linux/arch/mips/kernel/r4k_fpu.S
James Hogan 22b8ba765a MIPS: Fix MIPS64 FP save/restore on 32-bit kernels
32-bit kernels can be configured to support MIPS64, in which case
neither CONFIG_64BIT or CONFIG_CPU_MIPS32_R* will be set. This causes
the CP0_Status.FR checks at the point of floating point register save
and restore to be compiled out, which results in odd FP registers not
being saved or restored to the task or signal context even when
CP0_Status.FR is set.

Fix the ifdefs to use CONFIG_CPU_MIPSR2 and CONFIG_CPU_MIPSR6, which are
enabled for the relevant revisions of either MIPS32 or MIPS64, along
with some other CPUs such as Octeon (r2), Loongson1 (r2), XLP (r2),
Loongson 3A R2.

The suspect code originates from commit 597ce1723e ("MIPS: Support for
64-bit FP with O32 binaries") in v3.14, however the code in
__enable_fpu() was consistent and refused to set FR=1, falling back to
software FPU emulation. This was suboptimal but should be functionally
correct.

Commit fcc53b5f6c ("MIPS: fpu.h: Allow 64-bit FPU on a 64-bit MIPS R6
CPU") in v4.2 (and stable tagged back to 4.0) later introduced the bug
by updating __enable_fpu() to set FR=1 but failing to update the other
similar ifdefs to enable FR=1 state handling.

Fixes: fcc53b5f6c ("MIPS: fpu.h: Allow 64-bit FPU on a 64-bit MIPS R6 CPU")
Signed-off-by: James Hogan <jhogan@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: <stable@vger.kernel.org> # 4.0+
Patchwork: https://patchwork.linux-mips.org/patch/16739/
2017-11-09 14:13:40 +00:00

562 lines
11 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, 98, 99, 2000, 01 Ralf Baechle
*
* Multi-arch abstraction and asm macros for easier reading:
* Copyright (C) 1996 David S. Miller (davem@davemloft.net)
*
* Carsten Langgaard, carstenl@mips.com
* Copyright (C) 2000 MIPS Technologies, Inc.
* Copyright (C) 1999, 2001 Silicon Graphics, Inc.
*/
#include <asm/asm.h>
#include <asm/asmmacro.h>
#include <asm/errno.h>
#include <asm/export.h>
#include <asm/fpregdef.h>
#include <asm/mipsregs.h>
#include <asm/asm-offsets.h>
#include <asm/regdef.h>
/* preprocessor replaces the fp in ".set fp=64" with $30 otherwise */
#undef fp
.macro EX insn, reg, src
.set push
SET_HARDFLOAT
.set nomacro
.ex\@: \insn \reg, \src
.set pop
.section __ex_table,"a"
PTR .ex\@, fault
.previous
.endm
/*
* Save a thread's fp context.
*/
LEAF(_save_fp)
EXPORT_SYMBOL(_save_fp)
#if defined(CONFIG_64BIT) || defined(CONFIG_CPU_MIPSR2) || \
defined(CONFIG_CPU_MIPSR6)
mfc0 t0, CP0_STATUS
#endif
fpu_save_double a0 t0 t1 # clobbers t1
jr ra
END(_save_fp)
/*
* Restore a thread's fp context.
*/
LEAF(_restore_fp)
#if defined(CONFIG_64BIT) || defined(CONFIG_CPU_MIPSR2) || \
defined(CONFIG_CPU_MIPSR6)
mfc0 t0, CP0_STATUS
#endif
fpu_restore_double a0 t0 t1 # clobbers t1
jr ra
END(_restore_fp)
#ifdef CONFIG_CPU_HAS_MSA
/*
* Save a thread's MSA vector context.
*/
LEAF(_save_msa)
EXPORT_SYMBOL(_save_msa)
msa_save_all a0
jr ra
END(_save_msa)
/*
* Restore a thread's MSA vector context.
