feat: disconnect Bluetooth devices, flush disks on shutdown/reboot, display progress in login.elf window

kernel/src/Api/BuildNo.hpp

@@ -12,4 +12,4 @@
 
 #pragma once
 
-#define MONTAUK_BUILD_NUMBER 57
+#define MONTAUK_BUILD_NUMBER 64

kernel/src/Api/Power.hpp

@@ -13,8 +13,28 @@
 #include <ACPI/AcpiShutdown.hpp>
 #include <ACPI/AcpiSleep.hpp>
 
+#include "Syscall.hpp"
+
 namespace Montauk {
 
+    // Pending graceful power-off request, set by the desktop and consumed by
+    // login.elf. Kernel-global IPC channel (one outstanding request system-wide).
+    // `inline` so the single definition is shared across translation units.
+    inline int g_pendingPowerAction = POWER_REQ_QUERY;
+
+    // SYS_POWER_REQUEST. action == POWER_REQ_QUERY reads and clears the pending
+    // action; any other value records it as the pending action. Returns the
+    // pending action for queries, or 0 when recording one.
+    static int64_t Sys_PowerRequest(int action) {
+        if (action == POWER_REQ_QUERY) {
+            int pending = g_pendingPowerAction;
+            g_pendingPowerAction = POWER_REQ_QUERY;
+            return (int64_t)pending;
+        }
+        g_pendingPowerAction = action;
+        return 0;
+    }
+
     static void Sys_Reset() {
         if (Efi::g_ResetSystem) {
             /* Switch to kernel PML4 which has identity-mapped UEFI runtime regions */

kernel/src/Api/Storage.hpp

@@ -109,6 +109,12 @@ namespace Montauk {
         return (int64_t)Fs::FsProbe::MountPartition(partIndex, driveNum);
     }
 
+    // Flush all block-device write caches and cleanly unmount disk-backed
+    // volumes ahead of power-off. Returns the number of volumes unmounted.
+    static int64_t Sys_FsSync() {
+        return (int64_t)Fs::FsProbe::SyncAndUnmountAll();
+    }
+
     // Format a partition with a filesystem. Returns 0 on success, -1 on error.
     static int64_t Sys_FsFormat(const FsFormatParams* params) {
         if (params == nullptr) return -1;

kernel/src/Api/Syscall.cpp

@@ -145,6 +145,8 @@ namespace Montauk {
             case SYS_SHUTDOWN:
                 Sys_Shutdown();
                 return 0;
+            case SYS_POWER_REQUEST:
+                return Sys_PowerRequest((int)frame->arg1);
             case SYS_GETTIME:
                 if (!UserMemory::Writable<DateTime>(frame->arg1)) return -1;
                 Sys_GetTime((DateTime*)frame->arg1);
@@ -322,6 +324,8 @@ namespace Montauk {
                 return (int64_t)Sys_GptAdd((const GptAddParams*)frame->arg1);
             case SYS_FSMOUNT:
                 return (int64_t)Sys_FsMount((int)frame->arg1, (int)frame->arg2);
+            case SYS_FS_SYNC:
+                return Sys_FsSync();
             case SYS_FSFORMAT:
                 if (!UserMemory::Readable<FsFormatParams>(frame->arg1)) return -1;
                 return (int64_t)Sys_FsFormat((const FsFormatParams*)frame->arg1);

kernel/src/Api/Syscall.hpp

@@ -249,6 +249,21 @@ namespace Montauk {
     static constexpr uint64_t SYS_THREAD_JOIN         = 132;
     static constexpr uint64_t SYS_THREAD_SELF         = 133;
 
+    /* Storage.hpp -- flush + unmount persistent volumes for power-off */
+    static constexpr uint64_t SYS_FS_SYNC             = 134;
+
+    /* Power.hpp -- cross-process graceful power-off request channel */
+    static constexpr uint64_t SYS_POWER_REQUEST       = 135;
+
+    // Graceful power-off request actions (SYS_POWER_REQUEST). The desktop posts
+    // a pending action and exits; login.elf reads it, runs the shutdown stages,
+    // then issues the matching SYS_SHUTDOWN / SYS_RESET.
+    enum PowerRequestAction : int {
+        POWER_REQ_QUERY    = 0,  // read-and-clear the pending action
+        POWER_REQ_SHUTDOWN = 1,
+        POWER_REQ_REBOOT   = 2,
+    };
+
     static constexpr uint32_t CLIPBOARD_MAX_TEXT_BYTES = 256 * 1024;
 
     static constexpr uint32_t IPC_SIGNAL_READABLE   = 1u << 0;

kernel/src/Drivers/Storage/Ahci.cpp

@@ -745,6 +745,9 @@ namespace Drivers::Storage::Ahci {
                     bdev.WriteSectors = [](void* ctx, uint64_t lba, uint32_t count, const void* buffer) -> bool {
                         return WriteSectors((int)(uintptr_t)ctx, lba, count, buffer);
                     };
+                    bdev.Flush = [](void* ctx) -> bool {
+                        return FlushCache((int)(uintptr_t)ctx);
+                    };
                     bdev.Ctx = (void*)(uintptr_t)i;
                     bdev.SectorCount = g_ports[i].SectorCount;
                     bdev.SectorSize = g_ports[i].SectorSizeLog;
@@ -826,6 +829,37 @@ namespace Drivers::Storage::Ahci {
         return ok;
     }
 
