From: Paul Burton Date: Mon, 27 Jul 2015 19:58:20 +0000 (-0700) Subject: MIPS: Indicate FP mode in sigcontext sc_used_math X-Git-Tag: omap-for-v4.3/fixes-rc1~99^2~60 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0d071fa3772b85fe5d81032fbc011c623570d2fc;p=pandora-kernel.git MIPS: Indicate FP mode in sigcontext sc_used_math The sc_used_math field of struct sigcontext & its variants has traditionally been used as a boolean value indicating only whether or not floating point context is saved within the sigcontext. With various supported FP modes & the ability to switch between them this information will no longer be enough to decode the meaning of the data stored in the sc_fpregs fields of struct sigcontext. To make that possible 3 bits are defined within sc_used_math: - Bit 0 (USED_FP) represents whether FP was used, essentially providing the boolean flag which sc_used_math as a whole provided previously. - Bit 1 (USED_FR1) provides the value of the Status.FR bit at the time the FP context was saved. - Bit 2 (USED_HYBRID_FPRS) indicates whether the FP context was saved under the hybrid FPR scheme. Essentially, when set the odd singles are located in bits 63:32 of the preceding even indexed sc_fpregs element. Any userland that tests whether the sc_used_math field is zero or non-zero will continue to function as expected. Having said that, I could not find any userland which uses the sc_used_math field at all. [ralf@linux-mips.org: Fixed rejects.] Signed-off-by: Paul Burton Cc: linux-mips@linux-mips.org Cc: Guenter Roeck Cc: Matthew Fortune Cc: Michael Ellerman Cc: linux-kernel@vger.kernel.org Cc: Richard Weinberger Cc: Andy Lutomirski Cc: Maciej W. Rozycki Patchwork: https://patchwork.linux-mips.org/patch/10794/ Signed-off-by: Ralf Baechle --- Reading git-diff-tree failed