[RFC PATCH 04/10] powerpc/fsl_booke/32: introduce create_tlb_entry() helper

[Jason Yan]

Add a new helper create_tlb_entry() to create a tlb entry by the virtual
and physical address. This is a preparation to support boot kernel at a
randomized address.

Signed-off-by: Jason Yan <yanaijie at huawei.com>
Cc: Diana Craciun <diana.craciun at nxp.com>
Cc: Michael Ellerman <mpe at ellerman.id.au>
Cc: Christophe Leroy <christophe.leroy at c-s.fr>
Cc: Benjamin Herrenschmidt <benh at kernel.crashing.org>
Cc: Paul Mackerras <paulus at samba.org>
Cc: Nicholas Piggin <npiggin at gmail.com>
Cc: Kees Cook <keescook at chromium.org>
---
 arch/powerpc/kernel/head_fsl_booke.S | 30 ++++++++++++++++++++++++++++
 arch/powerpc/mm/mmu_decl.h           |  1 +
 2 files changed, 31 insertions(+)

diff --git a/arch/powerpc/kernel/head_fsl_booke.S b/arch/powerpc/kernel/head_fsl_booke.S
index adf0505dbe02..a57d44638031 100644
--- a/arch/powerpc/kernel/head_fsl_booke.S
+++ b/arch/powerpc/kernel/head_fsl_booke.S
@@ -1114,6 +1114,36 @@ __secondary_hold_acknowledge:
 	.long	-1
 #endif
 
+/*
+ * Create a 64M tlb by address and entry
+ * r3/r4 - physical address
+ * r5 - virtual address
+ * r6 - entry
+ */
+_GLOBAL(create_tlb_entry)
+	lis     r7,0x1000               /* Set MAS0(TLBSEL) = 1 */
+	rlwimi  r7,r6,16,4,15           /* Setup MAS0 = TLBSEL | ESEL(r6) */
+	mtspr   SPRN_MAS0,r7            /* Write MAS0 */
+
+	lis     r6,(MAS1_VALID|MAS1_IPROT)@h
+	ori     r6,r6,(MAS1_TSIZE(BOOK3E_PAGESZ_64M))@l
+	mtspr   SPRN_MAS1,r6            /* Write MAS1 */
+
+	lis     r6,MAS2_EPN_MASK(BOOK3E_PAGESZ_64M)@h
+	ori     r6,r6,MAS2_EPN_MASK(BOOK3E_PAGESZ_64M)@l
+	and     r6,r6,r5
+	ori	r6,r6,MAS2_M at l
+	mtspr   SPRN_MAS2,r6            /* Write MAS2(EPN) */
+
+	mr      r8,r4
+	ori     r8,r8,(MAS3_SW|MAS3_SR|MAS3_SX)
+	mtspr   SPRN_MAS3,r8            /* Write MAS3(RPN) */
+
+	tlbwe                           /* Write TLB */
+	isync
+	sync
+	blr
+
 /*
  * Create a tlb entry with the same effective and physical address as
  * the tlb entry used by the current running code. But set the TS to 1.
diff --git a/arch/powerpc/mm/mmu_decl.h b/arch/powerpc/mm/mmu_decl.h
index 32c1a191c28a..d7737cf97cee 100644
--- a/arch/powerpc/mm/mmu_decl.h
+++ b/arch/powerpc/mm/mmu_decl.h
@@ -142,6 +142,7 @@ extern unsigned long calc_cam_sz(unsigned long ram, unsigned long virt,
 extern void adjust_total_lowmem(void);
 extern int switch_to_as1(void);
 extern void restore_to_as0(int esel, int offset, void *dt_ptr, int bootcpu);
+extern void create_tlb_entry(phys_addr_t phys, unsigned long virt, int entry);
 #endif
 extern void loadcam_entry(unsigned int index);
 extern void loadcam_multi(int first_idx, int num, int tmp_idx);
-- 
2.17.2