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From: Tzung-Bi Shih <tzungbi@kernel.org>
To: Hsin-Te Yuan <yuanhsinte@chromium.org>
Cc: Brian Norris <briannorris@chromium.org>,
	Julius Werner <jwerner@chromium.org>,
	chrome-platform@lists.linux.dev, linux-kernel@vger.kernel.org,
	Yidi Lin <yidilin@google.com>
Subject: Re: [PATCH] firmware: google: coreboot_table: skip no-map CBMEM entries
Date: Thu, 16 Jul 2026 07:44:09 +0000	[thread overview]
Message-ID: <aliLyZOubSa6ARfS@google.com> (raw)
In-Reply-To: <20260714-coreboot-v1-1-f59754d71b55@chromium.org>

On Tue, Jul 14, 2026 at 09:19:18AM +0000, Hsin-Te Yuan wrote:
> @@ -147,6 +149,23 @@ static int coreboot_table_populate(struct device *dev, void *ptr, resource_size_
>  
>  		switch (device->entry.tag) {
>  		case LB_TAG_CBMEM_ENTRY:
> +			/*
> +			 * Skip entries that are not exclusively System RAM or
> +			 * Reserved memory.
> +			 * On ARM, no-map reserved regions are not System RAM.
> +			 * On x86, CBMEM often resides in IORES_DESC_RESERVED regions.
> +			 */
> +			if (region_intersects(device->cbmem_entry.address,
> +					      device->cbmem_entry.entry_size,
> +					      IORESOURCE_SYSTEM_RAM,
> +					      IORES_DESC_NONE) != REGION_INTERSECTS &&
> +			    region_intersects(device->cbmem_entry.address,
> +					      device->cbmem_entry.entry_size,
> +					      IORESOURCE_MEM,
> +					      IORES_DESC_RESERVED) != REGION_INTERSECTS) {

Per comments of region_intersects():
    Note that REGION_INTERSECTS is also returned in the case when the
    specified region overlaps RAM and undefined memory holes.

Won't the check falsely be bypassed if the region overlaps SYSTEM_RAM
and `no-map` memory?

      reply	other threads:[~2026-07-16  7:44 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-14  9:19 [PATCH] firmware: google: coreboot_table: skip no-map CBMEM entries Hsin-Te Yuan
2026-07-16  7:44 ` Tzung-Bi Shih [this message]

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