Mikael Pettersson e05c7d0fda math-emu: correct test for downshifting fraction in _FP_FROM_INT() ... commit f8324e20f8 upstream. The kernel's math-emu code contains a macro _FP_FROM_INT() which is used to convert an integer to a raw normalized floating-point value. It does this basically in three steps: 1. Compute the exponent from the number of leading zero bits. 2. Downshift large fractions to put the MSB in the right position for normalized fractions. 3. Upshift small fractions to put the MSB in the right position. There is an boundary error in step 2, causing a fraction with its MSB exactly one bit above the normalized MSB position to not be downshifted. This results in a non-normalized raw float, which when packed becomes a massively inaccurate representation for that input. The impact of this depends on a number of arch-specific factors, but it is known to have broken emulation of FXTOD instructions on UltraSPARC III, which was originally reported as GCC bug 44631 <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44631>. Any arch which uses math-emu to emulate conversions from integers to same-size floats may be affected. The fix is simple: the exponent comparison used to determine if the fraction should be downshifted must be "<=" not "<". I'm sending a kernel module to test this as a reply to this message. There are also SPARC user-space test cases in the GCC bug entry. Signed-off-by: Mikael Pettersson <mikpe@it.uu.se> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>		2010-08-02 10:20:44 -07:00
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acpi	ACPI: don't cond_resched if irq is disabled	2010-01-28 15:00:26 -08:00
asm-generic	dma-mapping: fix dma_sync_single_range_*	2010-05-26 14:29:14 -07:00
crypto	Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6	2009-09-11 09:38:37 -07:00
drm	drm/radeon/kms: add FireMV 2400 PCI ID.	2010-04-26 07:41:26 -07:00
keys	RxRPC: Use uX/sX rather than uintX_t/intX_t types	2009-09-16 00:01:13 -07:00
linux	ssb: Handle Netbook devices where the SPROM address is changed	2010-08-02 10:20:43 -07:00
math-emu	math-emu: correct test for downshifting fraction in _FP_FROM_INT()	2010-08-02 10:20:44 -07:00
media	V4L/DVB (13019): video: initial support for ADV7180	2009-09-19 00:53:39 -03:00
mtd
net	sctp: Fix skb_over_panic resulting from multiple invalid parameter errors (CVE-2010-1173) (v4)	2010-07-05 11:11:14 -07:00
pcmcia	PM / yenta: Split resume into early and late parts (rev. 4)	2009-11-03 10:54:58 +01:00
rdma	trivial: fix typo "to to" in multiple files	2009-09-21 15:14:55 +02:00
rxrpc
scsi	SCSI: fc-transport: Use packed modifier for fc_bsg_request structure.	2010-04-26 07:41:30 -07:00
sound	Merge branch 'topic/ymfpci' into for-linus	2009-09-10 15:33:09 +02:00
trace	tracing: Fix ftrace_event_call alignment for use with gcc 4.5	2010-05-12 14:57:14 -07:00
video	davinci-fb-frame-buffer-driver-for-ti-da8xx-omap-l1xx-v4	2009-09-23 07:39:51 -07:00
xen
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