root/drivers/soc/apple/rtkit-crashlog.c
// SPDX-License-Identifier: GPL-2.0-only OR MIT
/*
 * Apple RTKit IPC library
 * Copyright (C) The Asahi Linux Contributors
 */
#include "rtkit-internal.h"

#define FOURCC(a, b, c, d) \
        (((u32)(a) << 24) | ((u32)(b) << 16) | ((u32)(c) << 8) | ((u32)(d)))

#define APPLE_RTKIT_CRASHLOG_HEADER FOURCC('C', 'L', 'H', 'E')
#define APPLE_RTKIT_CRASHLOG_STR FOURCC('C', 's', 't', 'r')
#define APPLE_RTKIT_CRASHLOG_VERSION FOURCC('C', 'v', 'e', 'r')
#define APPLE_RTKIT_CRASHLOG_MBOX FOURCC('C', 'm', 'b', 'x')
#define APPLE_RTKIT_CRASHLOG_TIME FOURCC('C', 't', 'i', 'm')
#define APPLE_RTKIT_CRASHLOG_REGS FOURCC('C', 'r', 'g', '8')

/* For COMPILE_TEST on non-ARM64 architectures */
#ifndef PSR_MODE_EL0t
#define PSR_MODE_EL0t   0x00000000
#define PSR_MODE_EL1t   0x00000004
#define PSR_MODE_EL1h   0x00000005
#define PSR_MODE_EL2t   0x00000008
#define PSR_MODE_EL2h   0x00000009
#define PSR_MODE_MASK   0x0000000f
#endif

struct apple_rtkit_crashlog_header {
        u32 fourcc;
        u32 version;
        u32 size;
        u32 flags;
        u8 _unk[16];
};
static_assert(sizeof(struct apple_rtkit_crashlog_header) == 0x20);

struct apple_rtkit_crashlog_mbox_entry {
        u64 msg0;
        u64 msg1;
        u32 timestamp;
        u8 _unk[4];
};
static_assert(sizeof(struct apple_rtkit_crashlog_mbox_entry) == 0x18);

struct apple_rtkit_crashlog_regs {
        u32 unk_0;
        u32 unk_4;
        u64 regs[31];
        u64 sp;
        u64 pc;
        u64 psr;
        u64 cpacr;
        u64 fpsr;
        u64 fpcr;
        u64 unk[64];
        u64 far;
        u64 unk_X;
        u64 esr;
        u64 unk_Z;
} __packed;
static_assert(sizeof(struct apple_rtkit_crashlog_regs) == 0x350);

static void apple_rtkit_crashlog_dump_str(struct apple_rtkit *rtk, u8 *bfr,
                                          size_t size)
{
        u32 idx;
        u8 *ptr, *end;

        memcpy(&idx, bfr, 4);

        ptr = bfr + 4;
        end = bfr + size;
        while (ptr < end) {
                u8 *newline = memchr(ptr, '\n', end - ptr);

                if (newline) {
                        u8 tmp = *newline;
                        *newline = '\0';
                        dev_warn(rtk->dev, "RTKit: Message (id=%x): %s\n", idx,
                                 ptr);
                        *newline = tmp;
                        ptr = newline + 1;
                } else {
                        dev_warn(rtk->dev, "RTKit: Message (id=%x): %s", idx,
                                 ptr);
                        break;
                }
        }
}

static void apple_rtkit_crashlog_dump_version(struct apple_rtkit *rtk, u8 *bfr,
                                              size_t size)
{
        dev_warn(rtk->dev, "RTKit: Version: %s", bfr + 16);
}

static void apple_rtkit_crashlog_dump_time(struct apple_rtkit *rtk, u8 *bfr,
                                           size_t size)
{
        u64 crash_time;

        memcpy(&crash_time, bfr, 8);
        dev_warn(rtk->dev, "RTKit: Crash time: %lld", crash_time);
}

static void apple_rtkit_crashlog_dump_mailbox(struct apple_rtkit *rtk, u8 *bfr,
                                              size_t size)
{
        u32 type, index, i;
        size_t n_messages;
        struct apple_rtkit_crashlog_mbox_entry entry;

        memcpy(&type, bfr + 16, 4);
        memcpy(&index, bfr + 24, 4);
        n_messages = (size - 28) / sizeof(entry);

        dev_warn(rtk->dev, "RTKit: Mailbox history (type = %d, index = %d)",
                 type, index);
        for (i = 0; i < n_messages; ++i) {
                memcpy(&entry, bfr + 28 + i * sizeof(entry), sizeof(entry));
                dev_warn(rtk->dev, "RTKit:  #%03d@%08x: %016llx %016llx", i,
                         entry.timestamp, entry.msg0, entry.msg1);
        }
}

