/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2022 Beckhoff Automation GmbH & Co. KG
 * Author: Corvin Köhne <c.koehne@beckhoff.com>
 */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/endian.h>
#include <sys/linker_set.h>

#include <machine/vmm.h>

#include <assert.h>
#include <err.h>
#include <errno.h>
#include <vmmapi.h>

#include "acpi.h"
#include "acpi_device.h"
#include "config.h"
#include "mem.h"
#include "qemu_fwcfg.h"
#include "tpm_ppi.h"

#define TPM_PPI_ADDRESS 0xFED45000
#define TPM_PPI_SIZE 0x400

#define TPM_PPI_FWCFG_FILE "etc/tpm/config"

#define TPM_PPI_QEMU_NAME "qemu"

struct tpm_ppi_qemu {
        uint8_t func[256];          // FUNC
        uint8_t in;                 // PPIN
        uint32_t ip;                // PPIP
        uint32_t response;          // PPRP
        uint32_t request;           // PPRQ
        uint32_t request_parameter; // PPRM
        uint32_t last_request;      // LPPR
        uint32_t func_ret;          // FRET
        uint8_t _reserved1[0x40];   // RES1
        uint8_t next_step;          // next_step
} __packed;
static_assert(sizeof(struct tpm_ppi_qemu) <= TPM_PPI_SIZE,
    "Wrong size of tpm_ppi_qemu");

struct tpm_ppi_fwcfg {
        uint32_t ppi_address;
        uint8_t tpm_version;
        uint8_t ppi_version;
} __packed;

static int
tpm_ppi_mem_handler(struct vcpu *const vcpu __unused, const int dir,
    const uint64_t addr, const int size, uint64_t *const val, void *const arg1,
    const long arg2 __unused)
{
        struct tpm_ppi_qemu *ppi;
        uint8_t *ptr;
        uint64_t off;

        if ((addr & (size - 1)) != 0) {
                warnx("%s: unaligned %s access @ %16lx [size = %x]", __func__,
                    (dir == MEM_F_READ) ? "read" : "write", addr, size);
        }

        ppi = arg1;

        off = addr - TPM_PPI_ADDRESS;
        ptr = (uint8_t *)ppi + off;

        if (off > TPM_PPI_SIZE || off + size > TPM_PPI_SIZE) {
                return (EINVAL);
        }

        assert(size == 1 || size == 2 || size == 4 || size == 8);
        if (dir == MEM_F_READ) {
                memcpy(val, ptr, size);
        } else {
                memcpy(ptr, val, size);
        }

        return (0);
}

static struct mem_range ppi_mmio = {
        .name = "ppi-mmio",
        .base = TPM_PPI_ADDRESS,
        .size = TPM_PPI_SIZE,
        .flags = MEM_F_RW,
        .handler = tpm_ppi_mem_handler,
};

static int
tpm_ppi_init(void **sc)
{
        struct tpm_ppi_qemu *ppi = NULL;
        struct tpm_ppi_fwcfg *fwcfg = NULL;
        int error;

#ifdef  __FreeBSD__
        ppi = calloc(1, TPM_PPI_SIZE);
#else
        // SMATCH: double check that we're allocating correct size: 346 vs 1024
        void *ptr = calloc(1, TPM_PPI_SIZE);
        ppi = (struct tpm_ppi_qemu *)ptr;
#endif
        if (ppi == NULL) {
                warnx("%s: failed to allocate acpi region for ppi", __func__);
                error = ENOMEM;
                goto err_out;
        }

        fwcfg = calloc(1, sizeof(struct tpm_ppi_fwcfg));
        if (fwcfg == NULL) {
                warnx("%s: failed to allocate fwcfg item", __func__);
                error = ENOMEM;
                goto err_out;
        }

        fwcfg->ppi_address = htole32(TPM_PPI_ADDRESS);
        fwcfg->tpm_version = 2;
        fwcfg->ppi_version = 1;

        error = qemu_fwcfg_add_file(TPM_PPI_FWCFG_FILE,
            sizeof(struct tpm_ppi_fwcfg), fwcfg);
        if (error) {
                warnx("%s: failed to add fwcfg file", __func__);
                goto err_out;
        }

        /*
         * We would just need to create some guest memory for the PPI region.
         * Sadly, bhyve has a strange memory interface. We can't just add more
         * memory to the VM. So, create a trap instead which reads and writes to
         * the ppi region. It's very slow but ppi shouldn't be used frequently.
         */
        ppi_mmio.arg1 = ppi;
        error = register_mem(&ppi_mmio);
        if (error) {
                warnx("%s: failed to create trap for ppi accesses", __func__);
                goto err_out;
        }

        *sc = ppi;

        return (0);

err_out:
        free(fwcfg);
        free(ppi);

        return (error);
}

static void
tpm_ppi_deinit(void *sc)
{
        struct tpm_ppi_qemu *ppi;
        int error;

        if (sc == NULL)
                return;

        ppi = sc;

        error = unregister_mem(&ppi_mmio);
        assert(error == 0);

        free(ppi);
}

static int
tpm_ppi_write_dsdt_regions(void *sc __unused)
{
        /*
         * struct tpm_ppi_qemu
         */
        /*
         * According to qemu the Windows ACPI parser has a bug that DerefOf is
         * broken for SYSTEM_MEMORY. Due to that bug, qemu uses a dynamic
         * operation region inside a method.
         */
        dsdt_line("Method(TPFN, 1, Serialized)");
        dsdt_line("{");
        dsdt_line("  If(LGreaterEqual(Arg0, 0x100))");
        dsdt_line("  {");
        dsdt_line("    Return(Zero)");
        dsdt_line("  }");
        dsdt_line(
            "  OperationRegion(TPP1, SystemMemory, Add(0x%8x, Arg0), One)",
            TPM_PPI_ADDRESS);
        dsdt_line("  Field(TPP1, ByteAcc, NoLock, Preserve)");
        dsdt_line("  {");
        dsdt_line("    TPPF, 8,");
        dsdt_line("  }");
        dsdt_line("  Return(TPPF)");
        dsdt_line("}");
        dsdt_line("OperationRegion(TPP2, SystemMemory, 0x%8x, 0x%x)",
            TPM_PPI_ADDRESS + 0x100, 0x5A);
        dsdt_line("Field(TPP2, AnyAcc, NoLock, Preserve)");
        dsdt_line("{");
        dsdt_line("  PPIN, 8,");
        dsdt_line("  PPIP, 32,");
        dsdt_line("  PPRP, 32,");
        dsdt_line("  PPRQ, 32,");
        dsdt_line("  PPRM, 32,");
        dsdt_line("  LPPR, 32,");
        dsdt_line("}");
        /*
         * Used for TCG Platform Reset Attack Mitigation
         */
        dsdt_line("OperationRegion(TPP3, SystemMemory, 0x%8x, 1)",
            TPM_PPI_ADDRESS + sizeof(struct tpm_ppi_qemu));
        dsdt_line("Field(TPP3, ByteAcc, NoLock, Preserve)");
        dsdt_line("{");
        dsdt_line("  MOVV, 8,");
        dsdt_line("}");

        return (0);
}

static int
tpm_ppi_write_dsdt_dsm(void *sc __unused)
{
        /*
         * Physical Presence Interface
         */
        dsdt_line(
            "If(LEqual(Arg0, ToUUID(\"3DDDFAA6-361B-4EB4-A424-8D10089D1653\"))) /* UUID */");
        dsdt_line("{");
        /*
         * Function 0 - _DSM Query Function
         * Arguments:
         *   Empty Package
         * Return:
         *   Buffer - Index field of supported functions
         */
        dsdt_line("  If(LEqual(Arg2, 0)) /* Function */");
        dsdt_line("  {");
        dsdt_line("    Return(Buffer(0x02)");
        dsdt_line("    {");
        dsdt_line("      0xFF, 0x01");
        dsdt_line("    })");
        dsdt_line("  }");
        /*
         * Function 1 - Get Physical Presence Interface Version
         * Arguments:
         *   Empty Package
         * Return:
         *   String - Supported Physical Presence Interface revision
         */
        dsdt_line("  If(LEqual(Arg2, 1)) /* Function */");
        dsdt_line("  {");
        dsdt_line("    Return(\"1.3\")");
        dsdt_line("  }");
        /*
         * Function 2 - Submit TPM Operation Request to Pre-OS Environment
         * !!!DEPRECATED BUT MANDATORY!!!
         * Arguments:
         *   Integer - Operation Value of the Request
         * Return:
         *   Integer - Function Return Code
         *     0 - Success
         *     1 - Operation Value of the Request Not Supported
         *     2 - General Failure
         */
        dsdt_line("  If(LEqual(Arg2, 2)) /* Function */");
        dsdt_line("  {");
        dsdt_line("    Store(DerefOf(Index(Arg3, 0)), Local0)");
        dsdt_line("    Store(TPFN(Local0), Local1)");
        dsdt_line("    If (LEqual(And(Local1, 7), 0))");
        dsdt_line("    {");
        dsdt_line("      Return(1)");
        dsdt_line("    }");
        dsdt_line("    Store(Local0, PPRQ)");
        dsdt_line("    Store(0, PPRM)");
        dsdt_line("    Return(0)");
        dsdt_line("  }");
        /*
         * Function 3 - Get Pending TPM Operation Request By the OS
         * Arguments:
         *   Empty Package
         * Return:
         *   Package
         *     Integer 1 - Function Return Code
         *       0 - Success
         *       1 - General Failure
         *     Integer 2 - Pending operation requested by the OS
         *       0 - None
         *      >0 - Operation Value of the Pending Request
         *     Integer 3 - Optional argument to pending operation requested by
         *                 the OS
         *       0 - None
         *      >0 - Argument of the Pending Request
         */
        dsdt_line("  If(LEqual(Arg2, 3)) /* Function */");
        dsdt_line("  {");
        dsdt_line("    If(LEqual(Arg1, 1)) /* Revision */");
        dsdt_line("    {");
        dsdt_line("      Store(PPRQ, Index(TPM2, 1))");
        dsdt_line("      Return(TPM2)");
        dsdt_line("    }");
        dsdt_line("    If(LEqual(Arg1, 2)) /* Revision */");
        dsdt_line("    {");
        dsdt_line("      Store(PPRQ, Index(TPM3, 1))");
        dsdt_line("      Store(PPRM, Index(TPM3, 2))");
        dsdt_line("      Return(TPM3)");
        dsdt_line("    }");
        dsdt_line("  }");
        /*
         * Function 4 - Get Platform-Specific Action to Transition to Pre-OS
         *              Environment
         * Arguments:
         *   Empty Package
         * Return:
         *   Integer - Action that the OS should take to transition to the
         *             pre-OS environment for execution of a requested operation
         *     0 - None
         *     1 - Shutdown
         *     2 - Reboot
         *     3 - OS Vendor-specific
         */
        dsdt_line("  If(LEqual(Arg2, 4)) /* Function */");
        dsdt_line("  {");
        dsdt_line("    Return(2)");
        dsdt_line("  }");
        /*
         * Function 5 - Return TPM Operation Response to OS Environment
         * Arguments:
         *   Empty Package
         * Return:
         *   Package
         *     Integer 1 - Function Return Code
         *       0 - Success
         *       1 - General Failure
         *     Integer 2 - Most recent operation request
         *       0 - None
         *      >0 - Operation value of the most recent request
         *     Integer 3 - Response to the most recent operation request
         *       0 - Success
         *       0x00000001..0x000000FF - Corresponding TPM error code
         *       0xFFFFFFF0 - User Abort or timeout of dialog
         *       0xFFFFFFF1 - firmware failure
         */
        dsdt_line("  If(LEqual(Arg2, 5)) /* Function */");
        dsdt_line("  {");
        dsdt_line("    Store(LPPR, Index(TPM3, 1))");
        dsdt_line("    Store(PPRP, Index(TPM3, 2))");
        dsdt_line("    Return(TPM3)");
        dsdt_line("  }");
        /*
         * Function 6 - Submit preferred user language
         * !!!DEPRECATED BUT MANDATORY!!!
         * Arguments:
         *   Package
         *     String - Preferred language code
         * Return:
         *   Integer
         *     3 - Not implemented
         */
        dsdt_line("  If(LEqual(Arg2, 6)) /* Function */");
        dsdt_line("  {");
        dsdt_line("    Return(3)");
        dsdt_line("  }");
        /*
         * Function 7 - Submit TPM Operation Request to Pre-OS Environment 2
         * Arguments:
         *   Package
         *     Integer 1 - Operation Value of the Request
         *     Integer 2 - Argument for Operation
         * Return:
         *   Integer - Function Return Code
         *     0 - Success
         *     1 - Not Implemented
         *     2 - General Failure
         *     3 - Operation blocked by current firmware settings
         */
        dsdt_line("  If(LEqual(Arg2, 7)) /* Function */");
        dsdt_line("  {");
        dsdt_line("    Store(DerefOf(Index(Arg3, 0)), Local0)");
        dsdt_line("    Store(TPFN(Local0), Local1)");
        dsdt_line("    If (LEqual(And(Local1, 7), 0)) /* Not Implemented */");
        dsdt_line("    {");
        dsdt_line("      Return(1)");
        dsdt_line("    }");
        dsdt_line("    If (LEqual(And(Local1, 7), 2)) /* Blocked */ ");
        dsdt_line("    {");
        dsdt_line("      Return(3)");
        dsdt_line("    }");
        dsdt_line("    If(LEqual(Arg1, 1)) /* Revision */");
        dsdt_line("    {");
        dsdt_line("      Store(Local0, PPRQ)");
        dsdt_line("      Store(0, PPRM)");
        dsdt_line("    }");
        dsdt_line("    If(LEqual(Arg1, 2)) /* Revision */");
        dsdt_line("    {");
        dsdt_line("      Store(Local0, PPRQ)");
        dsdt_line("      Store(DerefOf(Index(Arg3, 1)), PPRM)");
        dsdt_line("    }");
        dsdt_line("    Return(0)");
        dsdt_line("  }");
        /*
         * Function 8 - Get User Confirmation Status for Operation
         * Arguments:
         *   Package
         *     Integer - Operation Value that may need user confirmation
         * Return:
         *   Integer - Function Return Code
         *     0 - Not implemented
         *     1 - Firmware only
         *     2 - Blocked for OS by firmware configuration
         *     3 - Allowed and physically present user required
         *     4 - Allowed and physically present user not required
         */
        dsdt_line("    If(LEqual(Arg2, 8)) /* Function */");
        dsdt_line("    {");
        dsdt_line("      Store(DerefOf(Index(Arg3, 0)), Local0)");
        dsdt_line("      Store(TPFN(Local0), Local1)");
        dsdt_line("      Return(And(Local1, 7))");
        dsdt_line("    }");
        /*
         * Unknown function
         */
        dsdt_line("  Return(Buffer(1)");
        dsdt_line("  {");
        dsdt_line("    0x00");
        dsdt_line("  })");
        dsdt_line("}");

