modules

.gitignore

@@ -5,3 +5,4 @@ build/
 *.o
 *.a
 *.so
+__pycache__/

Kconfig

@@ -1,7 +1,9 @@
 mainmenu "Zinnia Kernel Configuration"
 
-source "dev/Kconfig"
-
 config KERNEL_FLAVOR
   string "Kernel flavor name"
   default "vanilla"
+
+source "arch/$(ARCH)/Kconfig"
+source "core/Kconfig"
+source "dev/Kconfig"

arch/x86_64/Kconfig

@@ -0,0 +1,16 @@
+menu "x86_64 Architecture options"
+
+config X86_64
+  bool
+  default y
+  select ACPI
+  select HAVE_MMU
+  select HAVE_MMU_GENERIC
+  help
+    64-bit x86 CPU support for AMD and Intel CPUs.
+
+config TSC
+  bool "Invariant Timestamp Counter support"
+  default y
+
+endmenu

arch/x86_64/meson.build

@@ -1,7 +1,6 @@
 kernel_c_args += [
     '-mgeneral-regs-only',
     '-mno-red-zone',
-    '-mcmodel=kernel',
     '-masm=intel',
 ]
 

arch/x86_64/percpu.c

@@ -1,5 +1,6 @@
 #include <zinnia/percpu.h>
 #include <zinnia/print.h>
+#include <config.h>
 #include <stddef.h>
 #include <x86_64/apic.h>
 #include <x86_64/asm.h>
@@ -119,7 +120,9 @@ static void setup_cpu(struct percpu* cpu) {
 
 void arch_percpu_init() {
     hpet_init();
+#if CONFIG_TSC
     tsc_init();
+#endif
 
     // Init the BSP.
     setup_cpu(&percpu_bsp);

arch/x86_64/sched.c

@@ -94,9 +94,9 @@ void task_entry_thunk() {
     asm volatile(
         "mov rdi, rbx\n"
         "mov rsi, r12\n"
-        "jmp %c0"
+        "jmp %0"
         :
-        : "i"(task_entry)
+        : "r"(task_entry)
         : "memory"
     );
 }
@@ -173,7 +173,7 @@ bool arch_sched_preempt_enable() {
 void arch_sched_jump_to_context(struct arch_context* context) {
     asm volatile(
         "mov rsp, rdi\n"
-        "jmp %c0\n" ::"i"(interrupt_return)
+        "jmp %0\n" ::"r"(interrupt_return)
     );
 }
 

arch/x86_64/sys.c

@@ -11,9 +11,9 @@
 [[__init, __naked, __used]]
 void _start() {
     asm volatile(
-        "lea rsp, [rip + %0]\n"
+        "mov rsp, %0\n"
         "jmp %1"
         :
-        : "i"(__ld_stack_top), "r"(kernel_entry)
+        : "r"(__ld_stack_top), "r"(kernel_entry)
     );
 }

arch/x86_64/syscall.c

@@ -39,7 +39,7 @@ void arch_syscall_stub() {
         "    push r15\n"
         "    xor rbp, rbp\n"
         "    mov rdi, rsp\n" // SysV ABI first argument.
-        "    call %c4\n"     // Call syscall handler.
+        "    call %4\n"      // Call syscall handler.
         "    cli\n"
         "    pop r15\n"
         "    pop r14\n"
@@ -66,6 +66,6 @@ void arch_syscall_stub() {
           "i"(offsetof(struct percpu, kernel_stack)),        // 1
           "i"(offsetof(struct gdt, user_code64) | CPL_USER), // 2
           "i"(offsetof(struct gdt, user_data) | CPL_USER),   // 3
-          "i"(syscall_dispatch)                              // 4
+          "r"(syscall_dispatch)                              // 4
     );
 }

arch/x86_64/usercopy.c

@@ -1,6 +1,14 @@
 #include <zinnia/compiler.h>
 #include <arch/usercopy.h>
 
+void arch_usercopy_allow(bool state) {
+    if (state) {
+        asm volatile("stac" ::: "memory");
+    } else {
+        asm volatile("clac" ::: "memory");
+    }
+}
+
 extern void x86_64_read_start();
 extern void x86_64_read_end();
 extern void x86_64_read_fault();
@@ -11,37 +19,34 @@ static const struct usercopy_region read_region = {
     .fault_ip = x86_64_read_fault,
 };
 
