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Kernel: Print if image has become too large again
Instead of just disabling interrupts and halting when entering the C++ section, just halt with a printed message indicating the error.
This commit is contained in:
Liav A
Gunnar Beutner
parent
a95b726fd8
commit
cc98871383
Notes:
sideshowbarker
2024-07-18 10:08:55 +09:00
Author: https://github.com/supercomputer7 Commit: https://github.com/SerenityOS/serenity/commit/cc988713837 Pull-request: https://github.com/SerenityOS/serenity/pull/8535 Reviewed-by: https://github.com/gunnarbeutner ✅
2 changed files with 88 additions and 58 deletions
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@ -110,54 +110,47 @@ gdt64ptr:
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#endif
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start:
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cli
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cld
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jmp real_start
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#if ARCH(X86_64)
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/* test for long mode presence, save the most important registers from corruption */
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pushl %eax
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pushl %edx
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pushl %ebx
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/*
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this function assumes that paging is disabled (or everything is mapped 1:1)
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param 1: pointer to string ended with null terminator (C string)
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*/
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print_and_halt:
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movl $0x80000001, %eax
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cpuid
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testl $(1 << 29), %edx /* Test if the LM-bit, which is bit 29, is set in the edx register. */
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jnz continue /* If LM-bit is not enabled, there is no long mode. */
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/* from now on, we don't really care about booting because we don't have long mode supported.
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the flow from now is like so:
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1. Copy all necessary parts to low memory section in RAM
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2. Jump to that section
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3. In that section we do:
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a. exit protected mode to pure 16 bit real mode
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b. load the "Long mode is not supported" String, call the BIOS print to screen service
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c. halt
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*/
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.equ NO_LONG_MODE_STRING_LOCATION, 0x400
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.equ COPIED_STRING_LOCATION, 0x400
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.equ GDT_REAL_MODE_LOCATION, 0x45000
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.equ EXITING_PROTECTED_MODE_CODE_LOCATION, 0x10000
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.equ REAL_MODE_CODE, 0x500
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.equ PROTECTED_MODE_16_BIT_CODE, 0x600
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mov %esp, %ebp
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mov 4(%ebp), %edi
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/* Copy no_long_mode_string to low memory section */
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lea no_long_mode_string, %eax
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lea exiting_real_mode, %ebx
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sub $0xc0000000, %ebx
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sub $0xc0000000, %eax
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/* Copy string to low memory section */
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mov %edi, %esi
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xor %ecx, %ecx
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movl %ebx, %ecx
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sub %eax, %ecx
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mov %eax, %esi /* source address of the code */
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movw %cx, (NO_LONG_MODE_STRING_LOCATION)
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mov $NO_LONG_MODE_STRING_LOCATION+2, %edi /* destination address of the code */
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pushl %eax
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pushl %edi
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check_string_length:
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movb (%edi), %ah
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cmp $0, %ah
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je check_string_length_exit
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inc %ecx
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inc %edi
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jmp check_string_length
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check_string_length_exit:
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popl %edi
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popl %eax
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/* source address of the code is ESI */
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movw %cx, (COPIED_STRING_LOCATION)
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mov $COPIED_STRING_LOCATION + 2, %edi /* destination address of the code */
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rep movsb
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/* Copy gdt_table_real_mode to low memory section */
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lea gdt_table_real_mode, %eax
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lea gdt_table_real_mode_end, %ebx
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sub $0xc0000000, %ebx
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sub $0xc0000000, %eax
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movl $(gdt_table_real_mode - KERNEL_BASE), %eax
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movl $(gdt_table_real_mode_end - KERNEL_BASE), %ebx
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movl %ebx, %ecx
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sub %eax, %ecx
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@ -166,10 +159,8 @@ start:
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rep movsb
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/* Copy protected_mode_16_bit to real_mode to low memory section */
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lea protected_mode_16_bit, %eax
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lea real_mode, %ebx
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sub $0xc0000000, %ebx
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sub $0xc0000000, %eax
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movl $(protected_mode_16_bit - KERNEL_BASE), %eax
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movl $(real_mode - KERNEL_BASE), %ebx
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movl %ebx, %ecx
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sub %eax, %ecx
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@ -177,11 +168,9 @@ start:
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mov $PROTECTED_MODE_16_BIT_CODE, %edi /* destination address of the code */
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rep movsb
