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    Subject[PATCH 04/16] MIPS: use struct mips_abi offsets to save FP context
    Date
    When saving FP state to struct sigcontext, make use of the offsets
    provided by struct mips_abi to obtain appropriate addresses for the
    sc_fpregs & sc_fpc_csr fields of the sigcontext. This is done only for
    the native struct sigcontext in this patch (ie. for O32 in CONFIG_32BIT
    kernels or for N64 in CONFIG_64BIT kernels) but is done in preparation
    for sharing this code with compat ABIs in further patches.

    Signed-off-by: Paul Burton <paul.burton@imgtec.com>
    ---

    arch/mips/kernel/r4k_fpu.S | 151 +++++++++++++++++++++------------------
    arch/mips/kernel/signal-common.h | 6 ++
    arch/mips/kernel/signal.c | 85 +++++++++++++++-------
    3 files changed, 145 insertions(+), 97 deletions(-)

    diff --git a/arch/mips/kernel/r4k_fpu.S b/arch/mips/kernel/r4k_fpu.S
    index 1d88af2..9e2d18d 100644
    --- a/arch/mips/kernel/r4k_fpu.S
    +++ b/arch/mips/kernel/r4k_fpu.S
    @@ -35,6 +35,14 @@

    .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
    @@ -54,45 +62,45 @@ LEAF(_save_fp_context)
    nop
    #endif
    /* Store the 16 odd double precision registers */
    - EX sdc1 $f1, SC_FPREGS+8(a0)
    - EX sdc1 $f3, SC_FPREGS+24(a0)
    - EX sdc1 $f5, SC_FPREGS+40(a0)
    - EX sdc1 $f7, SC_FPREGS+56(a0)
    - EX sdc1 $f9, SC_FPREGS+72(a0)
    - EX sdc1 $f11, SC_FPREGS+88(a0)
    - EX sdc1 $f13, SC_FPREGS+104(a0)
    - EX sdc1 $f15, SC_FPREGS+120(a0)
    - EX sdc1 $f17, SC_FPREGS+136(a0)
    - EX sdc1 $f19, SC_FPREGS+152(a0)
    - EX sdc1 $f21, SC_FPREGS+168(a0)
    - EX sdc1 $f23, SC_FPREGS+184(a0)
    - EX sdc1 $f25, SC_FPREGS+200(a0)
    - EX sdc1 $f27, SC_FPREGS+216(a0)
    - EX sdc1 $f29, SC_FPREGS+232(a0)
    - EX sdc1 $f31, SC_FPREGS+248(a0)
    + 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, SC_FPREGS+0(a0)
    - EX sdc1 $f2, SC_FPREGS+16(a0)
    - EX sdc1 $f4, SC_FPREGS+32(a0)
    - EX sdc1 $f6, SC_FPREGS+48(a0)
    - EX sdc1 $f8, SC_FPREGS+64(a0)
    - EX sdc1 $f10, SC_FPREGS+80(a0)
    - EX sdc1 $f12, SC_FPREGS+96(a0)
    - EX sdc1 $f14, SC_FPREGS+112(a0)
    - EX sdc1 $f16, SC_FPREGS+128(a0)
    - EX sdc1 $f18, SC_FPREGS+144(a0)
    - EX sdc1 $f20, SC_FPREGS+160(a0)
    - EX sdc1 $f22, SC_FPREGS+176(a0)
    - EX sdc1 $f24, SC_FPREGS+192(a0)
    - EX sdc1 $f26, SC_FPREGS+208(a0)
    - EX sdc1 $f28, SC_FPREGS+224(a0)
    - EX sdc1 $f30, SC_FPREGS+240(a0)
    - EX sw t1, SC_FPC_CSR(a0)
    + 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
    @@ -158,13 +166,16 @@ LEAF(_save_fp_context32)
    END(_save_fp_context32)
    #endif

    -/*
    - * Restore FPU state:
    - * - fp gp registers
    - * - cp1 status/control register
    +/**
    + * _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, SC_FPC_CSR(a0)
    + EX lw t1, 0(a1)

