Commit Graph

5 Commits

Author SHA1 Message Date
Linus Torvalds
30d1d92a88 nds32 patches for 5.2-rc3
Here is the nds32 patchset based on 5.2-rc1
 Contained in here are
 1. fix warning for math-emu
 2. fix nds32 fpu exception handling
 3. fix nds32 fpu emulation implementation
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v2.0.17 (GNU/Linux)
 
 iQIcBAABAgAGBQJc9SRzAAoJEHfB0l0b2JxETZwQAJFERZU5ziU/UU5g4W8P2fn8
 KAS3bxqWk6mJ8qptSsvdggfXsJjCqxb+6Qhc9cAWQBiasfp6a6HR9zWFyAwOP7qo
 y0SydlRv/tMwhImpkF63Pp9omDfFVH0xpWSGIIF/PM7Uy2GrV9pmeTFX9R7Om4qV
 qdxGVPu2fe/aNP4W3/Typ2YttmWMAN5MJjTaig8hnsWQQGfVNuPZJNTAyt/iCmS/
 /XwxCRWpE4WIlYkcBV1LqhYRQ7xPN/IdnkD4EY4zPsDOq1+bgQQmGh8ekoiaITgB
 zSj1btl6FBcyeItFv/idaGxPjxmlN87Misix1P069pXOKVfbwB/HncZZJ3/msYFk
 tHbVMoVIsJ09kFiHUgXb9sjttf4o1xl8FM3uH32HEEJBOS4OPxbEhTbXRUECEDww
 xvrV6M0rKCp/Mbxvp3PmAJp75hY6/wE7Ygu7Enf9+OQBx1H6yAph25z9T2J7AoDl
 5rCGwaHw0SUHyz8GeE6vvcQ0JPRRGv59tVJEYKZmttoNlS6JebYDQJ7WPm1Rkp+V
 BmLv6SYeAJGdO1nhS7tMPUUWVD7cerRvz8VTmiMOSgbd/lwAR+4KIIMdi3cvaD9m
 TTyHcyxUNXwa7ox2OFvFXlvIEzqBiilzNgP89DKCAI7osvUuOviqRlgBNOvN0KxR
 ip/vG/xwDKXg1XVCaKdC
 =kAV3
 -----END PGP SIGNATURE-----

Merge tag 'nds32-for-linux-5.2-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/greentime/linux

Pull nds32 fixes from Greentime Hu:

 - fix warning for math-emu

 - fix nds32 fpu exception handling

 - fix nds32 fpu emulation implementation

* tag 'nds32-for-linux-5.2-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/greentime/linux:
  nds32: add new emulations for floating point instruction
  nds32: Avoid IEX status being incorrectly modified
  math-emu: Use statement expressions to fix Wshift-count-overflow warning
2019-06-03 10:23:41 -07:00
Vincent Chen
9322961205 nds32: add new emulations for floating point instruction
The existing floating point emulations is only available for floating
instruction that possibly issue denormalized input and underflow
exceptions. These existing FPU emulations are not sufficient when IEx
Trap is enabled because some floating point instructions only issue inexact
exception. This patch adds the emulations of such floating point
instructions.

Signed-off-by: Vincent Chen <vincentc@andestech.com>
Acked-by: Greentime Hu <greentime@andestech.com>
Signed-off-by: Greentime Hu <greentime@andestech.com>
2019-05-31 15:23:26 +08:00
Thomas Gleixner
ec8f24b7fa treewide: Add SPDX license identifier - Makefile/Kconfig
Add SPDX license identifiers to all Make/Kconfig files which:

 - Have no license information of any form

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

  GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-21 10:50:46 +02:00
Vincent Chen
44e92e0364 nds32: support denormalized result through FP emulator
Currently, the nds32 FPU dose not support the arithmetic of denormalized
number. When the nds32 FPU finds the result of the instruction is a
denormlized number, the nds32 FPU considers it to be an underflow condition
and rounds the result to an appropriate number. It may causes some loss
of precision. This commit proposes a solution to re-execute the
instruction by the FPU emulator to enhance the precision. To transfer
calculations from user space to kernel space, this feature will enable
the underflow exception trap by default. Enabling this feature may cause
some side effects:
  1. Performance loss due to extra FPU exception
  2. Need another scheme to control real underflow trap
       A new parameter, UDF_trap, which is belong to FPU context is used
     to control underflow trap.

User can configure this feature via CONFIG_SUPPORT_DENORMAL_ARITHMETIC

Signed-off-by: Vincent Chen <vincentc@andestech.com>
Acked-by: Greentime Hu <greentime@andestech.com>
Signed-off-by: Greentime Hu <greentime@andestech.com>
2018-11-22 18:13:27 +08:00
Vincent Chen
1ac832509f nds32: Support FP emulation
The Andes FPU coprocessor does not support denormalized number handling.
According to the specification, FPU generates a denorm input exception
that requires the kernel to deal with this instrution operation when it
encounters denormalized operands. Hence an nds32 FPU ISA emulator in the
kernel is required to meet requirement.

Signed-off-by: Vincent Chen <vincentc@andestech.com>
Signed-off-by: Nickhu <nickhu@andestech.com>
Acked-by: Greentime Hu <greentime@andestech.com>
Signed-off-by: Greentime Hu <greentime@andestech.com>
2018-11-22 18:13:21 +08:00