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, 190 insertions, 0 deletions

diff --git a/drivers/crypto/ccp/sp-dev.h b/drivers/crypto/ccp/sp-dev.h
new file mode 100644
index 000000000..a83751cfd
--- /dev/null
+++ b/drivers/crypto/ccp/sp-dev.h
@@ -0,0 +1,190 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * AMD Secure Processor driver
+ *
+ * Copyright (C) 2017-2019 Advanced Micro Devices, Inc.
+ *
+ * Author: Tom Lendacky <thomas.lendacky@amd.com>
+ * Author: Gary R Hook <gary.hook@amd.com>
+ * Author: Brijesh Singh <brijesh.singh@amd.com>
+ */
+
+#ifndef __SP_DEV_H__
+#define __SP_DEV_H__
+
+#include <linux/device.h>
+#include <linux/spinlock.h>
+#include <linux/mutex.h>
+#include <linux/list.h>
+#include <linux/wait.h>
+#include <linux/dmapool.h>
+#include <linux/hw_random.h>
+#include <linux/bitops.h>
+#include <linux/interrupt.h>
+#include <linux/irqreturn.h>
+
+#define SP_MAX_NAME_LEN		32
+
+#define CACHE_NONE			0x00
+#define CACHE_WB_NO_ALLOC		0xb7
+
+#define PLATFORM_FEATURE_DBC		0x1
+#define PLATFORM_FEATURE_HSTI		0x2
+
+#define PSP_FEATURE(psp, feat)	(psp->vdata && psp->vdata->platform_features & PLATFORM_FEATURE_##feat)
+
+/* Structure to hold CCP device data */
+struct ccp_device;
+struct ccp_vdata {
+	const unsigned int version;
+	const unsigned int dma_chan_attr;
+	void (*setup)(struct ccp_device *);
+	const struct ccp_actions *perform;
+	const unsigned int offset;
+	const unsigned int rsamax;
+};
+
+struct sev_vdata {
+	const unsigned int cmdresp_reg;
+	const unsigned int cmdbuff_addr_lo_reg;
+	const unsigned int cmdbuff_addr_hi_reg;
+};
+
+struct tee_vdata {
+	const unsigned int cmdresp_reg;
+	const unsigned int cmdbuff_addr_lo_reg;
+	const unsigned int cmdbuff_addr_hi_reg;
+	const unsigned int ring_wptr_reg;
+	const unsigned int ring_rptr_reg;
+	const unsigned int info_reg;
+};
+
+struct platform_access_vdata {
+	const unsigned int cmdresp_reg;
+	const unsigned int cmdbuff_addr_lo_reg;
+	const unsigned int cmdbuff_addr_hi_reg;
+	const unsigned int doorbell_button_reg;
+	const unsigned int doorbell_cmd_reg;
+
+};
+
+struct psp_vdata {
+	const struct sev_vdata *sev;
+	const struct tee_vdata *tee;
+	const struct platform_access_vdata *platform_access;
+	const unsigned int cmdresp_reg;
+	const unsigned int cmdbuff_addr_lo_reg;
+	const unsigned int cmdbuff_addr_hi_reg;
+	const unsigned int feature_reg;
+	const unsigned int inten_reg;
+	const unsigned int intsts_reg;
+	const unsigned int bootloader_info_reg;
+	const unsigned int platform_features;
+};
+
+/* Structure to hold SP device data */
+struct sp_dev_vdata {
+	const unsigned int bar;
+
+	const struct ccp_vdata *ccp_vdata;
+	const struct psp_vdata *psp_vdata;
+};
+
+struct sp_device {
+	struct list_head entry;
+
+	struct device *dev;
+
+	const struct sp_dev_vdata *dev_vdata;
+	unsigned int ord;
+	char name[SP_MAX_NAME_LEN];
+
+	/* Bus specific device information */
+	void *dev_specific;
+
+	/* I/O area used for device communication. */
+	void __iomem *io_map;
+
+	/* DMA caching attribute support */
+	unsigned int axcache;
+
+	/* get and set master device */
+	struct sp_device*(*get_psp_master_device)(void);
+	void (*set_psp_master_device)(struct sp_device *);
+	void (*clear_psp_master_device)(struct sp_device *);
+
+	bool irq_registered;
+	bool use_tasklet;
+
+	unsigned int ccp_irq;
+	irq_handler_t ccp_irq_handler;
+	void *ccp_irq_data;
+
+	unsigned int psp_irq;
+	irq_handler_t psp_irq_handler;
+	void *psp_irq_data;
+
+	void *ccp_data;
+	void *psp_data;
+};
+
+int sp_pci_init(void);
+void sp_pci_exit(void);
+
+int sp_platform_init(void);
+void sp_platform_exit(void);
+
+struct sp_device *sp_alloc_struct(struct device *dev);
+
+int sp_init(struct sp_device *sp);
+void sp_destroy(struct sp_device *sp);
+
+int sp_suspend(struct sp_device *sp);
+int sp_resume(struct sp_device *sp);
+int sp_restore(struct sp_device *sp);
+int sp_request_ccp_irq(struct sp_device *sp, irq_handler_t handler,
+		       const char *name, void *data);
+void sp_free_ccp_irq(struct sp_device *sp, void *data);
+int sp_request_psp_irq(struct sp_device *sp, irq_handler_t handler,
+		       const char *name, void *data);
+void sp_free_psp_irq(struct sp_device *sp, void *data);
+struct sp_device *sp_get_psp_master_device(void);
+
+#ifdef CONFIG_CRYPTO_DEV_SP_CCP
+
+int ccp_dev_init(struct sp_device *sp);
+void ccp_dev_destroy(struct sp_device *sp);
+
+void ccp_dev_suspend(struct sp_device *sp);
+void ccp_dev_resume(struct sp_device *sp);
+
+#else	/* !CONFIG_CRYPTO_DEV_SP_CCP */
+
+static inline int ccp_dev_init(struct sp_device *sp)
+{
+	return 0;
+}
+static inline void ccp_dev_destroy(struct sp_device *sp) { }
+static inline void ccp_dev_suspend(struct sp_device *sp) { }
+static inline void ccp_dev_resume(struct sp_device *sp) { }
+#endif	/* CONFIG_CRYPTO_DEV_SP_CCP */
+
+#ifdef CONFIG_CRYPTO_DEV_SP_PSP
+
+int psp_dev_init(struct sp_device *sp);
+void psp_pci_init(void);
+void psp_dev_destroy(struct sp_device *sp);
+void psp_pci_exit(void);
+int psp_restore(struct sp_device *sp);
+
+#else /* !CONFIG_CRYPTO_DEV_SP_PSP */
+
+static inline int psp_dev_init(struct sp_device *sp) { return 0; }
+static inline void psp_pci_init(void) { }
+static inline void psp_dev_destroy(struct sp_device *sp) { }
+static inline void psp_pci_exit(void) { }
+static inline int psp_restore(struct sp_device *sp) { return 0; }
+
+#endif /* CONFIG_CRYPTO_DEV_SP_PSP */
+
+#endif