+[[__naked]]
 bool arch_usercopy_read(void* dst, const __user void* src, size_t len, struct usercopy_region** region) {
     asm volatile(
-        "stac\n"
         // Setup regs for `rep movsb`.
-        "xchg rcx, rdx\n"
+        "    xchg rcx, rdx\n"
-        "mov rax, [rip + %0]\n"
+        "    mov rax, [rip + %0]\n"
-        "xchg [rdx], rax\n"
+        "    xchg [rdx], rax\n"
 
         ".global x86_64_read_start\n"
-        "x86_64_read_start:\n"
+        "    x86_64_read_start:\n"
-        "rep movsb\n"
+        "    rep movsb\n"
 
         ".global x86_64_read_end\n"
         "x86_64_read_end:\n"
-        "xor rax, rax\n"
+        "    xor rax, rax\n"
-        "xchg [rdx], rax\n"
+        "    xchg [rdx], rax\n"
-        "mov rax, 1\n"
+        "    mov rax, 1\n"
-        "clac\n"
+        "    ret\n"
-        "ret\n"
 
         ".global x86_64_read_fault\n"
         "x86_64_read_fault:\n"
-        "xor rax, rax\n"
+        "    xor rax, rax\n"
-        "xchg [rdx], rax\n"
+        "    xchg [rdx], rax\n"
-        "clac\n"
+        "    ret\n"
-        "ret\n"
         :
         : "i"(&read_region)
         : "memory"
     );
-    return false;
 }
 
 extern void x86_64_write_start();
@@ -54,37 +59,34 @@ static const struct usercopy_region write_region = {
     .fault_ip = x86_64_write_fault,
 };
 
+[[__naked]]
 bool arch_usercopy_write(__user void* dst, const void* src, size_t len, struct usercopy_region** region) {
     asm volatile(
-        "stac\n"
         // Setup regs for `rep movsb`.
-        "xchg rcx, rdx\n"
+        "    xchg rcx, rdx\n"
-        "mov rax, [rip + %0]\n"
+        "    mov rax, [rip + %0]\n"
-        "mov [rdx], rax\n"
+        "    mov [rdx], rax\n"
 
         ".global x86_64_write_start\n"
-        "x86_64_write_start:\n"
+        "    x86_64_write_start:\n"
-        "rep movsb\n"
+        "    rep movsb\n"
 
         ".global x86_64_write_end\n"
-        "x86_64_write_end:\n"
+        "    x86_64_write_end:\n"
-        "xor rax, rax\n"
+        "    xor rax, rax\n"
-        "xchg [rdx], rax\n"
+        "    xchg [rdx], rax\n"
-        "mov rax, 1\n"
+        "    mov rax, 1\n"
-        "clac\n"
+        "    ret\n"
-        "ret\n"
 
         ".global x86_64_write_fault\n"
         "x86_64_write_fault:\n"
-        "xor rax, rax\n"
+        "    xor rax, rax\n"
-        "xchg [rdx], rax\n"
+        "    xchg [rdx], rax\n"
-        "clac\n"
+        "    ret\n"
-        "ret\n"
         :
         : "i"(&write_region)
         : "memory"
     );
-    return false;
 }
 
 extern void x86_64_strlen_start();
@@ -100,36 +102,33 @@ static const struct usercopy_region strlen_region = {
 [[__naked]]
 bool arch_usercopy_strlen(const __user char* str, size_t max, size_t* len, struct usercopy_region** region) {
     asm volatile(
-        "stac\n"
+        "    mov rax, [rip + %0]\n"
-        "mov rax, [rip + %0]\n"
+        "    xchg [rcx], rax\n"
-        "xchg [rcx], rax\n"
 
         ".global x86_64_strlen_start\n"
-        "x86_64_strlen_start:\n"
+        "    x86_64_strlen_start:\n"
-        "xor r8, r8\n"
+        "    xor r8, r8\n"
         ".Lloop:\n"
-        "cmp byte ptr [rdi + r8], 0\n"
+        "    cmp byte ptr [rdi + r8], 0\n"
-        "je .Lleave\n"
+        "    je .Lleave\n"
-        "inc r8\n"
+        "    inc r8\n"
-        "cmp rsi, r8\n"
+        "    cmp rsi, r8\n"
-        "jne .Lloop\n"
+        "    jne .Lloop\n"
         ".Lleave:\n"
-        "mov [rdx], r8\n"
+        "    mov [rdx], r8\n"
 
