powerpc/book3e-64/kexec: create an identity TLB mapping

book3e has no real MMU mode so we have to create an identity TLB
mapping to make sure we can access the real physical address.

Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com>
[scottwood: cleanup, and split off some changes]
Signed-off-by: Scott Wood <scottwood@freescale.com>

diff --git a/arch/powerpc/kernel/misc_64.S b/arch/powerpc/kernel/misc_64.S
index 6e4168c..246ad8c 100644 (file)
--- a/arch/powerpc/kernel/misc_64.S
+++ b/arch/powerpc/kernel/misc_64.S
@@ -26,6 +26,7 @@
 #include <asm/thread_info.h>
 #include <asm/kexec.h>
 #include <asm/ptrace.h>
+#include <asm/mmu.h>
 
        .text
 
@@ -496,6 +497,51 @@ kexec_flag:
 
 
 #ifdef CONFIG_KEXEC
+#ifdef CONFIG_PPC_BOOK3E
+/*
+ * BOOK3E has no real MMU mode, so we have to setup the initial TLB
+ * for a core to identity map v:0 to p:0.  This current implementation
+ * assumes that 1G is enough for kexec.
+ */
+kexec_create_tlb:
+       /*
+        * Invalidate all non-IPROT TLB entries to avoid any TLB conflict.
+        * IPROT TLB entries should be >= PAGE_OFFSET and thus not conflict.
+        */
+       PPC_TLBILX_ALL(0,R0)
+       sync
+       isync
+
+       mfspr   r10,SPRN_TLB1CFG
+       andi.   r10,r10,TLBnCFG_N_ENTRY /* Extract # entries */
+       subi    r10,r10,1       /* Last entry: no conflict with kernel text */
+       lis     r9,MAS0_TLBSEL(1)@h
+       rlwimi  r9,r10,16,4,15          /* Setup MAS0 = TLBSEL | ESEL(r9) */
+
+/* Set up a temp identity mapping v:0 to p:0 and return to it. */
+#if defined(CONFIG_SMP) || defined(CONFIG_PPC_E500MC)
+#define M_IF_NEEDED    MAS2_M
+#else
+#define M_IF_NEEDED    0
+#endif
+       mtspr   SPRN_MAS0,r9
+
+       lis     r9,(MAS1_VALID|MAS1_IPROT)@h
+       ori     r9,r9,(MAS1_TSIZE(BOOK3E_PAGESZ_1GB))@l
+       mtspr   SPRN_MAS1,r9
+
+       LOAD_REG_IMMEDIATE(r9, 0x0 | M_IF_NEEDED)
+       mtspr   SPRN_MAS2,r9
+
+       LOAD_REG_IMMEDIATE(r9, 0x0 | MAS3_SR | MAS3_SW | MAS3_SX)
+       mtspr   SPRN_MAS3,r9
+       li      r9,0
+       mtspr   SPRN_MAS7,r9
+
+       tlbwe
+       isync
+       blr
+#endif
 
 /* kexec_smp_wait(void)
  *
@@ -525,6 +571,10 @@ _GLOBAL(kexec_smp_wait)
  * don't overwrite r3 here, it is live for kexec_wait above.
  */
 real_mode:     /* assume normal blr return */
+#ifdef CONFIG_PPC_BOOK3E
+       /* Create an identity mapping. */
+       b       kexec_create_tlb
+#else
 1:     li      r9,MSR_RI
        li      r10,MSR_DR|MSR_IR
        mflr    r11             /* return address to SRR0 */
@@ -536,7 +586,7 @@ real_mode:  /* assume normal blr return */
        mtspr   SPRN_SRR1,r10
        mtspr   SPRN_SRR0,r11
        rfid
-
+#endif
 
 /*
  * kexec_sequence(newstack, start, image, control, clear_all())