, required for resuming.  On successful
+	 * resume (indicated by a zero return code), we need to switch
+	 * back to the correct page tables.
+	 */
+	ret = __cpu_suspend(arg, fn);
+	if (ret == 0) {
+		cpu_switch_mm(mm->pgd, mm);
+		local_flush_bp_all();
+		local_flush_tlb_all();
+	}
+
+	return ret;
+}
+#else
+int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
+{
+	return __cpu_suspend(arg, fn);
+}
+#define	idmap_pgd	NULL
+#endif
+
 /*
  * This is called by __cpu_suspend() to save the state, and do whatever
  * flushing is required to ensure that when the CPU goes to sleep we have
@@ -46,31 +82,3 @@ void __cpu_suspend_save(u32 *ptr, u32 ptrsz, u32 sp, u32 *save_ptr)
 	outer_clean_range(virt_to_phys(save_ptr),
 			  virt_to_phys(save_ptr) + sizeof(*save_ptr));
 }
-
-/*
- * Hide the first two arguments to __cpu_suspend - these are an implementation
- * detail which platform code shouldn't have to know about.
- */
-int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
-{
-	struct mm_struct *mm = current->active_mm;
-	int ret;
-
-	if (!idmap_pgd)
-		return -EINVAL;
-
-	/*
-	 * Provide a temporary page table with an identity mapping for
-	 * the MMU-enable code, required for resuming.  On successful
-	 * resume (indicated by a zero return code), we need to switch
-	 * back to the correct page tables.
-	 */
-	ret = __cpu_suspend(arg, fn);
-	if (ret == 0) {
-		cpu_switch_mm(mm->pgd, mm);
-		local_flush_bp_all();
-		local_flush_tlb_all();
-	}
-
-	return ret;
-}