+    bool FlushCache(int port) {
+        if (!g_initialized || port < 0 || port >= MAX_PORTS || !g_ports[port].Active) {
+            return false;
+        }
+
+        int slot = FindFreeSlot(port);
+        if (slot < 0) {
+            KernelLogStream(ERROR, "AHCI") << "FlushCache: no free command slot";
+            return false;
+        }
+
+        CommandHeader* hdr = &g_ports[port].CmdList[slot];
+        CommandTable* tbl = g_ports[port].CmdTables[slot];
+
+        // FLUSH CACHE EXT is a non-data command: no PRDT, no transfer direction.
+        memset(tbl, 0, sizeof(CommandTable) + sizeof(PrdtEntry) * MAX_PRDT_ENTRIES);
+
+        FisRegH2D* fis = (FisRegH2D*)tbl->CommandFis;
+        fis->FisType = (uint8_t)FisType::RegH2D;
+        fis->CmdCtl = 1;  // Command
+        fis->Command = ATA_CMD_FLUSH_CACHE_EX;
+        fis->Device = (1 << 6); // LBA mode
+
+        hdr->CflPmpA = 5;       // CFL = FIS length in dwords (FisRegH2D = 20 bytes)
+        hdr->Flags = 0;         // read direction (no data either way)
+        hdr->PrdtLength = 0;
+        hdr->PrdByteCount = 0;
+
+        return IssueCommand(port, slot);
+    }
+
     bool WriteSectors(int port, uint64_t lba, uint32_t count, const void* buffer) {
         if (!g_initialized || port < 0 || port >= MAX_PORTS || !g_ports[port].Active) {
             return false;

kernel/src/Drivers/Storage/Ahci.hpp

@@ -167,9 +167,10 @@ namespace Drivers::Storage::Ahci {
     // ATA commands
     // =========================================================================
 
-    constexpr uint8_t ATA_CMD_IDENTIFY      = 0xEC;
-    constexpr uint8_t ATA_CMD_READ_DMA_EX   = 0x25;  // READ DMA EXT (48-bit LBA)
-    constexpr uint8_t ATA_CMD_WRITE_DMA_EX  = 0x35;  // WRITE DMA EXT (48-bit LBA)
+    constexpr uint8_t ATA_CMD_IDENTIFY       = 0xEC;
+    constexpr uint8_t ATA_CMD_READ_DMA_EX    = 0x25; // READ DMA EXT (48-bit LBA)
+    constexpr uint8_t ATA_CMD_WRITE_DMA_EX   = 0x35; // WRITE DMA EXT (48-bit LBA)
+    constexpr uint8_t ATA_CMD_FLUSH_CACHE_EX = 0xEA; // FLUSH CACHE EXT (48-bit)
 
     // =========================================================================
     // Constants
@@ -252,6 +253,10 @@ namespace Drivers::Storage::Ahci {
     // Write sectors to a SATA device
     bool WriteSectors(int port, uint64_t lba, uint32_t count, const void* buffer);
 
+    // Flush the device's write cache to media (FLUSH CACHE EXT). Returns true on
+    // success. Used during graceful shutdown to make pending writes durable.
+    bool FlushCache(int port);
+
     // Get info about a specific port
     const PortInfo* GetPortInfo(int port);
 

kernel/src/Drivers/Storage/BlockDevice.hpp

@@ -22,6 +22,10 @@ namespace Drivers::Storage {
     struct BlockDevice {
         bool (*ReadSectors)(void* ctx, uint64_t lba, uint32_t count, void* buffer);
         bool (*WriteSectors)(void* ctx, uint64_t lba, uint32_t count, const void* buffer);
+        // Flush the device's volatile write cache to non-volatile media. Optional:
+        // a null pointer means the device has no write-back cache to flush (so a
+        // completed WriteSectors is already durable). Returns true on success.
+        bool (*Flush)(void* ctx);
         void*    Ctx;
         uint64_t SectorCount;
         uint16_t SectorSize;

kernel/src/Drivers/Storage/Nvme.cpp

@@ -665,6 +665,9 @@ namespace Drivers::Storage::Nvme {
             bdev.WriteSectors = [](void* ctx, uint64_t lba, uint32_t count, const void* buffer) -> bool {
                 return WriteSectors((int)(uintptr_t)ctx, lba, count, buffer);
             };
+            bdev.Flush = [](void* ctx) -> bool {
+                return Flush((int)(uintptr_t)ctx);
+            };
             bdev.Ctx = (void*)(uintptr_t)i;
             bdev.SectorCount = g_namespaces[i].SectorCount;
             bdev.SectorSize = (uint16_t)g_namespaces[i].SectorSize;
@@ -770,6 +773,22 @@ namespace Drivers::Storage::Nvme {
         return ok;
     }
 
