Subject: Re: [PATCH v2 5/5] powerpc/64s: mm_context.addr_limit is only used on hash

From: "Aneesh Kumar K.V" <[email-masked]>
Date: Mon, 13 Nov 2017 10:31:09 +0530

Nicholas Piggin <[email-masked]> writes:

> Radix keeps no meaningful state in addr_limit, so remove it from
> radix code and rename to slb_addr_limit to make it clear it applies
> to hash only.
>

Reviewed-by: Aneesh Kumar K.V <[email-masked]>

> Signed-off-by: Nicholas Piggin <[email-masked]>
> ---
>  arch/powerpc/include/asm/book3s/64/mmu-hash.h |  2 +-
>  arch/powerpc/include/asm/book3s/64/mmu.h      |  2 +-
>  arch/powerpc/include/asm/paca.h               |  2 +-
>  arch/powerpc/kernel/asm-offsets.c             |  2 +-
>  arch/powerpc/kernel/paca.c                    |  4 ++--
>  arch/powerpc/kernel/setup-common.c            |  3 ++-
>  arch/powerpc/mm/hugetlbpage-radix.c           |  8 +-------
>  arch/powerpc/mm/mmap.c                        | 18 ++++--------------
>  arch/powerpc/mm/mmu_context_book3s64.c        |  4 ++--
>  arch/powerpc/mm/slb_low.S                     |  2 +-
>  arch/powerpc/mm/slice.c                       | 22 +++++++++++-----------
>  11 files changed, 27 insertions(+), 42 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/book3s/64/mmu-hash.h b/arch/powerpc/include/asm/book3s/64/mmu-hash.h
> index 508275bb05d5..e91e115a816f 100644
> --- a/arch/powerpc/include/asm/book3s/64/mmu-hash.h
> +++ b/arch/powerpc/include/asm/book3s/64/mmu-hash.h
> @@ -606,7 +606,7 @@ extern void slb_set_size(u16 size);
>
>  /* 4 bits per slice and we have one slice per 1TB */
>  #define SLICE_ARRAY_SIZE	(H_PGTABLE_RANGE >> 41)
> -#define TASK_SLICE_ARRAY_SZ(x)	((x)->context.addr_limit >> 41)
> +#define TASK_SLICE_ARRAY_SZ(x)	((x)->context.slb_addr_limit >> 41)
>
>  #ifndef __ASSEMBLY__
>
> diff --git a/arch/powerpc/include/asm/book3s/64/mmu.h b/arch/powerpc/include/asm/book3s/64/mmu.h
> index 37fdede5a24c..c9448e19847a 100644
> --- a/arch/powerpc/include/asm/book3s/64/mmu.h
> +++ b/arch/powerpc/include/asm/book3s/64/mmu.h
> @@ -93,7 +93,7 @@ typedef struct {
>  #ifdef CONFIG_PPC_MM_SLICES
>  	u64 low_slices_psize;	/* SLB page size encodings */
>  	unsigned char high_slices_psize[SLICE_ARRAY_SIZE];
> -	unsigned long addr_limit;
> +	unsigned long slb_addr_limit;
>  #else
>  	u16 sllp;		/* SLB page size encoding */
>  #endif
> diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h
> index c907ae23c956..3892db93b837 100644
> --- a/arch/powerpc/include/asm/paca.h
> +++ b/arch/powerpc/include/asm/paca.h
> @@ -143,7 +143,7 @@ struct paca_struct {
>  #ifdef CONFIG_PPC_MM_SLICES
>  	u64 mm_ctx_low_slices_psize;
>  	unsigned char mm_ctx_high_slices_psize[SLICE_ARRAY_SIZE];
> -	unsigned long addr_limit;
> +	unsigned long mm_ctx_slb_addr_limit;
>  #else
