[lcrash/gdb] ADD: Automatically load debug symbols when lcrashkern is ready

.gdbinit

@@ -0,0 +1,13 @@
+# INNNNNNNNNNNTRODUCING: the gdb unfucker 9000
+printf "Setting up Lindows debug tools\n"
+
+# We operate in MODES, modes are guessed by what we're connecting to
+set $XU_LWDBG_MODE = "INACTIVE"
+
+# Load guile code
+source common/gdb/guile/core.scm
+
+# Create guile hooks
+define target hookpost-remote
+	lwdbg internal handle-target-remote-post
+end

CMakeLists.txt

@@ -435,6 +435,8 @@ add_custom_command(OUTPUT lindows.img
 	BYPRODUCTS disk.sfdisk
 )
 
+configure_file(config.h.in config.h)
+
 add_custom_target(lindows ALL DEPENDS lindows.img)
 
 add_subdirectory(executive)

README

@@ -1,3 +1,8 @@
+== STYLE ==
+
+=== GUILE ===
+- Avoid direct use of (execute)
+
 == NAMING ==
 
 Mph: Metaprogramming helpers

common/gdb/guile/core.scm

@@ -0,0 +1,150 @@
+(use-modules (gdb)) ; import gdb libraries
+
+; == Misc libraries ==
+(use-modules (srfi srfi-9)) ; provides define-record-type
+(use-modules (ice-9 string-fun)) ; provides string-replace-substring
+
+; Types
+(define btp-u8   (lookup-type "unsigned char"))
+(define btp-u16  (lookup-type "unsigned short"))
+(define btp-u32  (lookup-type "unsigned int"))
+(define btp-u64  (lookup-type "unsigned long long"))
+(define btp-i8   (lookup-type "char"))
+(define btp-i16  (lookup-type "short"))
+(define btp-i32  (lookup-type "int"))
+(define btp-i64  (lookup-type "long long"))
+(define btp-c8   (lookup-type "char"))
+(define btp-bool btp-u8)
+(define btp-uptr btp-u64)
+
+; == Execute wrappers ==
+; Be careful modifying this, other commands depend on it for multiline commands
+(define gdbw-python (lambda (code) (execute (format #f "python ~a" code) #:to-string #t)))
+
+(define gdbw-remove-symbol-file (lambda (file) (execute (format #f "remove-symbol-file ~s" file))))
+
+(define gdbw-add-symbol-file (lambda* (file #:key (offset '()))
+	(define cmd (format #f "add-symbol-file ~s" file))
+	(when (number? offset) (set! cmd (string-append cmd (format #f " -o ~a" offset))))
+	(execute cmd)))
+
+; HACK: gdb doesn't support multiline execute for guile, so we use execute to call python's execute
+(define gdbw-commands (lambda (breakpoints cmds)
+	(for-each (lambda (breakpoint)
+		(define gdb-breakpoint breakpoint)	
+		(when (breakpoint? gdb-breakpoint) (set! gdb-breakpoint (breakpoint-number gdb-breakpoint)))
+		; HACK: This is a silly hack that abuses an unchecked cast from unsigned numbers to signed ones in the gdb shell, allowing us to bypass the "no negative numbers!" thing
+		(when (< gdb-breakpoint 0) (set! gdb-breakpoint (+ 4294967295 (+ 1 gdb-breakpoint))))
+		(gdbw-python (format #f "gdb.execute(~s)" (format #f "commands ~a\n~a\nend" gdb-breakpoint (string-join cmds "\n")))))
+		breakpoints)))
+
+; HACK: gdb doesn't support connection data for guile, so we have to implement it ourself with this incredible hack
+(define-record-type <gdbw-info-connections-result>
+	(make-gdbw-info-connections-result current number what description)
+	gdbw-info-connections-result?
+	(current     gdbw-info-connections-result-current)
+	(number      gdbw-info-connections-result-number)
+	(what        gdbw-info-connections-result-what)
+	(description gdbw-info-connections-result-description))
+(define gdbw-info-connections (lambda () ; TODO: this looks awful, i'm positive there's a better way to do a lot of this, come back when i understand scheme
+	(define compact-gdb-table-row (lambda (raw)
+		(define crunch (lambda (pos chunks remain)
+			(if (< pos (string-length remain))
+				(let ((nidx (string-index remain #\space pos)))
+			  		(if (< (+ nidx 1) (string-length remain))
+						(if (char=? (string-ref remain (+ nidx 1)) #\space)
+							(let ((fidx (string-skip remain #\space nidx)))
+								(crunch 0 (append chunks (list (substring remain 0 nidx))) (substring remain fidx)))
+							(crunch (+ nidx 1) chunks remain))
+						(append chunks (list (substring remain 0 (- (string-length remain) 1))))))
+				(append chunks (list (substring remain 0 (- (string-length remain) 1)))))))
+		(crunch 0 '() raw)))
+	(map (lambda (l) (let ((crow (compact-gdb-table-row l)))
+		(make-gdbw-info-connections-result
+		 	(char=? (string-ref (car crow) 0) #\*)
+			(string->number (substring (car crow) 2))
