[PATCH v2 4/5] powerpc/8xx: Increase the number of mm slices
From: Christophe Leroy <hidden>
Date: 2018-01-17 09:23:15
Also in:
lkml
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
On the 8xx, we can have as many slices as PMD entries. This means we could have 1024 slices in 4k size pages mode and 64 slices in 16k size pages. However, due to a stack overflow in slice_get_unmapped_area(), we limit to 512 slices. Signed-off-by: Christophe Leroy <redacted> --- v2: no change arch/powerpc/include/asm/mmu-8xx.h | 6 +++++- arch/powerpc/include/asm/page_32.h | 3 ++- 2 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/include/asm/mmu-8xx.h b/arch/powerpc/include/asm/mmu-8xx.h
index d669d0062da4..40aa7b0cd0dc 100644
--- a/arch/powerpc/include/asm/mmu-8xx.h
+++ b/arch/powerpc/include/asm/mmu-8xx.h@@ -171,7 +171,11 @@ typedef struct { unsigned long vdso_base; #ifdef CONFIG_PPC_MM_SLICES u16 user_psize; /* page size index */ - unsigned char low_slices_psize[8]; /* 16 slices */ +#if defined(CONFIG_PPC_16K_PAGES) + unsigned char low_slices_psize[32]; /* 64 slices */ +#else + unsigned char low_slices_psize[256]; /* 512 slices */ +#endif unsigned char high_slices_psize[0]; unsigned long slb_addr_limit; #endif
diff --git a/arch/powerpc/include/asm/page_32.h b/arch/powerpc/include/asm/page_32.h
index f7d1bd1183c8..43695ce7ee07 100644
--- a/arch/powerpc/include/asm/page_32.h
+++ b/arch/powerpc/include/asm/page_32.h@@ -62,7 +62,8 @@ extern void copy_page(void *to, void *from); #ifdef CONFIG_PPC_MM_SLICES -#define SLICE_LOW_SHIFT 28 +/* SLICE_LOW_SHIFT >= 23 to avoid stack overflow in slice_get_unmapped_area() */ +#define SLICE_LOW_SHIFT (PMD_SHIFT > 23 ? PMD_SHIFT : 23) #define SLICE_HIGH_SHIFT 0 #define SLICE_LOW_TOP (0xfffffffful)
--
2.13.3