fixes

include/ipc/common.h

@@ -0,0 +1,36 @@
+#pragma once
+
+#include <zinnia/channel.h>
+#include <zinnia/handle.h>
+#include <common/utils.h>
+#include <stdint.h>
+
+#define ZN_IPC_NUM(group, num) ((uint32_t)(group) << 24u) | ((uint32_t)(num) & 0xffffffu)
+
+#define ZN_IPC(name, group, num, num_handles) \
+    name##_inner; \
+    constexpr uint32_t name##_num = ZN_IPC_NUM(group, num); \
+    typedef struct { \
+        uint32_t id; \
+        zn_handle_t handles[num_handles]; \
+        name##_inner inner; \
+    } name
+
+#define zn_ipc_write(channel, obj) \
+    zn_channel_write(channel, (obj)->handles, &(obj)->inner, ARRAY_SIZE((obj)->handles), sizeof((obj)->inner))
+
+#define zn_ipc_read(channel, obj) \
+    zn_channel_read( \
+        channel, \
+        (obj)->handles, \
+        &(obj)->inner, \
+        ARRAY_SIZE((obj)->handles), \
+        sizeof((obj)->inner), \
+        nullptr, \
+        nullptr \
+    )
+
+#define zn_ipc_new(name) \
+    (zn_ipc_fw_rsdp) { \
+        .id = name##_num \
+    }

include/zinnia/channel.h

@@ -13,6 +13,7 @@ extern "C" {
 
 enum zn_channel_flags {
     ZN_CHANNEL_NONE = 0,
+    ZN_CHANNEL_NONBLOCK = 1 << 0,
 };
 
 // Creates a new channel.

kernel/arch/x86_64/include/bits/sched.h

@@ -40,7 +40,7 @@ struct arch_context {
     uint64_t ss;
 };
 
-static_assert(sizeof(struct arch_context) == 176);
+static_assert(sizeof(struct arch_context) == 22 * sizeof(uint64_t));
 
 #define ARCH_CTX_NUM  rax
 #define ARCH_CTX_A0   rdi

kernel/arch/x86_64/percpu.c

@@ -30,6 +30,8 @@ union ia32_star {
     };
 };
 
+static_assert(sizeof(union ia32_star) == 8);
+
 static void setup_cpu(struct percpu* cpu) {
     asm_wrmsr(MSR_GS_BASE, (uint64_t)cpu);
     asm_wrmsr(MSR_FS_BASE, 0);

kernel/arch/x86_64/usercopy.c

@@ -82,7 +82,7 @@ bool arch_usercopy_write(__user void* dst, const void* src, size_t len, struct u
         "clac\n"
         "ret\n"
         :
-        : "i"(&read_region)
+        : "i"(&write_region)
         : "memory"
     );
 }

kernel/core/channel.c

@@ -84,7 +84,7 @@ zn_status_t channel_read(struct channel* ch, struct channel_msg** msg_out) {
         return ZN_OK;
     }
 
-    // No message and peer is gone — nothing will ever arrive.
+    // No message and peer is gone.
     if (!ch->peer) {
         spin_unlock(&ch->lock);
         return ZN_ERR_BAD_HANDLE;

kernel/include/assert.h

@@ -5,7 +5,7 @@
 
 // Like the standard C assert, but also active in debug builds.
 #define assert(expr, msg, ...) \
-    ({ \
+    do { \
         if (__unlikely(!(expr))) { \
             panic( \
                 "In function \"%s\" (%s:%u):\n" \
@@ -17,7 +17,7 @@
                 ##__VA_ARGS__ \
             ); \
         } \
-    })
+    } while (0)
 
