wifi: iwlwifi: fw: don't use constant size with efi.get_variable

Use efi.get_variable() with NULL pointer for data in order to
obtain entry size and then call it again with the correct size
to get the entry itself.

Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230606103519.ef95a8055a50.Iae5389baaf0a9a3c89469f7502275ee119d378b6@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/drivers/net/wireless/intel/iwlwifi/fw/uefi.c b/drivers/net/wireless/intel/iwlwifi/fw/uefi.c
index 1666ef3a482efb40f23e1eb828dd46e07574a3bf..488b9fb797438a2f9613f8ecae1ff3a121131ae7 100644 (file)
--- a/drivers/net/wireless/intel/iwlwifi/fw/uefi.c
+++ b/drivers/net/wireless/intel/iwlwifi/fw/uefi.c
@@ -17,38 +17,53 @@
                                  0xb2, 0xec, 0xf5, 0xa3,       \
                                  0x59, 0x4f, 0x4a, 0xea)
 
-void *iwl_uefi_get_pnvm(struct iwl_trans *trans, size_t *len)
+static void *iwl_uefi_get_variable(efi_char16_t *name, efi_guid_t *guid,
+                                  unsigned long *data_size)
 {
-       void *data;
-       unsigned long package_size;
        efi_status_t status;
+       void *data;
 
-       *len = 0;
+       if (!data_size)
+               return ERR_PTR(-EINVAL);
 
        if (!efi_rt_services_supported(EFI_RT_SUPPORTED_GET_VARIABLE))
                return ERR_PTR(-ENODEV);
 
-       /*
-        * TODO: we hardcode a maximum length here, because reading
-        * from the UEFI is not working.  To implement this properly,
-        * we have to call efivar_entry_size().
-        */
-       package_size = IWL_HARDCODED_PNVM_SIZE;
+       /* first call with NULL data to get the exact entry size */
+       *data_size = 0;
+       status = efi.get_variable(name, guid, NULL, data_size, NULL);
+       if (status != EFI_BUFFER_TOO_SMALL || !*data_size)
+               return ERR_PTR(-EIO);
 
-       data = kmalloc(package_size, GFP_KERNEL);
+       data = kmalloc(*data_size, GFP_KERNEL);
        if (!data)
                return ERR_PTR(-ENOMEM);
 
-       status = efi.get_variable(IWL_UEFI_OEM_PNVM_NAME, &IWL_EFI_VAR_GUID,
-                                 NULL, &package_size, data);
+       status = efi.get_variable(name, guid, NULL, data_size, data);
        if (status != EFI_SUCCESS) {
-               IWL_DEBUG_FW(trans,
-                            "PNVM UEFI variable not found 0x%lx (len %lu)\n",
-                            status, package_size);
                kfree(data);
                return ERR_PTR(-ENOENT);
        }
 
+       return data;
+}
+
+void *iwl_uefi_get_pnvm(struct iwl_trans *trans, size_t *len)
+{
+       unsigned long package_size;
+       void *data;
+
+       *len = 0;
+
+       data = iwl_uefi_get_variable(IWL_UEFI_OEM_PNVM_NAME, &IWL_EFI_VAR_GUID,
+                                    &package_size);
+       if (IS_ERR(data)) {
+               IWL_DEBUG_FW(trans,
+                            "PNVM UEFI variable not found 0x%lx (len %lu)\n",
+                            PTR_ERR(data), package_size);
+               return data;
+       }
+
        IWL_DEBUG_FW(trans, "Read PNVM from UEFI with size %lu\n", package_size);
        *len = package_size;
 
@@ -185,31 +200,24 @@ u8 *iwl_uefi_get_reduced_power(struct iwl_trans *trans, size_t *len)
 {
        struct pnvm_sku_package *package;
        unsigned long package_size;
-       efi_status_t status;
        u8 *data;
 
