Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Unverified Commit 183b40f9 authored by Paul Burton's avatar Paul Burton
Browse files

MIPS: Allow FP support to be disabled 



Allow the user to configure the kernel to omit support for floating
point, by setting CONFIG_MIPS_FP_SUPPORT=n. In an attempt to avoid
problems for users who don't understand the impact of this, only expose
the option when CONFIG_EXPERT=y.

When CONFIG_MIPS_FP_SUPPORT=n all support for FPU hardware, FPU
emulation & FP context will be removed from the kernel. If a userland
program attempts to execute a floating point instruction it will receive
a SIGILL.

Setting CONFIG_MIPS_FP_SUPPORT=n shaves around 112KB from a
64r6el_defconfig build using GCC 8.1.0.

This also helps prepare us for supporting the nanoMIPS ISA, for which
floating point support has not been finalized.

Signed-off-by: default avatarPaul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21014/
Cc: linux-mips@linux-mips.org
parent 2725f377

arch/mips/Kconfig

+13 −1
Original line number Diff line number Diff line
@@ -2256,7 +2256,19 @@ config CPU_GENERIC_DUMP_TLB 
	default y if !(CPU_R3000 || CPU_R8000 || CPU_TX39XX)



config MIPS_FP_SUPPORT

	def_bool y

	bool "Floating Point support" if EXPERT

	default y

	help

	  Select y to include support for floating point in the kernel

	  including initialization of FPU hardware, FP context save & restore

	  and emulation of an FPU where necessary. Without this support any

	  userland program attempting to use floating point instructions will

	  receive a SIGILL.



	  If you know that your userland will not attempt to use floating point

	  instructions then you can say n here to shrink the kernel a little.



	  If unsure, say y.



config CPU_R2300_FPU

	bool