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Kernel: Allow to disable early boot console

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This aid debugging on bare metal when we suspect that the boot console
does something wrong that interferes with other kernel components.
This commit is contained in:
Liav A 2022-03-15 22:04:12 +02:00 • committed by Linus Groh
parent 0ef1137e88
commit eca8f292a5
Notes: sideshowbarker 2024-07-18 00:34:07 +09:00
4 changed files with 23 additions and 4 deletions
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6
Base/usr/share/man/man7/boot_parameters.md
View file

@ -35,6 +35,12 @@ List of options:
* **`disable_virtio`** - If present on the command line, virtio devices will not be detected, and initialized on boot.
* **`early_boot_console`** - This parameter expects **`on`** or **`off`** and is by default set to **`on`**.
When set to **`off`**, the kernel will not initialize any early console to show kernel dmesg output.
When set to **`on`**, the kernel will try to initialize either a text mode console (if VGA text mode was detected)
or framebuffer console, based on what the Multiboot bootloader specified on the physical address, width, height
and bit color depth.
* **`enable_ioapic`** - This parameter expects **`on`** or **`off`** and is by default set to **`on`**.
When set to **`off`**, the kernel will initialize the two i8259 PICs.
When set to **`on`**, the kernel will try to initialize the IOAPIC (or IOAPICs if there's more than one),

10
Kernel/CommandLine.cpp
View file

@ -135,6 +135,16 @@ UNMAP_AFTER_INIT bool CommandLine::is_ioapic_enabled() const
PANIC("Unknown enable_ioapic setting: {}", value);
}
UNMAP_AFTER_INIT bool CommandLine::is_early_boot_console_disabled() const
{
auto value = lookup("early_boot_console"sv).value_or("on"sv);
if (value == "on"sv)
return false;
if (value == "off"sv)
return true;
PANIC("Unknown early_boot_console setting: {}", value);
}
UNMAP_AFTER_INIT bool CommandLine::is_vmmouse_enabled() const
{
return lookup("vmmouse"sv).value_or("on"sv) == "on"sv;

1
Kernel/CommandLine.h
View file

@ -85,6 +85,7 @@ public:
[[nodiscard]] bool disable_uhci_controller() const;
[[nodiscard]] bool disable_usb() const;
[[nodiscard]] bool disable_virtio() const;
[[nodiscard]] bool is_early_boot_console_disabled() const;
[[nodiscard]] AHCIResetMode ahci_reset_mode() const;
[[nodiscard]] StringView userspace_init() const;
[[nodiscard]] NonnullOwnPtrVector<KString> userspace_init_args() const;

10
Kernel/init.cpp
View file

@ -195,10 +195,12 @@ extern "C" [[noreturn]] UNMAP_AFTER_INIT void init(BootInfo const& boot_info)
// NOTE: If the bootloader provided a framebuffer, then set up an initial console.
// If the bootloader didn't provide a framebuffer, then set up an initial text console.
// We do so we can see the output on the screen as soon as possible.
if (!multiboot_framebuffer_addr.is_null()) {
g_boot_console = &try_make_ref_counted<Graphics::BootFramebufferConsole>(multiboot_framebuffer_addr, multiboot_framebuffer_width, multiboot_framebuffer_height, multiboot_framebuffer_pitch).value().leak_ref();
} else {
g_boot_console = &Graphics::TextModeConsole::initialize().leak_ref();
if (!kernel_command_line().is_early_boot_console_disabled()) {
if (!multiboot_framebuffer_addr.is_null()) {
g_boot_console = &try_make_ref_counted<Graphics::BootFramebufferConsole>(multiboot_framebuffer_addr, multiboot_framebuffer_width, multiboot_framebuffer_height, multiboot_framebuffer_pitch).value().leak_ref();
} else {
g_boot_console = &Graphics::TextModeConsole::initialize().leak_ref();
}
}
dmesgln("Starting SerenityOS...");