-       if (!efi_rt_services_supported(EFI_RT_SUPPORTED_GET_VARIABLE))
-               return ERR_PTR(-ENODEV);
-
-       /*
-        * TODO: we hardcode a maximum length here, because reading
-        * from the UEFI is not working.  To implement this properly,
-        * we have to call efivar_entry_size().
-        */
-       package_size = IWL_HARDCODED_REDUCE_POWER_SIZE;
+       package = iwl_uefi_get_variable(IWL_UEFI_REDUCED_POWER_NAME,
+                                       &IWL_EFI_VAR_GUID, &package_size);
 
-       package = kmalloc(package_size, GFP_KERNEL);
-       if (!package)
-               return ERR_PTR(-ENOMEM);
-
-       status = efi.get_variable(IWL_UEFI_REDUCED_POWER_NAME, &IWL_EFI_VAR_GUID,
-                                 NULL, &package_size, package);
-       if (status != EFI_SUCCESS) {
+       if (IS_ERR(package)) {
                IWL_DEBUG_FW(trans,
                             "Reduced Power UEFI variable not found 0x%lx (len %lu)\n",
-                            status, package_size);
+                            PTR_ERR(package), package_size);
+               return ERR_CAST(package);
+       }
+
+       if (package_size < sizeof(*package)) {
+               IWL_DEBUG_FW(trans,
+                            "Invalid Reduced Power UEFI variable len (%lu)\n",
+                            package_size);
                kfree(package);
-               return ERR_PTR(-ENOENT);
+               return ERR_PTR(-EINVAL);
        }
 
        IWL_DEBUG_FW(trans, "Read reduced power from UEFI with size %lu\n",
@@ -220,8 +228,11 @@ u8 *iwl_uefi_get_reduced_power(struct iwl_trans *trans, size_t *len)
 
        *len = package_size - sizeof(*package);
        data = kmemdup(package->data, *len, GFP_KERNEL);
-       if (!data)
+       if (!data) {
+               kfree(package);
                return ERR_PTR(-ENOMEM);
+       }
+
        kfree(package);
 
        return data;
@@ -245,31 +256,27 @@ void iwl_uefi_get_step_table(struct iwl_trans *trans)
 {
        struct uefi_cnv_common_step_data *data;
        unsigned long package_size;
-       efi_status_t status;
        int ret;
 
        if (trans->trans_cfg->device_family < IWL_DEVICE_FAMILY_AX210)
                return;
 
-       if (!efi_rt_services_supported(EFI_RT_SUPPORTED_GET_VARIABLE))
-               return;
+       data = iwl_uefi_get_variable(IWL_UEFI_STEP_NAME, &IWL_EFI_VAR_GUID,
+                                    &package_size);
 
-       /* TODO: we hardcode a maximum length here, because reading
-        * from the UEFI is not working.  To implement this properly,
-        * we have to call efivar_entry_size().
-        */
-       package_size = IWL_HARDCODED_STEP_SIZE;
-
-       data = kmalloc(package_size, GFP_KERNEL);
-       if (!data)
+       if (IS_ERR(data)) {
+               IWL_DEBUG_FW(trans,
+                            "STEP UEFI variable not found 0x%lx\n",
+                            PTR_ERR(data));
                return;
+       }
 
-       status = efi.get_variable(IWL_UEFI_STEP_NAME, &IWL_EFI_VAR_GUID,
-                                 NULL, &package_size, data);
-       if (status != EFI_SUCCESS) {
+       if (package_size < sizeof(*data)) {
                IWL_DEBUG_FW(trans,
-                            "STEP UEFI variable not found 0x%lx\n", status);
-               goto out_free;
+                            "Invalid STEP table UEFI variable len (%lu)\n",
+                            package_size);
+               kfree(data);
+               return;
        }
 
        IWL_DEBUG_FW(trans, "Read STEP from UEFI with size %lu\n",
@@ -279,7 +286,6 @@ void iwl_uefi_get_step_table(struct iwl_trans *trans)
        if (ret < 0)
                IWL_DEBUG_FW(trans, "Cannot read STEP tables. rev is invalid\n");
 