         ".global x86_64_strlen_end\n"
         "x86_64_strlen_end:\n"
-        "xor rax, rax\n"
+        "    xor rax, rax\n"
-        "xchg [rcx], rax\n"
+        "    xchg [rcx], rax\n"
-        "mov rax, 1\n"
+        "    mov rax, 1\n"
-        "clac\n"
+        "    ret\n"
-        "ret\n"
 
         ".global x86_64_strlen_fault\n"
         "x86_64_strlen_fault:\n"
-        "xor rax, rax\n"
+        "    xor rax, rax\n"
-        "xchg [rcx], rax\n"
+        "    xchg [rcx], rax\n"
-        "clac\n"
+        "    ret\n"
-        "ret\n"
         :
         : "i"(&strlen_region)
         : "memory"

boot/kernel.ld

@@ -54,27 +54,29 @@ SECTIONS
 
     .dynsym : {
         __ld_dynsym_start = .;
-        *(.dynsym)
+        KEEP(*(.dynsym*))
         __ld_dynsym_end = .;
     } :data
 
     .dynstr : {
         __ld_dynstr_start = .;
-        *(.dynstr)
+        KEEP(*(.dynstr*))
         __ld_dynstr_end = .;
     } :data
 
     .dynamic : {
-        *(.dynamic)
+        *(.dynamic*)
     } :data :dynamic
 
-    .bss : {
+    .bss ALIGN(CONSTANT(MAXPAGESIZE)) (NOLOAD) : {
+        *(.*bss .*bss.*)
+        *(COMMON)
+
         /* Small stack to bootstrap the allocator */
+        . = ALIGN(16);
         __ld_stack_bottom = .;
         . += 0x2000;
         __ld_stack_top = .;
-        *(.*bss .*bss.*)
-        *(COMMON)
     } :data
 
     /* Per-CPU data block. MUST always come last. */

core/Kconfig

@@ -0,0 +1,18 @@
+menu "Kernel Core options"
+
+source "core/mem/Kconfig"
+
+choice SCHED_ALG
+  prompt "Scheduler algorithm"
+  default SCHED_DUMB
+  help
+    The algorithm to use for scheduling.
+
+config SCHED_DUMB
+  bool "Dumb Scheduler"
+  help
+    Very basic scheduler, without any priorities.
+
+endchoice
+
+endmenu

core/mem/Kconfig

@@ -0,0 +1,8 @@
+menu "Memory Management options"
+
+config HAVE_MMU
+  bool
+config HAVE_MMU_GENERIC
+  bool
+
+endmenu

core/mem/meson.build

@@ -1,7 +1,6 @@
 kernel_sources += files(
     'fault.c',
     'init.c',
-    'pmap.c',
     'pmm.c',
     'slab.c',
     'usercopy.c',
@@ -9,3 +8,9 @@ kernel_sources += files(
     'vma.c',
     'vmo.c',
 )
+
+if kconfig.get('CONFIG_HAVE_MMU', 'n') == 'y'
+    kernel_sources += files(
+        'pmap.c',
+    )
+endif

core/mem/pmap.c

@@ -3,8 +3,12 @@
 #include <zinnia/pmap.h>
 #include <zinnia/spin.h>
 #include <zinnia/vma.h>
+#include <config.h>
 #include <string.h>
 
+// TODO: For now, we assume that we can do generic PTE lookups on every arch that has a MMU.
+static_assert(CONFIG_HAVE_MMU_GENERIC);
+
 errno_t pmap_new_kernel(struct pmap* pt, enum alloc_flags flags) {
     flags &= ~ALLOC_NOZERO;
 

core/mem/usercopy.c

@@ -3,13 +3,22 @@
 #include <arch/usercopy.h>
 
 bool usercopy_read(void* dst, const __user void* src, size_t len) {
-    return arch_usercopy_read(dst, src, len, &percpu_get()->sched.current->usercopy_region);
+    arch_usercopy_allow(true);
+    bool success = arch_usercopy_read(dst, src, len, &percpu_get()->sched.current->usercopy_region);
+    arch_usercopy_allow(false);
+    return success;
 }
 
