x86/amd_node: Fix PCI device reference counting in amd_smn_init()grafted

The local "root" pointer is a temporary variable used during the device
search. Therefore, refcount related to the search iterators should be cleaned
up after the search is complete.

Use the __free() cleanup macro to ensure the refcount is decremented when the
temporary pointer goes out of scope.

Additionally, increment the refcount when caching a root pointer. This ensures
the in-use refcount is separate from the temporary search refcounting.

Finally, drop the redundant "root = NULL" before the second search loop. The
pci_get_class() iterator always decrements the refcount of its "from"
argument, so the first loop can only fall through with "root" already NULL.

Fixes: 0a4b61d9c2e4 ("x86/amd_node: Fix AMD root device caching")
Closes: https://sashiko.dev/#/patchset/20260806160159.230453-1-jason.andryuk%40amd.com
Reported-by: Sashiko <sashiko-bot@kernel.org>
Assisted-by: LLM
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Cc: <stable@kernel.org>
Link: https://patch.msgid.link/20260903154325.74343-1-yazen.ghannam@amd.com

1 files changed, 249 insertions, 0 deletions

diff --git a/drivers/cpufreq/cpufreq-dt-platdev.c b/drivers/cpufreq/cpufreq-dt-platdev.c
new file mode 100644
index 000000000..371ca1fe9
--- /dev/null
+++ b/drivers/cpufreq/cpufreq-dt-platdev.c
@@ -0,0 +1,249 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2016 Linaro.
+ * Viresh Kumar <viresh.kumar@linaro.org>
+ */
+
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+
+#include "cpufreq-dt.h"
+
+/*
+ * Machines for which the cpufreq device is *always* created, mostly used for
+ * platforms using "operating-points" (V1) property.
+ */
+static const struct of_device_id allowlist[] __initconst = {
+	{ .compatible = "allwinner,sun4i-a10", },
+	{ .compatible = "allwinner,sun5i-a10s", },
+	{ .compatible = "allwinner,sun5i-a13", },
+	{ .compatible = "allwinner,sun5i-r8", },
+	{ .compatible = "allwinner,sun6i-a31", },
+	{ .compatible = "allwinner,sun6i-a31s", },
+	{ .compatible = "allwinner,sun7i-a20", },
+	{ .compatible = "allwinner,sun8i-a23", },
+	{ .compatible = "allwinner,sun8i-a83t", },
+	{ .compatible = "allwinner,sun8i-h3", },
+
+	{ .compatible = "apm,xgene-shadowcat", },
+
+	{ .compatible = "arm,integrator-ap", },
+	{ .compatible = "arm,integrator-cp", },
+
+	{ .compatible = "hisilicon,hi3660", },
+
+	{ .compatible = "fsl,imx27", },
+	{ .compatible = "fsl,imx51", },
+	{ .compatible = "fsl,imx53", },
+
+	{ .compatible = "marvell,berlin", },
+	{ .compatible = "marvell,pxa250", },
+	{ .compatible = "marvell,pxa270", },
+
+	{ .compatible = "samsung,exynos3250", },
+	{ .compatible = "samsung,exynos4210", },
+	{ .compatible = "samsung,exynos5250", },
+#ifndef CONFIG_BL_SWITCHER
+	{ .compatible = "samsung,exynos5800", },
+#endif
+
+	{ .compatible = "renesas,emev2", },
+	{ .compatible = "renesas,r7s72100", },
+	{ .compatible = "renesas,r8a73a4", },
+	{ .compatible = "renesas,r8a7740", },