>  	u16 mm_ctx_user_psize;
>  	u16 mm_ctx_sllp;
> diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
> index 200623e71474..9aace433491a 100644
> --- a/arch/powerpc/kernel/asm-offsets.c
> +++ b/arch/powerpc/kernel/asm-offsets.c
> @@ -185,7 +185,7 @@ int main(void)
>  #ifdef CONFIG_PPC_MM_SLICES
>  	OFFSET(PACALOWSLICESPSIZE, paca_struct, mm_ctx_low_slices_psize);
>  	OFFSET(PACAHIGHSLICEPSIZE, paca_struct, mm_ctx_high_slices_psize);
> -	DEFINE(PACA_ADDR_LIMIT, offsetof(struct paca_struct, addr_limit));
> +	OFFSET(PACA_SLB_ADDR_LIMIT, paca_struct, mm_ctx_slb_addr_limit);
>  	DEFINE(MMUPSIZEDEFSIZE, sizeof(struct mmu_psize_def));
>  #endif /* CONFIG_PPC_MM_SLICES */
>  #endif
> diff --git a/arch/powerpc/kernel/paca.c b/arch/powerpc/kernel/paca.c
> index 5d38d5ea9a24..d6597038931d 100644
> --- a/arch/powerpc/kernel/paca.c
> +++ b/arch/powerpc/kernel/paca.c
> @@ -262,8 +262,8 @@ void copy_mm_to_paca(struct mm_struct *mm)
>
>  	get_paca()->mm_ctx_id = context->id;
>  #ifdef CONFIG_PPC_MM_SLICES
> -	VM_BUG_ON(!mm->context.addr_limit);
> -	get_paca()->addr_limit = mm->context.addr_limit;
> +	VM_BUG_ON(!mm->context.slb_addr_limit);
> +	get_paca()->mm_ctx_slb_addr_limit = mm->context.slb_addr_limit;
>  	get_paca()->mm_ctx_low_slices_psize = context->low_slices_psize;
>  	memcpy(&get_paca()->mm_ctx_high_slices_psize,
>  	       &context->high_slices_psize, TASK_SLICE_ARRAY_SZ(mm));
> diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
> index fa661ed616f5..2075322cd225 100644
> --- a/arch/powerpc/kernel/setup-common.c
> +++ b/arch/powerpc/kernel/setup-common.c
> @@ -898,7 +898,8 @@ void __init setup_arch(char **cmdline_p)
>
>  #ifdef CONFIG_PPC_MM_SLICES
>  #ifdef CONFIG_PPC64
> -	init_mm.context.addr_limit = DEFAULT_MAP_WINDOW_USER64;
> +	if (!radix_enabled())
> +		init_mm.context.slb_addr_limit = DEFAULT_MAP_WINDOW_USER64;
>  #else
>  #error	"context.addr_limit not initialized."
>  #endif
> diff --git a/arch/powerpc/mm/hugetlbpage-radix.c b/arch/powerpc/mm/hugetlbpage-radix.c
> index bd022d16745c..2486bee0f93e 100644
> --- a/arch/powerpc/mm/hugetlbpage-radix.c
> +++ b/arch/powerpc/mm/hugetlbpage-radix.c
> @@ -61,16 +61,10 @@ radix__hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
>  		return -EINVAL;
>  	if (len > high_limit)
>  		return -ENOMEM;
> +
>  	if (fixed) {
>  		if (addr > high_limit - len)
>  			return -ENOMEM;
> -	}
> -
> -	if (unlikely(addr > mm->context.addr_limit &&
> -		     mm->context.addr_limit != TASK_SIZE))
> -		mm->context.addr_limit = TASK_SIZE;
> -
> -	if (fixed) {
>  		if (prepare_hugepage_range(file, addr, len))
>  			return -EINVAL;
>  		return addr;
> diff --git a/arch/powerpc/mm/mmap.c b/arch/powerpc/mm/mmap.c
> index 6d476a7b5611..d503f344e476 100644
> --- a/arch/powerpc/mm/mmap.c
> +++ b/arch/powerpc/mm/mmap.c
