Revert "Revert "Revert "x86/mm: Identify the end of the kernel area to be reserved"""

This reverts commit f750a9e5b2.

Reason for revert: keep treehugger green

Change-Id: I65543f6d3e2a242d594014911b8d880937e5e044

arch/x86/include/asm/sections.h

@@ -13,6 +13,4 @@ extern char __end_rodata_aligned[];
 extern char __end_rodata_hpage_align[];
 #endif
 
-extern char __end_of_kernel_reserve[];
-
 #endif	/* _ASM_X86_SECTIONS_H */

arch/x86/kernel/setup.c

@@ -836,14 +836,8 @@ dump_kernel_offset(struct notifier_block *self, unsigned long v, void *p)
 
 void __init setup_arch(char **cmdline_p)
 {
-	/*
-	 * Reserve the memory occupied by the kernel between _text and
-	 * __end_of_kernel_reserve symbols. Any kernel sections after the
-	 * __end_of_kernel_reserve symbol must be explicitly reserved with a
-	 * separate memblock_reserve() or they will be discarded.
-	 */
 	memblock_reserve(__pa_symbol(_text),
-			 (unsigned long)__end_of_kernel_reserve - (unsigned long)_text);
+			 (unsigned long)__bss_stop - (unsigned long)_text);
 
 	/*
 	 * Make sure page 0 is always reserved because on systems with

arch/x86/kernel/vmlinux.lds.S

@@ -368,14 +368,6 @@ SECTIONS
 		__bss_stop = .;
 	}
 
-	/*
-	 * The memory occupied from _text to here, __end_of_kernel_reserve, is
-	 * automatically reserved in setup_arch(). Anything after here must be
-	 * explicitly reserved using memblock_reserve() or it will be discarded
-	 * and treated as available memory.
-	 */
-	__end_of_kernel_reserve = .;
-
 	. = ALIGN(PAGE_SIZE);
 	.brk : AT(ADDR(.brk) - LOAD_OFFSET) {
 		__brk_base = .;
@@ -415,6 +407,7 @@ SECTIONS
 	STABS_DEBUG
 	DWARF_DEBUG
 
+	/* Sections to be discarded */
 	DISCARDS
 	/DISCARD/ : {
 		*(.eh_frame)