Re: [PATCH 1/3] powerpc/32: Fix hugepage allocation on 8xx at hint address

On 01/16/2018 10:01 PM, Christophe LEROY wrote:

quoted

quoted

diff --git a/arch/powerpc/include/asm/page_64.h 

b/arch/powerpc/include/asm/page_64.h
index 56234c6fcd61..a7baef5bbe5f 100644

--- a/arch/powerpc/include/asm/page_64.h
+++ b/arch/powerpc/include/asm/page_64.h

@@ -91,30 +91,13 @@ extern u64 ppc64_pft_size;

  #define SLICE_LOW_SHIFT        28
  #define SLICE_HIGH_SHIFT    40
-#define SLICE_LOW_TOP        (0x100000000ul)
-#define SLICE_NUM_LOW        (SLICE_LOW_TOP >> SLICE_LOW_SHIFT)
+#define SLICE_LOW_TOP        (0xfffffffful)
+#define SLICE_NUM_LOW        ((SLICE_LOW_TOP >> SLICE_LOW_SHIFT) + 1)
  #define SLICE_NUM_HIGH        (H_PGTABLE_RANGE >> SLICE_HIGH_SHIFT)

Why are you changing this? is this a bug fix?

That's because 0x100000000ul is out of range of unsigned long on PPC32.

Ok that detail was important. I missed that.

quoted

quoted

  #define GET_LOW_SLICE_INDEX(addr)    ((addr) >> SLICE_LOW_SHIFT)
  #define GET_HIGH_SLICE_INDEX(addr)    ((addr) >> SLICE_HIGH_SHIFT)
-#ifndef __ASSEMBLY__
-struct mm_struct;
-
-extern unsigned long slice_get_unmapped_area(unsigned long addr,
-                         unsigned long len,
-                         unsigned long flags,
-                         unsigned int psize,
-                         int topdown);
-
-extern unsigned int get_slice_psize(struct mm_struct *mm,
-                    unsigned long addr);
-
-extern void slice_set_user_psize(struct mm_struct *mm, unsigned int 
psize);
-extern void slice_set_range_psize(struct mm_struct *mm, unsigned 
long start,
-                  unsigned long len, unsigned int psize);
-
-#endif /* __ASSEMBLY__ */
  #else
  #define slice_init()
  #ifdef CONFIG_PPC_BOOK3S_64

diff --git a/arch/powerpc/kernel/setup-common.c 

b/arch/powerpc/kernel/setup-common.c
index 9d213542a48b..a285e1067713 100644

--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c

@@ -928,7 +928,7 @@ void __init setup_arch(char **cmdline_p)

      if (!radix_enabled())
          init_mm.context.slb_addr_limit = DEFAULT_MAP_WINDOW_USER64;
  #else
-#error    "context.addr_limit not initialized."
+    init_mm.context.slb_addr_limit = DEFAULT_MAP_WINDOW;
  #endif

May be put this within #ifdef 8XX and retain the error?

Is this error really worth it ?
I wanted to avoid spreading too many #ifdef PPC_8xx, but ok I can do that.

quoted

quoted

  #endif

diff --git a/arch/powerpc/mm/8xx_mmu.c b/arch/powerpc/mm/8xx_mmu.c
index f29212e40f40..0be77709446c 100644
--- a/arch/powerpc/mm/8xx_mmu.c
+++ b/arch/powerpc/mm/8xx_mmu.c

@@ -192,7 +192,7 @@ void set_context(unsigned long id, pgd_t *pgd)

      mtspr(SPRN_M_TW, __pa(pgd) - offset);
      /* Update context */
-    mtspr(SPRN_M_CASID, id);
+    mtspr(SPRN_M_CASID, id - 1);
      /* sync */
      mb();
  }

diff --git a/arch/powerpc/mm/hash_utils_64.c 

b/arch/powerpc/mm/hash_utils_64.c
index 655a5a9a183d..3266b3326088 100644

--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c

@@ -1101,7 +1101,7 @@ static unsigned int get_paca_psize(unsigned 

long addr)
      unsigned char *hpsizes;
      unsigned long index, mask_index;
-    if (addr < SLICE_LOW_TOP) {
+    if (addr <= SLICE_LOW_TOP) {

If this is part of bug fix, please do it as part of seperate patch 
with details

As explained above, in order to allow comparison to work on PPC32, 
SLICE_LOW_TOP has to be 0xffffffff instead of 0x100000000

How should I split in separate patches ? Something like ?
1/ Slice support for PPC32 > 2/ Activate slice for 8xx

Yes something like that. Will you  be able to avoid that
  if (SLICE_NUM_HIGH) from the code? That makes the code ugly. Right now 
i don't have definite suggestion on what we could do though.


-aneesh