 #ifndef NDEBUG
 #define debug_assert(...) assert(__VA_ARGS__)

kernel/include/kernel/channel.h

@@ -1,5 +1,8 @@
+// SPDX-License-Identifier: MIT
+
 #pragma once
 
+#include <zinnia/channel.h>
 #include <zinnia/status.h>
 #include <kernel/spin.h>
 #include <kernel/tailq.h>
@@ -19,6 +22,7 @@ struct channel_msg {
 struct channel {
     struct channel* peer;
     struct spinlock lock;
+    enum zn_channel_flags flags;
     tailq_head(struct channel_msg) messages;
     struct wait_queue waiters;
 };

kernel/include/kernel/syscalls.h

@@ -6,32 +6,34 @@ typedef zn_status_t (*syscall_fn_t)(struct arch_context* ctx);
 
 void syscall_dispatch(struct arch_context* ctx);
 
-zn_status_t syscall_log(struct arch_context* ctx);
-zn_status_t syscall_archctl(struct arch_context* ctx);
-zn_status_t syscall_page_size(struct arch_context* ctx);
-zn_status_t syscall_time(struct arch_context* ctx);
+#define DEFINE_SYSCALL(name) zn_status_t syscall_##name(struct arch_context* ctx)
 
-zn_status_t syscall_handle_validate(struct arch_context* ctx);
-zn_status_t syscall_handle_drop(struct arch_context* ctx);
-zn_status_t syscall_handle_clone(struct arch_context* ctx);
+DEFINE_SYSCALL(log);
+DEFINE_SYSCALL(archctl);
+DEFINE_SYSCALL(page_size);
+DEFINE_SYSCALL(time);
 
-zn_status_t syscall_vas_create(struct arch_context* ctx);
+DEFINE_SYSCALL(handle_validate);
+DEFINE_SYSCALL(handle_drop);
+DEFINE_SYSCALL(handle_clone);
 
-zn_status_t syscall_vmo_create(struct arch_context* ctx);
-zn_status_t syscall_vmo_create_phys(struct arch_context* ctx);
-zn_status_t syscall_vmo_map(struct arch_context* ctx);
+DEFINE_SYSCALL(vas_create);
 
-zn_status_t syscall_channel_create(struct arch_context* ctx);
-zn_status_t syscall_channel_wait(struct arch_context* ctx);
-zn_status_t syscall_channel_read(struct arch_context* ctx);
-zn_status_t syscall_channel_write(struct arch_context* ctx);
+DEFINE_SYSCALL(vmo_create);
+DEFINE_SYSCALL(vmo_create_phys);
+DEFINE_SYSCALL(vmo_map);
 
-zn_status_t syscall_thread_create(struct arch_context* ctx);
-zn_status_t syscall_thread_start(struct arch_context* ctx);
-zn_status_t syscall_thread_exit(struct arch_context* ctx);
+DEFINE_SYSCALL(channel_create);
+DEFINE_SYSCALL(channel_wait);
+DEFINE_SYSCALL(channel_read);
+DEFINE_SYSCALL(channel_write);
 
-zn_status_t syscall_random_get(struct arch_context* ctx);
-zn_status_t syscall_random_entropy(struct arch_context* ctx);
+DEFINE_SYSCALL(thread_create);
+DEFINE_SYSCALL(thread_start);
+DEFINE_SYSCALL(thread_exit);
 
-zn_status_t syscall_futex_wait(struct arch_context* ctx);
-zn_status_t syscall_futex_wake(struct arch_context* ctx);
+DEFINE_SYSCALL(random_get);
+DEFINE_SYSCALL(random_entropy);
+
+DEFINE_SYSCALL(futex_wait);
+DEFINE_SYSCALL(futex_wake);

kernel/syscalls/channel.c

@@ -12,8 +12,14 @@
 #include <kernel/usercopy.h>
 
 zn_status_t syscall_channel_create(struct arch_context* ctx) {
-    __user zn_handle_t* end0 = (__user zn_handle_t*)ctx->ARCH_CTX_A1;
-    __user zn_handle_t* end1 = (__user zn_handle_t*)ctx->ARCH_CTX_A2;
+    auto flags = (enum zn_channel_flags)ctx->a0;
+    auto end0 = (__user zn_handle_t*)ctx->a1;
+    auto end1 = (__user zn_handle_t*)ctx->a2;
+
+    // Validate flags before doing anything.
+    if (flags & !(ZN_CHANNEL_NONE | ZN_CHANNEL_NONBLOCK)) {
+        return ZN_ERR_INVALID;
+    }
 
