linux/arch/mips/include/asm/asmmacro-32.h
Paul Burton 597ce1723e MIPS: Support for 64-bit FP with O32 binaries
CPUs implementing MIPS32 R2 may include a 64-bit FPU, just as MIPS64 CPUs
do. In order to preserve backwards compatibility a 64-bit FPU will act
like a 32-bit FPU (by accessing doubles from the least significant 32
bits of an even-odd pair of FP registers) when the Status.FR bit is
zero, again just like a mips64 CPU. The standard O32 ABI is defined
expecting a 32-bit FPU, however recent toolchains support use of a
64-bit FPU from an O32 MIPS32 executable. When an ELF executable is
built to use a 64-bit FPU a new flag (EF_MIPS_FP64) is set in the ELF
header.

With this patch the kernel will check the EF_MIPS_FP64 flag when
executing an O32 binary, and set Status.FR accordingly. The addition
of O32 64-bit FP support lessens the opportunity for optimisation in
the FPU emulator, so a CONFIG_MIPS_O32_FP64_SUPPORT Kconfig option is
introduced to allow this support to be disabled for those that don't
require it.

Inspired by an earlier patch by Leonid Yegoshin, but implemented more
cleanly & correctly.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Paul Burton <paul.burton@imgtec.com>
Patchwork: https://patchwork.linux-mips.org/patch/6154/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2014-01-13 23:40:56 +01:00

117 lines
3.4 KiB
C

/*
* asmmacro.h: Assembler macros to make things easier to read.
*
* Copyright (C) 1996 David S. Miller (davem@davemloft.net)
* Copyright (C) 1998, 1999, 2003 Ralf Baechle
*/
#ifndef _ASM_ASMMACRO_32_H
#define _ASM_ASMMACRO_32_H
#include <asm/asm-offsets.h>
#include <asm/regdef.h>
#include <asm/fpregdef.h>
#include <asm/mipsregs.h>
.macro fpu_save_single thread tmp=t0
cfc1 \tmp, fcr31
swc1 $f0, THREAD_FPR0(\thread)
swc1 $f1, THREAD_FPR1(\thread)
swc1 $f2, THREAD_FPR2(\thread)
swc1 $f3, THREAD_FPR3(\thread)
swc1 $f4, THREAD_FPR4(\thread)
swc1 $f5, THREAD_FPR5(\thread)
swc1 $f6, THREAD_FPR6(\thread)
swc1 $f7, THREAD_FPR7(\thread)
swc1 $f8, THREAD_FPR8(\thread)
swc1 $f9, THREAD_FPR9(\thread)
swc1 $f10, THREAD_FPR10(\thread)
swc1 $f11, THREAD_FPR11(\thread)
swc1 $f12, THREAD_FPR12(\thread)
swc1 $f13, THREAD_FPR13(\thread)
swc1 $f14, THREAD_FPR14(\thread)
swc1 $f15, THREAD_FPR15(\thread)
swc1 $f16, THREAD_FPR16(\thread)
swc1 $f17, THREAD_FPR17(\thread)
swc1 $f18, THREAD_FPR18(\thread)
swc1 $f19, THREAD_FPR19(\thread)
swc1 $f20, THREAD_FPR20(\thread)
swc1 $f21, THREAD_FPR21(\thread)
swc1 $f22, THREAD_FPR22(\thread)
swc1 $f23, THREAD_FPR23(\thread)
swc1 $f24, THREAD_FPR24(\thread)
swc1 $f25, THREAD_FPR25(\thread)
swc1 $f26, THREAD_FPR26(\thread)
swc1 $f27, THREAD_FPR27(\thread)
swc1 $f28, THREAD_FPR28(\thread)
swc1 $f29, THREAD_FPR29(\thread)
swc1 $f30, THREAD_FPR30(\thread)
swc1 $f31, THREAD_FPR31(\thread)
sw \tmp, THREAD_FCR31(\thread)
.endm
.macro fpu_restore_single thread tmp=t0
lw \tmp, THREAD_FCR31(\thread)
lwc1 $f0, THREAD_FPR0(\thread)
lwc1 $f1, THREAD_FPR1(\thread)
lwc1 $f2, THREAD_FPR2(\thread)
lwc1 $f3, THREAD_FPR3(\thread)
lwc1 $f4, THREAD_FPR4(\thread)
lwc1 $f5, THREAD_FPR5(\thread)
lwc1 $f6, THREAD_FPR6(\thread)
lwc1 $f7, THREAD_FPR7(\thread)
lwc1 $f8, THREAD_FPR8(\thread)
lwc1 $f9, THREAD_FPR9(\thread)
lwc1 $f10, THREAD_FPR10(\thread)
lwc1 $f11, THREAD_FPR11(\thread)
lwc1 $f12, THREAD_FPR12(\thread)
lwc1 $f13, THREAD_FPR13(\thread)
lwc1 $f14, THREAD_FPR14(\thread)
lwc1 $f15, THREAD_FPR15(\thread)
lwc1 $f16, THREAD_FPR16(\thread)
lwc1 $f17, THREAD_FPR17(\thread)
lwc1 $f18, THREAD_FPR18(\thread)
lwc1 $f19, THREAD_FPR19(\thread)
lwc1 $f20, THREAD_FPR20(\thread)
lwc1 $f21, THREAD_FPR21(\thread)
lwc1 $f22, THREAD_FPR22(\thread)
lwc1 $f23, THREAD_FPR23(\thread)
lwc1 $f24, THREAD_FPR24(\thread)
lwc1 $f25, THREAD_FPR25(\thread)
lwc1 $f26, THREAD_FPR26(\thread)
lwc1 $f27, THREAD_FPR27(\thread)
lwc1 $f28, THREAD_FPR28(\thread)
lwc1 $f29, THREAD_FPR29(\thread)
lwc1 $f30, THREAD_FPR30(\thread)
lwc1 $f31, THREAD_FPR31(\thread)
ctc1 \tmp, fcr31
.endm
.macro cpu_save_nonscratch thread
LONG_S s0, THREAD_REG16(\thread)
LONG_S s1, THREAD_REG17(\thread)
LONG_S s2, THREAD_REG18(\thread)
LONG_S s3, THREAD_REG19(\thread)
LONG_S s4, THREAD_REG20(\thread)
LONG_S s5, THREAD_REG21(\thread)
LONG_S s6, THREAD_REG22(\thread)
LONG_S s7, THREAD_REG23(\thread)
LONG_S sp, THREAD_REG29(\thread)
LONG_S fp, THREAD_REG30(\thread)
.endm
.macro cpu_restore_nonscratch thread
LONG_L s0, THREAD_REG16(\thread)
LONG_L s1, THREAD_REG17(\thread)
LONG_L s2, THREAD_REG18(\thread)
LONG_L s3, THREAD_REG19(\thread)
LONG_L s4, THREAD_REG20(\thread)
LONG_L s5, THREAD_REG21(\thread)
LONG_L s6, THREAD_REG22(\thread)
LONG_L s7, THREAD_REG23(\thread)
LONG_L sp, THREAD_REG29(\thread)
LONG_L fp, THREAD_REG30(\thread)
LONG_L ra, THREAD_REG31(\thread)
.endm
#endif /* _ASM_ASMMACRO_32_H */