diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/powerpc/Kconfig | 1 | ||||
| -rw-r--r-- | arch/powerpc/include/asm/set_memory.h | 32 | ||||
| -rw-r--r-- | arch/powerpc/mm/Makefile | 2 | ||||
| -rw-r--r-- | arch/powerpc/mm/pageattr.c | 101 |
4 files changed, 135 insertions, 1 deletions
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 36ba413f49d3..abfe2e9225fa 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -140,6 +140,7 @@ config PPC select ARCH_HAS_PTE_DEVMAP if PPC_BOOK3S_64 select ARCH_HAS_PTE_SPECIAL select ARCH_HAS_SCALED_CPUTIME if VIRT_CPU_ACCOUNTING_NATIVE && PPC_BOOK3S_64 + select ARCH_HAS_SET_MEMORY select ARCH_HAS_STRICT_KERNEL_RWX if ((PPC_BOOK3S_64 || PPC32) && !HIBERNATION) select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST select ARCH_HAS_UACCESS_FLUSHCACHE diff --git a/arch/powerpc/include/asm/set_memory.h b/arch/powerpc/include/asm/set_memory.h new file mode 100644 index 000000000000..64011ea444b4 --- /dev/null +++ b/arch/powerpc/include/asm/set_memory.h @@ -0,0 +1,32 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_POWERPC_SET_MEMORY_H +#define _ASM_POWERPC_SET_MEMORY_H + +#define SET_MEMORY_RO 0 +#define SET_MEMORY_RW 1 +#define SET_MEMORY_NX 2 +#define SET_MEMORY_X 3 + +int change_memory_attr(unsigned long addr, int numpages, long action); + +static inline int set_memory_ro(unsigned long addr, int numpages) +{ + return change_memory_attr(addr, numpages, SET_MEMORY_RO); +} + +static inline int set_memory_rw(unsigned long addr, int numpages) +{ + return change_memory_attr(addr, numpages, SET_MEMORY_RW); +} + +static inline int set_memory_nx(unsigned long addr, int numpages) +{ + return change_memory_attr(addr, numpages, SET_MEMORY_NX); +} + +static inline int set_memory_x(unsigned long addr, int numpages) +{ + return change_memory_attr(addr, numpages, SET_MEMORY_X); +} + +#endif diff --git a/arch/powerpc/mm/Makefile b/arch/powerpc/mm/Makefile index c3df3a8501d4..9142cf1fb0d5 100644 --- a/arch/powerpc/mm/Makefile +++ b/arch/powerpc/mm/Makefile @@ -5,7 +5,7 @@ ccflags-$(CONFIG_PPC64) := $(NO_MINIMAL_TOC) -obj-y := fault.o mem.o pgtable.o mmap.o maccess.o \ +obj-y := fault.o mem.o pgtable.o mmap.o maccess.o pageattr.o \ init_$(BITS).o pgtable_$(BITS).o \ pgtable-frag.o ioremap.o ioremap_$(BITS).o \ init-common.o mmu_context.o drmem.o \ diff --git a/arch/powerpc/mm/pageattr.c b/arch/powerpc/mm/pageattr.c new file mode 100644 index 000000000000..5e5ae50a7f23 --- /dev/null +++ b/arch/powerpc/mm/pageattr.c @@ -0,0 +1,101 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * MMU-generic set_memory implementation for powerpc + * + * Copyright 2019-2021, IBM Corporation. + */ + +#include <linux/mm.h> +#include <linux/vmalloc.h> +#include <linux/set_memory.h> + +#include <asm/mmu.h> +#include <asm/page.h> +#include <asm/pgtable.h> + + +/* + * Updates the attributes of a page in three steps: + * + * 1. invalidate the page table entry + * 2. flush the TLB + * 3. install the new entry with the updated attributes + * + * Invalidating the pte means there are situations where this will not work + * when in theory it should. + * For example: + * - removing write from page whilst it is being executed + * - setting a page read-only whilst it is being read by another CPU + * + */ +static int change_page_attr(pte_t *ptep, unsigned long addr, void *data) +{ + long action = (long)data; + pte_t pte; + + spin_lock(&init_mm.page_table_lock); + + /* invalidate the PTE so it's safe to modify */ + pte = ptep_get_and_clear(&init_mm, addr, ptep); + flush_tlb_kernel_range(addr, addr + PAGE_SIZE); + + /* modify the PTE bits as desired, then apply */ + switch (action) { + case SET_MEMORY_RO: + pte = pte_wrprotect(pte); + break; + case SET_MEMORY_RW: + pte = pte_mkwrite(pte_mkdirty(pte)); + break; + case SET_MEMORY_NX: + pte = pte_exprotect(pte); + break; + case SET_MEMORY_X: + pte = pte_mkexec(pte); + break; + default: + WARN_ON_ONCE(1); + break; + } + + set_pte_at(&init_mm, addr, ptep, pte); + + /* See ptesync comment in radix__set_pte_at() */ + if (radix_enabled()) + asm volatile("ptesync": : :"memory"); + spin_unlock(&init_mm.page_table_lock); + + return 0; +} + +int change_memory_attr(unsigned long addr, int numpages, long action) +{ + unsigned long start = ALIGN_DOWN(addr, PAGE_SIZE); + unsigned long size = numpages * PAGE_SIZE; + + if (!numpages) + return 0; + + if (WARN_ON_ONCE(is_vmalloc_or_module_addr((void *)addr) && + is_vm_area_hugepages((void *)addr))) + return -EINVAL; + +#ifdef CONFIG_PPC_BOOK3S_64 + /* + * On hash, the linear mapping is not in the Linux page table so + * apply_to_existing_page_range() will have no effect. If in the future + * the set_memory_* functions are used on the linear map this will need + * to be updated. + */ + if (!radix_enabled()) { + int region = get_region_id(addr); + + if (WARN_ON_ONCE(region != VMALLOC_REGION_ID && region != IO_REGION_ID)) + return -EINVAL; + } +#endif + + return apply_to_existing_page_range(&init_mm, start, size, + change_page_attr, (void *)action); +} |