*/
LEAF(_restore_msa)
msa_restore_all a0
jr ra
END(_restore_msa)
LEAF(_init_msa_upper)
msa_init_all_upper
jr ra
END(_init_msa_upper)
#endif
/*
* Load the FPU with signalling NANS. This bit pattern we're using has
* the property that no matter whether considered as single or as double
* precision represents signaling NANS.
*
* The value to initialize fcr31 to comes in $a0.
*/
.set push
SET_HARDFLOAT
LEAF(_init_fpu)
mfc0 t0, CP0_STATUS
li t1, ST0_CU1
or t0, t1
mtc0 t0, CP0_STATUS
enable_fpu_hazard
ctc1 a0, fcr31
li t1, -1 # SNaN
#ifdef CONFIG_64BIT
sll t0, t0, 5
bgez t0, 1f # 16 / 32 register mode?
dmtc1 t1, $f1
dmtc1 t1, $f3
dmtc1 t1, $f5
dmtc1 t1, $f7
dmtc1 t1, $f9
dmtc1 t1, $f11
dmtc1 t1, $f13
dmtc1 t1, $f15
dmtc1 t1, $f17
dmtc1 t1, $f19
dmtc1 t1, $f21
dmtc1 t1, $f23
dmtc1 t1, $f25
dmtc1 t1, $f27
dmtc1 t1, $f29
dmtc1 t1, $f31
1:
#endif
#ifdef CONFIG_CPU_MIPS32
mtc1 t1, $f0
mtc1 t1, $f1
mtc1 t1, $f2
mtc1 t1, $f3
mtc1 t1, $f4
mtc1 t1, $f5
mtc1 t1, $f6
mtc1 t1, $f7
mtc1 t1, $f8
mtc1 t1, $f9
mtc1 t1, $f10
mtc1 t1, $f11
mtc1 t1, $f12
mtc1 t1, $f13
mtc1 t1, $f14
mtc1 t1, $f15
mtc1 t1, $f16
mtc1 t1, $f17
mtc1 t1, $f18
mtc1 t1, $f19
mtc1 t1, $f20
mtc1 t1, $f21
mtc1 t1, $f22
mtc1 t1, $f23
mtc1 t1, $f24
mtc1 t1, $f25
mtc1 t1, $f26
mtc1 t1, $f27
mtc1 t1, $f28
mtc1 t1, $f29
mtc1 t1, $f30
mtc1 t1, $f31
#if defined(CONFIG_CPU_MIPS32_R2) || defined(CONFIG_CPU_MIPS32_R6)
.set push
.set MIPS_ISA_LEVEL_RAW
.set fp=64
sll t0, t0, 5 # is Status.FR set?
bgez t0, 1f # no: skip setting upper 32b
mthc1 t1, $f0
mthc1 t1, $f1
mthc1 t1, $f2
mthc1 t1, $f3
mthc1 t1, $f4
mthc1 t1, $f5
mthc1 t1, $f6
mthc1 t1, $f7
mthc1 t1, $f8
mthc1 t1, $f9
mthc1 t1, $f10
mthc1 t1, $f11
mthc1 t1, $f12
mthc1 t1, $f13
mthc1 t1, $f14
mthc1 t1, $f15
mthc1 t1, $f16
mthc1 t1, $f17
mthc1 t1, $f18
mthc1 t1, $f19
mthc1 t1, $f20
mthc1 t1, $f21
mthc1 t1, $f22
mthc1 t1, $f23
mthc1 t1, $f24
mthc1 t1, $f25
mthc1 t1, $f26
mthc1 t1, $f27
mthc1 t1, $f28
mthc1 t1, $f29
mthc1 t1, $f30
mthc1 t1, $f31
1: .set pop
#endif /* CONFIG_CPU_MIPS32_R2 || CONFIG_CPU_MIPS32_R6 */
#else
.set MIPS_ISA_ARCH_LEVEL_RAW
dmtc1 t1, $f0
dmtc1 t1, $f2
dmtc1 t1, $f4
dmtc1 t1, $f6
dmtc1 t1, $f8
dmtc1 t1, $f10
dmtc1 t1, $f12
dmtc1 t1, $f14
dmtc1 t1, $f16