+	{ .compatible = "renesas,r8a7742", },
+	{ .compatible = "renesas,r8a7743", },
+	{ .compatible = "renesas,r8a7744", },
+	{ .compatible = "renesas,r8a7745", },
+	{ .compatible = "renesas,r8a7778", },
+	{ .compatible = "renesas,r8a7779", },
+	{ .compatible = "renesas,r8a7790", },
+	{ .compatible = "renesas,r8a7791", },
+	{ .compatible = "renesas,r8a7792", },
+	{ .compatible = "renesas,r8a7793", },
+	{ .compatible = "renesas,r8a7794", },
+	{ .compatible = "renesas,sh73a0", },
+
+	{ .compatible = "rockchip,rk2928", },
+	{ .compatible = "rockchip,rk3036", },
+	{ .compatible = "rockchip,rk3066a", },
+	{ .compatible = "rockchip,rk3066b", },
+	{ .compatible = "rockchip,rk3188", },
+	{ .compatible = "rockchip,rk3228", },
+	{ .compatible = "rockchip,rk3288", },
+	{ .compatible = "rockchip,rk3328", },
+	{ .compatible = "rockchip,rk3366", },
+	{ .compatible = "rockchip,rk3368", },
+	{ .compatible = "rockchip,rk3399",
+	  .data = &(struct cpufreq_dt_platform_data)
+		{ .have_governor_per_policy = true, },
+	},
+
+	{ .compatible = "spacemit,k1", },
+
+	{ .compatible = "st-ericsson,u8500", },
+	{ .compatible = "st-ericsson,u8540", },
+	{ .compatible = "st-ericsson,u9500", },
+	{ .compatible = "st-ericsson,u9540", },
+
+	{ .compatible = "starfive,jh7110", },
+	{ .compatible = "starfive,jh7110s", },
+
+	{ .compatible = "ti,omap2", },
+	{ .compatible = "ti,omap4", },
+	{ .compatible = "ti,omap5", },
+
+	{ .compatible = "xlnx,zynq-7000", },
+	{ .compatible = "xlnx,zynqmp", },
+
+	{ }
+};
+
+/*
+ * Machines for which the cpufreq device is *not* created, mostly used for
+ * platforms using "operating-points-v2" property.
+ */
+static const struct of_device_id blocklist[] __initconst = {
+	{ .compatible = "airoha,an7583", },
+	{ .compatible = "airoha,en7581", },
+
+	{ .compatible = "allwinner,sun50i-a100" },
+	{ .compatible = "allwinner,sun50i-h6", },
+	{ .compatible = "allwinner,sun50i-h616", },
+	{ .compatible = "allwinner,sun50i-h618", },
+	{ .compatible = "allwinner,sun50i-h700", },
+
+	{ .compatible = "apple,arm-platform", },
+
+	{ .compatible = "arm,vexpress", },
+
+	{ .compatible = "calxeda,highbank", },
+	{ .compatible = "calxeda,ecx-2000", },
+
+	{ .compatible = "fsl,imx7ulp", },
+	{ .compatible = "fsl,imx7d", },
+	{ .compatible = "fsl,imx7s", },
+	{ .compatible = "fsl,imx8mq", },
+	{ .compatible = "fsl,imx8mm", },
+	{ .compatible = "fsl,imx8mn", },
+	{ .compatible = "fsl,imx8mp", },
+
+	{ .compatible = "marvell,armadaxp", },
+
+	{ .compatible = "mediatek,mt2701", },
+	{ .compatible = "mediatek,mt2712", },
+	{ .compatible = "mediatek,mt7622", },
+	{ .compatible = "mediatek,mt7623", },
+	{ .compatible = "mediatek,mt8167", },
+	{ .compatible = "mediatek,mt817x", },
+	{ .compatible = "mediatek,mt8173", },
+	{ .compatible = "mediatek,mt8176", },
+	{ .compatible = "mediatek,mt8183", },
+	{ .compatible = "mediatek,mt8186", },
+	{ .compatible = "mediatek,mt8365", },
+	{ .compatible = "mediatek,mt8516", },
+
+	{ .compatible = "nvidia,tegra20", },
+	{ .compatible = "nvidia,tegra30", },