    #if defined(CONFIG_64BIT) || defined(CONFIG_CPU_MIPS32_R2) || \
    defined(CONFIG_CPU_MIPS32_R6)
    @@ -178,42 +189,42 @@ LEAF(_restore_fp_context)
    bgez t0, 1f # skip loading odd if FR=0
    nop
    #endif
    - EX ldc1 $f1, SC_FPREGS+8(a0)
    - EX ldc1 $f3, SC_FPREGS+24(a0)
    - EX ldc1 $f5, SC_FPREGS+40(a0)
    - EX ldc1 $f7, SC_FPREGS+56(a0)
    - EX ldc1 $f9, SC_FPREGS+72(a0)
    - EX ldc1 $f11, SC_FPREGS+88(a0)
    - EX ldc1 $f13, SC_FPREGS+104(a0)
    - EX ldc1 $f15, SC_FPREGS+120(a0)
    - EX ldc1 $f17, SC_FPREGS+136(a0)
    - EX ldc1 $f19, SC_FPREGS+152(a0)
    - EX ldc1 $f21, SC_FPREGS+168(a0)
    - EX ldc1 $f23, SC_FPREGS+184(a0)
    - EX ldc1 $f25, SC_FPREGS+200(a0)
    - EX ldc1 $f27, SC_FPREGS+216(a0)
    - EX ldc1 $f29, SC_FPREGS+232(a0)
    - EX ldc1 $f31, SC_FPREGS+248(a0)
    + 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, SC_FPREGS+0(a0)
    - EX ldc1 $f2, SC_FPREGS+16(a0)
    - EX ldc1 $f4, SC_FPREGS+32(a0)
    - EX ldc1 $f6, SC_FPREGS+48(a0)
    - EX ldc1 $f8, SC_FPREGS+64(a0)
    - EX ldc1 $f10, SC_FPREGS+80(a0)
    - EX ldc1 $f12, SC_FPREGS+96(a0)
    - EX ldc1 $f14, SC_FPREGS+112(a0)
    - EX ldc1 $f16, SC_FPREGS+128(a0)
    - EX ldc1 $f18, SC_FPREGS+144(a0)
    - EX ldc1 $f20, SC_FPREGS+160(a0)
    - EX ldc1 $f22, SC_FPREGS+176(a0)
    - EX ldc1 $f24, SC_FPREGS+192(a0)
    - EX ldc1 $f26, SC_FPREGS+208(a0)
    - EX ldc1 $f28, SC_FPREGS+224(a0)
    - EX ldc1 $f30, SC_FPREGS+240(a0)
    + 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
    diff --git a/arch/mips/kernel/signal-common.h b/arch/mips/kernel/signal-common.h
    index 06805e0..d594695 100644
    --- a/arch/mips/kernel/signal-common.h
    +++ b/arch/mips/kernel/signal-common.h
    @@ -36,4 +36,10 @@ extern int fpcsr_pending(unsigned int __user *fpcsr);
    #define unlock_fpu_owner() pagefault_enable()
    #endif

    +/* Assembly functions to move context to/from the FPU */
    +extern asmlinkage int
    +_save_fp_context(void __user *fpregs, void __user *csr);
    +extern asmlinkage int
    +_restore_fp_context(void __user *fpregs, void __user *csr);
    +
    #endif /* __SIGNAL_COMMON_H */
    diff --git a/arch/mips/kernel/signal.c b/arch/mips/kernel/signal.c
    index ddf8318..10f7dbc 100644
    --- a/arch/mips/kernel/signal.c
    +++ b/arch/mips/kernel/signal.c
    @@ -41,11 +41,8 @@

    #include "signal-common.h"

    -static int (*save_fp_context)(struct sigcontext __user *sc);
    -static int (*restore_fp_context)(struct sigcontext __user *sc);
    -
    -extern asmlinkage int _save_fp_context(struct sigcontext __user *sc);
    -extern asmlinkage int _restore_fp_context(struct sigcontext __user *sc);
    +static int (*save_fp_context)(void __user *sc);
    +static int (*restore_fp_context)(void __user *sc);

    struct sigframe {
    u32 sf_ass[4]; /* argument save space for o32 */
    @@ -65,41 +62,71 @@ struct rt_sigframe {
    * Thread saved context copy to/from a signal context presumed to be on the
    * user stack, and therefore accessed with appropriate macros from uaccess.h.
    */
    -static int copy_fp_to_sigcontext(struct sigcontext __user *sc)
    +static int copy_fp_to_sigcontext(void __user *sc)
    {
    + struct mips_abi *abi = current->thread.abi;
    + uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
    + uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
    int i;
    int err = 0;

    for (i = 0; i < NUM_FPU_REGS; i++) {
    err |=
    __put_user(get_fpr64(&current->thread.fpu.fpr[i], 0),
    - &sc->sc_fpregs[i]);
    + &fpregs[i]);
    }
    - err |= __put_user(current->thread.fpu.fcr31, &sc->sc_fpc_csr);
    + err |= __put_user(current->thread.fpu.fcr31, csr);

    return err;
    }

    -static int copy_fp_from_sigcontext(struct sigcontext __user *sc)
    +static int copy_fp_from_sigcontext(void __user *sc)
    {
    + struct mips_abi *abi = current->thread.abi;
    + uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
    + uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
    int i;
    int err = 0;
    u64 fpr_val;

