From: Nathan Chancellor nathan@kernel.org
stable inclusion from linux-4.19.207 commit aca58859ee7254f195745d98f33192a008427835
--------------------------------
[ Upstream commit 4367355dd90942a71641c98c40c74589c9bddf90 ]
When compiling with clang in certain configurations, an objtool warning appears:
drivers/net/ethernet/stmicro/stmmac/dwmac-ipq806x.o: warning: objtool: ipq806x_gmac_probe() falls through to next function phy_modes()
This happens because the unreachable annotation in the third switch statement is not eliminated. The compiler should know that the first default case would prevent the second and third from being reached as the comment notes but sanitizer options can make it harder for the compiler to reason this out.
Help the compiler out by eliminating the unreachable() annotation and unifying the default case error handling so that there is no objtool warning, the meaning of the code stays the same, and there is less duplication.
Reported-by: Sami Tolvanen samitolvanen@google.com Tested-by: Sami Tolvanen samitolvanen@google.com Signed-off-by: Nathan Chancellor nathan@kernel.org Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- .../ethernet/stmicro/stmmac/dwmac-ipq806x.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-)
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-ipq806x.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-ipq806x.c index 0f56f8e336917..03b11f191c262 100644 --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-ipq806x.c +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-ipq806x.c @@ -288,10 +288,7 @@ static int ipq806x_gmac_probe(struct platform_device *pdev) val &= ~NSS_COMMON_GMAC_CTL_PHY_IFACE_SEL; break; default: - dev_err(&pdev->dev, "Unsupported PHY mode: "%s"\n", - phy_modes(gmac->phy_mode)); - err = -EINVAL; - goto err_remove_config_dt; + goto err_unsupported_phy; } regmap_write(gmac->nss_common, NSS_COMMON_GMAC_CTL(gmac->id), val);
@@ -308,10 +305,7 @@ static int ipq806x_gmac_probe(struct platform_device *pdev) NSS_COMMON_CLK_SRC_CTRL_OFFSET(gmac->id); break; default: - dev_err(&pdev->dev, "Unsupported PHY mode: "%s"\n", - phy_modes(gmac->phy_mode)); - err = -EINVAL; - goto err_remove_config_dt; + goto err_unsupported_phy; } regmap_write(gmac->nss_common, NSS_COMMON_CLK_SRC_CTRL, val);
@@ -328,8 +322,7 @@ static int ipq806x_gmac_probe(struct platform_device *pdev) NSS_COMMON_CLK_GATE_GMII_TX_EN(gmac->id); break; default: - /* We don't get here; the switch above will have errored out */ - unreachable(); + goto err_unsupported_phy; } regmap_write(gmac->nss_common, NSS_COMMON_CLK_GATE, val);
@@ -360,6 +353,11 @@ static int ipq806x_gmac_probe(struct platform_device *pdev)
return 0;
+err_unsupported_phy: + dev_err(&pdev->dev, "Unsupported PHY mode: "%s"\n", + phy_modes(gmac->phy_mode)); + err = -EINVAL; + err_remove_config_dt: stmmac_remove_config_dt(pdev, plat_dat);