+	{ .compatible = "nvidia,tegra114", },
+	{ .compatible = "nvidia,tegra124", },
+	{ .compatible = "nvidia,tegra186", },
+	{ .compatible = "nvidia,tegra194", },
+	{ .compatible = "nvidia,tegra210", },
+	{ .compatible = "nvidia,tegra234", },
+
+	{ .compatible = "qcom,apq8096", },
+	{ .compatible = "qcom,msm8909", },
+	{ .compatible = "qcom,msm8996", },
+	{ .compatible = "qcom,msm8998", },
+	{ .compatible = "qcom,qcm2290", },
+	{ .compatible = "qcom,qcm6490", },
+	{ .compatible = "qcom,qcs404", },
+	{ .compatible = "qcom,qcs8300", },
+	{ .compatible = "qcom,qdu1000", },
+	{ .compatible = "qcom,sa8155p" },
+	{ .compatible = "qcom,sa8540p" },
+	{ .compatible = "qcom,sa8775p" },
+	{ .compatible = "qcom,sc7180", },
+	{ .compatible = "qcom,sc7280", },
+	{ .compatible = "qcom,sc8180x", },
+	{ .compatible = "qcom,sc8280xp", },
+	{ .compatible = "qcom,sdm670", },
+	{ .compatible = "qcom,sdm845", },
+	{ .compatible = "qcom,sdx75", },
+	{ .compatible = "qcom,sm6115", },
+	{ .compatible = "qcom,sm6125", },
+	{ .compatible = "qcom,sm6150", },
+	{ .compatible = "qcom,sm6350", },
+	{ .compatible = "qcom,sm6375", },
+	{ .compatible = "qcom,sm7125", },
+	{ .compatible = "qcom,sm7225", },
+	{ .compatible = "qcom,sm7325", },
+	{ .compatible = "qcom,sm8150", },
+	{ .compatible = "qcom,sm8250", },
+	{ .compatible = "qcom,sm8350", },
+	{ .compatible = "qcom,sm8450", },
+	{ .compatible = "qcom,sm8550", },
+	{ .compatible = "qcom,sm8650", },
+
+	{ .compatible = "st,stih407", },
+	{ .compatible = "st,stih410", },
+	{ .compatible = "st,stih418", },
+
+	{ .compatible = "ti,am33xx", },
+	{ .compatible = "ti,am43", },
+	{ .compatible = "ti,dra7", },
+	{ .compatible = "ti,omap3", },
+	{ .compatible = "ti,am625", },
+	{ .compatible = "ti,am62a7", },
+	{ .compatible = "ti,am62d2", },
+	{ .compatible = "ti,am62l3", },
+	{ .compatible = "ti,am62p5", },
+
+	{ .compatible = "qcom,ipq5210", },
+	{ .compatible = "qcom,ipq5332", },
+	{ .compatible = "qcom,ipq5424", },
+	{ .compatible = "qcom,ipq6018", },
+	{ .compatible = "qcom,ipq8064", },
+	{ .compatible = "qcom,ipq8074", },
+	{ .compatible = "qcom,ipq9574", },
+	{ .compatible = "qcom,apq8064", },
+	{ .compatible = "qcom,msm8974", },
+	{ .compatible = "qcom,msm8960", },
+
+	{ }
+};
+
+static bool __init cpu0_node_has_opp_v2_prop(void)
+{
+	struct device_node *np __free(device_node) = of_cpu_device_node_get(0);
+	bool ret = false;
+
+	if (of_property_present(np, "operating-points-v2"))
+		ret = true;
+
+	return ret;
+}
+
+static int __init cpufreq_dt_platdev_init(void)
+{
+	const void *data = NULL;
+
+	if (of_machine_device_match(allowlist)) {
+		data = of_machine_get_match_data(allowlist);
+		goto create_pdev;
+	}
+
+	if (cpu0_node_has_opp_v2_prop() && !of_machine_device_match(blocklist))
+		goto create_pdev;
+
+	return -ENODEV;
+
+create_pdev:
+	return PTR_ERR_OR_ZERO(platform_device_register_data(NULL, "cpufreq-dt",
+			       -1, data,
+			       sizeof(struct cpufreq_dt_platform_data)));
+}
+core_initcall(cpufreq_dt_platdev_init);