Re: [Xen-devel] [PATCH 09/13] xen/arm: vtimer: Move emulate_sysreg* callback in a separate header

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Wed, 7 Dec 2016, Julien Grall wrote:
> The core emulation of sysreg (reading/writing registers) is not specific
> to the virtual timer. Move the helpers in a new header vreg.h.
> 
> Signed-off-by: Julien Grall <julien.grall@xxxxxxx>

Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>

> ---
> 
> The helpers will be necessary in a follow-up patch to emulate sysreg
> for another components.
> ---
>  xen/arch/arm/vtimer.c      | 53 ++++---------------------------------------
>  xen/include/asm-arm/vreg.h | 56 
> ++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 60 insertions(+), 49 deletions(-)
>  create mode 100644 xen/include/asm-arm/vreg.h
> 
> diff --git a/xen/arch/arm/vtimer.c b/xen/arch/arm/vtimer.c
> index 3fc97b3..091b5e7 100644
> --- a/xen/arch/arm/vtimer.c
> +++ b/xen/arch/arm/vtimer.c
> @@ -27,6 +27,7 @@
>  #include <asm/time.h>
>  #include <asm/gic.h>
>  #include <asm/vgic.h>
> +#include <asm/vreg.h>
>  #include <asm/regs.h>
>  
>  /*
> @@ -321,52 +322,6 @@ static bool vtimer_emulate_cp64(struct cpu_user_regs 
> *regs, union hsr hsr)
>  }
>  
>  #ifdef CONFIG_ARM_64
> -typedef bool (*vtimer_sysreg32_fn_t)(struct cpu_user_regs *regs, uint32_t *r,
> -                                     bool read);
> -typedef bool (*vtimer_sysreg64_fn_t)(struct cpu_user_regs *regs, uint64_t *r,
> -                                     bool read);
> -
> -static bool vtimer_emulate_sysreg32(struct cpu_user_regs *regs, union hsr 
> hsr,
> -                                    vtimer_sysreg32_fn_t fn)
> -{
> -    struct hsr_sysreg sysreg = hsr.sysreg;
> -    uint32_t r = 0;
> -    bool ret;
> -
> -    if ( !sysreg.read )
> -        r = get_user_reg(regs, sysreg.reg);
> -
> -    ret = fn(regs, &r, sysreg.read);
> -
> -    if ( ret && sysreg.read )
> -        set_user_reg(regs, sysreg.reg, r);
> -
> -    return ret;
> -}
> -
> -static bool vtimer_emulate_sysreg64(struct cpu_user_regs *regs, union hsr 
> hsr,
> -                                    vtimer_sysreg64_fn_t fn)
> -{
> -    struct hsr_sysreg sysreg = hsr.sysreg;
> -    /*
> -     * Initialize to zero to avoid leaking data if there is an
> -     * implementation error in the emulation (such as not correctly
> -     * setting x).
> -     */
> -    uint64_t x = 0;
> -    bool ret;
> -
> -    if ( !sysreg.read )
> -        x = get_user_reg(regs, sysreg.reg);
> -
> -    ret = fn(regs, &x, sysreg.read);
> -
> -    if ( ret && sysreg.read )
> -        set_user_reg(regs, sysreg.reg, x);
> -
> -    return ret;
> -}
> -
>  static bool vtimer_emulate_sysreg(struct cpu_user_regs *regs, union hsr hsr)
>  {
>      struct hsr_sysreg sysreg = hsr.sysreg;
> @@ -379,11 +334,11 @@ static bool vtimer_emulate_sysreg(struct cpu_user_regs 
> *regs, union hsr hsr)
>      switch ( hsr.bits & HSR_SYSREG_REGS_MASK )
>      {
>      case HSR_SYSREG_CNTP_CTL_EL0:
> -        return vtimer_emulate_sysreg32(regs, hsr, vtimer_cntp_ctl);
> +        return vreg_emulate_sysreg32(regs, hsr, vtimer_cntp_ctl);
>      case HSR_SYSREG_CNTP_TVAL_EL0:
> -        return vtimer_emulate_sysreg32(regs, hsr, vtimer_cntp_tval);
> +        return vreg_emulate_sysreg32(regs, hsr, vtimer_cntp_tval);
>      case HSR_SYSREG_CNTP_CVAL_EL0:
> -        return vtimer_emulate_sysreg64(regs, hsr, vtimer_cntp_cval);
> +        return vreg_emulate_sysreg64(regs, hsr, vtimer_cntp_cval);
>  
>      default:
>          return false;
> diff --git a/xen/include/asm-arm/vreg.h b/xen/include/asm-arm/vreg.h
> new file mode 100644
> index 0000000..2671f6e
> --- /dev/null
> +++ b/xen/include/asm-arm/vreg.h
> @@ -0,0 +1,56 @@
> +/*
> + * Helpers to emulate co-processor and system registers
> + */
> +#ifndef __ASM_ARM_VREG__
> +#define __ASM_ARM_VREG__
> +
> +#ifdef CONFIG_ARM_64
> +typedef bool (*vreg_sysreg32_fn_t)(struct cpu_user_regs *regs, uint32_t *r,
> +                                   bool read);
> +typedef bool (*vreg_sysreg64_fn_t)(struct cpu_user_regs *regs, uint64_t *r,
> +                                   bool read);
> +
> +static inline bool vreg_emulate_sysreg32(struct cpu_user_regs *regs, union 
> hsr hsr,
> +                                         vreg_sysreg32_fn_t fn)
> +{
> +    struct hsr_sysreg sysreg = hsr.sysreg;
> +    uint32_t r = 0;
> +    bool ret;
> +
> +    if ( !sysreg.read )
> +        r = get_user_reg(regs, sysreg.reg);
> +
> +    ret = fn(regs, &r, sysreg.read);
> +
> +    if ( ret && sysreg.read )
> +        set_user_reg(regs, sysreg.reg, r);
> +
> +    return ret;
> +}
> +
> +static inline bool vreg_emulate_sysreg64(struct cpu_user_regs *regs, union 
> hsr hsr,
> +                                         vreg_sysreg64_fn_t fn)
> +{
> +    struct hsr_sysreg sysreg = hsr.sysreg;
> +    /*
> +     * Initialize to zero to avoid leaking data if there is an
> +     * implementation error in the emulation (such as not correctly
> +     * setting x).
> +     */
> +    uint64_t x = 0;
> +    bool ret;
> +
> +    if ( !sysreg.read )
> +        x = get_user_reg(regs, sysreg.reg);
> +
> +    ret = fn(regs, &x, sysreg.read);
> +
> +    if ( ret && sysreg.read )
> +        set_user_reg(regs, sysreg.reg, x);
> +
> +    return ret;
> +}
> +
> +#endif
> +
> +#endif /* __ASM_ARM_VREG__ */
> -- 
> 1.9.1
> 

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