     struct channel* ep0;
     struct channel* ep1;
@@ -61,11 +67,11 @@ zn_status_t syscall_channel_create(struct arch_context* ctx) {
 }
 
 zn_status_t syscall_channel_write(struct arch_context* ctx) {
-    zn_handle_t ch_handle = ctx->ARCH_CTX_A0;
-    __user zn_handle_t* handles = (__user zn_handle_t*)ctx->ARCH_CTX_A1;
-    __user void* bytes = (__user void*)ctx->ARCH_CTX_A2;
-    size_t num_handles = ctx->ARCH_CTX_A3;
-    size_t num_bytes = ctx->ARCH_CTX_A4;
+    auto ch_handle = (zn_handle_t)ctx->a0;
+    auto handles = (__user zn_handle_t*)ctx->a0;
+    auto bytes = (__user void*)ctx->a2;
+    size_t num_handles = ctx->a3;
+    size_t num_bytes = ctx->a4;
 
     struct task* current = percpu_get()->sched.current;
 
@@ -95,7 +101,7 @@ zn_status_t syscall_channel_write(struct arch_context* ctx) {
         }
     }
 
-    // Copy and transfer handles (move semantics).
+    // Copy and transfer handles.
     struct namespace_desc* descs = nullptr;
     if (num_handles > 0) {
         if (!handles) {
@@ -155,13 +161,13 @@ zn_status_t syscall_channel_write(struct arch_context* ctx) {
 }
 
 zn_status_t syscall_channel_read(struct arch_context* ctx) {
-    zn_handle_t ch_handle = ctx->ARCH_CTX_A0;
-    __user zn_handle_t* handles = (__user zn_handle_t*)ctx->ARCH_CTX_A1;
-    __user void* bytes = (__user void*)ctx->ARCH_CTX_A2;
-    size_t num_handles = ctx->ARCH_CTX_A3;
-    size_t num_bytes = ctx->ARCH_CTX_A4;
-    __user size_t* read_handles = (__user size_t*)ctx->ARCH_CTX_A5;
-    __user size_t* read_bytes = (__user size_t*)ctx->ARCH_CTX_A6;
+    zn_handle_t ch_handle = ctx->a0;
+    __user zn_handle_t* handles = (__user zn_handle_t*)ctx->a1;
+    __user void* bytes = (__user void*)ctx->a2;
+    size_t num_handles = ctx->a3;
+    size_t num_bytes = ctx->a4;
+    __user size_t* read_handles = (__user size_t*)ctx->a5;
+    __user size_t* read_bytes = (__user size_t*)ctx->a6;
 
     struct task* current = percpu_get()->sched.current;
     struct sched_percpu* sched = &percpu_get()->sched;
@@ -183,7 +189,7 @@ zn_status_t syscall_channel_read(struct arch_context* ctx) {
 
         if (status == ZN_OK) {
             // Copy byte data to userspace.
-            size_t bytes_to_copy = msg->num_bytes < num_bytes ? msg->num_bytes : num_bytes;
+            size_t bytes_to_copy = MIN(msg->num_bytes, num_bytes);
             if (bytes_to_copy > 0 && bytes) {
                 if (!usercopy_write(bytes, msg->data, bytes_to_copy)) {
                     channel_msg_free(msg);
@@ -192,7 +198,7 @@ zn_status_t syscall_channel_read(struct arch_context* ctx) {
             }
 
