MIPS: Use struct mips_abi offsets to save FP context

When saving FP state to struct sigcontext, make use of the offsets
provided by struct mips_abi to obtain appropriate addresses for the
sc_fpregs & sc_fpc_csr fields of the sigcontext. This is done only for
the native struct sigcontext in this patch (ie. for O32 in CONFIG_32BIT
kernels or for N64 in CONFIG_64BIT kernels) but is done in preparation
for sharing this code with compat ABIs in further patches.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Matthew Fortune <matthew.fortune@imgtec.com>
Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: linux-kernel@vger.kernel.org
Cc: Richard Weinberger <richard@nod.at>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Manuel Lauss <manuel.lauss@gmail.com>
Cc: Maciej W. Rozycki <macro@codesourcery.com>
Patchwork: https://patchwork.linux-mips.org/patch/10789/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/arch/mips/kernel/signal-common.h b/arch/mips/kernel/signal-common.h
index 0b85f827cd18..96b0fd82f8b5 100644
--- a/arch/mips/kernel/signal-common.h
+++ b/arch/mips/kernel/signal-common.h
@@ -31,4 +31,10 @@ extern int fpcsr_pending(unsigned int __user *fpcsr);
 #define lock_fpu_owner()	({ preempt_disable(); pagefault_disable(); })
 #define unlock_fpu_owner()	({ pagefault_enable(); preempt_enable(); })
 
+/* Assembly functions to move context to/from the FPU */
+extern asmlinkage int
+_save_fp_context(void __user *fpregs, void __user *csr);
+extern asmlinkage int
+_restore_fp_context(void __user *fpregs, void __user *csr);
+
 #endif	/* __SIGNAL_COMMON_H */