0d071fa377
The sc_used_math field of struct sigcontext & its variants has
traditionally been used as a boolean value indicating only whether or
not floating point context is saved within the sigcontext. With various
supported FP modes & the ability to switch between them this information
will no longer be enough to decode the meaning of the data stored in the
sc_fpregs fields of struct sigcontext.
To make that possible 3 bits are defined within sc_used_math:
- Bit 0 (USED_FP) represents whether FP was used, essentially
providing the boolean flag which sc_used_math as a whole provided
previously.
- Bit 1 (USED_FR1) provides the value of the Status.FR bit at the time
the FP context was saved.
- Bit 2 (USED_HYBRID_FPRS) indicates whether the FP context was saved
under the hybrid FPR scheme. Essentially, when set the odd singles
are located in bits 63:32 of the preceding even indexed sc_fpregs
element.
Any userland that tests whether the sc_used_math field is zero or
non-zero will continue to function as expected. Having said that, I
could not find any userland which uses the sc_used_math field at all.
[ralf@linux-mips.org: Fixed rejects.]
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: Michael Ellerman <mpe@ellerman.id.au>
Cc: linux-kernel@vger.kernel.org
Cc: Richard Weinberger <richard@nod.at>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Maciej W. Rozycki <macro@codesourcery.com>
Patchwork: https://patchwork.linux-mips.org/patch/10794/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
88 lines
2.4 KiB
C
88 lines
2.4 KiB
C
/*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (C) 1996, 1997, 1999 by Ralf Baechle
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* Copyright (C) 1999 Silicon Graphics, Inc.
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*/
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#ifndef _UAPI_ASM_SIGCONTEXT_H
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#define _UAPI_ASM_SIGCONTEXT_H
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#include <linux/types.h>
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#include <asm/sgidefs.h>
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/* scalar FP context was used */
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#define USED_FP (1 << 0)
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/* the value of Status.FR when context was saved */
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#define USED_FR1 (1 << 1)
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/* FR=1, but with odd singles in bits 63:32 of preceding even double */
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#define USED_HYBRID_FPRS (1 << 2)
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#if _MIPS_SIM == _MIPS_SIM_ABI32
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/*
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* Keep this struct definition in sync with the sigcontext fragment
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* in arch/mips/kernel/asm-offsets.c
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*/
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struct sigcontext {
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unsigned int sc_regmask; /* Unused */
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unsigned int sc_status; /* Unused */
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unsigned long long sc_pc;
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unsigned long long sc_regs[32];
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unsigned long long sc_fpregs[32];
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unsigned int sc_acx; /* Was sc_ownedfp */
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unsigned int sc_fpc_csr;
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unsigned int sc_fpc_eir; /* Unused */
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unsigned int sc_used_math;
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unsigned int sc_dsp; /* dsp status, was sc_ssflags */
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unsigned long long sc_mdhi;
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unsigned long long sc_mdlo;
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unsigned long sc_hi1; /* Was sc_cause */
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unsigned long sc_lo1; /* Was sc_badvaddr */
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unsigned long sc_hi2; /* Was sc_sigset[4] */
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unsigned long sc_lo2;
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unsigned long sc_hi3;
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unsigned long sc_lo3;
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};
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#endif /* _MIPS_SIM == _MIPS_SIM_ABI32 */
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#if _MIPS_SIM == _MIPS_SIM_ABI64 || _MIPS_SIM == _MIPS_SIM_NABI32
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#include <linux/posix_types.h>
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/*
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* Keep this struct definition in sync with the sigcontext fragment
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* in arch/mips/kernel/asm-offsets.c
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*
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* Warning: this structure illdefined with sc_badvaddr being just an unsigned
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* int so it was changed to unsigned long in 2.6.0-test1. This may break
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* binary compatibility - no prisoners.
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* DSP ASE in 2.6.12-rc4. Turn sc_mdhi and sc_mdlo into an array of four
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* entries, add sc_dsp and sc_reserved for padding. No prisoners.
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*/
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struct sigcontext {
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__u64 sc_regs[32];
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__u64 sc_fpregs[32];
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__u64 sc_mdhi;
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__u64 sc_hi1;
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__u64 sc_hi2;
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__u64 sc_hi3;
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__u64 sc_mdlo;
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__u64 sc_lo1;
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__u64 sc_lo2;
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__u64 sc_lo3;
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__u64 sc_pc;
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__u32 sc_fpc_csr;
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__u32 sc_used_math;
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__u32 sc_dsp;
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__u32 sc_reserved;
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};
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#endif /* _MIPS_SIM == _MIPS_SIM_ABI64 || _MIPS_SIM == _MIPS_SIM_NABI32 */
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#endif /* _UAPI_ASM_SIGCONTEXT_H */
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