[RFC][PATCH 4/12] x86: introduce copy_in_user() for 32-bit
in [Kernel]
|
Prev: [RFC][PATCH 7/12 not tested yet] PPC: introduce __set_bit() like function for bitmaps in user space
Next: [RFC][PATCH 5/12] x86: introduce __set_bit() like function for bitmaps in user space
From: Takuya Yoshikawa on 4 May 2010 09:10 During the work of KVM's dirty page logging optimization, we encountered the need of copy_in_user() for 32-bit x86 and ppc: these will be used for manipulating dirty bitmaps in user space. So we implement copy_in_user() for 32-bit with existing generic copy user helpers. Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya(a)oss.ntt.co.jp> Signed-off-by: Fernando Luis Vazquez Cao <fernando(a)oss.ntt.co.jp> CC: Avi Kivity <avi(a)redhat.com> Cc: Thomas Gleixner <tglx(a)linutronix.de> CC: Ingo Molnar <mingo(a)redhat.com> Cc: "H. Peter Anvin" <hpa(a)zytor.com> --- arch/x86/include/asm/uaccess_32.h | 2 ++ arch/x86/lib/usercopy_32.c | 26 ++++++++++++++++++++++++++ 2 files changed, 28 insertions(+), 0 deletions(-) diff --git a/arch/x86/include/asm/uaccess_32.h b/arch/x86/include/asm/uaccess_32.h index 088d09f..85d396d 100644 --- a/arch/x86/include/asm/uaccess_32.h +++ b/arch/x86/include/asm/uaccess_32.h @@ -21,6 +21,8 @@ unsigned long __must_check __copy_from_user_ll_nocache (void *to, const void __user *from, unsigned long n); unsigned long __must_check __copy_from_user_ll_nocache_nozero (void *to, const void __user *from, unsigned long n); +unsigned long __must_check copy_in_user + (void __user *to, const void __user *from, unsigned n); /** * __copy_to_user_inatomic: - Copy a block of data into user space, with less checking. diff --git a/arch/x86/lib/usercopy_32.c b/arch/x86/lib/usercopy_32.c index e218d5d..e90ffc3 100644 --- a/arch/x86/lib/usercopy_32.c +++ b/arch/x86/lib/usercopy_32.c @@ -889,3 +889,29 @@ void copy_from_user_overflow(void) WARN(1, "Buffer overflow detected!\n"); } EXPORT_SYMBOL(copy_from_user_overflow); + +/** + * copy_in_user: - Copy a block of data from user space to user space. + * @to: Destination address, in user space. + * @from: Source address, in user space. + * @n: Number of bytes to copy. + * + * Context: User context only. This function may sleep. + * + * Copy data from user space to user space. + * + * Returns number of bytes that could not be copied. + * On success, this will be zero. + */ +unsigned long +copy_in_user(void __user *to, const void __user *from, unsigned n) +{ + if (access_ok(VERIFY_WRITE, to, n) && access_ok(VERIFY_READ, from, n)) { + if (movsl_is_ok(to, from, n)) + __copy_user(to, from, n); + else + n = __copy_user_intel(to, (const void *)from, n); + } + return n; +} +EXPORT_SYMBOL(copy_in_user); -- 1.7.0.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |