Re: [PATCH v2 04/13] KVM: arm64: Refactor sys_regs.h, c for nVHE reuse

[Will Deacon <will@kernel.org>]

On Tue, Jun 15, 2021 at 02:39:41PM +0100, Fuad Tabba wrote:
> Refactor sys_regs.h and sys_regs.c to make it easier to reuse
> common code. It will be used in nVHE in a later patch.
> 
> No functional change intended.
> 
> Signed-off-by: Fuad Tabba <tabba@google.com>
> ---
>  arch/arm64/kvm/sys_regs.c | 30 +-----------------------------
>  arch/arm64/kvm/sys_regs.h | 35 +++++++++++++++++++++++++++++++++++
>  2 files changed, 36 insertions(+), 29 deletions(-)

[...]

> diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h
> index 9d0621417c2a..b8e2a4dd830f 100644
> --- a/arch/arm64/kvm/sys_regs.h
> +++ b/arch/arm64/kvm/sys_regs.h
> @@ -11,6 +11,12 @@
>  #ifndef __ARM64_KVM_SYS_REGS_LOCAL_H__
>  #define __ARM64_KVM_SYS_REGS_LOCAL_H__
>  
> +#include <linux/bsearch.h>
> +
> +#define reg_to_encoding(x)						\
> +	sys_reg((u32)(x)->Op0, (u32)(x)->Op1,				\
> +		(u32)(x)->CRn, (u32)(x)->CRm, (u32)(x)->Op2)
> +
>  struct sys_reg_params {
>  	u8	Op0;
>  	u8	Op1;
> @@ -21,6 +27,14 @@ struct sys_reg_params {
>  	bool	is_write;
>  };
>  
> +#define esr_sys64_to_params(esr)                                               \
> +	((struct sys_reg_params){ .Op0 = ((esr) >> 20) & 3,                    \
> +				  .Op1 = ((esr) >> 14) & 0x7,                  \
> +				  .CRn = ((esr) >> 10) & 0xf,                  \
> +				  .CRm = ((esr) >> 1) & 0xf,                   \
> +				  .Op2 = ((esr) >> 17) & 0x7,                  \
> +				  .is_write = !((esr)&1) })

Formatting has gone funny here (need spaces around the '&' in that last
entry).

> +
>  struct sys_reg_desc {
>  	/* Sysreg string for debug */
>  	const char *name;
> @@ -152,6 +166,24 @@ static inline int cmp_sys_reg(const struct sys_reg_desc *i1,
>  	return i1->Op2 - i2->Op2;
>  }
>  
> +static inline int match_sys_reg(const void *key, const void *elt)
> +{
> +	const unsigned long pval = (unsigned long)key;
> +	const struct sys_reg_desc *r = elt;
> +
> +	return pval - reg_to_encoding(r);
> +}
> +
> +static inline const struct sys_reg_desc *
> +find_reg(const struct sys_reg_params *params, const struct sys_reg_desc table[],
> +	 unsigned int num)
> +{
> +	unsigned long pval = reg_to_encoding(params);
> +
> +	return __inline_bsearch((void *)pval, table, num, sizeof(table[0]),
> +				match_sys_reg);

You don't mention why you change bsearch() to __inline_bsearch().

Will

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