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| author |   Paul Burton <paul.burton@mips.com> | 2018-11-07 23:14:11 +0000 |
|---|---|---|
| committer | Paul Burton <paul.burton@mips.com> | 2018-11-09 10:23:19 -0800 |
| commit | 183b40f992c8f98082c4d72043ecdeba0e6a4367 (patch) | |
| tree | a22b758fffbbae318784855fa5a1497e3388a0d9 /arch/mips/Kconfig | |
| parent | MIPS: Remove struct task_struct fpu state when CONFIG_MIPS_FP_SUPPORT=n (diff) | |
| download | linux-dev-183b40f992c8f98082c4d72043ecdeba0e6a4367.tar.xz linux-dev-183b40f992c8f98082c4d72043ecdeba0e6a4367.zip | |
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: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21014/
Cc: linux-mips@linux-mips.org
Diffstat (limited to '')
| -rw-r--r-- | arch/mips/Kconfig | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index 378379c098c9..9006ae11981d 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -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 |