static void apple_rtkit_crashlog_dump_regs(struct apple_rtkit *rtk, u8 *bfr,
                                           size_t size)
{
        struct apple_rtkit_crashlog_regs *regs;
        const char *el;
        int i;

        if (size < sizeof(*regs)) {
                dev_warn(rtk->dev, "RTKit: Regs section too small: 0x%zx", size);
                return;
        }

        regs = (struct apple_rtkit_crashlog_regs *)bfr;

        switch (regs->psr & PSR_MODE_MASK) {
        case PSR_MODE_EL0t:
                el = "EL0t";
                break;
        case PSR_MODE_EL1t:
                el = "EL1t";
                break;
        case PSR_MODE_EL1h:
                el = "EL1h";
                break;
        case PSR_MODE_EL2t:
                el = "EL2t";
                break;
        case PSR_MODE_EL2h:
                el = "EL2h";
                break;
        default:
                el = "unknown";
                break;
        }

        dev_warn(rtk->dev, "RTKit: Exception dump:");
        dev_warn(rtk->dev, "  == Exception taken from %s ==", el);
        dev_warn(rtk->dev, "  PSR    = 0x%llx", regs->psr);
        dev_warn(rtk->dev, "  PC     = 0x%llx\n", regs->pc);
        dev_warn(rtk->dev, "  ESR    = 0x%llx\n", regs->esr);
        dev_warn(rtk->dev, "  FAR    = 0x%llx\n", regs->far);
        dev_warn(rtk->dev, "  SP     = 0x%llx\n", regs->sp);
        dev_warn(rtk->dev, "\n");

        for (i = 0; i < 31; i += 4) {
                if (i < 28)
                        dev_warn(rtk->dev,
                                         "  x%02d-x%02d = %016llx %016llx %016llx %016llx\n",
                                         i, i + 3,
                                         regs->regs[i], regs->regs[i + 1],
                                         regs->regs[i + 2], regs->regs[i + 3]);
                else
                        dev_warn(rtk->dev,
                                         "  x%02d-x%02d = %016llx %016llx %016llx\n", i, i + 3,
                                         regs->regs[i], regs->regs[i + 1], regs->regs[i + 2]);
        }

        dev_warn(rtk->dev, "\n");
}

void apple_rtkit_crashlog_dump(struct apple_rtkit *rtk, u8 *bfr, size_t size)
{
        size_t offset;
        u32 section_fourcc, section_size;
        struct apple_rtkit_crashlog_header header;

        memcpy(&header, bfr, sizeof(header));
        if (header.fourcc != APPLE_RTKIT_CRASHLOG_HEADER) {
                dev_warn(rtk->dev, "RTKit: Expected crashlog header but got %x",
                         header.fourcc);
                return;
        }

        if (header.size > size) {
                dev_warn(rtk->dev, "RTKit: Crashlog size (%x) is too large",
                         header.size);
                return;
        }

        size = header.size;
        offset = sizeof(header);

        while (offset < size) {
                memcpy(&section_fourcc, bfr + offset, 4);
                memcpy(&section_size, bfr + offset + 12, 4);

                switch (section_fourcc) {
                case APPLE_RTKIT_CRASHLOG_HEADER:
                        dev_dbg(rtk->dev, "RTKit: End of crashlog reached");
                        return;
                case APPLE_RTKIT_CRASHLOG_STR:
                        apple_rtkit_crashlog_dump_str(rtk, bfr + offset + 16,
                                                      section_size);
                        break;
                case APPLE_RTKIT_CRASHLOG_VERSION:
                        apple_rtkit_crashlog_dump_version(
                                rtk, bfr + offset + 16, section_size);
                        break;
                case APPLE_RTKIT_CRASHLOG_MBOX:
                        apple_rtkit_crashlog_dump_mailbox(
                                rtk, bfr + offset + 16, section_size);
                        break;
                case APPLE_RTKIT_CRASHLOG_TIME:
                        apple_rtkit_crashlog_dump_time(rtk, bfr + offset + 16,
                                                       section_size);
                        break;
                case APPLE_RTKIT_CRASHLOG_REGS:
                        apple_rtkit_crashlog_dump_regs(rtk, bfr + offset + 16,
                                                       section_size);
                        break;
                default:
                        dev_warn(rtk->dev,
                                 "RTKit: Unknown crashlog section: %x",
                                 section_fourcc);
                }

                offset += section_size;
        }

        dev_warn(rtk->dev,
                 "RTKit: End of crashlog reached but no footer present");
}