 bool usercopy_write(__user void* dst, const void* src, size_t len) {
-    return arch_usercopy_write(dst, src, len, &percpu_get()->sched.current->usercopy_region);
+    arch_usercopy_allow(true);
+    bool success = arch_usercopy_write(dst, src, len, &percpu_get()->sched.current->usercopy_region);
+    arch_usercopy_allow(false);
+    return success;
 }
 
 bool usercopy_strlen(const __user char* str, size_t max, size_t* len) {
-    return arch_usercopy_strlen(str, max, len, &percpu_get()->sched.current->usercopy_region);
+    arch_usercopy_allow(true);
+    bool success = arch_usercopy_strlen(str, max, len, &percpu_get()->sched.current->usercopy_region);
+    arch_usercopy_allow(false);
+    return success;
 }

core/sched/meson.build

@@ -1,4 +1,7 @@
 kernel_sources += files(
     'core.c',
-    'sched_dumb.c',
 )
+
+if kconfig.get('CONFIG_SCHED_DUMB', 'n') == 'y'
+    kernel_sources += files('sched_dumb.c')
+endif

dev/Kconfig

@@ -12,4 +12,7 @@ config ACPI
   help
     Adds support for ACPI firmware, tables and devices.
 
+source "dev/block/Kconfig"
+source "dev/pci/Kconfig"
+
 endmenu

dev/block/Kconfig

@@ -0,0 +1,5 @@
+menu "Block device drivers"
+
+source "dev/block/nvme/Kconfig"
+
+endmenu

dev/block/meson.build

@@ -0,0 +1,3 @@
+if kconfig.get('CONFIG_NVME_CORE', 'n') != 'n'
+    subdir('nvme')
+endif

dev/block/nvme/Kconfig

@@ -0,0 +1,13 @@
+menu "NVMe Support"
+
+config NVME_CORE
+  bool
+  default y
+
+config NVME_PCI
+  bool "NVMe via PCI transport"
+  default y
+  depends on PCI
+  depends on NVME_CORE
+
+endmenu

dev/block/nvme/core.c

@@ -0,0 +1,12 @@
+#include <zinnia/cmdline.h>
+#include <zinnia/module.h>
+#include <zinnia/print.h>
+
+void nvme_init(struct module* mod) {
+    log("Hello world from NVMe!\n");
+}
+
+void do_nvme(bool on) {}
+CMDLINE_OPTION("nvme_on", "My description", do_nvme);
+
+MODULE("NVME", "Marvin Friedrich", "ISC", "1.0", nvme_init);

dev/block/nvme/meson.build

@@ -0,0 +1,12 @@
+nvme_sources = files('core.c')
+
+if kconfig.get('CONFIG_NVME_PCI', 'n') == 'y'
+    nvme_sources += files('pci.c')
+endif
+
+modules += {
+    'nvme': {
+        'modular': true, #kconfig.get('CONFIG_NVME_CORE') == 'm',
+        'sources': nvme_sources,
+    },
+}

dev/block/nvme/spec.h

@@ -0,0 +1 @@
+#pragma once

dev/meson.build

@@ -1,9 +1,12 @@
 subdir('common')
+subdir('block')
 
-if cfg.get('CONFIG_ACPI', 0) == 1
+if kconfig.get('CONFIG_ACPI', 'n') == 'y'
     subdir('acpi')
 endif
 
-if cfg.get('CONFIG_DT', 0) == 1
+if kconfig.get('CONFIG_DT', 'n') == 'y'
     subdir('dt')
 endif
+
+module_lds = meson.current_source_dir() / 'module.ld'

dev/module.ld

@@ -0,0 +1,101 @@
+/* Linker script for kernel modules */
+
+ENTRY(__module_start)
+
+PHDRS
+{
+    text        PT_LOAD     FLAGS(5);
+    rodata      PT_LOAD     FLAGS(4);
+    data        PT_LOAD     FLAGS(6);
+    dynamic     PT_DYNAMIC  FLAGS(6);
+    modversion  0x60000001;
+    modauthor   0x60000002;
+    moddesc     0x60000003;
+    modlicense  0x60000004;
+    modcmdline  0x60000005;
+}
+
+SECTIONS
+{
+    . = ALIGN(CONSTANT(MAXPAGESIZE));
+
+    /* Code */
+    .text : {
+        *(.init .init.*)
+        *(.text .text.*)
+        *(.fini .fini.*)
+        *(.plt .plt.*)
+    } :text
+
+    . = ALIGN(CONSTANT(MAXPAGESIZE));
+
+    /* Read-only data */
+    .rodata : {
+        *(.rodata .rodata.*)
+        *(.hash .hash.*)
+        *(.got .got.*)
+        *(.got.plt .got.plt.*)
+    } :rodata
+
+    .cmdline : {
+        KEEP(*(.cmdline))
+    } :rodata :modcmdline
+
+    .mod.version : {
+        KEEP(*(.mod.version))
+    } :rodata :modversion
+
+    .mod.author : {
+        KEEP(*(.mod.author))
+    } :rodata :modauthor
+
+    .mod.desc : {
+        KEEP(*(.mod.desc))
+    } :rodata :moddesc
+
+    .mod.license : {
+        KEEP(*(.mod.license))
+    } :rodata :modlicense
+
+    . = ALIGN(CONSTANT(MAXPAGESIZE));
+
+    /* Read-Write data */
+    .data : {
+        *(.data)
+        *(.data.*)
+    } :data
+
+    /* Zero-initialized memory */
+    .bss : {
+        *(.*bss .*bss.*)
+        *(COMMON)
+    } :data
+
+    .dynsym : {
+        *(.dynsym .dynsym.*)
+    } :data
+
+    .dynstr : {
+        *(.dynstr .dynstr.*)
+    } :data
+
+    .rela.dyn : {
+        *(.rela.dyn .rela.dyn.*)
+    } :data
+
+    /* Dynamic tags */
+    .dynamic : {
+        *(.dynamic)
+    } :data :dynamic
+
+    /DISCARD/ :
+    {
+        *(.comment*)
+        *(.eh_frame*)
+        *(.rel.eh_frame*)
+        *(.relr.dyn .relr.dyn.*)
+        *(.gcc_except_table*)
+        *(.note*)
+        *(.interp)
+    }
+}

dev/pci/Kconfig

@@ -0,0 +1,7 @@
+menu "PCI bus drivers"
+
+config PCI
+  bool "PCI core drivers"
+  default y
+
+endmenu

include/arch/archctl.h

@@ -2,6 +2,5 @@
 
 #include <zinnia/errno.h>
 #include <stdint.h>
-#include <uapi/archctl.h>
 
 errno_t arch_archctl(uintptr_t op, uintptr_t value);

include/arch/elf.h

@@ -1,3 +1,3 @@
 #pragma once
 
-#include <zinnia/elf.h>
+// TODO: Ensure bits are defining values right.

include/zinnia/cmdline.h

@@ -57,10 +57,10 @@ struct cmdline_option {
     };
     union {
         const char** str_limit;
-        struct cmdline_option_limit_int {
+        struct cmdline_limit_int {
             intptr_t min, max;
         }* intptr_limit;
-        struct cmdline_option_limit_uint {
+        struct cmdline_limit_uint {
             uintptr_t min, max;
         }* uintptr_limit;
         void* limit;
@@ -69,14 +69,3 @@ struct cmdline_option {
 
 // Parses the command line and invokes all options.
 void cmdline_parse(const char* cmdline);
-
-static_assert(
-    0 ==
-    _Generic(
-        (cmdline_parse),
-        void (*)(const char*): CMDLINE_STRING,
-        void (*)(bool): CMDLINE_BOOL,
-        void (*)(intptr_t): CMDLINE_INTPTR,
-        void (*)(uintptr_t): CMDLINE_UINTPTR
-    )
-);

include/zinnia/compiler.h

@@ -15,6 +15,7 @@
 #define __likely(x)         __builtin_expect(!!(x), 1)
 #define __unlikely(x)       __builtin_expect(!!(x), 0)
 #define __always_inline     gnu::always_inline
+#define __visibility        gnu::visibility
 
 // Only clang has these hints, GCC will throw a warning here.
 // They also don't support the C23 attribute format.

include/zinnia/device.h

@@ -0,0 +1,7 @@
+#pragma once
+#include <zinnia/module.h>
+
+struct device {
+    const char* name;
+    struct module* owner;
+};

include/zinnia/init.h

@@ -1,10 +1,10 @@
 #pragma once
 
-#include <stddef.h>
-#include <stdint.h>
 #include <zinnia/compiler.h>
 #include <zinnia/types.h>
 #include <zinnia/utils.h>
+#include <stddef.h>
+#include <stdint.h>
 
 #define __init                  __used, __section(".init.text"), __cold
 #define __initdata              __used, __section(".init.data")
@@ -28,7 +28,9 @@ struct boot_info {
     phys_t rsdp;
 };
 
+[[__visibility("hidden")]]
 extern uint8_t __ld_stack_top[];
+[[__visibility("hidden")]]
 extern uint8_t __ld_stack_bottom[];
 
 extern phys_t rsdp_addr;

include/zinnia/module.h

@@ -0,0 +1,24 @@
+#pragma once
+#include <zinnia/compiler.h>
+#include <zinnia/utils.h>
+#include <stdint.h>
+
+#define MODULE_PROPERTY(name, data) \
+    [[__used, __section(".mod." name)]] \
+    static const char UNIQUE_IDENT(_name)[] = data;
+
+#define MODULE(desc, author, license, version, entry) \
+    void __module_start(struct module* _module) { \
+        entry(_module); \
+    } \
+    MODULE_PROPERTY("author", author); \
+    MODULE_PROPERTY("desc", desc); \
+    MODULE_PROPERTY("version", version); \
+    MODULE_PROPERTY("license", license);
+
+struct module {
+    const char* name;
+    struct module* owner;
+};
+
+#define THIS_MODULE (struct module*)nullptr

include/zinnia/percpu.h

@@ -9,7 +9,25 @@
 
 ASSERT_TYPE(struct arch_percpu); // bits/percpu.h
 
-#define __percpu __used, __section(".percpu")
+/*
+On using per-CPU data
+---------------------
+
+Defining variables with `[[__percpu]]` will put them in a special section.
+This section is unique for every CPU. To access the correct memory of the
+caller's CPU, use `percpu_ref`.
+
+# Example
+
+[[__percpu]]
+int my_cpu_data = 0;
+int get_foo() {
+    return *percpu_ref(my_cpu_data);
+}
+*/
+
+#define __percpu      __used, __section(".percpu")
+#define percpu_ref(x) ((typeof(&(x)))((void*)percpu_get() + ((void*)&(x) - (void*)&percpu_bsp)))
 
 // CPU-relative information.
 struct percpu {

include/zinnia/vma.h

@@ -19,7 +19,7 @@ errno_t vma_new(struct vma** out);
 void vma_free(struct vma* v);
 
 errno_t vma_map(
-    struct vma* vm,
+    struct vma* vma,
     struct vmo* vmo,
     uintptr_t addr,
     size_t len,

meson.build

@@ -38,57 +38,58 @@ add_project_arguments(
     '-fno-stack-protector',
     '-ffunction-sections',
     '-fdata-sections',
+    '-ffreestanding',
+    '-nostdinc', # We provide our own headers.
+    '-fno-stack-protector',
     language: 'c',
 )
 
 add_project_link_arguments(
+    '-ffreestanding',
+    '-nostdlib',
     '-znoexecstack',
     '-Wl,--gc-sections',
     '-Wl,--build-id=none',
     language: 'c',
 )
 
-common_includes = include_directories('include')
+common_includes = [
+    include_directories('include'),
+    include_directories('arch' / target_machine.cpu_family() / 'include'),
+]
 
 cfg = configuration_data()
 cfg.set_quoted('ZINNIA_VERSION', meson.project_version())
 cfg.set_quoted('ZINNIA_ARCH', target_machine.cpu_family())
 cfg.set_quoted('ZINNIA_COMPILER_ID', c_compiler.get_id() + ' ' + c_compiler.version())
 cfg.set_quoted('ZINNIA_LINKER_ID', c_compiler.get_linker_id())
-
+#
 # Parse kernel config
 kv = import('keyval')
 kconfig = kv.load(get_option('config_path'))
 foreach k, v : kconfig
     if v == 'y'
         cfg.set10(k, true)
+    elif v == 'n'
+        cfg.set10(k, false)
     else
         cfg.set(k, v)
     endif
 endforeach
 
