Use elf symbol table instead of map file for kernel

6 files changed, 61 insertions, 36 deletions

diff --git a/src/kernel/bam.lua b/src/kernel/bam.lua
index 4a82f49..2dc724e 100644
--- a/src/kernel/bam.lua
+++ b/src/kernel/bam.lua
@@ -3,8 +3,7 @@ local kernel_settings = TableDeepCopy(common_settings)
 kernel_settings.cc.includes:Add("src/common/include/kogata",
 								"src/kernel/include")
 
-kernel_settings.link.flags:Add("-T src/kernel/linker.ld",
-							   "-Xlinker -Map=build/kernel.map")
+kernel_settings.link.flags:Add("-T src/kernel/linker.ld")
 
 kernel_source = {
 	Collect('src/kernel/core/*.s'),
diff --git a/src/kernel/core/kmain.c b/src/kernel/core/kmain.c
index d09a1b5..dd66805 100644
--- a/src/kernel/core/kmain.c
+++ b/src/kernel/core/kmain.c
@@ -69,6 +69,9 @@ void kmain(multiboot_info_t *mbd, int32_t mb_magic) {
 	// to allocate memory ; they just increment it of the allocated quantity
 	void* kernel_data_end = (void*)&k_end_addr;
 
+	elf_shdr_t *elf_sections = (elf_shdr_t*)(mbd->elf_sec.addr + K_HIGHHALF_ADDR);
+	ASSERT(sizeof(elf_shdr_t) == mbd->elf_sec.size);
+
 	dbglog_setup();
 
 	dbg_printf("Hello, kernel world!\n");
@@ -95,6 +98,14 @@ void kmain(multiboot_info_t *mbd, int32_t mb_magic) {
 			kernel_data_end = mod_end_pa;
 	}
 
+	for (unsigned i = 0; i < mbd->elf_sec.num; i++) {
+		elf_sections[i].sh_addr += K_HIGHHALF_ADDR;
+		size_t section_end = elf_sections[i].sh_addr + elf_sections[i].sh_size;
+		void* section_end_pa = (void*)((section_end & 0xFFFFF000) + 0x1000);
+		if (section_end_pa > kernel_data_end)
+			kernel_data_end = section_end_pa;
+	}
+
 	gdt_init(); dbg_printf("GDT set up.\n");
 
 	idt_init(); dbg_printf("IDT set up.\n");
@@ -125,17 +136,13 @@ void kmain(multiboot_info_t *mbd, int32_t mb_magic) {
 	setup_syscall_table();
 	dbg_printf("System calls setup ok.\n");
 
-	// If we have a kernel map, load it now
-	for (unsigned i = 0; i < mbd->mods_count; i++) {
-		char* modname = (char*)mods[i].string;
-		size_t len = mods[i].mod_end - mods[i].mod_start;
-
-		if (strlen(modname) > 4 && strcmp(modname + strlen(modname) - 4, ".map") == 0) {
-			// Copy data to somewhere safe, as it will be modified
-			void* dup_data = malloc(len + 1);
-			memcpy(dup_data, (void*)mods[i].mod_start, len);
-
-			load_kernel_symbol_map((char*)dup_data, len);
+	// Look for kernel symbol table section
+	for (unsigned i = 0; i < mbd->elf_sec.num; i++) {
+		dbg_printf("0x%p section type %d addr 0x%p - 0x%p\n",
+			&elf_sections[i], elf_sections[i].sh_type,
+			elf_sections[i].sh_addr, elf_sections[i].sh_addr + elf_sections[i].sh_size);
+		if (elf_sections[i].sh_type == SHT_SYMTAB) {
+			load_kernel_symbol_table(&elf_sections[i], &elf_sections[elf_sections[i].sh_link]);
 		}
 	}
 
diff --git a/src/kernel/core/sys.c b/src/kernel/core/sys.c
index 725843e..2908868 100644
--- a/src/kernel/core/sys.c
+++ b/src/kernel/core/sys.c
@@ -3,6 +3,8 @@
 #include <thread.h>
 #include <string.h>
 
+#include <elf.h>
+
 #include <btree.h>
 
 
@@ -44,31 +46,21 @@ void sys_panic_assert(const char* assertion, const char* file, int line) {
 
 btree_t *kernel_symbol_map = 0;
 
-void load_kernel_symbol_map(char* text, size_t len) {
+void load_kernel_symbol_table(elf_shdr_t *sym, elf_shdr_t *str) {
 	kernel_symbol_map = create_btree(id_key_cmp_fun, 0);
 	ASSERT (kernel_symbol_map != 0);
 
