linux-kernel - Re: [PATCH v5 7/8] arm64/efi: remove free_boot

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Date:	Fri, 9 Jan 2015 15:49:24 +0000
From:	Will Deacon <will.deacon@....com>
To:	Ard Biesheuvel <ard.biesheuvel@...aro.org>
Cc:	"leif.lindholm@...aro.org" <leif.lindholm@...aro.org>,
	"roy.franz@...aro.org" <roy.franz@...aro.org>,
	"matt.fleming@...el.com" <matt.fleming@...el.com>,
	Catalin Marinas <Catalin.Marinas@....com>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"linux-efi@...r.kernel.org" <linux-efi@...r.kernel.org>,
	"bp@...en8.de" <bp@...en8.de>,
	"msalter@...hat.com" <msalter@...hat.com>,
	"geoff.levand@...aro.org" <geoff.levand@...aro.org>,
	"dyoung@...hat.com" <dyoung@...hat.com>,
	Mark Rutland <Mark.Rutland@....com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v5 7/8] arm64/efi: remove free_boot_services() and friends

On Thu, Jan 08, 2015 at 06:48:33PM +0000, Ard Biesheuvel wrote:
> Now that we are calling SetVirtualAddressMap() from the stub, there is no
> need to reserve boot-only memory regions, which implies that there is also
> no reason to free them again later.
> 
> Acked-by: Leif Lindholm <leif.lindholm@...aro.org>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@...aro.org>
> ---
>  arch/arm64/kernel/efi.c | 123 +-----------------------------------------------
>  1 file changed, 1 insertion(+), 122 deletions(-)

[...]

> -static void __init free_boot_services(void)
> -{
> -	u64 total_freed = 0;
> -	u64 keep_end, free_start, free_end;
> -	efi_memory_desc_t *md;
> -
> -	/*
> -	 * If kernel uses larger pages than UEFI, we have to be careful
> -	 * not to inadvertantly free memory we want to keep if there is
> -	 * overlap at the kernel page size alignment. We do not want to
> -	 * free is_reserve_region() memory nor the UEFI memmap itself.
> -	 *
> -	 * The memory map is sorted, so we keep track of the end of
> -	 * any previous region we want to keep, remember any region
> -	 * we want to free and defer freeing it until we encounter
> -	 * the next region we want to keep. This way, before freeing
> -	 * it, we can clip it as needed to avoid freeing memory we
> -	 * want to keep for UEFI.
> -	 */
> -
> -	keep_end = 0;
> -	free_start = 0;
> -
> -	for_each_efi_memory_desc(&memmap, md) {
> -		u64 paddr, npages, size;

I'm glad to see the back of this function, thanks.

Acked-by: Will Deacon <will.deacon@....com>

Will
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