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From:   Ard Biesheuvel <ardb@kernel.org>
To:     linux-efi@vger.kernel.org
Cc:     keescook@chromium.org, Ard Biesheuvel <ardb@kernel.org>,
        Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        Arend van Spriel <aspriel@gmail.com>,
        Franky Lin <franky.lin@broadcom.com>,
        Hante Meuleman <hante.meuleman@broadcom.com>,
        Kalle Valo <kvalo@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Gregory Greenman <gregory.greenman@intel.com>,
        linux-input@vger.kernel.org, linux-wireless@vger.kernel.org,
        brcm80211-dev-list.pdl@broadcom.com
Subject: [PATCH 4/4] brcmfmac: Switch to appropriate helper to load EFI variable contents
Date:   Fri, 17 Jun 2022 19:48:51 +0200
Message-Id: <20220617174851.1286026-5-ardb@kernel.org>
In-Reply-To: <20220617174851.1286026-1-ardb@kernel.org>
References: <20220617174851.1286026-1-ardb@kernel.org>
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Avoid abusing the efivar layer by invoking it with locally constructed
efivar_entry instances, and instead, just call the EFI routines directly
if available.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c | 25 +++++++-------------
 1 file changed, 8 insertions(+), 17 deletions(-)

diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c
index dcbe55b56e43..b8379e4034a4 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c
@@ -459,43 +459,34 @@ static void brcmf_fw_fix_efi_nvram_ccode(char *data, unsigned long data_len)
 
 static u8 *brcmf_fw_nvram_from_efi(size_t *data_len_ret)
 {
-	const u16 name[] = { 'n', 'v', 'r', 'a', 'm', 0 };
-	struct efivar_entry *nvram_efivar;
+	efi_guid_t guid = EFI_GUID(0x74b00bd9, 0x805a, 0x4d61, 0xb5, 0x1f,
+				   0x43, 0x26, 0x81, 0x23, 0xd1, 0x13);
 	unsigned long data_len = 0;
+	efi_status_t status;
 	u8 *data = NULL;
-	int err;
 
-	nvram_efivar = kzalloc(sizeof(*nvram_efivar), GFP_KERNEL);
-	if (!nvram_efivar)
+	if (!efi_rt_services_supported(EFI_RT_SUPPORTED_GET_VARIABLE))
 		return NULL;
 
-	memcpy(&nvram_efivar->var.VariableName, name, sizeof(name));
-	nvram_efivar->var.VendorGuid = EFI_GUID(0x74b00bd9, 0x805a, 0x4d61,
-						0xb5, 0x1f, 0x43, 0x26,
-						0x81, 0x23, 0xd1, 0x13);
-
-	err = efivar_entry_size(nvram_efivar, &data_len);
-	if (err)
+	status = efi.get_variable(L"nvram", &guid, NULL, &data_len, NULL);
+	if (status != EFI_BUFFER_TOO_SMALL)
 		goto fail;
 
 	data = kmalloc(data_len, GFP_KERNEL);
 	if (!data)
 		goto fail;
 
-	err = efivar_entry_get(nvram_efivar, NULL, &data_len, data);
-	if (err)
+	status = efi.get_variable(L"nvram", &guid, NULL, &data_len, data);
+	if (status != EFI_SUCCESS)
 		goto fail;
 
 	brcmf_fw_fix_efi_nvram_ccode(data, data_len);
 	brcmf_info("Using nvram EFI variable\n");
 
-	kfree(nvram_efivar);
 	*data_len_ret = data_len;
 	return data;
-
 fail:
 	kfree(data);
-	kfree(nvram_efivar);
 	return NULL;
 }
 #else
-- 
2.35.1