| Message ID | 1341839621-28332-9-git-send-email-aneesh.kumar@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Benjamin Herrenschmidt |
| Headers | show |
On Mon, Jul 09, 2012 at 06:43:38PM +0530, Aneesh Kumar K.V wrote: > From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> > > slice array size and slice mask size depend on PGTABLE_RANGE. We > can't directly include pgtable.h in these header because there is > a circular dependency. So add compile time check for these values. Some comments below... > struct slice_mask { > u16 low_slices; > /* > - * This should be derived out of PGTABLE_RANGE. For the current > - * max 64TB, u64 should be ok. > + * We do this as a union so that we can verify > + * SLICE_MASK_SIZE against PGTABLE_RANGE > */ > - u64 high_slices; > + union { > + u64 high_slices; > + unsigned char not_used[SLICE_MASK_SIZE]; > + }; Seems ugly to have to have a union just for that. Can't we do something like BUILD_BUG_ON(sizeof(u64) < SLICE_MASK_SIZE) instead? > @@ -73,7 +73,7 @@ static struct slice_mask slice_range_to_mask(unsigned long start, > unsigned long len) > { > unsigned long end = start + len - 1; > - struct slice_mask ret = { 0, 0 }; > + struct slice_mask ret = { 0, {0} }; Wouldn't { 0 } suffice? Similarly in several places below. Paul.
Paul Mackerras <paulus@samba.org> writes: > On Mon, Jul 09, 2012 at 06:43:38PM +0530, Aneesh Kumar K.V wrote: >> From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> >> >> slice array size and slice mask size depend on PGTABLE_RANGE. We >> can't directly include pgtable.h in these header because there is >> a circular dependency. So add compile time check for these values. > > Some comments below... > >> struct slice_mask { >> u16 low_slices; >> /* >> - * This should be derived out of PGTABLE_RANGE. For the current >> - * max 64TB, u64 should be ok. >> + * We do this as a union so that we can verify >> + * SLICE_MASK_SIZE against PGTABLE_RANGE >> */ >> - u64 high_slices; >> + union { >> + u64 high_slices; >> + unsigned char not_used[SLICE_MASK_SIZE]; >> + }; > > Seems ugly to have to have a union just for that. Can't we do > something like BUILD_BUG_ON(sizeof(u64) < SLICE_MASK_SIZE) instead? Dropped the union from the patch > >> @@ -73,7 +73,7 @@ static struct slice_mask slice_range_to_mask(unsigned long start, >> unsigned long len) >> { >> unsigned long end = start + len - 1; >> - struct slice_mask ret = { 0, 0 }; >> + struct slice_mask ret = { 0, {0} }; > > Wouldn't { 0 } suffice? Similarly in several places below. Once i drop the union all these changes can be dropped. -aneesh
diff --git a/arch/powerpc/include/asm/mmu-hash64.h b/arch/powerpc/include/asm/mmu-hash64.h index 35b74e8..aa0d560 100644 --- a/arch/powerpc/include/asm/mmu-hash64.h +++ b/arch/powerpc/include/asm/mmu-hash64.h @@ -419,6 +419,13 @@ extern void slb_set_size(u16 size); srdi rx,rx,VSID_BITS_##size; /* extract 2^VSID_BITS bit */ \ add rt,rt,rx +/* 4 bits per slice and we have one slice per 1TB */ +#if 0 /* We can't directly include pgtable.h hence this hack */ +#define SLICE_ARRAY_SIZE (PGTABLE_RANGE >> 41) +#else +/* Right now we only support 64TB */ +#define SLICE_ARRAY_SIZE 32 +#endif #ifndef __ASSEMBLY__ @@ -463,11 +470,7 @@ typedef struct { #ifdef CONFIG_PPC_MM_SLICES u64 low_slices_psize; /* SLB page size encodings */ - /* - * Right now we support 64TB and 