[x86] fix typo in tidy_boot_pg_tables that corrupted the page tables …

…for the kernel's lower virtual space. oops. also increase the boot stack space because it was crashed into the page tables - do we need a canary to detect that in future? probably. also make sure all text areas are included between __kernel_ro_start/end

platform/x86/asm/start32.s

@@ -395,7 +395,7 @@ boot_pt1_table:
   resb 4096	; reserve 4KB for a page table aka level 1 page table
 
 boot_stack_bottom:
-  resb 4096
+  resb 2 * 4096	; reserve 2 x 4KB pages for the stack
 boot_stack_top:
 
 ; stash a pointer to the boot PML4 table

platform/x86/asm/start64.s

@@ -111,7 +111,7 @@ tidy_boot_pg_tables:
   shr rax, 12
   and rax, 0x3ff		; turn start address into table index
   mov rbx, __kernel_ro_end
-  shr rax, 12
+  shr rbx, 12
   and rbx, 0x3ff		; turn end address into table index
 
   mov rcx, __kernel_ro_start	; this should be page aligned
@@ -128,7 +128,7 @@ tidy_boot_pg_tables:
   shr rax, 12
   and rax, 0x3ff		; turn start address into table index
   mov rbx, __kernel_rw_end
-  shr rax, 12
+  shr rbx, 12
   and rbx, 0x3ff		; turn end address into table index
 
   mov rcx, __kernel_rw_start	; this should be page aligned

platform/x86/linker.ld

@@ -19,7 +19,7 @@ SECTIONS {
       __kernel_ro_start = ALIGN(0x1000);
       KEEP(*(.multiboot_head)) /* keep our multiboot header at the start */
 
-      *(.text)
+      *(.text*)
       *(.rodata*)
       __kernel_ro_end = ALIGN(0x1000);
     }