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authorArnd Bergmann <arnd@arndb.de>2022-02-15 17:55:04 +0100
committerArnd Bergmann <arnd@arndb.de>2022-02-25 09:36:05 +0100
commit12700c17fc286149324f92d6d380bc48e43f253d (patch)
tree63157067b99d0adec5db4058ab9235b4802d1e49 /arch/sparc
parent23fc539e81295b14b50c6ccc5baeb4f3d59d822d (diff)
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uaccess: generalize access_ok()
There are many different ways that access_ok() is defined across architectures, but in the end, they all just compare against the user_addr_max() value or they accept anything. Provide one definition that works for most architectures, checking against TASK_SIZE_MAX for user processes or skipping the check inside of uaccess_kernel() sections. For architectures without CONFIG_SET_FS(), this should be the fastest check, as it comes down to a single comparison of a pointer against a compile-time constant, while the architecture specific versions tend to do something more complex for historic reasons or get something wrong. Type checking for __user annotations is handled inconsistently across architectures, but this is easily simplified as well by using an inline function that takes a 'const void __user *' argument. A handful of callers need an extra __user annotation for this. Some architectures had trick to use 33-bit or 65-bit arithmetic on the addresses to calculate the overflow, however this simpler version uses fewer registers, which means it can produce better object code in the end despite needing a second (statically predicted) branch. Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Mark Rutland <mark.rutland@arm.com> [arm64, asm-generic] Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Stafford Horne <shorne@gmail.com> Acked-by: Dinh Nguyen <dinguyen@kernel.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Diffstat (limited to 'arch/sparc')
-rw-r--r--arch/sparc/Kconfig1
-rw-r--r--arch/sparc/include/asm/uaccess.h3
-rw-r--r--arch/sparc/include/asm/uaccess_32.h18
-rw-r--r--arch/sparc/include/asm/uaccess_64.h12
4 files changed, 6 insertions, 28 deletions
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index 1cab1b284f1a..9f6f9bce5292 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -62,6 +62,7 @@ config SPARC32
config SPARC64
def_bool 64BIT
+ select ALTERNATE_USER_ADDRESS_SPACE
select HAVE_FUNCTION_TRACER
select HAVE_FUNCTION_GRAPH_TRACER
select HAVE_KRETPROBES
diff --git a/arch/sparc/include/asm/uaccess.h b/arch/sparc/include/asm/uaccess.h
index 390094200fc4..ee75f69e3fcd 100644
--- a/arch/sparc/include/asm/uaccess.h
+++ b/arch/sparc/include/asm/uaccess.h
@@ -10,9 +10,6 @@
#include <asm/uaccess_32.h>
#endif
-#define user_addr_max() \
- (uaccess_kernel() ? ~0UL : TASK_SIZE)
-
long strncpy_from_user(char *dest, const char __user *src, long count);
#endif
diff --git a/arch/sparc/include/asm/uaccess_32.h b/arch/sparc/include/asm/uaccess_32.h
index 4a12346bb69c..367747116260 100644
--- a/arch/sparc/include/asm/uaccess_32.h
+++ b/arch/sparc/include/asm/uaccess_32.h
@@ -25,17 +25,7 @@
#define get_fs() (current->thread.current_ds)
#define set_fs(val) ((current->thread.current_ds) = (val))
-#define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg)
-
-/* We have there a nice not-mapped page at PAGE_OFFSET - PAGE_SIZE, so that this test
- * can be fairly lightweight.
- * No one can read/write anything from userland in the kernel space by setting
- * large size and address near to PAGE_OFFSET - a fault will break his intentions.
- */
-#define __user_ok(addr, size) ({ (void)(size); (addr) < STACK_TOP; })
-#define __kernel_ok (uaccess_kernel())
-#define __access_ok(addr, size) (__user_ok((addr) & get_fs().seg, (size)))
-#define access_ok(addr, size) __access_ok((unsigned long)(addr), size)
+#include <asm-generic/access_ok.h>
/* Uh, these should become the main single-value transfer routines..
* They automatically use the right size if we just have the right
@@ -47,13 +37,13 @@
* and hide all the ugliness from the user.
*/
#define put_user(x, ptr) ({ \
- unsigned long __pu_addr = (unsigned long)(ptr); \
+ void __user *__pu_addr = (ptr); \
__chk_user_ptr(ptr); \
__put_user_check((__typeof__(*(ptr)))(x), __pu_addr, sizeof(*(ptr))); \
})
#define get_user(x, ptr) ({ \
- unsigned long __gu_addr = (unsigned long)(ptr); \
+ const void __user *__gu_addr = (ptr); \
__chk_user_ptr(ptr); \
__get_user_check((x), __gu_addr, sizeof(*(ptr)), __typeof__(*(ptr))); \
})
@@ -232,7 +222,7 @@ static inline unsigned long __clear_user(void __user *addr, unsigned long size)
static inline unsigned long clear_user(void __user *addr, unsigned long n)
{
- if (n && __access_ok((unsigned long) addr, n))
+ if (n && __access_ok(addr, n))
return __clear_user(addr, n);
else
return n;
diff --git a/arch/sparc/include/asm/uaccess_64.h b/arch/sparc/include/asm/uaccess_64.h
index 5c12fb46bc61..59b9a545df23 100644
--- a/arch/sparc/include/asm/uaccess_64.h
+++ b/arch/sparc/include/asm/uaccess_64.h
@@ -31,7 +31,7 @@
#define get_fs() ((mm_segment_t){(current_thread_info()->current_ds)})
-#define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg)
+#include <asm-generic/access_ok.h>
#define set_fs(val) \
do { \
@@ -61,16 +61,6 @@ static inline bool __chk_range_not_ok(unsigned long addr, unsigned long size, un
__chk_range_not_ok((unsigned long __force)(addr), size, limit); \
})
-static inline int __access_ok(const void __user * addr, unsigned long size)
-{
- return 1;
-}
-
-static inline int access_ok(const void __user * addr, unsigned long size)
-{
- return 1;
-}
-
void __retl_efault(void);
/* Uh, these should become the main single-value transfer routines..