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authorArnd Bergmann <arnd@arndb.de>2022-02-15 19:55:04 +0300
committerArnd Bergmann <arnd@arndb.de>2022-02-25 11:36:05 +0300
commit12700c17fc286149324f92d6d380bc48e43f253d (patch)
tree63157067b99d0adec5db4058ab9235b4802d1e49 /arch/nios2
parent23fc539e81295b14b50c6ccc5baeb4f3d59d822d (diff)
downloadlinux-12700c17fc286149324f92d6d380bc48e43f253d.tar.xz
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/nios2')
-rw-r--r--arch/nios2/include/asm/uaccess.h11
1 files changed, 1 insertions, 10 deletions
diff --git a/arch/nios2/include/asm/uaccess.h b/arch/nios2/include/asm/uaccess.h
index a5cbe07cf0da..6664ddc0e8e5 100644
--- a/arch/nios2/include/asm/uaccess.h
+++ b/arch/nios2/include/asm/uaccess.h
@@ -30,19 +30,10 @@
#define get_fs() (current_thread_info()->addr_limit)
#define set_fs(seg) (current_thread_info()->addr_limit = (seg))
-#define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg)
-
-#define __access_ok(addr, len) \
- (((signed long)(((long)get_fs().seg) & \
- ((long)(addr) | (((long)(addr)) + (len)) | (len)))) == 0)
-
-#define access_ok(addr, len) \
- likely(__access_ok((unsigned long)(addr), (unsigned long)(len)))
+#include <asm-generic/access_ok.h>
# define __EX_TABLE_SECTION ".section __ex_table,\"a\"\n"
-#define user_addr_max() (uaccess_kernel() ? ~0UL : TASK_SIZE)
-
/*
* Zero Userspace
*/