On 2019/7/29 19:05, Christophe Leroy wrote:

Le 17/07/2019 à 10:06, Jason Yan a écrit :

quoted

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@huawei.com>
Cc: Diana Craciun <redacted>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Christophe Leroy <redacted>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <redacted>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Kees Cook <redacted>
---
  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@l
+    mtspr   SPRN_MAS2,r6            /* Write MAS2(EPN) */
+
+    mr      r8,r4
+    ori     r8,r8,(MAS3_SW|MAS3_SR|MAS3_SX)

Could drop the mr r8, r4 and do:

ori     r8,r4,(MAS3_SW|MAS3_SR|MAS3_SX)

OK, thanks for the suggestion.

quoted

+    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);

Please please do not add new declarations with the useless 'extern' 
keyword. See checkpatch report: 
https://openpower.xyz/job/snowpatch/job/snowpatch-linux-checkpatch/8124//artifact/linux/checkpatch.log 

Will drop all useless 'extern' in this and other patches, thanks.

quoted

  #endif
  extern void loadcam_entry(unsigned int index);
  extern void loadcam_multi(int first_idx, int num, int tmp_idx);

.