dmtc1 t1, $f18
dmtc1 t1, $f20
dmtc1 t1, $f22
dmtc1 t1, $f24
dmtc1 t1, $f26
dmtc1 t1, $f28
dmtc1 t1, $f30
#endif
jr ra
END(_init_fpu)
.set pop /* SET_HARDFLOAT */
.set noreorder
/**
* _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
cfc1 t1, fcr31
.set pop
#if defined(CONFIG_64BIT) || defined(CONFIG_CPU_MIPSR2) || \
defined(CONFIG_CPU_MIPSR6)
.set push
SET_HARDFLOAT
#ifdef CONFIG_CPU_MIPSR2
.set mips32r2
.set fp=64
mfc0 t0, CP0_STATUS
sll t0, t0, 5
bgez t0, 1f # skip storing odd if FR=0
nop
#endif
/* Store the 16 odd double precision registers */
EX sdc1 $f1, 8(a0)
EX sdc1 $f3, 24(a0)
EX sdc1 $f5, 40(a0)
EX sdc1 $f7, 56(a0)
EX sdc1 $f9, 72(a0)
EX sdc1 $f11, 88(a0)
EX sdc1 $f13, 104(a0)
EX sdc1 $f15, 120(a0)
EX sdc1 $f17, 136(a0)
EX sdc1 $f19, 152(a0)
EX sdc1 $f21, 168(a0)
EX sdc1 $f23, 184(a0)
EX sdc1 $f25, 200(a0)
EX sdc1 $f27, 216(a0)
EX sdc1 $f29, 232(a0)
EX sdc1 $f31, 248(a0)
1: .set pop
#endif
.set push
SET_HARDFLOAT
/* Store the 16 even double precision registers */
EX sdc1 $f0, 0(a0)
EX sdc1 $f2, 16(a0)
EX sdc1 $f4, 32(a0)
EX sdc1 $f6, 48(a0)
EX sdc1 $f8, 64(a0)
EX sdc1 $f10, 80(a0)
EX sdc1 $f12, 96(a0)
EX sdc1 $f14, 112(a0)
EX sdc1 $f16, 128(a0)
EX sdc1 $f18, 144(a0)
EX sdc1 $f20, 160(a0)
EX sdc1 $f22, 176(a0)
EX sdc1 $f24, 192(a0)
EX sdc1 $f26, 208(a0)
EX sdc1 $f28, 224(a0)
EX sdc1 $f30, 240(a0)
EX sw t1, 0(a1)
jr ra
li v0, 0 # success
.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)
EX lw t1, 0(a1)
#if defined(CONFIG_64BIT) || defined(CONFIG_CPU_MIPSR2) || \
defined(CONFIG_CPU_MIPSR6)
.set push
SET_HARDFLOAT
#ifdef CONFIG_CPU_MIPSR2
.set mips32r2
.set fp=64
mfc0 t0, CP0_STATUS
sll t0, t0, 5
bgez t0, 1f # skip loading odd if FR=0
nop
#endif
EX ldc1 $f1, 8(a0)
EX ldc1 $f3, 24(a0)
EX ldc1 $f5, 40(a0)
EX ldc1 $f7, 56(a0)
EX ldc1 $f9, 72(a0)
EX ldc1 $f11, 88(a0)
EX ldc1 $f13, 104(a0)
EX ldc1 $f15, 120(a0)
EX ldc1 $f17, 136(a0)
EX ldc1 $f19, 152(a0)
EX ldc1 $f21, 168(a0)
EX ldc1 $f23, 184(a0)
EX ldc1 $f25, 200(a0)
EX ldc1 $f27, 216(a0)
EX ldc1 $f29, 232(a0)
EX ldc1 $f31, 248(a0)
1: .set pop
#endif
.set push
SET_HARDFLOAT
EX ldc1 $f0, 0(a0)
EX ldc1 $f2, 16(a0)
EX ldc1 $f4, 32(a0)
EX ldc1 $f6, 48(a0)
EX ldc1 $f8, 64(a0)
EX ldc1 $f10, 80(a0)
EX ldc1 $f12, 96(a0)