4 bits for each - * 1TB slice we need 32 bytes for 64TB. - */ - unsigned char high_slices_psize[32]; /* 4 bits per slice for now */ + unsigned char high_slices_psize[SLICE_ARRAY_SIZE]; #else u16 sllp; /* SLB page size encoding */ #endif diff --git a/arch/powerpc/include/asm/page_64.h b/arch/powerpc/include/asm/page_64.h index 6c9bef4..141853e 100644 --- a/arch/powerpc/include/asm/page_64.h +++ b/arch/powerpc/include/asm/page_64.h @@ -78,15 +78,26 @@ extern u64 ppc64_pft_size; #define GET_LOW_SLICE_INDEX(addr) ((addr) >> SLICE_LOW_SHIFT) #define GET_HIGH_SLICE_INDEX(addr) ((addr) >> SLICE_HIGH_SHIFT) +/* 1 bit per slice and we have one slice per 1TB */ +#if 0 /* We can't directly include pgtable.h hence this hack */ +#define SLICE_MASK_SIZE (PGTABLE_RANG >> 43) +#else +/* Right now we support only 64TB */ +#define SLICE_MASK_SIZE 8 +#endif + #ifndef __ASSEMBLY__ struct slice_mask { u16 low_slices; /* - * This should be derived out of PGTABLE_RANGE. For the current - * max 64TB, u64 should be ok. + * We do this as a union so that we can verify + * SLICE_MASK_SIZE against PGTABLE_RANGE */ - u64 high_slices; + union { + u64 high_slices; + unsigned char not_used[SLICE_MASK_SIZE]; + }; }; struct mm_struct; diff --git a/arch/powerpc/include/asm/pgtable-ppc64.h b/arch/powerpc/include/asm/pgtable-ppc64.h index 8af1cf2..dea953f 100644 --- a/arch/powerpc/include/asm/pgtable-ppc64.h +++ b/arch/powerpc/include/asm/pgtable-ppc64.h @@ -32,6 +32,14 @@ #endif #endif +#if (PGTABLE_RANGE >> 41) > SLICE_ARRAY_SIZE +#error PGTABLE_RANGE exceeds SLICE_ARRAY_SIZE +#endif + +#if (PGTABLE_RANGE >> 43) > SLICE_MASK_SIZE +#error PGTABLE_RANGE exceeds slice_mask high_slices size +#endif + /* * Define the address range of the kernel non-linear virtual area */ diff --git a/arch/powerpc/mm/slice.c b/arch/powerpc/mm/slice.c index 302a481..0aa1b2d 100644 --- a/arch/powerpc/mm/slice.c +++ b/arch/powerpc/mm/slice.c @@ -73,7 +73,7 @@ static struct slice_mask slice_range_to_mask(unsigned long start, unsigned long len) { unsigned long end = start + len - 1; - struct slice_mask ret = { 0, 0 }; + struct slice_mask ret = { 0, {0} }; if (start < SLICE_LOW_TOP) { unsigned long mend = min(end, SLICE_LOW_TOP); @@ -123,7 +123,7 @@ static int slice_high_has_vma(struct mm_struct *mm, unsigned long slice) static struct slice_mask slice_mask_for_free(struct mm_struct *mm) { - struct slice_mask ret = { 0, 0 }; + struct slice_mask ret = { 0, {0} }; unsigned long i; for (i = 0; i < SLICE_NUM_LOW; i++) @@ -144,7 +144,7 @@ static struct slice_mask slice_mask_for_size(struct mm_struct *mm, int psize) { unsigned char *hpsizes; int index, mask_index; - struct slice_mask ret = { 0, 0 }; + struct slice_mask ret = { 0, {0} }; unsigned long i; u64 lpsizes; @@ -412,10 +412,10 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len, unsigned long flags, unsigned int psize, int topdown, int use_cache) { - struct slice_mask mask = {0, 0}; + struct slice_mask mask = {0, {0} }; struct slice_mask good_mask; - struct slice_mask potential_mask = {0,0} /* silence stupid warning */; - struct slice_mask compat_mask = {0, 0}; + struct slice_mask potential_mask = {0, {0} } /* silence stupid warning */; + struct slice_mask compat_mask = {0, {0} }; int fixed = (flags & MAP_FIXED); int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT); struct mm_struct *mm = current->mm;