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author | Arnd Bergmann <arnd@arndb.de> | 2022-02-15 17:55:04 +0100 |
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committer | Arnd Bergmann <arnd@arndb.de> | 2022-02-25 09:36:05 +0100 |
commit | 12700c17fc286149324f92d6d380bc48e43f253d (patch) | |
tree | 63157067b99d0adec5db4058ab9235b4802d1e49 /arch/xtensa/include/asm | |
parent | 23fc539e81295b14b50c6ccc5baeb4f3d59d822d (diff) | |
download | linux-stable-12700c17fc286149324f92d6d380bc48e43f253d.tar.gz linux-stable-12700c17fc286149324f92d6d380bc48e43f253d.tar.bz2 linux-stable-12700c17fc286149324f92d6d380bc48e43f253d.zip |
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/xtensa/include/asm')
-rw-r--r-- | arch/xtensa/include/asm/uaccess.h | 10 |
1 files changed, 1 insertions, 9 deletions
diff --git a/arch/xtensa/include/asm/uaccess.h b/arch/xtensa/include/asm/uaccess.h index 75bd8fbf52ba..0edd9e4b23d0 100644 --- a/arch/xtensa/include/asm/uaccess.h +++ b/arch/xtensa/include/asm/uaccess.h @@ -35,15 +35,7 @@ #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) - -#define __kernel_ok (uaccess_kernel()) -#define __user_ok(addr, size) \ - (((size) <= TASK_SIZE)&&((addr) <= TASK_SIZE-(size))) -#define __access_ok(addr, size) (__kernel_ok || __user_ok((addr), (size))) -#define access_ok(addr, size) __access_ok((unsigned long)(addr), (size)) - -#define user_addr_max() (uaccess_kernel() ? ~0UL : TASK_SIZE) +#include <asm-generic/access_ok.h> /* * These are the main single-value transfer routines. They |