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/* Copy real_mode to continue to low memory section */
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lea real_mode, %eax
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lea continue, %ebx
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sub $0xc0000000, %ebx
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sub $0xc0000000, %eax
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/* Copy real_mode to end_of_print_and_halt_function to low memory section */
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movl $(real_mode - KERNEL_BASE), %eax
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movl $(end_of_print_and_halt_function - KERNEL_BASE), %ebx
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movl %ebx, %ecx
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sub %eax, %ecx
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@ -191,10 +180,8 @@ start:
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/* Copy all opcodes from exiting_real_mode label to protected_mode_16_bit label to low memory RAM */
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lea exiting_real_mode, %eax
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lea protected_mode_16_bit, %ebx
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sub $0xc0000000, %ebx
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sub $0xc0000000, %eax
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movl $(exiting_real_mode - KERNEL_BASE), %eax
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movl $(protected_mode_16_bit - KERNEL_BASE), %ebx
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movl %ebx, %ecx
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sub %eax, %ecx
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@ -227,6 +214,9 @@ gdt_table_real_mode_end:
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no_long_mode_string:
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.asciz "Your computer does not support long mode (64-bit mode). Halting!"
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kernel_image_too_big_string:
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.asciz "Error: Kernel Image too big for memory slot. Halting!"
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/*
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This part is completely standalone - it doesn't involve any location from this
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near code. It uses arbitrary locations in the low memory section of the RAM.
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@ -292,19 +282,64 @@ real_mode:
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movb $0x13, %ah
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movb $0x0, %bh
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movb $0xf, %bl
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movw (NO_LONG_MODE_STRING_LOCATION), %cx
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movw (COPIED_STRING_LOCATION), %cx
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movw $0, %dx
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movw $NO_LONG_MODE_STRING_LOCATION + 2, %bp
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movw $COPIED_STRING_LOCATION + 2, %bp
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int $0x10
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movl $0xdeadcafe, %ebx
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cli
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hlt
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end_of_print_and_halt_function:
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.code32
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real_start:
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cli
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cld
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mov $end_of_kernel_image, %esi
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cmp $0xc2000000, %esi
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jbe kernel_not_too_large
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movl $(kernel_image_too_big_string - KERNEL_BASE), %esi
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pushl %esi
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call print_and_halt
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/* We should not return, but just in case, halt */
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hlt
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kernel_not_too_large:
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#if ARCH(X86_64)
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/* test for long mode presence, save the most important registers from corruption */
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pushl %eax
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pushl %edx
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pushl %ebx
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movl $0x80000001, %eax
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cpuid
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testl $(1 << 29), %edx /* Test if the LM-bit, which is bit 29, is set in the edx register. */
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jnz long_mode_supported /* If LM-bit is not enabled, there is no long mode. */
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/* from now on, we don't really care about booting because we don't have long mode supported.
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the flow from now is like so:
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1. Copy all necessary parts to low memory section in RAM
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2. Jump to that section
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3. In that section we do:
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a. exit protected mode to pure 16 bit real mode
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b. load the "Long mode is not supported" String, call the BIOS print to screen service
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c. halt
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*/
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movl $(no_long_mode_string - KERNEL_BASE), %esi
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pushl %esi
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call print_and_halt
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/* We should not return, but just in case, halt */
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hlt
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/* If long mode is supported, continue with booting the system */
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.code32
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continue:
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long_mode_supported:
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/* restore the pushed registers and continue with booting */
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popl %ebx
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popl %edx
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@ -107,11 +107,6 @@ static Processor s_bsp_processor; // global but let's keep it "private"
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extern "C" [[noreturn]] UNMAP_AFTER_INIT void init()
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{
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if ((FlatPtr)&end_of_kernel_image >= 0xc2000000u) {
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// The kernel has grown too large again!
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asm volatile("cli;hlt");
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}
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g_in_early_boot = true;
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setup_serial_debug();
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