Re: [RFC] [PATCH] cache pollution aware __copy_from_user_ll()

Hiro Yoshioka
2005-09-03T12:03:46Z

From: Hiro Yoshioka <hyoshiok@miraclelinux.com>
Subject: Re: [RFC] [PATCH] cache pollution aware __copy_from_user_ll()
Date: Fri, 02 Sep 2005 13:37:16 +0900 (JST)
Message-ID: <20050902.133716.610538020.hyoshiok@miraclelinux.com>

> From: Andrew Morton <akpm@osdl.org>
> > Hiro Yoshioka <hyoshiok@miraclelinux.com> wrote:
> > >
> > > --- linux-2.6.12.4.orig/arch/i386/lib/usercopy.c 2005-08-05 16:04:37.000000000 +0900
> > > +++ linux-2.6.12.4.nt/arch/i386/lib/usercopy.c 2005-09-01 17:09:41.000000000 +0900
> >
> > Really. Please redo and retest the patch against a current kernel.
>
> Does it mean 2.6.13? I'll do it.
>
> Regards,
> Hiro

Hi,

The following is the patch against 2.6.13

Hiro

diff -ur linux-2.6.13/Makefile linux-2.6.13.nt/Makefile
--- linux-2.6.13/Makefile 2005-08-29 08:41:01.000000000 +0900
+++ linux-2.6.13.nt/Makefile 2005-09-03 14:11:27.000000000 +0900
@@ -1,7 +1,7 @@
VERSION = 2
PATCHLEVEL = 6
SUBLEVEL = 13
-EXTRAVERSION =
+EXTRAVERSION = .nt
NAME=Woozy Numbat

# *DOCUMENTATION*
diff -ur linux-2.6.13/arch/i386/lib/usercopy.c linux-2.6.13.nt/arch/i386/lib/usercopy.c
--- linux-2.6.13/arch/i386/lib/usercopy.c 2005-08-29 08:41:01.000000000 +0900
+++ linux-2.6.13.nt/arch/i386/lib/usercopy.c 2005-09-03 14:09:18.000000000 +0900
@@ -425,6 +425,107 @@
: "eax", "edx", "memory");
return size;
}
+
+/* Non Temporal Hint version of __copy_user_zeroing_intel */
+/* It is cache aware. */
+/* hyoshiok@miraclelinux.com */
+static unsigned long
+__copy_user_zeroing_intel_nocache(void *to, const void __user *from, unsigned long size)
+{
+ int d0, d1;
+
+ __asm__ __volatile__(
+ " .align 2,0x90\n"
+ "0: movl 32(%4), %%eax\n"
+ " cmpl $67, %0\n"
+ " jbe 2f\n"
+ "1: movl 64(%4), %%eax\n"
+ " .align 2,0x90\n"
+ "2: movl 0(%4), %%eax\n"
+ "21: movl 4(%4), %%edx\n"
+ " movnti %%eax, 0(%3)\n"
+ " movnti %%edx, 4(%3)\n"
+ "3: movl 8(%4), %%eax\n"
+ "31: movl 12(%4),%%edx\n"
+ " movnti %%eax, 8(%3)\n"
+ " movnti %%edx, 12(%3)\n"
+ "4: movl 16(%4), %%eax\n"
+ "41: movl 20(%4), %%edx\n"
+ " movnti %%eax, 16(%3)\n"
+ " movnti %%edx, 20(%3)\n"
+ "10: movl 24(%4), %%eax\n"
+ "51: movl 28(%4), %%edx\n"
+ " movnti %%eax, 24(%3)\n"
+ " movnti %%edx, 28(%3)\n"
+ "11: movl 32(%4), %%eax\n"
+ "61: movl 36(%4), %%edx\n"
+ " movnti %%eax, 32(%3)\n"
+ " movnti %%edx, 36(%3)\n"
+ "12: movl 40(%4), %%eax\n"
+ "71: movl 44(%4), %%edx\n"
+ " movnti %%eax, 40(%3)\n"
+ " movnti %%edx, 44(%3)\n"
+ "13: movl 48(%4), %%eax\n"
+ "81: movl 52(%4), %%edx\n"
+ " movnti %%eax, 48(%3)\n"
+ " movnti %%edx, 52(%3)\n"
+ "14: movl 56(%4), %%eax\n"
+ "91: movl 60(%4), %%edx\n"
+ " movnti %%eax, 56(%3)\n"
+ " movnti %%edx, 60(%3)\n"
+ " addl $-64, %0\n"
+ " addl $64, %4\n"
+ " addl $64, %3\n"
+ " cmpl $63, %0\n"
+ " ja 0b\n"
+ " sfence \n"
+ "5: movl %0, %%eax\n"
+ " shrl $2, %0\n"
+ " andl $3, %%eax\n"
+ " cld\n"
+ "6: rep; movsl\n"
+ " movl %%eax,%0\n"
+ "7: rep; movsb\n"
+ "8:\n"
+ ".section .fixup,\"ax\"\n"
+ "9: lea 0(%%eax,%0,4),%0\n"
+ "16: pushl %0\n"
+ " pushl %%eax\n"
+ " xorl %%eax,%%eax\n"
+ " rep; stosb\n"
+ " popl %%eax\n"
+ " popl %0\n"
+ " jmp 8b\n"
+ ".previous\n"
+ ".section __ex_table,\"a\"\n"
+ " .align 4\n"
+ " .long 0b,16b\n"
+ " .long 1b,16b\n"
+ " .long 2b,16b\n"
+ " .long 21b,16b\n"
+ " .long 3b,16b\n"
+ " .long 31b,16b\n"
+ " .long 4b,16b\n"
+ " .long 41b,16b\n"
+ " .long 10b,16b\n"
+ " .long 51b,16b\n"
+ " .long 11b,16b\n"
+ " .long 61b,16b\n"
+ " .long 12b,16b\n"
+ " .long 71b,16b\n"
+ " .long 13b,16b\n"
+ " .long 81b,16b\n"
+ " .long 14b,16b\n"
+ " .long 91b,16b\n"
+ " .long 6b,9b\n"
+ " .long 7b,16b\n"
+ ".previous"
+ : "=&c"(size), "=&D" (d0), "=&S" (d1)
+ : "1"(to), "2"(from), "0"(size)
+ : "eax", "edx", "memory");
+ return size;
+}
+
#else
/*
* Leave these declared but undefined. They should not be any references to
@@ -434,6 +535,8 @@
__copy_user_zeroing_intel(void *to, const void __user *from, unsigned long size);
unsigned long
__copy_user_intel(void __user *to, const void *from, unsigned long size);
+unsigned long
+__copy_user_zeroing_intel_nocache(void *to, const void __user *from, unsigned long size);
#endif /* CONFIG_X86_INTEL_USERCOPY */