             // Transfer handle descriptors into the reader's namespace.
-            size_t handles_to_copy = msg->num_handles < num_handles ? msg->num_handles : num_handles;
+            size_t handles_to_copy = MIN(msg->num_handles, num_handles);
             if (handles_to_copy > 0 && handles) {
                 for (size_t i = 0; i < handles_to_copy; i++) {
                     zn_handle_t new_handle;
@@ -231,13 +237,13 @@ zn_status_t syscall_channel_read(struct arch_context* ctx) {
         if (status == ZN_ERR_BAD_HANDLE)
             return status;
 
-        // Empty but peer alive — block until a message arrives or peer closes.
+        // Block until a message arrives or peer closes.
         sched_block(sched, &ch->waiters);
     }
 }
 
 zn_status_t syscall_channel_wait(struct arch_context* ctx) {
-    zn_handle_t ch_handle = ctx->ARCH_CTX_A0;
+    zn_handle_t ch_handle = ctx->a0;
 
     struct task* current = percpu_get()->sched.current;
     struct sched_percpu* sched = &percpu_get()->sched;

kernel/syscalls/vmo.c

@@ -15,8 +15,8 @@
 #include <stdatomic.h>
 
 zn_status_t syscall_vmo_create(struct arch_context* ctx) {
-    size_t length = ctx->ARCH_CTX_A0;
-    __user zn_handle_t* out = (__user zn_handle_t*)ctx->ARCH_CTX_A1;
+    size_t length = ctx->a0;
+    __user zn_handle_t* out = (__user zn_handle_t*)ctx->a1;
 
     // Allocate new VMO.
     struct paged_vmo* vmo;
@@ -43,9 +43,9 @@ zn_status_t syscall_vmo_create(struct arch_context* ctx) {
 }
 
 zn_status_t syscall_vmo_create_phys(struct arch_context* ctx) {
-    uintptr_t addr = ctx->ARCH_CTX_A0;
-    size_t length = ctx->ARCH_CTX_A1;
-    __user zn_handle_t* out = (__user zn_handle_t*)ctx->ARCH_CTX_A2;
+    uintptr_t addr = ctx->a0;
+    size_t length = ctx->a1;
+    __user zn_handle_t* out = (__user zn_handle_t*)ctx->a2;
 
     struct vmo* vmo;
     zn_status_t status = vmo_new_phys_range(addr, length, &vmo);
@@ -71,12 +71,12 @@ zn_status_t syscall_vmo_create_phys(struct arch_context* ctx) {
 }
 
 zn_status_t syscall_vmo_map(struct arch_context* ctx) {
-    zn_handle_t vmo_handle = ctx->ARCH_CTX_A0;
-    zn_handle_t vas_handle = ctx->ARCH_CTX_A1;
-    uintptr_t vmo_offset = ctx->ARCH_CTX_A2;
-    __user uintptr_t* addr = (__user uintptr_t*)ctx->ARCH_CTX_A3;
-    size_t bytes = ctx->ARCH_CTX_A4;
-    enum zn_vm_flags flags = ctx->ARCH_CTX_A5;
+    zn_handle_t vmo_handle = ctx->a0;
+    zn_handle_t vas_handle = ctx->a1;
+    uintptr_t vmo_offset = ctx->a2;
+    auto addr = (__user uintptr_t*)ctx->a3;
+    size_t bytes = ctx->a4;
+    enum zn_vm_flags flags = ctx->a5;
 
     struct task* current = percpu_get()->sched.current;
 
@@ -112,8 +112,8 @@ zn_status_t syscall_vmo_map(struct arch_context* ctx) {
 
     // TODO: Use actual allocator for user task.
     if (target_addr == 0) {
-        static uintptr_t map_offset = 0xA000'0000;
-        target_addr = atomic_fetch_add(&map_offset, ALIGN_UP(bytes, arch_mem_page_size()));
+        static _Atomic uintptr_t map_offset = 0xA000'0000;
+        target_addr = atomic_fetch_add((volatile uintptr_t*)&map_offset, ALIGN_UP(bytes, arch_mem_page_size()));
     }
 
     if (addr != nullptr) {