+    bool Flush(int ns) {
+        if (!g_initialized || ns < 0 || ns >= g_nsCount || !g_namespaces[ns].Active) {
+            return false;
+        }
+
+        // NVM Flush: commits the namespace's volatile write cache to media.
+        SqEntry cmd = {};
+        cmd.Opcode = IO_CMD_FLUSH;
+        cmd.Nsid = g_namespaces[ns].Nsid;
+
+        SubmitIoCommand(cmd);
+
+        CqEntry cqe;
+        return WaitIoCompletion(cqe);
+    }
+
     bool WriteSectors(int ns, uint64_t lba, uint32_t count, const void* buffer) {
         if (!g_initialized || ns < 0 || ns >= g_nsCount || !g_namespaces[ns].Active) {
             return false;

kernel/src/Drivers/Storage/Nvme.hpp

@@ -120,6 +120,7 @@ namespace Drivers::Storage::Nvme {
     // NVM I/O opcodes
     // =========================================================================
 
+    constexpr uint8_t IO_CMD_FLUSH = 0x00;
     constexpr uint8_t IO_CMD_READ  = 0x02;
     constexpr uint8_t IO_CMD_WRITE = 0x01;
 
@@ -187,6 +188,10 @@ namespace Drivers::Storage::Nvme {
     // Write sectors to an NVMe namespace
     bool WriteSectors(int ns, uint64_t lba, uint32_t count, const void* buffer);
 
+    // Flush the namespace's volatile write cache to media (NVM Flush command).
+    // Returns true on success. Used during graceful shutdown.
+    bool Flush(int ns);
+
     // Get info about a specific namespace
     const NamespaceInfo* GetNamespaceInfo(int ns);
 

kernel/src/Fs/FsProbe.cpp

@@ -6,6 +6,7 @@
 
 #include "FsProbe.hpp"
 #include <Drivers/Storage/Gpt.hpp>
+#include <Drivers/Storage/BlockDevice.hpp>
 #include <Terminal/Terminal.hpp>
 #include <Libraries/Memory.hpp>
 
@@ -195,4 +196,43 @@ namespace Fs::FsProbe {
         return unmounted;
     }
 
+    int SyncAndUnmountAll() {
+        // 1. Flush every block device's volatile write cache to media. FAT32 and
+        //    ext2 are write-through, so file data already reached the device; the
+        //    flush makes the device commit it to non-volatile storage.
+        int devCount = Drivers::Storage::GetBlockDeviceCount();
+        for (int i = 0; i < devCount; i++) {
+            const auto* dev = Drivers::Storage::GetBlockDevice(i);
+            if (dev && dev->Flush) {
+                dev->Flush(dev->Ctx);
+            }
+        }
+
+        // 2. Cleanly unmount every disk-backed VFS drive. The ramdisk has no
+        //    backing block device (GetBlockDeviceForDrive < 0) and is left
+        //    mounted so the rest of userspace keeps running until power-off.
+        int drives[Vfs::MaxDrives];
+        int n = Vfs::VfsDriveList(drives, Vfs::MaxDrives);
+        int unmounted = 0;
+
+        for (int i = 0; i < n; i++) {
+            int driveNum = drives[i];
+            if (GetBlockDeviceForDrive(driveNum) < 0) continue;
+
+            if (Vfs::UnregisterDrive(driveNum) == 0) {
+                unmounted++;
+                for (int p = 0; p < Drivers::Storage::Gpt::MaxPartitions; p++) {
+                    if (g_mounted[p] && g_driveForPart[p] == driveNum) {
+                        g_mounted[p] = false;
+                        g_driveForPart[p] = -1;
+                    }
+                }
+            }
+        }
+
+        Kt::KernelLogStream(Kt::OK, "FsProbe") << "Synced and unmounted "
+            << unmounted << " disk-backed volume(s) for power-off";
+        return unmounted;
+    }
+
 };

kernel/src/Fs/FsProbe.hpp

@@ -38,4 +38,10 @@ namespace Fs::FsProbe {
     // drive isn't backed by a partition (e.g. ramdisk).
     int GetBlockDeviceForDrive(int driveNum);
 
+    // Prepare persistent storage for power-off: flush every block device's
+    // write cache to media, then cleanly unmount all disk-backed VFS drives.
+    // The ramdisk (which has no backing block device) is left mounted. Returns
+    // the number of disk-backed volumes that were unmounted.
+    int SyncAndUnmountAll();
+
 };