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authorHugh Dickins <hughd@google.com>2017-09-03 18:57:03 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-01-05 15:46:32 +0100
commit0994a2cf8fe4e884bad4810681117a7d0096c8e7 (patch)
tree524d647d9dc1bde3133cd09aca758e76792aad53 /include
parentac2f1018ac210cfedcfab82dbafbda4e2db7ed08 (diff)
kaiser: stack map PAGE_SIZE at THREAD_SIZE-PAGE_SIZE
Kaiser only needs to map one page of the stack; and kernel/fork.c did not build on powerpc (no __PAGE_KERNEL). It's all cleaner if linux/kaiser.h provides kaiser_map_thread_stack() and kaiser_unmap_thread_stack() wrappers around asm/kaiser.h's kaiser_add_mapping() and kaiser_remove_mapping(). And use linux/kaiser.h in init/main.c to avoid the #ifdefs there. Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/kaiser.h40
1 files changed, 33 insertions, 7 deletions
diff --git a/include/linux/kaiser.h b/include/linux/kaiser.h
index 9db5433c2284..4a4d6d911a14 100644
--- a/include/linux/kaiser.h
+++ b/include/linux/kaiser.h
@@ -1,26 +1,52 @@
-#ifndef _INCLUDE_KAISER_H
-#define _INCLUDE_KAISER_H
+#ifndef _LINUX_KAISER_H
+#define _LINUX_KAISER_H
#ifdef CONFIG_KAISER
#include <asm/kaiser.h>
+
+static inline int kaiser_map_thread_stack(void *stack)
+{
+ /*
+ * Map that page of kernel stack on which we enter from user context.
+ */
+ return kaiser_add_mapping((unsigned long)stack +
+ THREAD_SIZE - PAGE_SIZE, PAGE_SIZE, __PAGE_KERNEL);
+}
+
+static inline void kaiser_unmap_thread_stack(void *stack)
+{
+ /*
+ * Note: may be called even when kaiser_map_thread_stack() failed.
+ */
+ kaiser_remove_mapping((unsigned long)stack +
+ THREAD_SIZE - PAGE_SIZE, PAGE_SIZE);
+}
#else
/*
* These stubs are used whenever CONFIG_KAISER is off, which
- * includes architectures that support KAISER, but have it
- * disabled.
+ * includes architectures that support KAISER, but have it disabled.
*/
static inline void kaiser_init(void)
{
}
-static inline void kaiser_remove_mapping(unsigned long start, unsigned long size)
+static inline int kaiser_add_mapping(unsigned long addr,
+ unsigned long size, unsigned long flags)
+{
+ return 0;
+}
+static inline void kaiser_remove_mapping(unsigned long start,
+ unsigned long size)
{
}
-static inline int kaiser_add_mapping(unsigned long addr, unsigned long size, unsigned long flags)
+static inline int kaiser_map_thread_stack(void *stack)
{
return 0;
}
+static inline void kaiser_unmap_thread_stack(void *stack)
+{
+}
#endif /* !CONFIG_KAISER */
-#endif /* _INCLUDE_KAISER_H */
+#endif /* _LINUX_KAISER_H */