-out_free:
        kfree(data);
 }
 IWL_EXPORT_SYMBOL(iwl_uefi_get_step_table);
@@ -322,29 +328,26 @@ void iwl_uefi_get_sgom_table(struct iwl_trans *trans,
 {
        struct uefi_cnv_wlan_sgom_data *data;
        unsigned long package_size;
-       efi_status_t status;
        int ret;
 
-       if (!fwrt->geo_enabled ||
-           !efi_rt_services_supported(EFI_RT_SUPPORTED_GET_VARIABLE))
+       if (!fwrt->geo_enabled)
                return;
 
-       /* TODO: we hardcode a maximum length here, because reading
-        * from the UEFI is not working.  To implement this properly,
-        * we have to call efivar_entry_size().
-        */
-       package_size = IWL_HARDCODED_SGOM_SIZE;
-
-       data = kmalloc(package_size, GFP_KERNEL);
-       if (!data)
+       data = iwl_uefi_get_variable(IWL_UEFI_SGOM_NAME, &IWL_EFI_VAR_GUID,
+                                    &package_size);
+       if (IS_ERR(data)) {
+               IWL_DEBUG_FW(trans,
+                            "SGOM UEFI variable not found 0x%lx\n",
+                            PTR_ERR(data));
                return;
+       }
 
-       status = efi.get_variable(IWL_UEFI_SGOM_NAME, &IWL_EFI_VAR_GUID,
-                                 NULL, &package_size, data);
-       if (status != EFI_SUCCESS) {
+       if (package_size < sizeof(*data)) {
                IWL_DEBUG_FW(trans,
-                            "SGOM UEFI variable not found 0x%lx\n", status);
-               goto out_free;
+                            "Invalid SGOM table UEFI variable len (%lu)\n",
+                            package_size);
+               kfree(data);
+               return;
        }
 
        IWL_DEBUG_FW(trans, "Read SGOM from UEFI with size %lu\n",
@@ -354,9 +357,7 @@ void iwl_uefi_get_sgom_table(struct iwl_trans *trans,
        if (ret < 0)
                IWL_DEBUG_FW(trans, "Cannot read SGOM tables. rev is invalid\n");
 
-out_free:
        kfree(data);
-
 }
 IWL_EXPORT_SYMBOL(iwl_uefi_get_sgom_table);
 #endif /* CONFIG_ACPI */

diff --git a/drivers/net/wireless/intel/iwlwifi/fw/uefi.h b/drivers/net/wireless/intel/iwlwifi/fw/uefi.h
index 10bed372e67cb7d668bc588e7a64cbf0b0bb3040..dc7ccf49d92d3020cd1ca495d6c67fa501c80ddd 100644 (file)
--- a/drivers/net/wireless/intel/iwlwifi/fw/uefi.h
+++ b/drivers/net/wireless/intel/iwlwifi/fw/uefi.h
@@ -10,16 +10,7 @@
 #define IWL_UEFI_SGOM_NAME             L"UefiCnvWlanSarGeoOffsetMapping"
 #define IWL_UEFI_STEP_NAME             L"UefiCnvCommonSTEP"
 
-/*
- * TODO: we have these hardcoded values that the caller must pass,
- * because reading from the UEFI is not working.  To implement this
- * properly, we have to change iwl_pnvm_get_from_uefi() to call
- * efivar_entry_size() and return the value to the caller instead.
- */
-#define IWL_HARDCODED_PNVM_SIZE                4096
-#define IWL_HARDCODED_REDUCE_POWER_SIZE        32768
-#define IWL_HARDCODED_SGOM_SIZE                339
-#define IWL_HARDCODED_STEP_SIZE                6
+#define IWL_SGOM_MAP_SIZE              339
 
 struct pnvm_sku_package {
        u8 rev;
@@ -31,7 +22,7 @@ struct pnvm_sku_package {
 
 struct uefi_cnv_wlan_sgom_data {
        u8 revision;
-       u8 offset_map[IWL_HARDCODED_SGOM_SIZE - 1];
+       u8 offset_map[IWL_SGOM_MAP_SIZE - 1];
 } __packed;
 
 struct uefi_cnv_common_step_data {