+			(car (cdr crow))
+			(car (cdr (cdr crow))))))
+		(list-head (list-tail (string-split (execute "info connections" #:to-string #t) #\newline) 1) 1))))
+
+; == Debugging mode stuff ==
+(define DEBUG_MODE_KERNEL  'KERNEL)
+(define DEBUG_MODE_INVALID 'INVALID)
+(define DEBUG_MODE_NONE    'NONE)
+
+(define debug-mode         DEBUG_MODE_NONE)
+
+(define debug-mode-transition (lambda (mode) ; Reconfigure internal state to debug a new target
+	; Check for major fuckups
+	(when (equal? mode DEBUG_MODE_INVALID) (error "Transitioned into an invalid debug mode, this should never happen!"))
+	
+	; Deinitialize the previous target's debug code
+	(cond
+		((equal? debug-mode DEBUG_MODE_KERNEL)
+			(delete-breakpoint! kernel-debug-table-update-watcher)))
+
+	; Set the new debug mode
+	(set! debug-mode mode)
+
+	; Initialize the current target's debug code
+	(cond
+		((equal? debug-mode DEBUG_MODE_KERNEL)
+			(register-breakpoint! kernel-debug-table-update-watcher)
+			(gdbw-commands (list kernel-debug-table-update-watcher) '("silent" "lwdbg kernel refresh-debug-tables" "continue"))
+			(process-kernel-debug-tables)))))
+
+; == Code for processing data in kernel debug tables ==
+(define cckernel-binary-location '())
+(define cckernel-binary-offset   '())
+(define   kernel-binary-location '())
+(define   kernel-binary-offset   '())
+(define kernel-debug-table-update-watcher (make-breakpoint "*(0x100000)"
+	#:type BP_WATCHPOINT
+	#:wp-class WP_WRITE
+	#:internal #t))
+(define process-kernel-debug-tables (lambda ()
+	(define build-dir (value-dereference (value-cast (make-value #x100008) (type-pointer (type-pointer btp-c8)))))
+	(when (not (value=? build-dir (make-value 0)))
+	  	(set! build-dir (value->string build-dir))
+		(if (value=? (value-dereference (value-cast (make-value #x100010) (type-pointer btp-bool))) 1)
+			((lambda () (define new-cckernel-binary-offset   (value->integer (value-dereference (value-cast (make-value #x100018) (type-pointer btp-uptr)))))
+				    (define new-cckernel-binary-location (string-append build-dir "/lcrash/cckernel"))
+				    (when (not (null? cckernel-binary-location))
+				      	(gdbw-remove-symbol-file cckernel-binary-location)
+					(set! cckernel-binary-location '())
+					(set! cckernel-binary-offset   '()))
+				    (gdbw-add-symbol-file new-cckernel-binary-location #:offset new-cckernel-binary-offset)
+				    (set! cckernel-binary-location new-cckernel-binary-location)
+				    (set! cckernel-binary-offset   new-cckernel-binary-offset)))
+			(display "TODO: CCKERNEL UNLOADED\n"))
+		(if (value=? (value-dereference (value-cast (make-value #x100020) (type-pointer btp-bool))) 1)
+			((lambda () (define new-kernel-binary-offset   (value->integer (value-dereference (value-cast (make-value #x100028) (type-pointer btp-uptr)))))
+				    (define new-kernel-binary-location (string-append build-dir "/lcrash/lcrashkern"))
+				    (when (not (null? kernel-binary-location))
+				      	(gdbw-remove-symbol-file kernel-binary-location)
+					(set! kernel-binary-location '())
+					(set! kernel-binary-offset   '()))
+				    (gdbw-add-symbol-file new-kernel-binary-location #:offset new-kernel-binary-offset)
+				    (set! kernel-binary-location new-kernel-binary-location)
+				    (set! kernel-binary-offset   new-kernel-binary-offset)))
+			(display "TODO: KERNEL UNLOADED\n")))))
+
+; == Command prefixes ==
+(register-command! (make-command "lwdbg" #:prefix? #t))
+(register-command! (make-command "lwdbg internal" #:prefix? #t))
+(register-command! (make-command "lwdbg kernel" #:prefix? #t))
+
+; Called by gdb hookpost for target remote
+(register-command! (make-command "lwdbg internal handle-target-remote-post"
+	#:invoke (lambda (self arg from-tty)
+		(debug-mode-transition 
+			(let ((target (string-split (gdbw-info-connections-result-what (car (filter gdbw-info-connections-result-current (gdbw-info-connections)))) #\space)))
+				(if (string=? (car target) "remote")
+					DEBUG_MODE_KERNEL
+					DEBUG_MODE_INVALID))))))
+
+; Command to forcefully refresh the thing
+(register-command! (make-command "lwdbg kernel refresh-debug-tables"
+	#:command-class COMMAND_USER
+	#:doc "Refresh the kernel debug tables"
+	#:invoke (lambda (self arg from-tty) (process-kernel-debug-tables))))

