From ab9988a3dafb8c94c2a19637fb00f7d1db799347 Mon Sep 17 00:00:00 2001 From: Paul Burton Date: Mon, 14 Jul 2014 10:32:15 +0100 Subject: MIPS: Initialise MAARs Add initialisation for Memory Accessibility Attribute Registers. Generic code cannot know the platform-specific requirements with regards to speculative accesses, so it simply calls a platform_maar_init function which platforms with MAARs are expected to implement by calling the provided write_maar_pair function & returning the number of MAAR pairs used. A weak default implementation will simply use no MAAR pairs. Any present but unused MAAR pairs are then marked invalid, effectively disabling them. The end result of this patch is that MAARs are all marked invalid, until platforms implement the platform_maar_init function. Signed-off-by: Paul Burton Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/7331/ Signed-off-by: Ralf Baechle --- arch/mips/mm/init.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) (limited to 'arch/mips/mm/init.c') diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c index 6e4413330e36..571aab064936 100644 --- a/arch/mips/mm/init.c +++ b/arch/mips/mm/init.c @@ -325,6 +325,38 @@ static inline void mem_init_free_highmem(void) #endif } +unsigned __weak platform_maar_init(unsigned num_maars) +{ + return 0; +} + +static void maar_init(void) +{ + unsigned num_maars, used, i; + + if (!cpu_has_maar) + return; + + /* Detect the number of MAARs */ + write_c0_maari(~0); + back_to_back_c0_hazard(); + num_maars = read_c0_maari() + 1; + + /* MAARs should be in pairs */ + WARN_ON(num_maars % 2); + + /* Configure the required MAARs */ + used = platform_maar_init(num_maars / 2); + + /* Disable any further MAARs */ + for (i = (used * 2); i < num_maars; i++) { + write_c0_maari(i); + back_to_back_c0_hazard(); + write_c0_maar(0); + back_to_back_c0_hazard(); + } +} + void __init mem_init(void) { #ifdef CONFIG_HIGHMEM @@ -337,6 +369,7 @@ void __init mem_init(void) #endif high_memory = (void *) __va(max_low_pfn << PAGE_SHIFT); + maar_init(); free_all_bootmem(); setup_zero_pages(); /* Setup zeroed pages. */ mem_init_free_highmem(); -- cgit v1.2.3 From 0b70068e47e8f0c813a902dc3d6def601fd15acb Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Fri, 12 Sep 2014 22:17:23 +0200 Subject: mm: export symbol dependencies of is_zero_pfn() In order to make the static inline function is_zero_pfn() callable by modules, export its symbol dependencies 'zero_pfn' and (for s390 and mips) 'zero_page_mask'. We need this for KVM, as CONFIG_KVM is a tristate for all supported architectures except ARM and arm64, and testing a pfn whether it refers to the zero page is required to correctly distinguish the zero page from other special RAM ranges that may also have the PG_reserved bit set, but need to be treated as MMIO memory. Signed-off-by: Ard Biesheuvel Acked-by: Andrew Morton Signed-off-by: Paolo Bonzini --- arch/mips/mm/init.c | 1 + arch/s390/mm/init.c | 1 + mm/memory.c | 2 ++ 3 files changed, 4 insertions(+) (limited to 'arch/mips/mm/init.c') diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c index 571aab064936..f42e35e42790 100644 --- a/arch/mips/mm/init.c +++ b/arch/mips/mm/init.c @@ -53,6 +53,7 @@ */ unsigned long empty_zero_page, zero_page_mask; EXPORT_SYMBOL_GPL(empty_zero_page); +EXPORT_SYMBOL(zero_page_mask); /* * Not static inline because used by IP27 special magic initialization code diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c index 0c1073ed1e84..c7235e01fd67 100644 --- a/arch/s390/mm/init.c +++ b/arch/s390/mm/init.c @@ -43,6 +43,7 @@ pgd_t swapper_pg_dir[PTRS_PER_PGD] __attribute__((__aligned__(PAGE_SIZE))); unsigned long empty_zero_page, zero_page_mask; EXPORT_SYMBOL(empty_zero_page); +EXPORT_SYMBOL(zero_page_mask); static void __init setup_zero_pages(void) { diff --git a/mm/memory.c b/mm/memory.c index ab3537bcfed2..1fcf59a097b3 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -118,6 +118,8 @@ __setup("norandmaps", disable_randmaps); unsigned long zero_pfn __read_mostly; unsigned long highest_memmap_pfn __read_mostly; +EXPORT_SYMBOL(zero_pfn); + /* * CONFIG_MMU architectures set up ZERO_PAGE in their paging_init() */ -- cgit v1.2.3