wifi: rtlwifi: avoid stack size warning for _read_eeprom_info

PATCH In review Arnd Bergmann 2 participants 2 messages Jun 10, 2025 – Jun 16, 2025 Realtek wireless driver (rtlwifi family)

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Arnd Bergmann

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2025-06-10 09:22 UTC #0 lore raw

PATCH 1/1 wifi: rtlwifi: avoid stack size warning for _read_eeprom_info

From: Arnd Bergmann <[email protected]>

txpower_info_{2g,5g} are too big to fit on the stack, but in most of the rtlwifi variants this stays below the warning limit for stack frames. In rtl8192ee and a few others, I see a case where clang decides to fully inline this into rtl92ee_read_eeprom_info, triggering this warning:

drivers/net/wireless/realtek/rtlwifi/rtl8192ee/hw.c:2178:6: error: stack frame size (1312) exceeds limit (1280) in 'rtl92ee_read_eeprom_info' [-Werror,-Wframe-larger-than]

Mark _rtl92ee_read_txpower_info_from_hwpg() as noinline_for_stack to and mark _rtl92ee_get_chnl_group() as __always_inline to make clang behave the same way as gcc. Inlining _rtl92ee_get_chnl_group helps let the compiler see that the index is always in range. The same change appears to be necessary in all rtlwifi variants.

A more thorough approach would be to avoid the use of the two structures on the stack entirely and combine them with the struct rtl_efuse data that is dynamically allocated and holds the same information.

Signed-off-by Arnd Bergmann <[email protected]>

---
 drivers/net/wireless/realtek/rtlwifi/rtl8188ee/hw.c | 6 +++---
 drivers/net/wireless/realtek/rtlwifi/rtl8192ce/hw.c | 6 +++---
 drivers/net/wireless/realtek/rtlwifi/rtl8192cu/hw.c | 6 +++---
 drivers/net/wireless/realtek/rtlwifi/rtl8192ee/hw.c | 7 ++++---
 drivers/net/wireless/realtek/rtlwifi/rtl8723ae/hw.c | 6 +++---
 drivers/net/wireless/realtek/rtlwifi/rtl8723be/hw.c | 6 +++---
 drivers/net/wireless/realtek/rtlwifi/rtl8821ae/hw.c | 6 +++---
 7 files changed, 22 insertions(+), 21 deletions(-)

drivers/net/wireless/realtek/rtlwifi/rtl8188ee/hw.c +3 -3

index d122f1eb345e..53c32e1de7e4 100644
@@ -1738,9 +1738,9 @@ static void read_power_value_fromprom(struct ieee80211_hw *hw,
 	}
 }
 
-static void _rtl88ee_read_txpower_info_from_hwpg(struct ieee80211_hw *hw,
-						 bool autoload_fail,
-						 u8 *hwinfo)
+static noinline_for_stack void
+_rtl88ee_read_txpower_info_from_hwpg(struct ieee80211_hw *hw,
+				     bool autoload_fail, u8 *hwinfo)
 {
 	struct rtl_priv *rtlpriv = rtl_priv(hw);
 	struct rtl_efuse *rtlefuse = rtl_efuse(rtl_priv(hw));

drivers/net/wireless/realtek/rtlwifi/rtl8192ce/hw.c +3 -3

index 0bc915723b93..5ca6b49e73c7 100644
@@ -1412,9 +1412,9 @@ void rtl92ce_update_interrupt_mask(struct ieee80211_hw *hw,
 	rtl92ce_enable_interrupt(hw);
 }
 
-static void _rtl92ce_read_txpower_info_from_hwpg(struct ieee80211_hw *hw,
-						 bool autoload_fail,
-						 u8 *hwinfo)
+static noinline_for_stack void
+_rtl92ce_read_txpower_info_from_hwpg(struct ieee80211_hw *hw,
+				     bool autoload_fail, u8 *hwinfo)
 {
 	struct rtl_priv *rtlpriv = rtl_priv(hw);
 	struct rtl_efuse *rtlefuse = rtl_efuse(rtl_priv(hw));

drivers/net/wireless/realtek/rtlwifi/rtl8192cu/hw.c +3 -3

index 0195c9a3e9e8..ec5d558609fe 100644
@@ -95,9 +95,9 @@ static void _rtl92cu_phy_param_tab_init(struct ieee80211_hw *hw)
 	}
 }
 
-static void _rtl92cu_read_txpower_info_from_hwpg(struct ieee80211_hw *hw,
-						 bool autoload_fail,
-						 u8 *hwinfo)
+static noinline_for_stack void
+_rtl92cu_read_txpower_info_from_hwpg(struct ieee80211_hw *hw,
+				     bool autoload_fail, u8 *hwinfo)
 {
 	struct rtl_priv *rtlpriv = rtl_priv(hw);
 	struct rtl_efuse *rtlefuse = rtl_efuse(rtl_priv(hw));

drivers/net/wireless/realtek/rtlwifi/rtl8192ee/hw.c +4 -3

index d4da5cdc8414..48a3c94606be 100644
@@ -1731,7 +1731,7 @@ void rtl92ee_update_interrupt_mask(struct ieee80211_hw *hw,
 	rtl92ee_enable_interrupt(hw);
 }
 
