From: Paul Burton Date: Mon, 27 Jan 2014 15:23:03 +0000 (+0000) Subject: MIPS: Don't require FPU on sigcontext setup/restore X-Git-Tag: v3.15-rc1~125^2~134 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ff3aa5f296392b4bdc46ce975e6403bc7d27b191;p=pandora-kernel.git MIPS: Don't require FPU on sigcontext setup/restore When a task which has used the FPU at some point in its past takes a signal the kernel would previously always require the task to take ownership of the FPU whilst setting up or restoring from the sigcontext. That means that if the task has not used the FPU within this timeslice then the kernel would enable the FPU, restore the task's FP context into FPU registers and then save them into the sigcontext. This seems inefficient, and if the signal handler doesn't use FP then enabling the FPU & the extra memory accesses are entirely wasted work. This patch modifies the sigcontext setup & restore code to copy directly between the tasks saved FP context & the sigcontext for any tasks which have used FP in the past but are not currently the FPU owner (ie. have not used FP in this timeslice). Signed-off-by: Paul Burton Reviewed-by: Qais Yousef Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/6423/ Signed-off-by: Ralf Baechle --- Reading git-diff-tree failed