linux-kernel - Re: [PATCH v14 3/5] x86/boot: Introduce bios_get_rsdp

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Message-ID: <20181217173837.GC90818@gmail.com>
Date:   Mon, 17 Dec 2018 18:38:37 +0100
From:   Ingo Molnar <mingo@...nel.org>
To:     Chao Fan <fanc.fnst@...fujitsu.com>
Cc:     linux-kernel@...r.kernel.org, x86@...nel.org, bp@...en8.de,
        tglx@...utronix.de, mingo@...hat.com, hpa@...or.com,
        keescook@...omium.org, bhe@...hat.com, msys.mizuma@...il.com,
        indou.takao@...fujitsu.com, caoj.fnst@...fujitsu.com
Subject: Re: [PATCH v14 3/5] x86/boot: Introduce bios_get_rsdp_addr() to
 search RSDP in memory


* Chao Fan <fanc.fnst@...fujitsu.com> wrote:

> +		/* Check the standard checksum */
> +		if (compute_checksum((u8 *) rsdp, ACPI_RSDP_CHECKSUM_LENGTH))
> +			continue;

Could you please run your patches through checkpatch, does it not 
complain about this line?

> +/* Search RSDP address, based on acpi_find_root_pointer(). */
> +static acpi_physical_address bios_get_rsdp_addr(void)
> +{
> +	u8 *table_ptr;
> +	u32 address;
> +	u8 *rsdp;
> +
> +	/* Get the location of the Extended BIOS Data Area (EBDA) */
> +	table_ptr = (u8 *)ACPI_EBDA_PTR_LOCATION;
> +	*(u32 *)(void *)&address = *(u16 *)(void *)table_ptr;

what? So you take the address of 'u32 address', which turns it into an 
u32 * - then you cast it to void *, then back to u32 * and then deference 
it???

Thanks,

	Ingo