> @@ -116,17 +116,12 @@ radix__arch_get_unmapped_area(struct file *filp, unsigned long addr,
>
>  	if (len > high_limit)
>  		return -ENOMEM;
> +
>  	if (fixed) {
>  		if (addr > high_limit - len)
>  			return -ENOMEM;
> -	}
> -
> -	if (unlikely(addr > mm->context.addr_limit &&
> -		     mm->context.addr_limit != TASK_SIZE))
> -		mm->context.addr_limit = TASK_SIZE;
> -
> -	if (fixed)
>  		return addr;
> +	}
>
>  	if (addr) {
>  		addr = PAGE_ALIGN(addr);
> @@ -165,17 +160,12 @@ radix__arch_get_unmapped_area_topdown(struct file *filp,
>
>  	if (len > high_limit)
>  		return -ENOMEM;
> +
>  	if (fixed) {
>  		if (addr > high_limit - len)
>  			return -ENOMEM;
> -	}
> -
> -	if (unlikely(addr > mm->context.addr_limit &&
> -		     mm->context.addr_limit != TASK_SIZE))
> -		mm->context.addr_limit = TASK_SIZE;
> -
> -	if (fixed)
>  		return addr;
> +	}
>
>  	if (addr) {
>  		addr = PAGE_ALIGN(addr);
> diff --git a/arch/powerpc/mm/mmu_context_book3s64.c b/arch/powerpc/mm/mmu_context_book3s64.c
> index 846cbad45fce..5e193e444ee8 100644
> --- a/arch/powerpc/mm/mmu_context_book3s64.c
> +++ b/arch/powerpc/mm/mmu_context_book3s64.c
> @@ -96,8 +96,8 @@ static int hash__init_new_context(struct mm_struct *mm)
>  	 * In the case of exec, use the default limit,
>  	 * otherwise inherit it from the mm we are duplicating.
>  	 */
> -	if (!mm->context.addr_limit)
> -		mm->context.addr_limit = DEFAULT_MAP_WINDOW_USER64;
> +	if (!mm->context.slb_addr_limit)
> +		mm->context.slb_addr_limit = DEFAULT_MAP_WINDOW_USER64;
>
>  	/*
>  	 * The old code would re-promote on fork, we don't do that when using
> diff --git a/arch/powerpc/mm/slb_low.S b/arch/powerpc/mm/slb_low.S
> index 906a86fe457b..7046bb389704 100644
> --- a/arch/powerpc/mm/slb_low.S
> +++ b/arch/powerpc/mm/slb_low.S
> @@ -167,7 +167,7 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_1T_SEGMENT)
>          /*
>           * user space make sure we are within the allowed limit
>  	 */
> -	ld	r11,PACA_ADDR_LIMIT(r13)
> +	ld	r11,PACA_SLB_ADDR_LIMIT(r13)
>  	cmpld	r3,r11
>  	bge-	8f
>
> diff --git a/arch/powerpc/mm/slice.c b/arch/powerpc/mm/slice.c
> index a4f93699194b..564fff06f5c1 100644
> --- a/arch/powerpc/mm/slice.c
> +++ b/arch/powerpc/mm/slice.c
> @@ -96,7 +96,7 @@ static int slice_area_is_free(struct mm_struct *mm, unsigned long addr,
>  {
>  	struct vm_area_struct *vma;
>
> -	if ((mm->context.addr_limit - len) < addr)
> +	if ((mm->context.slb_addr_limit - len) < addr)
>  		return 0;
>  	vma = find_vma(mm, addr);
>  	return (!vma || (addr + len) <= vm_start_gap(vma));
> @@ -133,10 +133,10 @@ static void slice_mask_for_free(struct mm_struct *mm, struct slice_mask *ret)
>  		if (!slice_low_has_vma(mm, i))
>  			ret->low_slices |= 1u << i;
>
> -	if (mm->context.addr_limit <= SLICE_LOW_TOP)
