Re: [boot-wrapper PATCH 08/12] Consistently use logical CPU IDs

From: Andre Przywara <andre.przywara@arm.com>
To: Mark Rutland <mark.rutland@arm.com>
Cc: linux-arm-kernel@lists.infradead.org, Jaxson.Han@arm.com,
	Wei.Chen@arm.com
Subject: Re: [boot-wrapper PATCH 08/12] Consistently use logical CPU IDs
Date: Fri, 30 Jul 2021 18:38:30 +0100	[thread overview]
Message-ID: <20210730183830.3fcf59e8@slackpad.fritz.box> (raw)
In-Reply-To: <20210729152050.23635-9-mark.rutland@arm.com>

On Thu, 29 Jul 2021 16:20:46 +0100
Mark Rutland <mark.rutland@arm.com> wrote:

> In some places we assume that the cpu with MPIDR_EL1.Aff* == 0 is the
> same as logical CPU 0. While this is almost certainly true, it would be
> best to consistently use the ligical ID.

                               logical

Indeed, and I think can we can configure the model to have the primary
CPU with an MPIDR != 0.

> 
> Add a new `this_cpu_logical_id()` helper, and use this in preference to
> checking the MPIDR_EL1.Aff* bits directly.
> 
> Signed-off-by: Mark Rutland <mark.rutland@arm.com>

Reviewed-by: Andre Przywara <andre.przywara@arm.com>

Cheers,
Andre

> ---
>  gic-v3.c      | 4 +---
>  gic.c         | 3 +--
>  include/cpu.h | 2 ++
>  psci.c        | 5 ++---
>  4 files changed, 6 insertions(+), 8 deletions(-)
> 
> diff --git a/gic-v3.c b/gic-v3.c
> index ae2d2bc..62f9676 100644
> --- a/gic-v3.c
> +++ b/gic-v3.c
> @@ -101,8 +101,6 @@ void gic_secure_init_primary(void)
>  
>  void gic_secure_init(void)
>  {
> -	uint32_t cpu = read_mpidr();
> -
>  	uint32_t sre;
>  
>  	/*
> @@ -113,7 +111,7 @@ void gic_secure_init(void)
>  	if (!has_gicv3_sysreg())
>  		return;
>  
> -	if (cpu == 0)
> +	if (this_cpu_logical_id() == 0)
>  		gic_secure_init_primary();
>  
>  	sre = gic_read_icc_sre();
> diff --git a/gic.c b/gic.c
> index a84779e..04d4289 100644
> --- a/gic.c
> +++ b/gic.c
> @@ -31,14 +31,13 @@ void gic_secure_init(void)
>  {
>  	unsigned int i;
>  
> -	uint32_t cpu = read_mpidr();
>  	void *gicd_base = (void *)GIC_DIST_BASE;
>  	void *gicc_base = (void *)GIC_CPU_BASE;
>  
>  	/* Set local interrupts to Group 1 (those fields are banked) */
>  	raw_writel(~0, gicd_base + GICD_IGROUPRn);
>  
> -	if (cpu == 0) {
> +	if (this_cpu_logical_id() == 0) {
>  		uint32_t typer = raw_readl(gicd_base + GICD_TYPER);
>  
>  		/* Set SPIs to Group 1 */
> diff --git a/include/cpu.h b/include/cpu.h
> index 704d6d8..4bfb172 100644
> --- a/include/cpu.h
> +++ b/include/cpu.h
> @@ -25,5 +25,7 @@
>  
>  unsigned int find_logical_id(unsigned long mpidr);
>  
> +#define this_cpu_logical_id()	find_logical_id(read_mpidr())
> +
>  #endif /* !__ASSEMBLY__ */
>  #endif
> diff --git a/psci.c b/psci.c
> index e5d54b7..df5b0f2 100644
> --- a/psci.c
> +++ b/psci.c
> @@ -35,7 +35,7 @@ static int psci_cpu_on(unsigned long target_mpidr, unsigned long address)
>  {
>  	int ret;
>  	unsigned int cpu = find_logical_id(target_mpidr);
> -	unsigned int this_cpu = find_logical_id(read_mpidr());
> +	unsigned int this_cpu = this_cpu_logical_id();
>  
>  	if (cpu == MPIDR_INVALID)
>  		return PSCI_RET_INVALID_PARAMETERS;
> @@ -49,8 +49,7 @@ static int psci_cpu_on(unsigned long target_mpidr, unsigned long address)
>  
>  static int psci_cpu_off(void)
>  {
> -	unsigned long mpidr = read_mpidr();
> -	unsigned int cpu = find_logical_id(mpidr);
> +	unsigned int cpu = this_cpu_logical_id();
>  
>  	if (cpu == MPIDR_INVALID)
>  		return PSCI_RET_DENIED;

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