        /*
         * TCG Platform Reset Attack Mitigation
         */
        dsdt_line(
            "If(LEqual(Arg0, ToUUID(\"376054ED-CC13-4675-901C-4756D7F2D45D\"))) /* UUID */");
        dsdt_line("{");
        /*
         * Function 0 - _DSM Query Function
         * Arguments:
         *   Empty Package
         * Return:
         *   Buffer - Index field of supported functions
         */
        dsdt_line("  If(LEqual(Arg2, 0)) /* Function */");
        dsdt_line("  {");
        dsdt_line("    Return(Buffer(1)");
        dsdt_line("    {");
        dsdt_line("      0x03");
        dsdt_line("    })");
        dsdt_line("  }");
        /*
         * Function 1 - Memory Clear
         * Arguments:
         *   Package
         *     Integer - Operation Value of the Request
         * Return:
         *   Integer - Function Return Code
         *     0 - Success
         *     1 - General Failure
         */
        dsdt_line("  If(LEqual(Arg2, 1)) /* Function */");
        dsdt_line("  {");
        dsdt_line("    Store(DerefOf(Index(Arg3, 0)), Local0)");
        dsdt_line("    Store(Local0, MOVV)");
        dsdt_line("    Return(0)");
        dsdt_line("  }");
        dsdt_line("}");

        return (0);
}

static struct tpm_ppi tpm_ppi_qemu = {
        .name = TPM_PPI_QEMU_NAME,
        .init = tpm_ppi_init,
        .deinit = tpm_ppi_deinit,
        .write_dsdt_regions = tpm_ppi_write_dsdt_regions,
        .write_dsdt_dsm = tpm_ppi_write_dsdt_dsm,
};
TPM_PPI_SET(tpm_ppi_qemu);