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author | Hugh Dickins <hughd@google.com> | 2017-09-03 18:57:03 -0700 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-01-05 15:44:23 +0100 |
commit | 003e476716906afa135faf605ae0a5c3598c0293 (patch) | |
tree | 407dda926970073f3bebd47655a1fa151ce0174a | |
parent | edde73205b3fdde8c8a3adfce78cc6d0de72386b (diff) | |
download | linux-stable-003e476716906afa135faf605ae0a5c3598c0293.tar.gz linux-stable-003e476716906afa135faf605ae0a5c3598c0293.tar.bz2 linux-stable-003e476716906afa135faf605ae0a5c3598c0293.zip |
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>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r-- | include/linux/kaiser.h | 40 | ||||
-rw-r--r-- | init/main.c | 6 | ||||
-rw-r--r-- | kernel/fork.c | 7 |
3 files changed, 36 insertions, 17 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 */ diff --git a/init/main.c b/init/main.c index 0cc5c4b6841f..49926d95442f 100644 --- a/init/main.c +++ b/init/main.c @@ -81,15 +81,13 @@ #include <linux/integrity.h> #include <linux/proc_ns.h> #include <linux/io.h> +#include <linux/kaiser.h> #include <asm/io.h> #include <asm/bugs.h> #include <asm/setup.h> #include <asm/sections.h> #include <asm/cacheflush.h> -#ifdef CONFIG_KAISER -#include <asm/kaiser.h> -#endif static int kernel_init(void *); @@ -495,9 +493,7 @@ static void __init mm_init(void) pgtable_init(); vmalloc_init(); ioremap_huge_init(); -#ifdef CONFIG_KAISER kaiser_init(); -#endif } asmlinkage __visible void __init start_kernel(void) diff --git a/kernel/fork.c b/kernel/fork.c index 3842ceddb7f9..ac00f14208b7 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -168,12 +168,9 @@ static struct thread_info *alloc_thread_info_node(struct task_struct *tsk, return page ? page_address(page) : NULL; } -extern void kaiser_remove_mapping(unsigned long start_addr, unsigned long size); static inline void free_thread_info(struct thread_info *ti) { -#ifdef CONFIG_KAISER - kaiser_remove_mapping((unsigned long)ti, THREAD_SIZE); -#endif + kaiser_unmap_thread_stack(ti); free_kmem_pages((unsigned long)ti, THREAD_SIZE_ORDER); } # else @@ -358,7 +355,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node) tsk->stack = ti; - err= kaiser_add_mapping((unsigned long)tsk->stack, THREAD_SIZE, __PAGE_KERNEL); + err = kaiser_map_thread_stack(tsk->stack); if (err) goto free_ti; #ifdef CONFIG_SECCOMP |