[PATCH] parisc: use memblock_alloc() instead of custom get_memblock()

[PATCH] parisc: use memblock_alloc() instead of custom get_memblock()

[Mike Rapoport]

The get_memblock() function implements custom bottom-up memblock allocator.
Setting 'memblock_bottom_up = true' before any memblock allocation is done
allows replacing get_memblock() calls with memblock_alloc().

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
---
 arch/parisc/mm/init.c | 52 +++++++++++++++++++--------------------------------
 1 file changed, 19 insertions(+), 33 deletions(-)

diff --git a/arch/parisc/mm/init.c b/arch/parisc/mm/init.c
index 059187a..38b928e 100644
--- a/arch/parisc/mm/init.c
+++ b/arch/parisc/mm/init.c
@@ -79,36 +79,6 @@ static struct resource sysram_resources[MAX_PHYSMEM_RANGES] __read_mostly;
 physmem_range_t pmem_ranges[MAX_PHYSMEM_RANGES] __read_mostly;
 int npmem_ranges __read_mostly;
 
-/*
- * get_memblock() allocates pages via memblock.
- * We can't use memblock_find_in_range(0, KERNEL_INITIAL_SIZE) here since it
- * doesn't allocate from bottom to top which is needed because we only created
- * the initial mapping up to KERNEL_INITIAL_SIZE in the assembly bootup code.
- */
-static void * __init get_memblock(unsigned long size)
-{
-	static phys_addr_t search_addr __initdata;
-	phys_addr_t phys;
-
-	if (!search_addr)
-		search_addr = PAGE_ALIGN(__pa((unsigned long) &_end));
-	search_addr = ALIGN(search_addr, size);
-	while (!memblock_is_region_memory(search_addr, size) ||
-		memblock_is_region_reserved(search_addr, size)) {
-		search_addr += size;
-	}
-	phys = search_addr;
-
-	if (phys)
-		memblock_reserve(phys, size);
-	else
-		panic("get_memblock() failed.\n");
-
-	memset(__va(phys), 0, size);
-
-	return __va(phys);
-}
-
 #ifdef CONFIG_64BIT
 #define MAX_MEM         (~0UL)
 #else /* !CONFIG_64BIT */
@@ -321,6 +291,13 @@ static void __init setup_bootmem(void)
 			max_pfn = start_pfn + npages;
 	}
 
+	/*
+	 * We can't use memblock top-down allocations because we only
+	 * created the initial mapping up to KERNEL_INITIAL_SIZE in
+	 * the assembly bootup code.
+	 */
+	memblock_set_bottom_up(true);
+
 	/* IOMMU is always used to access "high mem" on those boxes
 	 * that can support enough mem that a PCI device couldn't
 	 * directly DMA to any physical addresses.
@@ -442,7 +419,10 @@ static void __init map_pages(unsigned long start_vaddr,
 		 */
 
 		if (!pmd) {
-			pmd = (pmd_t *) get_memblock(PAGE_SIZE << PMD_ORDER);
+			pmd = memblock_alloc(PAGE_SIZE << PMD_ORDER,
+					     SMP_CACHE_BYTES);
+			if (!pmd)
+				panic("pmd allocation failed.\n");
 			pmd = (pmd_t *) __pa(pmd);
 		}
 
@@ -461,7 +441,10 @@ static void __init map_pages(unsigned long start_vaddr,
 
 			pg_table = (pte_t *)pmd_address(*pmd);
 			if (!pg_table) {
-				pg_table = (pte_t *) get_memblock(PAGE_SIZE);
+				pg_table = memblock_alloc(PAGE_SIZE,
+							  SMP_CACHE_BYTES);
+				if (!pg_table)
+					panic("page table allocation failed\n");
 				pg_table = (pte_t *) __pa(pg_table);
 			}
 
@@ -700,7 +683,10 @@ static void __init pagetable_init(void)
 	}
 #endif
 
-	empty_zero_page = get_memblock(PAGE_SIZE);
+	empty_zero_page = memblock_alloc(PAGE_SIZE, SMP_CACHE_BYTES);
+	if (!empty_zero_page)
+		panic("zero page allocation failed.\n");
+
 }
 
 static void __init gateway_init(void)
-- 
2.7.4

Re: [PATCH] parisc: use memblock_alloc() instead of custom get_memblock()

[Matthew Wilcox]

On Tue, Feb 12, 2019 at 03:59:50PM +0200, Mike Rapoport wrote:
> -static void * __init get_memblock(unsigned long size)
> -{
> -	static phys_addr_t search_addr __initdata;
> -	phys_addr_t phys;
> -
> -	if (!search_addr)
> -		search_addr = PAGE_ALIGN(__pa((unsigned long) &_end));
> -	search_addr = ALIGN(search_addr, size);
> -	while (!memblock_is_region_memory(search_addr, size) ||
> -		memblock_is_region_reserved(search_addr, size)) {
> -		search_addr += size;
> -	}
> -	phys = search_addr;

This implies to me that the allocation will be 'size' aligned.

>  		if (!pmd) {
> -			pmd = (pmd_t *) get_memblock(PAGE_SIZE << PMD_ORDER);
> +			pmd = memblock_alloc(PAGE_SIZE << PMD_ORDER,
> +					     SMP_CACHE_BYTES);

So why would this only need to be cacheline aligned?  It's pretty common
for hardware to require that pgd/pud/pmd/pte tables be naturally aligned.

> @@ -700,7 +683,10 @@ static void __init pagetable_init(void)
>  	}
>  #endif
>  
> -	empty_zero_page = get_memblock(PAGE_SIZE);
> +	empty_zero_page = memblock_alloc(PAGE_SIZE, SMP_CACHE_BYTES);

... and surely the zero page also needs to be page aligned, by definition.

Re: [PATCH] parisc: use memblock_alloc() instead of custom get_memblock()

[Mike Rapoport]

On Tue, Feb 12, 2019 at 06:14:18AM -0800, Matthew Wilcox wrote:
> On Tue, Feb 12, 2019 at 03:59:50PM +0200, Mike Rapoport wrote:
> > -static void * __init get_memblock(unsigned long size)
> > -{
> > -	static phys_addr_t search_addr __initdata;
> > -	phys_addr_t phys;
> > -
> > -	if (!search_addr)
> > -		search_addr = PAGE_ALIGN(__pa((unsigned long) &_end));
> > -	search_addr = ALIGN(search_addr, size);
> > -	while (!memblock_is_region_memory(search_addr, size) ||
> > -		memblock_is_region_reserved(search_addr, size)) {
> > -		search_addr += size;
> > -	}
> > -	phys = search_addr;
> 
> This implies to me that the allocation will be 'size' aligned.
> 
> >  		if (!pmd) {
> > -			pmd = (pmd_t *) get_memblock(PAGE_SIZE << PMD_ORDER);
> > +			pmd = memblock_alloc(PAGE_SIZE << PMD_ORDER,
> > +					     SMP_CACHE_BYTES);
> 
> So why would this only need to be cacheline aligned?  It's pretty common
> for hardware to require that pgd/pud/pmd/pte tables be naturally aligned.
> 
> > @@ -700,7 +683,10 @@ static void __init pagetable_init(void)
> >  	}
> >  #endif
> >  
> > -	empty_zero_page = get_memblock(PAGE_SIZE);
> > +	empty_zero_page = memblock_alloc(PAGE_SIZE, SMP_CACHE_BYTES);
> 
> ... and surely the zero page also needs to be page aligned, by definition.
 
Right, I've completely missed the alignment. Will fix.

-- 
Sincerely yours,
Mike.