-static u8 _rtl92ee_get_chnl_group(u8 chnl)
+static __always_inline u8 _rtl92ee_get_chnl_group(u8 chnl)
 {
 	u8 group = 0;

@@ -2009,8 +2009,9 @@ static void _rtl8192ee_read_power_value_fromprom(struct ieee80211_hw *hw,
 	}
 }
 
-static void _rtl92ee_read_txpower_info_from_hwpg(struct ieee80211_hw *hw,
-						 bool autoload_fail, u8 *hwinfo)
+static noinline_for_stack void
+_rtl92ee_read_txpower_info_from_hwpg(struct ieee80211_hw *hw,
+				     bool autoload_fail, u8 *hwinfo)
 {
 	struct rtl_priv *rtlpriv = rtl_priv(hw);
 	struct rtl_efuse *efu = rtl_efuse(rtl_priv(hw));

drivers/net/wireless/realtek/rtlwifi/rtl8723ae/hw.c +3 -3

index 6991713a66d0..21b827f519b6 100644
@@ -1381,9 +1381,9 @@ static u8 _rtl8723e_get_chnl_group(u8 chnl)
 	return group;
 }
 
-static void _rtl8723e_read_txpower_info_from_hwpg(struct ieee80211_hw *hw,
-						  bool autoload_fail,
-						  u8 *hwinfo)
+static noinline_for_stack void
+_rtl8723e_read_txpower_info_from_hwpg(struct ieee80211_hw *hw,
+				      bool autoload_fail, u8 *hwinfo)
 {
 	struct rtl_priv *rtlpriv = rtl_priv(hw);
 	struct rtl_efuse *rtlefuse = rtl_efuse(rtl_priv(hw));

drivers/net/wireless/realtek/rtlwifi/rtl8723be/hw.c +3 -3

index bcfc53af4c1a..e1f811218894 100644
@@ -1935,9 +1935,9 @@ static void _rtl8723be_read_power_value_fromprom(struct ieee80211_hw *hw,
 	}
 }
 
-static void _rtl8723be_read_txpower_info_from_hwpg(struct ieee80211_hw *hw,
-						   bool autoload_fail,
-						   u8 *hwinfo)
+static noinline_for_stack void
+_rtl8723be_read_txpower_info_from_hwpg(struct ieee80211_hw *hw,
+				       bool autoload_fail, u8 *hwinfo)
 {
 	struct rtl_priv *rtlpriv = rtl_priv(hw);
 	struct rtl_efuse *rtlefuse = rtl_efuse(rtl_priv(hw));

drivers/net/wireless/realtek/rtlwifi/rtl8821ae/hw.c +3 -3

index f4b232f038a9..8c51f4d36820 100644
@@ -2782,9 +2782,9 @@ static void _rtl8812ae_read_txpower_info_from_hwpg(struct ieee80211_hw *hw,
 	"eeprom_regulatory = 0x%x\n", rtlefuse->eeprom_regulatory);
 }
 #endif
-static void _rtl8821ae_read_txpower_info_from_hwpg(struct ieee80211_hw *hw,
-						 bool autoload_fail,
-						 u8 *hwinfo)
+static noinline_for_stack void
+_rtl8821ae_read_txpower_info_from_hwpg(struct ieee80211_hw *hw,
+				       bool autoload_fail, u8 *hwinfo)
 {
 	struct rtl_priv *rtlpriv = rtl_priv(hw);
 	struct rtl_efuse *rtlefuse = rtl_efuse(rtl_priv(hw));

Signature · 1 line

2.39.5

Ping-Ke Shih

maintainer

2025-06-16 03:51 UTC #1 lore raw

Quoted 15 lines · Arnd Bergmann

From: Arnd Bergmann <[email protected]>
txpower_info_{2g,5g} are too big to fit on the stack, but in most of the rtlwifi variants this stays below the warning limit for stack frames. In rtl8192ee and a few others, I see a case where clang decides to fully inline this into rtl92ee_read_eeprom_info, triggering this warning:
drivers/net/wireless/realtek/rtlwifi/rtl8192ee/hw.c:2178:6: error: stack frame size (1312) exceeds limit (1280) in 'rtl92ee_read_eeprom_info' [-Werror,-Wframe-larger-than]
Mark _rtl92ee_read_txpower_info_from_hwpg() as noinline_for_stack to and mark _rtl92ee_get_chnl_group() as __always_inline to make clang behave the same way as gcc. Inlining _rtl92ee_get_chnl_group helps let the compiler see that the index is always in range. The same change appears to be necessary in all rtlwifi variants.

Quoted 5 lines

A more thorough approach would be to avoid the use of the two structures on the stack entirely and combine them with the struct rtl_efuse data that is dynamically allocated and holds the same information.
Signed-off-by Arnd Bergmann <[email protected]>

1 patch(es) applied to rtw-next branch of rtw.git, thanks.

2baacfe83346 wifi: rtlwifi: avoid stack size warning for _read_eeprom_info

---
https://github.com/pkshih/rtw.git