alistair23-linux/arch/mips/kernel/r2300_fpu.S
Maciej W. Rozycki f92722dc45 MIPS: Correct MIPS I FP sigcontext layout
Complement commit 80cbfad790 ("MIPS: Correct MIPS I FP context
layout") and correct the way Floating Point General registers are stored
in a signal context with MIPS I hardware.

Use the S.D and L.D assembly macros to have pairs of SWC1 instructions
and pairs of LWC1 instructions produced, respectively, in an arrangement
which makes the memory representation of floating-point data passed
compatible with that used by hardware SDC1 and LDC1 instructions, where
available, regardless of the hardware endianness used.  This matches the
layout used by r4k_fpu.S, ensuring run-time compatibility for MIPS I
software across all o32 hardware platforms.

Define an EX2 macro to handle exceptions from both hardware instructions
implicitly produced from S.D and L.D assembly macros.

Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/14477/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-11-04 01:39:23 +01:00

111 lines
2.5 KiB
ArmAsm

/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1996, 1998 by Ralf Baechle
*
* Multi-arch abstraction and asm macros for easier reading:
* Copyright (C) 1996 David S. Miller (davem@davemloft.net)
*
* Further modifications to make this work:
* Copyright (c) 1998 Harald Koerfgen
*/
#include <asm/asm.h>
#include <asm/errno.h>
#include <asm/fpregdef.h>
#include <asm/mipsregs.h>
#include <asm/asm-offsets.h>
#include <asm/regdef.h>
#define EX(a,b) \
9: a,##b; \
.section __ex_table,"a"; \
PTR 9b,fault; \
.previous
#define EX2(a,b) \
9: a,##b; \
.section __ex_table,"a"; \
PTR 9b,bad_stack; \
PTR 9b+4,bad_stack; \
.previous
.set noreorder
.set mips1
/**
* _save_fp_context() - save FP context from the FPU
* @a0 - pointer to fpregs field of sigcontext
* @a1 - pointer to fpc_csr field of sigcontext
*
* Save FP context, including the 32 FP data registers and the FP
* control & status register, from the FPU to signal context.
*/
LEAF(_save_fp_context)
.set push
SET_HARDFLOAT
li v0, 0 # assume success
cfc1 t1, fcr31
EX2(s.d $f0, 0(a0))
EX2(s.d $f2, 16(a0))
EX2(s.d $f4, 32(a0))
EX2(s.d $f6, 48(a0))
EX2(s.d $f8, 64(a0))
EX2(s.d $f10, 80(a0))
EX2(s.d $f12, 96(a0))
EX2(s.d $f14, 112(a0))
EX2(s.d $f16, 128(a0))
EX2(s.d $f18, 144(a0))
EX2(s.d $f20, 160(a0))
EX2(s.d $f22, 176(a0))
EX2(s.d $f24, 192(a0))
EX2(s.d $f26, 208(a0))
EX2(s.d $f28, 224(a0))
EX2(s.d $f30, 240(a0))
jr ra
EX(sw t1, (a1))
.set pop
END(_save_fp_context)
/**
* _restore_fp_context() - restore FP context to the FPU
* @a0 - pointer to fpregs field of sigcontext
* @a1 - pointer to fpc_csr field of sigcontext
*
* Restore FP context, including the 32 FP data registers and the FP
* control & status register, from signal context to the FPU.
*/
LEAF(_restore_fp_context)
.set push
SET_HARDFLOAT
li v0, 0 # assume success
EX(lw t0, (a1))
EX2(l.d $f0, 0(a0))
EX2(l.d $f2, 16(a0))
EX2(l.d $f4, 32(a0))
EX2(l.d $f6, 48(a0))
EX2(l.d $f8, 64(a0))
EX2(l.d $f10, 80(a0))
EX2(l.d $f12, 96(a0))
EX2(l.d $f14, 112(a0))
EX2(l.d $f16, 128(a0))
EX2(l.d $f18, 144(a0))
EX2(l.d $f20, 160(a0))
EX2(l.d $f22, 176(a0))
EX2(l.d $f24, 192(a0))
EX2(l.d $f26, 208(a0))
EX2(l.d $f28, 224(a0))
EX2(l.d $f30, 240(a0))
jr ra
ctc1 t0, fcr31
.set pop
END(_restore_fp_context)
.set reorder
.type fault, @function
.ent fault
fault: li v0, -EFAULT
jr ra
.end fault