[linux-yocto] [PATCH 13/26] arm64: Enable the identity mapping to allow the MMU disabling

[Daniel Dragomir]

From: Geoff Levand <geoff at infradead.org>

Add the setup_mm_for_reboot() function needed for kexec.

Signed-off-by: Geoff Levand <geoff at infradead.org>
---
 arch/arm64/include/asm/mmu.h |  1 -
 arch/arm64/mm/mmu.c          | 11 +++++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/mmu.h b/arch/arm64/include/asm/mmu.h
index 3d31176..99064c0 100644
--- a/arch/arm64/include/asm/mmu.h
+++ b/arch/arm64/include/asm/mmu.h
@@ -28,7 +28,6 @@ typedef struct {
 #define ASID(mm)	((mm)->context.id & 0xffff)
 
 extern void paging_init(void);
-extern void setup_mm_for_reboot(void);
 extern void __iomem *early_io_map(phys_addr_t phys, unsigned long virt);
 extern void init_mem_pgprot(void);
 extern void create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index cb34eb8..adf2f08 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -474,6 +474,17 @@ void setup_mm_for_reboot(void)
 }
 
 /*
+ * Enable the identity mapping to allow the MMU disabling.
+ */
+void setup_mm_for_reboot(void)
+{
+	cpu_set_reserved_ttbr0();
+	flush_tlb_all();
+	cpu_set_idmap_tcr_t0sz();
+	cpu_switch_mm(idmap_pg_dir, &init_mm);
+}
+
+/*
  * Check whether a kernel address is valid (derived from arch/x86/).
  */
 int kern_addr_valid(unsigned long addr)
-- 
2.7.4