powerpc/8xx: add support for huge pages on VMAP and VMALLOC

powerpc 8xx has 4 page sizes:
- 4k
- 16k
- 512k
- 8M

At the time being, vmalloc and vmap only support huge pages which are leaf
at PMD level.

Here the PMD level is 4M, it doesn't correspond to any supported page
size.

For now, implement use of 16k and 512k pages which is done at PTE level.

Support of 8M pages will be implemented later, it requires vmalloc to
support hugepd tables.

Link: https://lkml.kernel.org/r/8b972f1c03fb6bd59953035f0a3e4d26659de4f8.1620795204.git.christophe.leroy@csgroup.eu
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Uladzislau Rezki <uladzislau.rezki@sony.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 43 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/nohash/32/mmu-8xx.h b/arch/powerpc/include/asm/nohash/32/mmu-8xx.h
index 6e4faa0a9b35..997cec973406 100644
--- a/arch/powerpc/include/asm/nohash/32/mmu-8xx.h
+++ b/arch/powerpc/include/asm/nohash/32/mmu-8xx.h
@@ -178,6 +178,7 @@
 #ifndef __ASSEMBLY__
 
 #include <linux/mmdebug.h>
+#include <linux/sizes.h>
 
 void mmu_pin_tlb(unsigned long top, bool readonly);
 
@@ -225,6 +226,48 @@ static inline unsigned int mmu_psize_to_shift(unsigned int mmu_psize)
 	BUG();
 }
 
+static inline bool arch_vmap_try_size(unsigned long addr, unsigned long end, u64 pfn,
+				      unsigned int max_page_shift, unsigned long size)
+{
+	if (end - addr < size)
+		return false;
+
+	if ((1UL << max_page_shift) < size)
+		return false;
+
+	if (!IS_ALIGNED(addr, size))
+		return false;
+
+	if (!IS_ALIGNED(PFN_PHYS(pfn), size))
+		return false;
+
+	return true;
+}
+
+static inline unsigned long arch_vmap_pte_range_map_size(unsigned long addr, unsigned long end,
+							 u64 pfn, unsigned int max_page_shift)
+{
+	if (arch_vmap_try_size(addr, end, pfn, max_page_shift, SZ_512K))
+		return SZ_512K;
+	if (PAGE_SIZE == SZ_16K)
+		return SZ_16K;
+	if (arch_vmap_try_size(addr, end, pfn, max_page_shift, SZ_16K))
+		return SZ_16K;
+	return PAGE_SIZE;
+}
+#define arch_vmap_pte_range_map_size arch_vmap_pte_range_map_size
+
+static inline int arch_vmap_pte_supported_shift(unsigned long size)
+{
+	if (size >= SZ_512K)
+		return 19;
+	else if (size >= SZ_16K)
+		return 14;
+	else
+		return PAGE_SHIFT;
+}
+#define arch_vmap_pte_supported_shift arch_vmap_pte_supported_shift
+
 /* patch sites */
 extern s32 patch__itlbmiss_exit_1, patch__dtlbmiss_exit_1;
 extern s32 patch__itlbmiss_perf, patch__dtlbmiss_perf;