> +	if (mm->context.slb_addr_limit <= SLICE_LOW_TOP)
>  		return;
>
> -	for (i = 0; i < GET_HIGH_SLICE_INDEX(mm->context.addr_limit); i++)
> +	for (i = 0; i < GET_HIGH_SLICE_INDEX(mm->context.slb_addr_limit); i++)
>  		if (!slice_high_has_vma(mm, i))
>  			__set_bit(i, ret->high_slices);
>  }
> @@ -157,7 +157,7 @@ static void slice_mask_for_size(struct mm_struct *mm, int psize, struct slice_ma
>  			ret->low_slices |= 1u << i;
>
>  	hpsizes = mm->context.high_slices_psize;
> -	for (i = 0; i < GET_HIGH_SLICE_INDEX(mm->context.addr_limit); i++) {
> +	for (i = 0; i < GET_HIGH_SLICE_INDEX(mm->context.slb_addr_limit); i++) {
>  		mask_index = i & 0x1;
>  		index = i >> 1;
>  		if (((hpsizes[index] >> (mask_index * 4)) & 0xf) == psize)
> @@ -169,7 +169,7 @@ static int slice_check_fit(struct mm_struct *mm,
>  			   struct slice_mask mask, struct slice_mask available)
>  {
>  	DECLARE_BITMAP(result, SLICE_NUM_HIGH);
> -	unsigned long slice_count = GET_HIGH_SLICE_INDEX(mm->context.addr_limit);
> +	unsigned long slice_count = GET_HIGH_SLICE_INDEX(mm->context.slb_addr_limit);
>
>  	bitmap_and(result, mask.high_slices,
>  		   available.high_slices, slice_count);
> @@ -219,7 +219,7 @@ static void slice_convert(struct mm_struct *mm, struct slice_mask mask, int psiz
>  	mm->context.low_slices_psize = lpsizes;
>
>  	hpsizes = mm->context.high_slices_psize;
> -	for (i = 0; i < GET_HIGH_SLICE_INDEX(mm->context.addr_limit); i++) {
> +	for (i = 0; i < GET_HIGH_SLICE_INDEX(mm->context.slb_addr_limit); i++) {
>  		mask_index = i & 0x1;
>  		index = i >> 1;
>  		if (test_bit(i, mask.high_slices))
> @@ -329,8 +329,8 @@ static unsigned long slice_find_area_topdown(struct mm_struct *mm,
>  	 * Only for that request for which high_limit is above
>  	 * DEFAULT_MAP_WINDOW we should apply this.
>  	 */
> -	if (high_limit  > DEFAULT_MAP_WINDOW)
> -		addr += mm->context.addr_limit - DEFAULT_MAP_WINDOW;
> +	if (high_limit > DEFAULT_MAP_WINDOW)
> +		addr += mm->context.slb_addr_limit - DEFAULT_MAP_WINDOW;
>
>  	while (addr > PAGE_SIZE) {
>  		info.high_limit = addr;
> @@ -432,8 +432,8 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
>  			return -ENOMEM;
>  	}
>
> -	if (high_limit > mm->context.addr_limit) {
> -		mm->context.addr_limit = high_limit;
> +	if (high_limit > mm->context.slb_addr_limit) {
> +		mm->context.slb_addr_limit = high_limit;
>  		on_each_cpu(slice_flush_segments, mm, 1);
>  	}
>
> @@ -452,7 +452,7 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
>
>  	/* Sanity checks */
>  	BUG_ON(mm->task_size == 0);
> -	BUG_ON(mm->context.addr_limit == 0);
> +	BUG_ON(mm->context.slb_addr_limit == 0);
>  	VM_BUG_ON(radix_enabled());
>
>  	slice_dbg("slice_get_unmapped_area(mm=%p, psize=%d...\n", mm, psize);
> -- 
> 2.15.0