/* Generic arbitrary sized copy. */
@@ -515,7 +618,6 @@
: "memory"); \
} while (0)

-
unsigned long __copy_to_user_ll(void __user *to, const void *from, unsigned long n)
{
BUG_ON((long) n < 0);
@@ -588,6 +690,21 @@
}
EXPORT_SYMBOL(__copy_from_user_ll);

+unsigned long
+__copy_from_user_ll_nocache(void *to, const void __user *from, unsigned long n)
+{
+ BUG_ON((long)n < 0);
+#ifdef CONFIG_X86_INTEL_USERCOPY
+ if ( n > 64 && cpu_has_xmm2)
+ n = __copy_user_zeroing_intel_nocache(to, from, n);
+ else
+ __copy_user_zeroing(to, from, n);
+#else
+ __copy_user_zeroing(to, from, n);
+#endif
+ return n;
+}
+
/**
* copy_to_user: - Copy a block of data into user space.
* @to: Destination address, in user space.
diff -ur linux-2.6.13/include/asm-i386/uaccess.h linux-2.6.13.nt/include/asm-i386/uaccess.h
--- linux-2.6.13/include/asm-i386/uaccess.h 2005-08-29 08:41:01.000000000 +0900
+++ linux-2.6.13.nt/include/asm-i386/uaccess.h 2005-09-03 14:09:18.000000000 +0900
@@ -413,6 +413,8 @@
const void *from, unsigned long n);
unsigned long __must_check __copy_from_user_ll(void *to,
const void __user *from, unsigned long n);
+unsigned long __must_check __copy_from_user_ll_nocache(void *to,
+ const void __user *from, unsigned long n);

/*
* Here we special-case 1, 2 and 4-byte copy_*_user invocations. On a fault
@@ -502,11 +504,40 @@
}

static inline unsigned long
+__copy_from_user_inatomic_nocache(void *to, const void __user *from, unsigned long n)
+{
+ if (__builtin_constant_p(n)) {
+ unsigned long ret;
+
+ switch (n) {
+ case 1:
+ __get_user_size(*(u8 *)to, from, 1, ret, 1);
+ return ret;
+ case 2:
+ __get_user_size(*(u16 *)to, from, 2, ret, 2);
+ return ret;
+ case 4:
+ __get_user_size(*(u32 *)to, from, 4, ret, 4);
+ return ret;
+ }
+ }
+ return __copy_from_user_ll_nocache(to, from, n);
+}
+
+static inline unsigned long
__copy_from_user(void *to, const void __user *from, unsigned long n)
{
might_sleep();
return __copy_from_user_inatomic(to, from, n);
}
+
+static inline unsigned long
+__copy_from_user_nocache(void *to, const void __user *from, unsigned long n)
+{
+ might_sleep();
+ return __copy_from_user_inatomic_nocache(to, from, n);
+}
+
unsigned long __must_check copy_to_user(void __user *to,
const void *from, unsigned long n);
unsigned long __must_check copy_from_user(void *to,
diff -ur linux-2.6.13/mm/filemap.c linux-2.6.13.nt/mm/filemap.c
--- linux-2.6.13/mm/filemap.c 2005-08-29 08:41:01.000000000 +0900
+++ linux-2.6.13.nt/mm/filemap.c 2005-09-03 14:09:18.000000000 +0900
@@ -1726,7 +1726,7 @@
int copy = min(bytes, iov->iov_len - base);

base = 0;
- left = __copy_from_user_inatomic(vaddr, buf, copy);
+ left = __copy_from_user_inatomic_nocache(vaddr, buf, copy);
copied += copy;
bytes -= copy;
vaddr += copy;
diff -ur linux-2.6.13/mm/filemap.h linux-2.6.13.nt/mm/filemap.h
--- linux-2.6.13/mm/filemap.h 2005-08-29 08:41:01.000000000 +0900
+++ linux-2.6.13.nt/mm/filemap.h 2005-09-03 16:47:39.000000000 +0900
@@ -34,13 +34,13 @@
int left;

kaddr = kmap_atomic(page, KM_USER0);
- left = __copy_from_user_inatomic(kaddr + offset, buf, bytes);
+ left = __copy_from_user_inatomic_nocache(kaddr + offset, buf, bytes);
kunmap_atomic(kaddr, KM_USER0);

if (left != 0) {
/* Do it the slow way */
kaddr = kmap(page);
- left = __copy_from_user(kaddr + offset, buf, bytes);
+ left = __copy_from_user_nocache(kaddr + offset, buf, bytes);
kunmap(page);
}
return bytes - left;