config.h.in

@@ -0,0 +1,3 @@
+#pragma once
+
+#define LW_CONFIG_PROJECT_OUTPUT_DIR "@CMAKE_BINARY_DIR@"

lcrash/CMakeLists.txt

@@ -19,6 +19,7 @@ set_property(TARGET lcrashkern PROPERTY LINK_DEPENDS
 set_property(TARGET lcrashkern PROPERTY LINK_OPTIONS -nostdlib -Wl,-T,${CMAKE_CURRENT_SOURCE_DIR}/lcrash.ld )
 target_compile_options(lcrashkern PRIVATE -ggdb -fpic -pie -Wall -fanalyzer)
 target_link_options(lcrashkern PRIVATE -fpic -pie)
+target_include_directories(lcrashkern PRIVATE ${CMAKE_BINARY_DIR} ${CMAKE_SOURCE_DIR})
 
 add_custom_command(
 	OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/lcrashkern.gz
@@ -54,6 +55,7 @@ set_property(TARGET cckernel PROPERTY LINK_DEPENDS
 )
 set(COMPRESSED_KERNEL_PATH ${CMAKE_CURRENT_BINARY_DIR}/lcrashkern.gz)
 configure_file(setup/compressed/cckernel.S.in setup/compressed/cckernel.S)
+target_include_directories(cckernel PRIVATE ${CMAKE_BINARY_DIR} ${CMAKE_SOURCE_DIR})
 
 # This is the actual bzImage used by linux/grub
 lw_add_executable(lcrash

lcrash/acpi/acpi.c

@@ -11,6 +11,8 @@
 bool AcpiIsPresent = false;
 
 struct AcpiRSDP* AcpiTheRSDP    = 0;
+struct AcpiXSDT* AcpiTheXSDT    = 0; 
+       u32       AcpiXSDTLength = 0;
 
 void AcpiInitialize() {
 	// Check boot params
@@ -42,6 +44,15 @@ found:	// Is this a valid ACPI table?
 	for (int i = 0; i < sizeof(struct AcpiRSDP); i++) Sum += ((u8*)AcpiTheRSDP)[i];
 	if (Sum != 0) goto fail;
 	
+	// Grab the XSDT
+	AcpiTheXSDT = AcpiTheRSDP->XSDTAddress;
+
+	// Is this a valid XSDT?
+	if (!CompareMemory(AcpiTheXSDT->Header.Signature, "XSDT", 4)) goto fail;
+
+	// Get the XSDT length 
+	AcpiXSDTLength = (AcpiTheXSDT->Header.Length - sizeof(struct AcpiXSDT)) / 8;
+
 	AcpiIsPresent = true;	
 	return;
 
@@ -51,3 +62,15 @@ fail:   AcpiIsPresent = false;
 
 bool AcpiPresent() { return AcpiIsPresent; }
 struct AcpiRSDP* AcpiGetRSDP() { return AcpiTheRSDP; }
+struct AcpiXSDT* AcpiGetXSDT() { return AcpiTheXSDT; }
+u32 AcpiGetXSDTLength() { return AcpiXSDTLength; }
+
+void* AcpiGetTable(const char TableName[4]) {
+	// Let's not fuck this up this early
+	if (!AcpiPresent()) return NULL;
+
+	// Alright let's see here...
+	for (int i = 0; i < AcpiXSDTLength; i++) {
+		
+	}
+}