    for (i = 0; i < NUM_FPU_REGS; i++) {
    - err |= __get_user(fpr_val, &sc->sc_fpregs[i]);
    + err |= __get_user(fpr_val, &fpregs[i]);
    set_fpr64(&current->thread.fpu.fpr[i], 0, fpr_val);
    }
    - err |= __get_user(current->thread.fpu.fcr31, &sc->sc_fpc_csr);
    + err |= __get_user(current->thread.fpu.fcr31, csr);

    return err;
    }

    /*
    + * Wrappers for the assembly _{save,restore}_fp_context functions.
    + */
    +static int save_hw_fp_context(void __user *sc)
    +{
    + struct mips_abi *abi = current->thread.abi;
    + uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
    + uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
    +
    + return _save_fp_context(fpregs, csr);
    +}
    +
    +static int restore_hw_fp_context(void __user *sc)
    +{
    + struct mips_abi *abi = current->thread.abi;
    + uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
    + uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
    +
    + return _restore_fp_context(fpregs, csr);
    +}
    +
    +/*
    * Helper routines
    */
    -static int protected_save_fp_context(struct sigcontext __user *sc)
    +static int protected_save_fp_context(void __user *sc)
    {
    + struct mips_abi *abi = current->thread.abi;
    + uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
    + uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
    int err;

    /*
    @@ -121,9 +148,9 @@ static int protected_save_fp_context(struct sigcontext __user *sc)
    if (likely(!err))
    break;
    /* touch the sigcontext and try again */
    - err = __put_user(0, &sc->sc_fpregs[0]) |
    - __put_user(0, &sc->sc_fpregs[31]) |
    - __put_user(0, &sc->sc_fpc_csr);
    + err = __put_user(0, &fpregs[0]) |
    + __put_user(0, &fpregs[31]) |
    + __put_user(0, csr);
    if (err)
    break; /* really bad sigcontext */
    }
    @@ -131,8 +158,11 @@ static int protected_save_fp_context(struct sigcontext __user *sc)
    return err;
    }

    -static int protected_restore_fp_context(struct sigcontext __user *sc)
    +static int protected_restore_fp_context(void __user *sc)
    {
    + struct mips_abi *abi = current->thread.abi;
    + uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
    + uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
    int err, tmp __maybe_unused;

    /*
    @@ -155,9 +185,9 @@ static int protected_restore_fp_context(struct sigcontext __user *sc)
    if (likely(!err))
    break;
    /* touch the sigcontext and try again */
    - err = __get_user(tmp, &sc->sc_fpregs[0]) |
    - __get_user(tmp, &sc->sc_fpregs[31]) |
    - __get_user(tmp, &sc->sc_fpc_csr);
    + err = __get_user(tmp, &fpregs[0]) |
    + __get_user(tmp, &fpregs[31]) |
    + __get_user(tmp, csr);
    if (err)
    break; /* really bad sigcontext */
    }
    @@ -225,11 +255,12 @@ int fpcsr_pending(unsigned int __user *fpcsr)
    }

    static int
    -check_and_restore_fp_context(struct sigcontext __user *sc)
    +check_and_restore_fp_context(void __user *sc)
    {
    + struct mips_abi *abi = current->thread.abi;
    int err, sig;

    - err = sig = fpcsr_pending(&sc->sc_fpc_csr);
    + err = sig = fpcsr_pending(sc + abi->off_sc_fpc_csr);
    if (err > 0)
    err = 0;
    err |= protected_restore_fp_context(sc);
    @@ -634,17 +665,17 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
    }

    #ifdef CONFIG_SMP
    -static int smp_save_fp_context(struct sigcontext __user *sc)
    +static int smp_save_fp_context(void __user *sc)
    {
    return raw_cpu_has_fpu
    - ? _save_fp_context(sc)
    + ? save_hw_fp_context(sc)
    : copy_fp_to_sigcontext(sc);
    }

    -static int smp_restore_fp_context(struct sigcontext __user *sc)
    +static int smp_restore_fp_context(void __user *sc)
    {
    return raw_cpu_has_fpu
    - ? _restore_fp_context(sc)
    + ? restore_hw_fp_context(sc)
    : copy_fp_from_sigcontext(sc);
    }
    #endif
    @@ -657,8 +688,8 @@ static int signal_setup(void)
    restore_fp_context = smp_restore_fp_context;
    #else
    if (cpu_has_fpu) {
    - save_fp_context = _save_fp_context;
    - restore_fp_context = _restore_fp_context;
    + save_fp_context = save_hw_fp_context;
    + restore_fp_context = restore_hw_fp_context;
    } else {
    save_fp_context = copy_fp_to_sigcontext;
    restore_fp_context = copy_fp_from_sigcontext;
    --
    2.4.4


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