EX ldc1 $f14, 112(a0)
EX ldc1 $f16, 128(a0)
EX ldc1 $f18, 144(a0)
EX ldc1 $f20, 160(a0)
EX ldc1 $f22, 176(a0)
EX ldc1 $f24, 192(a0)
EX ldc1 $f26, 208(a0)
EX ldc1 $f28, 224(a0)
EX ldc1 $f30, 240(a0)
ctc1 t1, fcr31
.set pop
jr ra
li v0, 0 # success
END(_restore_fp_context)
#ifdef CONFIG_CPU_HAS_MSA
.macro op_one_wr op, idx, base
.align 4
\idx: \op \idx, 0, \base
jr ra
nop
.endm
.macro op_msa_wr name, op
LEAF(\name)
.set push
.set noreorder
sll t0, a0, 4
PTR_LA t1, 0f
PTR_ADDU t0, t0, t1
jr t0
nop
op_one_wr \op, 0, a1
op_one_wr \op, 1, a1
op_one_wr \op, 2, a1
op_one_wr \op, 3, a1
op_one_wr \op, 4, a1
op_one_wr \op, 5, a1
op_one_wr \op, 6, a1
op_one_wr \op, 7, a1
op_one_wr \op, 8, a1
op_one_wr \op, 9, a1
op_one_wr \op, 10, a1
op_one_wr \op, 11, a1
op_one_wr \op, 12, a1
op_one_wr \op, 13, a1
op_one_wr \op, 14, a1
op_one_wr \op, 15, a1
op_one_wr \op, 16, a1
op_one_wr \op, 17, a1
op_one_wr \op, 18, a1
op_one_wr \op, 19, a1
op_one_wr \op, 20, a1
op_one_wr \op, 21, a1
op_one_wr \op, 22, a1
op_one_wr \op, 23, a1
op_one_wr \op, 24, a1
op_one_wr \op, 25, a1
op_one_wr \op, 26, a1
op_one_wr \op, 27, a1
op_one_wr \op, 28, a1
op_one_wr \op, 29, a1
op_one_wr \op, 30, a1
op_one_wr \op, 31, a1
.set pop
END(\name)
.endm
op_msa_wr read_msa_wr_b, st_b
op_msa_wr read_msa_wr_h, st_h
op_msa_wr read_msa_wr_w, st_w
op_msa_wr read_msa_wr_d, st_d
op_msa_wr write_msa_wr_b, ld_b
op_msa_wr write_msa_wr_h, ld_h
op_msa_wr write_msa_wr_w, ld_w
op_msa_wr write_msa_wr_d, ld_d
#endif /* CONFIG_CPU_HAS_MSA */
#ifdef CONFIG_CPU_HAS_MSA
.macro save_msa_upper wr, off, base
.set push
.set noat
#ifdef CONFIG_64BIT
copy_s_d \wr, 1
EX sd $1, \off(\base)
#elif defined(CONFIG_CPU_LITTLE_ENDIAN)
copy_s_w \wr, 2
EX sw $1, \off(\base)
copy_s_w \wr, 3
EX sw $1, (\off+4)(\base)
#else /* CONFIG_CPU_BIG_ENDIAN */
copy_s_w \wr, 2
EX sw $1, (\off+4)(\base)
copy_s_w \wr, 3
EX sw $1, \off(\base)
#endif
.set pop
.endm
LEAF(_save_msa_all_upper)
save_msa_upper 0, 0x00, a0
save_msa_upper 1, 0x08, a0
save_msa_upper 2, 0x10, a0
save_msa_upper 3, 0x18, a0
save_msa_upper 4, 0x20, a0
save_msa_upper 5, 0x28, a0
save_msa_upper 6, 0x30, a0
save_msa_upper 7, 0x38, a0
save_msa_upper 8, 0x40, a0
save_msa_upper 9, 0x48, a0
