| From: Jeff Hansen <jhansen@cardaccess-inc.com> |
| Subject: [PATCH] no highpage |
| |
| On ASUS WL-500gP there are many unexpected "Segmentation fault"s that |
| seem to be caused by a kernel. They can be avoided by: |
| 1) Disabling highpage |
| 2) Using flush_cache_mm in flush_cache_dup_mm |
| |
| For details see OpenWrt ticket #2035 https://dev.openwrt.org/ticket/2035 |
| --- |
| --- a/arch/mips/include/asm/page.h |
| +++ b/arch/mips/include/asm/page.h |
| @@ -71,6 +71,7 @@ static inline unsigned int page_size_ftl |
| #endif /* CONFIG_MIPS_HUGE_TLB_SUPPORT */ |
| |
| #include <linux/pfn.h> |
| +#include <asm/cpu-features.h> |
| |
| extern void build_clear_page(void); |
| extern void build_copy_page(void); |
| @@ -110,11 +111,16 @@ static inline void clear_user_page(void |
| flush_data_cache_page((unsigned long)addr); |
| } |
| |
| -struct vm_area_struct; |
| -extern void copy_user_highpage(struct page *to, struct page *from, |
| - unsigned long vaddr, struct vm_area_struct *vma); |
| +static inline void copy_user_page(void *vto, void *vfrom, unsigned long vaddr, |
| + struct page *to) |
| +{ |
| + extern void (*flush_data_cache_page)(unsigned long addr); |
| |
| -#define __HAVE_ARCH_COPY_USER_HIGHPAGE |
| + copy_page(vto, vfrom); |
| + if (!cpu_has_ic_fills_f_dc || |
| + pages_do_alias((unsigned long)vto, vaddr & PAGE_MASK)) |
| + flush_data_cache_page((unsigned long)vto); |
| +} |
| |
| /* |
| * These are used to make use of C type-checking.. |
| --- a/arch/mips/mm/init.c |
| +++ b/arch/mips/mm/init.c |
| @@ -168,30 +168,6 @@ void kunmap_coherent(void) |
| preempt_enable(); |
| } |
| |
| -void copy_user_highpage(struct page *to, struct page *from, |
| - unsigned long vaddr, struct vm_area_struct *vma) |
| -{ |
| - void *vfrom, *vto; |
| - |
| - vto = kmap_atomic(to); |
| - if (cpu_has_dc_aliases && cpu_use_kmap_coherent && |
| - page_mapcount(from) && !Page_dcache_dirty(from)) { |
| - vfrom = kmap_coherent(from, vaddr); |
| - copy_page(vto, vfrom); |
| - kunmap_coherent(); |
| - } else { |
| - vfrom = kmap_atomic(from); |
| - copy_page(vto, vfrom); |
| - kunmap_atomic(vfrom); |
| - } |
| - if ((!cpu_has_ic_fills_f_dc) || |
| - pages_do_alias((unsigned long)vto, vaddr & PAGE_MASK)) |
| - flush_data_cache_page((unsigned long)vto); |
| - kunmap_atomic(vto); |
| - /* Make sure this page is cleared on other CPU's too before using it */ |
| - smp_wmb(); |
| -} |
| - |
| void copy_to_user_page(struct vm_area_struct *vma, |
| struct page *page, unsigned long vaddr, void *dst, const void *src, |
| unsigned long len) |