-	dbg_printf("Loading kernel symbol map...\n");
-
-	char* it = text;
-	while (it < text + len) {
-		char* eol = it;
-		while (eol < text + len && *eol != 0 && *eol != '\n') eol++;
-		if (eol >= text + len) break;
-		*eol = 0;
-
-		if (it[16] == '0' && it[17] == 'x' && it[34] == ' ' && it[49] == ' ') {
-			uint32_t addr = 0;
-			for (unsigned i = 18; i < 34; i++) {
-				addr *= 16;
-				if (it[i] >= '0' && it[i] <= '9') addr += it[i] - '0';
-				if (it[i] >= 'a' && it[i] <= 'f') addr += it[i] - 'a' + 10;
-			}
-			btree_add(kernel_symbol_map, (void*)addr, it + 50);
-		}
+	dbg_printf("Loading kernel symbol table...\n");
 
-		it = eol + 1;
-	} 
+	
+	ASSERT(sym->sh_entsize == sizeof(elf_sym_t));
+	unsigned nsym = sym->sh_size / sym->sh_entsize;
+
+	elf_sym_t *st = (elf_sym_t*)sym->sh_addr;
+	const char* strtab = (const char*)(str->sh_addr);
+	for (unsigned j = 0; j < nsym; j++) {
+		btree_add(kernel_symbol_map, (void*)st[j].st_value, (void*)(strtab + st[j].st_name));
+	}
 }
 
 void kernel_stacktrace(uint32_t ebp, uint32_t eip) {
diff --git a/src/kernel/include/elf.h b/src/kernel/include/elf.h
index 6e0c7cb..79ec023 100644
--- a/src/kernel/include/elf.h
+++ b/src/kernel/include/elf.h
@@ -16,6 +16,9 @@
 #define	PT_PHDR             6
 #define	PT_LOPROC  0x70000000
 #define	PT_HIPROC  0x7fffffff
+
+#define SHT_SYMTAB 2
+#define SHT_STRTAB 3
  
 /* elf_phdr_t :: p_flags : program header entries flags */
 #define PF_X	(1 << 0)
@@ -52,6 +55,28 @@ typedef struct {
 	uint32_t p_flags;
 	uint32_t p_align;
 } elf_phdr_t;
+
+typedef struct elf_shdr {
+	uint32_t sh_name;
+	uint32_t sh_type;
+	uint32_t sh_flags;
+	uint32_t sh_addr;
+	uint32_t sh_offset;
+	uint32_t sh_size;
+	uint32_t sh_link;
+	uint32_t sh_info;
+	uint32_t sh_addralign;
+	uint32_t sh_entsize;
+} elf_shdr_t;
+
+typedef struct {
+	uint32_t st_name;
+	uint32_t st_value;
+	uint32_t st_size;
+	uint8_t st_info;
+	uint8_t st_other;
+	uint16_t st_shndx;
+} elf_sym_t;
  
 bool is_elf(fs_handle_t *f);
 proc_entry_t elf_load(fs_handle_t *f, process_t *process);	//Load an ELF to a process, return entry point
diff --git a/src/kernel/include/multiboot.h b/src/kernel/include/multiboot.h
index f84b626..b340a38 100644
--- a/src/kernel/include/multiboot.h
+++ b/src/kernel/include/multiboot.h
@@ -39,7 +39,7 @@ typedef struct {
 	union {
 		struct aout_symbol_table_t aout_sym;
 		struct elf_section_header_table_t elf_sec;
-	} u;
+	};
 	unsigned long mmap_length;
 	unsigned long mmap_addr;
 } multiboot_info_t;
diff --git a/src/kernel/include/sys.h b/src/kernel/include/sys.h
index 038135b..7d62d9e 100644
--- a/src/kernel/include/sys.h
+++ b/src/kernel/include/sys.h
@@ -3,6 +3,8 @@
 #include <debug.h> 		// common header
 #include <config.h>
 
+typedef struct elf_shdr elf_shdr_t;
+
 static inline void outb(uint16_t port, uint8_t value) {
 	asm volatile("outb %1, %0" : : "dN"(port), "a"(value));
 }
@@ -92,7 +94,7 @@ static inline void invlpg(void* addr) {
 #define ALIGN4_DOWN(x)	(((size_t)x)&MASK4)
 
 
-void load_kernel_symbol_map(char* text, size_t len);
+void load_kernel_symbol_table(elf_shdr_t *sym, elf_shdr_t *str);
 void kernel_stacktrace(uint32_t ebp, uint32_t eip);
 
 /* vim: set ts=4 sw=4 tw=0 noet :*/