linux_dsm_epyc7002/arch/powerpc/include/asm/page_32.h
Christophe Leroy 55c8fc3f49 powerpc/8xx: reintroduce 16K pages with HW assistance
Using this HW assistance implies some constraints on the
page table structure:
- Regardless of the main page size used (4k or 16k), the
level 1 table (PGD) contains 1024 entries and each PGD entry covers
a 4Mbytes area which is managed by a level 2 table (PTE) containing
also 1024 entries each describing a 4k page.
- 16k pages require 4 identifical entries in the L2 table
- 512k pages PTE have to be spread every 128 bytes in the L2 table
- 8M pages PTE are at the address pointed by the L1 entry and each
8M page require 2 identical entries in the PGD.

In order to use hardware assistance with 16K pages, this patch does
the following modifications:
- Make PGD size independent of the main page size
- In 16k pages mode, redefine pte_t as a struct with 4 elements,
and populate those 4 elements in __set_pte_at() and pte_update()
- Adapt the size of the hugepage tables.
- Define a PTE_FRAGMENT_NB so that a 16k page contains 4 page tables.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-12-04 19:45:01 +11:00

65 lines
1.6 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_POWERPC_PAGE_32_H
#define _ASM_POWERPC_PAGE_32_H
#include <asm/cache.h>
#if defined(CONFIG_PHYSICAL_ALIGN) && (CONFIG_PHYSICAL_START != 0)
#if (CONFIG_PHYSICAL_START % CONFIG_PHYSICAL_ALIGN) != 0
#error "CONFIG_PHYSICAL_START must be a multiple of CONFIG_PHYSICAL_ALIGN"
#endif
#endif
#define VM_DATA_DEFAULT_FLAGS VM_DATA_DEFAULT_FLAGS32
#ifdef CONFIG_NOT_COHERENT_CACHE
#define ARCH_DMA_MINALIGN L1_CACHE_BYTES
#endif
#ifdef CONFIG_PTE_64BIT
#define PTE_FLAGS_OFFSET 4 /* offset of PTE flags, in bytes */
#else
#define PTE_FLAGS_OFFSET 0
#endif
#if defined(CONFIG_PPC_256K_PAGES) || \
(defined(CONFIG_PPC_8xx) && defined(CONFIG_PPC_16K_PAGES))
#define PTE_SHIFT (PAGE_SHIFT - PTE_T_LOG2 - 2) /* 1/4 of a page */
#else
#define PTE_SHIFT (PAGE_SHIFT - PTE_T_LOG2) /* full page */
#endif
#ifndef __ASSEMBLY__
/*
* The basic type of a PTE - 64 bits for those CPUs with > 32 bit
* physical addressing.
*/
#ifdef CONFIG_PTE_64BIT
typedef unsigned long long pte_basic_t;
#else
typedef unsigned long pte_basic_t;
#endif
/*
* Clear page using the dcbz instruction, which doesn't cause any
* memory traffic (except to write out any cache lines which get
* displaced). This only works on cacheable memory.
*/
static inline void clear_page(void *addr)
{
unsigned int i;
for (i = 0; i < PAGE_SIZE / L1_CACHE_BYTES; i++, addr += L1_CACHE_BYTES)
dcbz(addr);
}
extern void copy_page(void *to, void *from);
#include <asm-generic/getorder.h>
#define PGD_T_LOG2 (__builtin_ffs(sizeof(pgd_t)) - 1)
#define PTE_T_LOG2 (__builtin_ffs(sizeof(pte_t)) - 1)
#endif /* __ASSEMBLY__ */
#endif /* _ASM_POWERPC_PAGE_32_H */