lcrash/acpi/acpi.h

@@ -56,3 +56,23 @@ void AcpiInitialize();
  * Check if ACPI is present
  */
 bool AcpiPresent();
+
+/**
+ * Get the ACPI RSDP, only call if ACPI is present
+ */
+struct AcpiRSDP* AcpiGetRSDP();
+
+/**
+ * Get the ACPI XSDT, only call if ACPI is present
+ */
+struct AcpiXSDT* AcpiGetXSDT();
+
+/**
+ * Get the ACPI XSDT entry count, only call if ACPI is present
+ */
+u32 AcpiGetXSDTLength();
+
+/**
+ * Get the ACPI table with the specified name, returns NULL if not found
+ */
+void* AcpiGetTable(const char TableName[4]);

lcrash/gdb/gdb.h

@@ -1,5 +1,7 @@
 #pragma once
 
+#include "../types.h"
+
 #define DEFINE_GDB_PY_SCRIPT(name) \
 	asm("\
 		.pushsection \".debug_gdb_scripts\", \"MS\", @progbits, 1\n\
@@ -7,3 +9,26 @@
 			.asciz \""name"\"\n\
 		.popsection \n\
 	");
+
+/// Fixed data block placed at the address 0x100000
+/// Please update the initialization code in /lcrash/setup/compressed/main.c when this is changed
+struct GdbDataBlock {
+	/// Update tick thing stored at the beginning of the fixed data block for debuggers
+	/// TODO: Optimization may break this, should this be volatile?
+	u64 Update;
+	
+	/// Base of the cmake build directory. This is needed for lwdbg to configure itself
+	c8* BuildDirectory;
+
+	/// cckernel is present
+	bool CCKernelLoaded;
+
+	/// Base address of the cckernel
+	void* CCKernelBase;
+
+	/// Full kernel is present
+	bool KernelLoaded;
+
+	/// Base address of the kernel
+	void* KernelBase;
+};

lcrash/main.c

@@ -1,6 +1,8 @@
 /// lcrash entry point
 /// super awesome...
 
+#include <lcrash/gdb/gdb.h>
+
 #include "types.h"
 #include "lnxboot.h"
 
@@ -11,6 +13,12 @@ void entry64(struct boot_params* BootParams) {
 	BootBootParams = BootParams;
 	BootSetupInfo  = (void*)BootParams + 0x1f1;
 
+	// Notify the debugger that we're ready
+	struct GdbDataBlock* GdbDataBlock = (struct GdbDataBlock*)0x100000;
+	GdbDataBlock->KernelLoaded = true;
+	GdbDataBlock->KernelBase = BootSetupInfo->code32_start;
+	GdbDataBlock->Update++;
+
 	// Initialize EFI code if we had EFI
 	EfiInitialize();
 

lcrash/setup/compressed/compressed.ld

@@ -7,6 +7,10 @@ SECTIONS {
 		*(.text)
 	}
 
+	.rodata : {
+		*(.rodata)
+	}
+
 	.cckernel : {
 		*(.cckernel)
 	}

lcrash/setup/compressed/main.c

@@ -1,4 +1,6 @@
 #include "../../lnxboot.h"
+#include "../../gdb/gdb.h"
+#include <config.h>
 
 #include "gzip.h"
 #include "elf.h"
@@ -11,8 +13,18 @@ extern void* _CC_ecckernel;
 void ccmain(void* imgbase, struct boot_params* boot_params) {
 	struct setup_info* setup_info = (struct setup_info*)((void*)boot_params + 0x1f1);
 
+	// Fill the lcrash debug data block
+	struct GdbDataBlock* GdbDataBlock = (struct GdbDataBlock*)0x100000;
+	GdbDataBlock->BuildDirectory = LW_CONFIG_PROJECT_OUTPUT_DIR + (uptr)imgbase;
+	GdbDataBlock->CCKernelLoaded = true;
+	GdbDataBlock->CCKernelBase = imgbase;
+	GdbDataBlock->KernelLoaded = false;
+	GdbDataBlock->KernelBase = NULL;
+	GdbDataBlock->Update++;
+
+	// Determine the kernel load address
 	char* kernel_load_addr = (char*)setup_info->code32_start;
-	if (kernel_load_addr == 0) kernel_load_addr = (char*)0x100000;	
+	if (kernel_load_addr == 0) kernel_load_addr = (char*)0x101000;	
 
 	char* cckernel = imgbase + (uptr)&_CC_cckernel;
 	//for (long i = 0; i < setup_info->payload_length; i++) {

lcrash/types.h

@@ -27,3 +27,6 @@ typedef u8 bool;
 #else
 	#error What the fuck? [pointers are not 4 or 8 bytes long]
 #endif
+
+/// Null may become part of the nullptr type, so it's defined here
+#define NULL 0