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authorPeter Zijlstra <peterz@infradead.org>2020-11-26 13:53:33 +0300
committerPeter Zijlstra <peterz@infradead.org>2020-12-09 19:08:56 +0300
commitc5eecbb58f65bf1c4effab9a7f283184b469768c (patch)
treeca562dc2cb5fe999331a2c23f523329ebb7b2c4a /arch/powerpc
parentd55863db1dfec8845067f5625f1b0ab18c8948be (diff)
downloadlinux-c5eecbb58f65bf1c4effab9a7f283184b469768c.tar.xz
powerpc/8xx: Implement pXX_leaf_size() support
Christophe Leroy wrote: > I can help with powerpc 8xx. It is a 32 bits powerpc. The PGD has 1024 > entries, that means each entry maps 4M. > > Page sizes are 4k, 16k, 512k and 8M. > > For the 8M pages we use hugepd with a single entry. The two related PGD > entries point to the same hugepd. > > For the other sizes, they are in standard page tables. 16k pages appear > 4 times in the page table. 512k entries appear 128 times in the page > table. > > When the PGD entry has _PMD_PAGE_8M bits, the PMD entry points to a > hugepd with holds the single 8M entry. > > In the PTE, we have two bits: _PAGE_SPS and _PAGE_HUGE > > _PAGE_HUGE means it is a 512k page > _PAGE_SPS means it is not a 4k page > > The kernel can by build either with 4k pages as standard page size, or > 16k pages. It doesn't change the page table layout though. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20201126121121.364451610@infradead.org
Diffstat (limited to 'arch/powerpc')
-rw-r--r--arch/powerpc/include/asm/nohash/32/pte-8xx.h23
1 files changed, 23 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/nohash/32/pte-8xx.h b/arch/powerpc/include/asm/nohash/32/pte-8xx.h
index 1581204467e1..fcc48d590d88 100644
--- a/arch/powerpc/include/asm/nohash/32/pte-8xx.h
+++ b/arch/powerpc/include/asm/nohash/32/pte-8xx.h
@@ -135,6 +135,29 @@ static inline pte_t pte_mkhuge(pte_t pte)
}
#define pte_mkhuge pte_mkhuge
+
+static inline unsigned long pgd_leaf_size(pgd_t pgd)
+{
+ if (pgd_val(pgd) & _PMD_PAGE_8M)
+ return SZ_8M;
+ return SZ_4M;
+}
+
+#define pgd_leaf_size pgd_leaf_size
+
+static inline unsigned long pte_leaf_size(pte_t pte)
+{
+ pte_basic_t val = pte_val(pte);
+
+ if (val & _PAGE_HUGE)
+ return SZ_512K;
+ if (val & _PAGE_SPS)
+ return SZ_16K;
+ return SZ_4K;
+}
+
+#define pte_leaf_size pte_leaf_size
+
#endif
#endif /* __KERNEL__ */