597ce1723e
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>
43 lines
1.2 KiB
C
43 lines
1.2 KiB
C
/*
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* asmmacro.h: Assembler macros to make things easier to read.
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*
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* Copyright (C) 1996 David S. Miller (davem@davemloft.net)
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* Copyright (C) 1998, 1999 Ralf Baechle
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* Copyright (C) 1999 Silicon Graphics, Inc.
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*/
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#ifndef _ASM_ASMMACRO_64_H
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#define _ASM_ASMMACRO_64_H
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#include <asm/asm-offsets.h>
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#include <asm/regdef.h>
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#include <asm/fpregdef.h>
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#include <asm/mipsregs.h>
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.macro cpu_save_nonscratch thread
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LONG_S s0, THREAD_REG16(\thread)
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LONG_S s1, THREAD_REG17(\thread)
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LONG_S s2, THREAD_REG18(\thread)
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LONG_S s3, THREAD_REG19(\thread)
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LONG_S s4, THREAD_REG20(\thread)
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LONG_S s5, THREAD_REG21(\thread)
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LONG_S s6, THREAD_REG22(\thread)
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LONG_S s7, THREAD_REG23(\thread)
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LONG_S sp, THREAD_REG29(\thread)
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LONG_S fp, THREAD_REG30(\thread)
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.endm
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.macro cpu_restore_nonscratch thread
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LONG_L s0, THREAD_REG16(\thread)
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LONG_L s1, THREAD_REG17(\thread)
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LONG_L s2, THREAD_REG18(\thread)
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LONG_L s3, THREAD_REG19(\thread)
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LONG_L s4, THREAD_REG20(\thread)
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LONG_L s5, THREAD_REG21(\thread)
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LONG_L s6, THREAD_REG22(\thread)
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LONG_L s7, THREAD_REG23(\thread)
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LONG_L sp, THREAD_REG29(\thread)
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LONG_L fp, THREAD_REG30(\thread)
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LONG_L ra, THREAD_REG31(\thread)
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.endm
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#endif /* _ASM_ASMMACRO_64_H */
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