linux-kernel - [PATCH v2 2/2] efi/fdt: ignore dtb when acpi option is used with force

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Message-Id: <20241125170758.518943-3-yeoreum.yun@arm.com>
Date: Mon, 25 Nov 2024 17:07:58 +0000
From: Yeoreum Yun <yeoreum.yun@....com>
To: ardb@...nel.org,
	broonie@...nel.org,
	sami.mujawar@....com,
	sudeep.holla@....com,
	pierre.gondois@....com,
	hagarhem@...zon.com,
	catalin.marinas@....com,
	will@...nel.org,
	guohanjun@...wei.com,
	Jonathan.Cameron@...wei.com
Cc: linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	linux-efi@...r.kernel.org,
	Yeoreum Yun <yeoreum.yun@....com>
Subject: [PATCH v2 2/2] efi/fdt: ignore dtb when acpi option is used with force

Since acpi=force doesn't use dt fallback, it's meaningless to load dt
from comaand line option or from configuration table.
Skip loading dt when acpi=force option is used.
otherwise it could produce unnecessary error message
while scanning dt if passed dt's format is invalid.

Signed-off-by: Yeoreum Yun <yeoreum.yun@....com>
---
 drivers/firmware/efi/libstub/fdt.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/firmware/efi/libstub/fdt.c b/drivers/firmware/efi/libstub/fdt.c
index 6a337f1f8787..27291ef7c773 100644
--- a/drivers/firmware/efi/libstub/fdt.c
+++ b/drivers/firmware/efi/libstub/fdt.c
@@ -231,6 +231,8 @@ efi_status_t allocate_new_fdt_and_exit_boot(void *handle,
 	struct exit_boot_struct priv;
 	unsigned long fdt_addr = 0;
 	unsigned long fdt_size = 0;
+	bool acpi_force = false;
+

 	if (!efi_novamap) {
 		status = efi_alloc_virtmap(&priv.runtime_map, &desc_size,
@@ -241,13 +243,17 @@ efi_status_t allocate_new_fdt_and_exit_boot(void *handle,
 		}
 	}

+	if (strstr(cmdline_ptr, "acpi=force"))
+		acpi_force = true;
+
 	/*
 	 * Unauthenticated device tree data is a security hazard, so ignore
 	 * 'dtb=' unless UEFI Secure Boot is disabled.  We assume that secure
 	 * boot is enabled if we can't determine its state.
 	 */
 	if (!IS_ENABLED(CONFIG_EFI_ARMSTUB_DTB_LOADER) ||
-	    efi_get_secureboot() != efi_secureboot_mode_disabled) {
+	    efi_get_secureboot() != efi_secureboot_mode_disabled ||
+			acpi_force) {
 		if (strstr(cmdline_ptr, "dtb="))
 			efi_err("Ignoring DTB from command line.\n");
 	} else {
@@ -261,7 +267,7 @@ efi_status_t allocate_new_fdt_and_exit_boot(void *handle,

 	if (fdt_addr) {
 		efi_info("Using DTB from command line\n");
-	} else {
+	} else if (!acpi_force) {
 		/* Look for a device tree configuration table entry. */
 		fdt_addr = (uintptr_t)get_fdt(&fdt_size);
 		if (fdt_addr)
--
LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}