disk: More properly detect non-present removable media

stage23/Makefile

@@ -20,7 +20,7 @@ E9_OUTPUT = false
 BUILD_ID := $(shell dd if=/dev/urandom count=8 bs=1 | od -An -t x8 | sed 's/^ /0x/')
 LIMINE_VERSION := $(shell git describe --exact-match --tags `git log -n1 --pretty='%h'` || git log -n1 --pretty='%h')
 WERROR = -Werror
-CFLAGS = -Os -pipe -Wall -Wextra $(WERROR)
+CFLAGS = -Os -g -pipe -Wall -Wextra $(WERROR)
 
 INTERNAL_CFLAGS := \
 	-std=gnu11 \
@@ -52,7 +52,7 @@ ifeq ($(TARGET), uefi)
 		-mcmodel=small
 endif
 
-LDFLAGS = -Os
+LDFLAGS = -Os -g
 
 INTERNAL_LDFLAGS := \
 	-fno-lto \
@@ -85,9 +85,9 @@ endif
 HEADER_DEPS := $(C_FILES:.c=.d)
 
 ifeq ($(TARGET), bios)
-all: limine.sys stage2.bin stage2.bin.gz
+all: limine_dbg.elf limine.sys stage2.bin stage2.bin.gz
 else ifeq ($(TARGET), uefi)
-all: BOOTX64.EFI
+all: limine_dbg.elf BOOTX64.EFI
 endif
 
 BOOTX64.EFI: limine.elf
@@ -109,7 +109,7 @@ endif
 limine.sys: limine.elf
 	$(OBJCOPY) -O binary $< $@
 
-limine_nomap.elf: $(OBJ)
+limine_nomap.elf: $(OBJ) font.o
 	$(LD) $(OBJ) font.o $(LDFLAGS) $(INTERNAL_LDFLAGS) -Tlinker_nomap_$(TARGET).ld -o $@
 ifeq ($(TARGET), bios)
 	$(LD) $(OBJ) font.o $(LDFLAGS) $(INTERNAL_LDFLAGS) -Wl,--gc-sections -Tlinker_stage2only.ld -o limine_stage2only.elf || \
@@ -117,6 +117,9 @@ ifeq ($(TARGET), bios)
 		  false )
 endif
 
+limine_dbg.elf: $(OBJ) font.o
+	$(LD) $(OBJ) font.o $(LDFLAGS) $(INTERNAL_LDFLAGS) -Tlinker_dbg.ld -o $@
+
 font.o:
 	$(OBJCOPY) -B i8086 -I binary -O default font.bin $@
 

stage23/drivers/disk.s2.c

@@ -50,9 +50,16 @@ bool disk_read_sectors(struct volume *volume, void *buf, uint64_t block, size_t
 
     if (r.eflags & EFLAGS_CF) {
         int ah = (r.eax >> 8) & 0xff;
-        panic("Disk error %x. Drive %x, LBA %x.", ah, volume->drive, dap->lba);
+        switch (ah) {
+            case 0x0c:
+                return false;
+            default:
+                panic("Disk error %x. Drive %x, LBA %x.",
+                      ah, volume->drive, dap->lba);
+        }
     }
 
+    if (buf != NULL)
         memcpy(buf, xfer_buf, count * volume->sector_size);
 
     return true;
@@ -91,6 +98,13 @@ size_t disk_create_index(struct volume **ret) {
         block.first_sect = 0;
         block.sect_count = drive_params.lba_count;
 
+        // The medium could not be present (e.g.: CD-ROMs)
+        // Do a test run to see if we can actually read it
+        if (!disk_read_sectors(&block, NULL, 0, 1)) {
+            print(" ... Ignoring drive...\n");
+            continue;
+        }
+
         for (int part = 0; ; part++) {
             struct volume p;
             int ret = part_get(&p, &block, part);
@@ -130,6 +144,12 @@ size_t disk_create_index(struct volume **ret) {
         block->first_sect = 0;
         block->sect_count = drive_params.lba_count;
 
+        // The medium could not be present (e.g.: CD-ROMs)
+        // Do a test run to see if we can actually read it
+        if (!disk_read_sectors(block, NULL, 0, 1)) {
+            continue;
+        }
+
         if (gpt_get_guid(&block->guid, block)) {
             block->guid_valid = true;
         }

stage23/lib/trace.s2.c

@@ -32,13 +32,6 @@ char *trace_address(size_t *off, size_t addr) {
 }
 
 void print_stacktrace(size_t *base_ptr) {
-#if defined (bios)
-    if (!stage3_loaded) {
-        print("trace: Stack trace omitted because stage 3 was not loaded yet.\n");
-        return;
-    }
-#endif
-
     if (base_ptr == NULL) {
         asm volatile (
 #if defined (bios)

stage23/linker_dbg.ld

@@ -0,0 +1,51 @@
+OUTPUT_FORMAT(elf32-i386)
+ENTRY(_start)
+
+SECTIONS
+{
+    . = 0x8000;
+
+    .entry : {
+        *(.entry*)
+    }
+
+    .realmode : {
+        *(.realmode*)
+    }
+
+    .stage2.text : {
+        *.s2.o(.text*)
+        *libgcc.a:*(.text*)
+    }
+
+    .stage2.data : {
+        *.s2.o(.data*)
+        *.s2.o(.rodata*)
+        *libgcc.a:*(.data*)
+        *libgcc.a:*(.rodata*)
+    }
+
+    .stage3.text : {
+        stage3_addr = .;
+        *(.stage3_entry*)
+        *(.stage3_build_id*)
+        *(.text*)
+    }
+
+    .stage3.data : {
+        *(.data*)
+        *(.rodata*)
+    }
+
+    .map : {
+        limine_map = .;
+        limine_sys_size = .;
+    }
+
+    .bss : {
+        bss_begin = .;
+        *(COMMON)
+        *(.bss*)
+        bss_end = .;
+    }
+}