linux-kernel - Re: [PATCH] arm64: move efi

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Date:   Mon, 17 Jan 2022 13:44:41 +0100
From:   Alexander Sverdlin <alexander.sverdlin@...ia.com>
To:     Krzysztof Adamski <krzysztof.adamski@...ia.com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Peter Collingbourne <pcc@...gle.com>,
        Guenter Roeck <linux@...ck-us.net>,
        Wolfram Sang <wsa+renesas@...g-engineering.com>
Cc:     Matija Glavinic-Pecotic <matija.glavinic-pecotic.ext@...ia.com>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] arm64: move efi_reboot to restart handler

Hi!

On 17/01/2022 13:31, Krzysztof Adamski wrote:
> On EFI enabled arm64 systems, efi_reboot was called before
> do_kernel_restart, completely omitting the reset_handlers functionality.
> By registering efi_reboot as part of the chain with slightly elevated
> priority, we make it run before the default handler but still allow
> plugging in other handlers.
> Thanks to that, things like gpio_restart, restart handlers in
> watchdog_core, mmc or mtds are working on those platforms.
> 
> The priority 129 should be high enough as we will likely be the first
> one to register on this prio so we will be called before others, like
> PSCI handler.
> 
> Signed-off-by: Krzysztof Adamski <krzysztof.adamski@...ia.com>

Reviewed-by: Alexander Sverdlin <alexander.sverdlin@...ia.com>

> ---
>  arch/arm64/kernel/process.c |  7 -------
>  arch/arm64/kernel/setup.c   | 21 +++++++++++++++++++++
>  2 files changed, 21 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
> index 5369e649fa79..b86ef77bb0c8 100644
> --- a/arch/arm64/kernel/process.c
> +++ b/arch/arm64/kernel/process.c
> @@ -130,13 +130,6 @@ void machine_restart(char *cmd)
>  	local_irq_disable();
>  	smp_send_stop();
>  
> -	/*
> -	 * UpdateCapsule() depends on the system being reset via
> -	 * ResetSystem().
> -	 */
> -	if (efi_enabled(EFI_RUNTIME_SERVICES))
> -		efi_reboot(reboot_mode, NULL);
> -
>  	/* Now call the architecture specific reboot code. */
>  	do_kernel_restart(cmd);
>  
> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
> index f70573928f1b..5fa95980ba73 100644
> --- a/arch/arm64/kernel/setup.c
> +++ b/arch/arm64/kernel/setup.c
> @@ -12,6 +12,7 @@
>  #include <linux/stddef.h>
>  #include <linux/ioport.h>
>  #include <linux/delay.h>
> +#include <linux/reboot.h>
>  #include <linux/initrd.h>
>  #include <linux/console.h>
>  #include <linux/cache.h>
> @@ -298,6 +299,24 @@ u64 cpu_logical_map(unsigned int cpu)
>  	return __cpu_logical_map[cpu];
>  }
>  
> +static int efi_restart(struct notifier_block *nb, unsigned long action,
> +		       void *data)
> +{
> +	/*
> +	 * UpdateCapsule() depends on the system being reset via
> +	 * ResetSystem().
> +	 */
> +	if (efi_enabled(EFI_RUNTIME_SERVICES))
> +		efi_reboot(reboot_mode, NULL);
> +
> +	return NOTIFY_DONE;
> +}
> +
> +static struct notifier_block efi_restart_nb = {
> +	.notifier_call = efi_restart,
> +	.priority = 129,
> +};
> +
>  void __init __no_sanitize_address setup_arch(char **cmdline_p)
>  {
>  	setup_initial_init_mm(_stext, _etext, _edata, _end);
> @@ -346,6 +365,8 @@ void __init __no_sanitize_address setup_arch(char **cmdline_p)
>  
>  	paging_init();
>  
> +	register_restart_handler(&efi_restart_nb);
> +
>  	acpi_table_upgrade();
>  
>  	/* Parse the ACPI tables for possible boot-time configuration */

-- 
Best regards,
Alexander Sverdlin.