Re: [PATCH v8 24/40] x86/compressed/acpi: move EFI system table lookup to helper

[Borislav Petkov]

On Fri, Dec 10, 2021 at 09:43:16AM -0600, Brijesh Singh wrote:
> +int efi_get_system_table(struct boot_params *boot_params, unsigned long *sys_tbl_pa,
> +			 bool *is_efi_64)

Nah, that's doing two things in one function.

The signature should be a lot simpler:

unsigned long efi_get_system_table(struct boot_params *bp)

returns 0 on failure, non-null on success and then it returns the
physical address of the system table.

> +{
> +	unsigned long sys_tbl;
> +	struct efi_info *ei;
> +	bool efi_64;
> +	char *sig;
> +
> +	if (!sys_tbl_pa || !is_efi_64)
> +		return -EINVAL;
> +

This...

> +	ei = &boot_params->efi_info;
> +	sig = (char *)&ei->efi_loader_signature;
> +
> +	if (!strncmp(sig, EFI64_LOADER_SIGNATURE, 4)) {
> +		efi_64 = true;
> +	} else if (!strncmp(sig, EFI32_LOADER_SIGNATURE, 4)) {
> +		efi_64 = false;
> +	} else {
> +		debug_putstr("Wrong EFI loader signature.\n");
> +		return -EOPNOTSUPP;
> +	}

... up to here needs to be another function:

enum get_efi_type(sig)

where enum is { EFI64, EFI32, INVALID } or so.

And you call this function at the call sites:

	if (efi_get_type(sig) == INVALID)
		error...

	sys_tbl_pa = efi_get_system_table(bp);
	if (!sys_tbl_pa)
		error...


Completely pseudo but you get the idea.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette