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authorGeorge G. Davis <davis_g@mvista.com>2006-09-02 18:43:20 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2006-09-02 18:43:20 +0100
commita188ad2bc7dbfa16ccdcaa8d43ade185b969baff (patch)
tree7938fff8dded204e92bd7c3149875abb8d7060aa
parent57bcdafcb1e0782e7ae13471d9223c69e3a6cba2 (diff)
downloadlinux-a188ad2bc7dbfa16ccdcaa8d43ade185b969baff.tar.gz
[ARM] 3762/1: Fix ptrace cache coherency bug for ARM1136 VIPT nonaliasing Harvard caches
Patch from George G. Davis Resolve ARM1136 VIPT non-aliasing cache coherency issues observed when using ptrace to set breakpoints and cleanup copy_{to,from}_user_page() while we're here as requested by Russell King because "it's also far too heavy on non-v6 CPUs". NOTES: 1. Only access_process_vm() calls copy_{to,from}_user_page(). 2. access_process_vm() calls get_user_pages() to pin down the "page". 3. get_user_pages() calls flush_dcache_page(page) which ensures cache coherency between kernel and userspace mappings of "page". However flush_dcache_page(page) may not invalidate I-Cache over this range for all cases, specifically, I-Cache is not invalidated for the VIPT non-aliasing case. So memory is consistent between kernel and user space mappings of "page" but I-Cache may still be hot over this range. IOW, we don't have to worry about flush_cache_page() before memcpy(). 4. Now, for the copy_to_user_page() case, after memcpy(), we must flush the caches so memory is consistent with kernel cache entries and invalidate the I-Cache if this mm region is executable. We don't need to do anything after memcpy() for the copy_from_user_page() case since kernel cache entries will be invalidated via the same process above if we access "page" again. The flush_ptrace_access() function (borrowed from SPARC64 implementation) is added to handle cache flushing after memcpy() for the copy_to_user_page() case. Signed-off-by: George G. Davis <gdavis@mvista.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
-rw-r--r--arch/arm/mm/flush.c26
-rw-r--r--include/asm-arm/cacheflush.h18
2 files changed, 41 insertions, 3 deletions
diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c
index b103e56806b..d438ce41cdd 100644
--- a/arch/arm/mm/flush.c
+++ b/arch/arm/mm/flush.c
@@ -87,6 +87,32 @@ void flush_cache_page(struct vm_area_struct *vma, unsigned long user_addr, unsig
if (cache_is_vipt_aliasing())
flush_pfn_alias(pfn, user_addr);
}
+
+void flush_ptrace_access(struct vm_area_struct *vma, struct page *page,
+ unsigned long uaddr, void *kaddr,
+ unsigned long len, int write)
+{
+ if (cache_is_vivt()) {
+ if (cpu_isset(smp_processor_id(), vma->vm_mm->cpu_vm_mask)) {
+ unsigned long addr = (unsigned long)kaddr;
+ __cpuc_coherent_kern_range(addr, addr + len);
+ }
+ return;
+ }
+
+ if (cache_is_vipt_aliasing()) {
+ flush_pfn_alias(page_to_pfn(page), uaddr);
+ return;
+ }
+
+ /* VIPT non-aliasing cache */
+ if (cpu_isset(smp_processor_id(), vma->vm_mm->cpu_vm_mask) &&
+ vma->vm_flags | VM_EXEC) {
+ unsigned long addr = (unsigned long)kaddr;
+ /* only flushing the kernel mapping on non-aliasing VIPT */
+ __cpuc_coherent_kern_range(addr, addr + len);
+ }
+}
#else
#define flush_pfn_alias(pfn,vaddr) do { } while (0)
#endif
diff --git a/include/asm-arm/cacheflush.h b/include/asm-arm/cacheflush.h
index fe0c744e026..e4a2569c636 100644
--- a/include/asm-arm/cacheflush.h
+++ b/include/asm-arm/cacheflush.h
@@ -247,14 +247,12 @@ extern void dmac_flush_range(unsigned long, unsigned long);
*/
#define copy_to_user_page(vma, page, vaddr, dst, src, len) \
do { \
- flush_cache_page(vma, vaddr, page_to_pfn(page));\
memcpy(dst, src, len); \
- flush_dcache_page(page); \
+ flush_ptrace_access(vma, page, vaddr, dst, len, 1);\
} while (0)
#define copy_from_user_page(vma, page, vaddr, dst, src, len) \
do { \
- flush_cache_page(vma, vaddr, page_to_pfn(page));\
memcpy(dst, src, len); \
} while (0)
@@ -285,10 +283,24 @@ flush_cache_page(struct vm_area_struct *vma, unsigned long user_addr, unsigned l
__cpuc_flush_user_range(addr, addr + PAGE_SIZE, vma->vm_flags);
}
}
+
+static inline void
+flush_ptrace_access(struct vm_area_struct *vma, struct page *page,
+ unsigned long uaddr, void *kaddr,
+ unsigned long len, int write)
+{
+ if (cpu_isset(smp_processor_id(), vma->vm_mm->cpu_vm_mask)) {
+ unsigned long addr = (unsigned long)kaddr;
+ __cpuc_coherent_kern_range(addr, addr + len);
+ }
+}
#else
extern void flush_cache_mm(struct mm_struct *mm);
extern void flush_cache_range(struct vm_area_struct *vma, unsigned long start, unsigned long end);
extern void flush_cache_page(struct vm_area_struct *vma, unsigned long user_addr, unsigned long pfn);
+extern void flush_ptrace_access(struct vm_area_struct *vma, struct page *page,
+ unsigned long uaddr, void *kaddr,
+ unsigned long len, int write);
#endif
/*