-kernel_c_args = [
+kernel_c_args = []
-    '-ffreestanding',
-    '-nostdinc', # We provide our own headers.
-    '-fno-stack-protector',
-    '-fno-pie',
-]
 
 kernel_lds = meson.current_source_dir() / 'boot' / 'kernel.ld'
-
 kernel_link_args = [
-    '-ffreestanding',
-    '-nostdlib',
-    '-static',
     '-lgcc',
+    '-static-libgcc',
     '-T' + kernel_lds,
+    '-Wl,--export-dynamic',
 ]
 
-kernel_includes = [
+kernel_includes = []
-    include_directories('arch' / target_machine.cpu_family() / 'include'),
-]
-
 kernel_sources = []
+modules = {}
 
 # Goes first so we can add arch-specific flags to drivers.
 subdir('arch' / target_machine.cpu_family())
@@ -104,18 +105,61 @@ configure_file(
     output: 'config.h',
 )
 
+mod_summary = {}
+foreach name, v : modules
+    is_modular = v.get('modular', false)
+    mod_sources = v.get('sources')
+    mod_c_args = v.get('c_args', [])
+    mod_link_args = v.get('link_args', [])
+    mod_includes = v.get('include_directories', [])
+    mod_link = v.get('link_with', [])
+
+    if is_modular
+        shared_library(
+            name,
+            sources: mod_sources,
+            c_args: ['-fPIC', '-fPIE', '-DIN_MODULE', mod_c_args],
+            link_args: [
+                '-T' + module_lds, mod_link_args,
+            ],
+            link_depends: module_lds,
+            include_directories: [
+                common_includes,
+                kernel_includes, # We want this, actually
+                mod_includes,
+            ],
+            name_prefix: '',
+            name_suffix: 'kso',
+            link_with: mod_link,
+            override_options: ['b_lundef=false'],
+            #link_depends: kernel.full_path(),
+        )
+    else
+        kernel_sources += mod_sources
+        kernel_c_args += mod_c_args
+        kernel_includes += mod_includes
+        kernel_link_args += mod_link_args
+    endif
+
+    mod_summary += {name: is_modular}
+endforeach
+
+# Kernel
 executable(
     'zinnia',
     include_directories: [
         common_includes,
         kernel_includes,
     ],
-    c_args: kernel_c_args,
+    c_args: ['-DIN_KERNEL', kernel_c_args],
     link_args: kernel_link_args,
     link_depends: kernel_lds,
-    sources: [
+    sources: kernel_sources,
-        kernel_sources,
-    ],
     install: true,
     install_dir: get_option('datadir') / 'zinnia',
+    pie: true,
 )
+
+# Print a summary
+summary(mod_summary, section: 'Driver configuration')
+summary(kconfig, bool_yn: true, section: 'Kernel configuration')

scripts/get_modinfo.py

@@ -0,0 +1,37 @@
+#!/usr/bin/env python3
+# Small script to print all options available inside a built kernel.
+# fmt: off
+import sys
+
+from elftools.elf.elffile import ELFFile
+
+SIZEOF_PTR = 8
+SIZEOF_STRUCT = 40
+ENDIAN = "little"
+
+
+if __name__ == "__main__":
+    if len(sys.argv) < 2:
+        print("Provide a path to the kernel binary to use")
+        sys.exit(1)
+
+    with open(sys.argv[1], "rb") as elffile:
+        file = ELFFile(elffile)
+
+        version = "?"
+        author = "?"
+        desc = "?"
+        license = "?"
+
+        for segment in file.iter_segments():
+            match segment["p_type"]:
+                case 0x60000001: version = segment.data()[:-1].decode()
+                case 0x60000002: author = segment.data()[:-1].decode()
+                case 0x60000003: desc = segment.data()[:-1].decode()
+                case 0x60000004: license = segment.data()[:-1].decode()
+
+        print(f"Module info for \"{sys.argv[1]}\"")
+        print(f"Description:\t{desc}")
+        print(f"Version:\t{version}")
+        print(f"Author(s):\t{author}")
+        print(f"License:\t{license}")