Le 27/08/2020 à 17:00, Christoph Hellwig a écrit :
Stop providing the possibility to override the address space using
set_fs() now that there is no need for that any more.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
arch/powerpc/Kconfig | 1 -
arch/powerpc/include/asm/processor.h | 7 ---
arch/powerpc/include/asm/thread_info.h | 5 +--
arch/powerpc/include/asm/uaccess.h | 62 ++++++++------------------
arch/powerpc/kernel/signal.c | 3 --
arch/powerpc/lib/sstep.c | 6 +--
6 files changed, 22 insertions(+), 62 deletions(-)
diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h
index 7fe3531ad36a77..39727537d39701 100644
--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h
@@ -8,62 +8,36 @@
#include <asm/extable.h>
#include <asm/kup.h>
-/*
- * The fs value determines whether argument validity checking should be
- * performed or not. If get_fs() == USER_DS, checking is performed, with
- * get_fs() == KERNEL_DS, checking is bypassed.
- *
- * For historical reasons, these macros are grossly misnamed.
- *
- * The fs/ds values are now the highest legal address in the "segment".
- * This simplifies the checking in the routines below.
- */
-
-#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
-
-#define KERNEL_DS MAKE_MM_SEG(~0UL)
#ifdef __powerpc64__
/* We use TASK_SIZE_USER64 as TASK_SIZE is not constant */
-#define USER_DS MAKE_MM_SEG(TASK_SIZE_USER64 - 1)
-#else
-#define USER_DS MAKE_MM_SEG(TASK_SIZE - 1)
-#endif
-
-#define get_fs() (current->thread.addr_limit)
+#define TASK_SIZE_MAX TASK_SIZE_USER64
-static inline void set_fs(mm_segment_t fs)
+static inline bool __access_ok(unsigned long addr, unsigned long size)
{
- current->thread.addr_limit = fs;
- /* On user-mode return check addr_limit (fs) is correct */
- set_thread_flag(TIF_FSCHECK);
+ if (addr >= TASK_SIZE_MAX)
+ return false;
+ /*
+ * This check is sufficient because there is a large enough gap between
+ * user addresses and the kernel addresses.
+ */
+ return size <= TASK_SIZE_MAX;
}
-
-#define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg)
-#define user_addr_max() (get_fs().seg)
-
-#ifdef __powerpc64__
-/*
- * This check is sufficient because there is a large enough
- * gap between user addresses and the kernel addresses
- */
-#define __access_ok(addr, size, segment) \
- (((addr) <= (segment).seg) && ((size) <= (segment).seg))
-
#else
+#define TASK_SIZE_MAX TASK_SIZE
-static inline int __access_ok(unsigned long addr, unsigned long size,
- mm_segment_t seg)
+static inline bool __access_ok(unsigned long addr, unsigned long size)
{
- if (addr > seg.seg)
- return 0;
- return (size == 0 || size - 1 <= seg.seg - addr);
+ if (addr >= TASK_SIZE_MAX)
+ return false;
+ if (size == 0)
+ return false;
__access_ok() was returning true when size == 0 up to now. Any reason to
return false now ?
+ return size <= TASK_SIZE_MAX - addr;
}
-
-#endif
+#endif /* __powerpc64__ */
#define access_ok(addr, size) \
(__chk_user_ptr(addr), \
- __access_ok((__force unsigned long)(addr), (size), get_fs()))
+ __access_ok((unsigned long)(addr), (size)))
/*
* These are the main single-value transfer routines. They automatically
Christophe
