crypto: ccp - create a generic psp-dev file

The PSP (Platform Security Processor) provides support for key management
commands in Secure Encrypted Virtualization (SEV) mode, along with
software-based Trusted Execution Environment (TEE) to enable third-party
Trusted Applications.

Therefore, introduce psp-dev.c and psp-dev.h files, which can invoke
SEV (or TEE) initialization based on platform feature support.

TEE interface support will be introduced in a later patch.

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Jens Wiklander <jens.wiklander@linaro.org>
Co-developed-by: Devaraj Rangasamy <Devaraj.Rangasamy@amd.com>
Signed-off-by: Devaraj Rangasamy <Devaraj.Rangasamy@amd.com>
Signed-off-by: Rijo Thomas <Rijo-john.Thomas@amd.com>
Acked-by: Gary R Hook <gary.hook@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 194 insertions, 0 deletions

diff --git a/drivers/crypto/ccp/psp-dev.c b/drivers/crypto/ccp/psp-dev.c
new file mode 100644
index 000000000000..2cd7a5ea4156
--- /dev/null
+++ b/drivers/crypto/ccp/psp-dev.c
@@ -0,0 +1,194 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * AMD Platform Security Processor (PSP) interface
+ *
+ * Copyright (C) 2016,2019 Advanced Micro Devices, Inc.
+ *
+ * Author: Brijesh Singh <brijesh.singh@amd.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/irqreturn.h>
+
+#include "sp-dev.h"
+#include "psp-dev.h"
+#include "sev-dev.h"
+
+struct psp_device *psp_master;
+
+static struct psp_device *psp_alloc_struct(struct sp_device *sp)
+{
+	struct device *dev = sp->dev;
+	struct psp_device *psp;
+
+	psp = devm_kzalloc(dev, sizeof(*psp), GFP_KERNEL);
+	if (!psp)
+		return NULL;
+
+	psp->dev = dev;
+	psp->sp = sp;
+
+	snprintf(psp->name, sizeof(psp->name), "psp-%u", sp->ord);
+
+	return psp;
+}
+
+static irqreturn_t psp_irq_handler(int irq, void *data)
+{
+	struct psp_device *psp = data;
+	unsigned int status;
+
+	/* Read the interrupt status: */
+	status = ioread32(psp->io_regs + psp->vdata->intsts_reg);
+
+	/* invoke subdevice interrupt handlers */
+	if (status) {
+		if (psp->sev_irq_handler)
+			psp->sev_irq_handler(irq, psp->sev_irq_data, status);
+	}
+
+	/* Clear the interrupt status by writing the same value we read. */
+	iowrite32(status, psp->io_regs + psp->vdata->intsts_reg);
+
+	return IRQ_HANDLED;
+}
+
+static int psp_check_sev_support(struct psp_device *psp)
+{
+	unsigned int val = ioread32(psp->io_regs + psp->vdata->feature_reg);
+
+	/*
+	 * Check for a access to the registers.  If this read returns
+	 * 0xffffffff, it's likely that the system is running a broken
+	 * BIOS which disallows access to the device. Stop here and
+	 * fail the PSP initialization (but not the load, as the CCP
+	 * could get properly initialized).
+	 */
+	if (val == 0xffffffff) {
+		dev_notice(psp->dev, "psp: unable to access the device: you might be running a broken BIOS.\n");
+		return -ENODEV;
+	}
+
+	if (!(val & 1)) {
+		/* Device does not support the SEV feature */
+		dev_dbg(psp->dev, "psp does not support SEV\n");
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+int psp_dev_init(struct sp_device *sp)
+{
+	struct device *dev = sp->dev;
+	struct psp_device *psp;
+	int ret;
+
+	ret = -ENOMEM;
+	psp = psp_alloc_struct(sp);
+	if (!psp)
+		goto e_err;
+
+	sp->psp_data = psp;
+
+	psp->vdata = (struct psp_vdata *)sp->dev_vdata->psp_vdata;
+	if (!psp->vdata) {
+		ret = -ENODEV;
+		dev_err(dev, "missing driver data\n");
+		goto e_err;
+	}
+
+	psp->io_regs = sp->io_map;
+
+	ret = psp_check_sev_support(psp);
+	if (ret)
+		goto e_disable;
+
+	/* Disable and clear interrupts until ready */
+	iowrite32(0, psp->io_regs + psp->vdata->inten_reg);
+	iowrite32(-1, psp->io_regs + psp->vdata->intsts_reg);
+
+	/* Request an irq */
+	ret = sp_request_psp_irq(psp->sp, psp_irq_handler, psp->name, psp);
+	if (ret) {
+		dev_err(dev, "psp: unable to allocate an IRQ\n");
+		goto e_err;
+	}
+
+	ret = sev_dev_init(psp);
+	if (ret)
+		goto e_irq;
+
+	if (sp->set_psp_master_device)
+		sp->set_psp_master_device(sp);
+
+	/* Enable interrupt */
+	iowrite32(-1, psp->io_regs + psp->vdata->inten_reg);
+
+	dev_notice(dev, "psp enabled\n");
+
+	return 0;
+
+e_irq:
+	sp_free_psp_irq(psp->sp, psp);
+e_err:
+	sp->psp_data = NULL;
+
+	dev_notice(dev, "psp initialization failed\n");
+
+	return ret;
+
+e_disable:
+	sp->psp_data = NULL;
+
+	return ret;
+}
+
+void psp_dev_destroy(struct sp_device *sp)
+{
+	struct psp_device *psp = sp->psp_data;
+
+	if (!psp)
+		return;
+
+	sev_dev_destroy(psp);
+
+	sp_free_psp_irq(sp, psp);
+}
+
+void psp_set_sev_irq_handler(struct psp_device *psp, psp_irq_handler_t handler,
+			     void *data)
+{
+	psp->sev_irq_data = data;
+	psp->sev_irq_handler = handler;
+}
+
+void psp_clear_sev_irq_handler(struct psp_device *psp)
+{
+	psp_set_sev_irq_handler(psp, NULL, NULL);
+}
+
+struct psp_device *psp_get_master_device(void)
+{
+	struct sp_device *sp = sp_get_psp_master_device();
+
+	return sp ? sp->psp_data : NULL;
+}
+
+void psp_pci_init(void)
+{
+	psp_master = psp_get_master_device();
+
+	if (!psp_master)
+		return;
+
+	sev_pci_init();
+}
+
+void psp_pci_exit(void)
+{
+	if (!psp_master)
+		return;
+
+	sev_pci_exit();
+}