save_msa_upper 10, 0x50, a0
save_msa_upper 11, 0x58, a0
save_msa_upper 12, 0x60, a0
save_msa_upper 13, 0x68, a0
save_msa_upper 14, 0x70, a0
save_msa_upper 15, 0x78, a0
save_msa_upper 16, 0x80, a0
save_msa_upper 17, 0x88, a0
save_msa_upper 18, 0x90, a0
save_msa_upper 19, 0x98, a0
save_msa_upper 20, 0xa0, a0
save_msa_upper 21, 0xa8, a0
save_msa_upper 22, 0xb0, a0
save_msa_upper 23, 0xb8, a0
save_msa_upper 24, 0xc0, a0
save_msa_upper 25, 0xc8, a0
save_msa_upper 26, 0xd0, a0
save_msa_upper 27, 0xd8, a0
save_msa_upper 28, 0xe0, a0
save_msa_upper 29, 0xe8, a0
save_msa_upper 30, 0xf0, a0
save_msa_upper 31, 0xf8, a0
jr ra
li v0, 0
END(_save_msa_all_upper)
.macro restore_msa_upper wr, off, base
.set push
.set noat
#ifdef CONFIG_64BIT
EX ld $1, \off(\base)
insert_d \wr, 1
#elif defined(CONFIG_CPU_LITTLE_ENDIAN)
EX lw $1, \off(\base)
insert_w \wr, 2
EX lw $1, (\off+4)(\base)
insert_w \wr, 3
#else /* CONFIG_CPU_BIG_ENDIAN */
EX lw $1, (\off+4)(\base)
insert_w \wr, 2
EX lw $1, \off(\base)
insert_w \wr, 3
#endif
.set pop
.endm
LEAF(_restore_msa_all_upper)
restore_msa_upper 0, 0x00, a0
restore_msa_upper 1, 0x08, a0
restore_msa_upper 2, 0x10, a0
restore_msa_upper 3, 0x18, a0
restore_msa_upper 4, 0x20, a0
restore_msa_upper 5, 0x28, a0
restore_msa_upper 6, 0x30, a0
restore_msa_upper 7, 0x38, a0
restore_msa_upper 8, 0x40, a0
restore_msa_upper 9, 0x48, a0
restore_msa_upper 10, 0x50, a0
restore_msa_upper 11, 0x58, a0
restore_msa_upper 12, 0x60, a0
restore_msa_upper 13, 0x68, a0
restore_msa_upper 14, 0x70, a0
restore_msa_upper 15, 0x78, a0
restore_msa_upper 16, 0x80, a0
restore_msa_upper 17, 0x88, a0
restore_msa_upper 18, 0x90, a0
restore_msa_upper 19, 0x98, a0
restore_msa_upper 20, 0xa0, a0
restore_msa_upper 21, 0xa8, a0
restore_msa_upper 22, 0xb0, a0
restore_msa_upper 23, 0xb8, a0
restore_msa_upper 24, 0xc0, a0
restore_msa_upper 25, 0xc8, a0
restore_msa_upper 26, 0xd0, a0
restore_msa_upper 27, 0xd8, a0
restore_msa_upper 28, 0xe0, a0
restore_msa_upper 29, 0xe8, a0
restore_msa_upper 30, 0xf0, a0
restore_msa_upper 31, 0xf8, a0
jr ra
li v0, 0
END(_restore_msa_all_upper)
#endif /* CONFIG_CPU_HAS_MSA */
.set reorder
.type fault, @function
.ent fault
fault: li v0, -EFAULT # failure
jr ra
.end fault