Revert "x86: remove the kernel code/data/bss resources from /proc/iomem"

This reverts commit c4004b02f8e5b9ce357a0bb1641756cc86962664.

Sadly, my hope that nobody would actually use the special kernel entries
in /proc/iomem were dashed by kexec.  Which reads /proc/iomem explicitly
to find the kernel base address.  Nasty.

Anyway, that means we can't do the sane and simple thing and just remove
the entries, and we'll instead have to mask them out based on permissions.

Reported-by: Zhengyu Zhang <zhezhang@redhat.com>
Reported-by: Dave Young <dyoung@redhat.com>
Reported-by: Freeman Zhang <freeman.zhang1992@gmail.com>
Reported-by: Emrah Demir <ed@abdsec.com>
Reported-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/x86/kernel/setup.c

@@ -146,6 +146,31 @@ int default_check_phys_apicid_present(int phys_apicid)
 
 struct boot_params boot_params;
 
+/*
+ * Machine setup..
+ */
+static struct resource data_resource = {
+	.name	= "Kernel data",
+	.start	= 0,
+	.end	= 0,
+	.flags	= IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM
+};
+
+static struct resource code_resource = {
+	.name	= "Kernel code",
+	.start	= 0,
+	.end	= 0,
+	.flags	= IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM
+};
+
+static struct resource bss_resource = {
+	.name	= "Kernel bss",
+	.start	= 0,
+	.end	= 0,
+	.flags	= IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM
+};
+
+
 #ifdef CONFIG_X86_32
 /* cpu data as detected by the assembly code in head.S */
 struct cpuinfo_x86 new_cpu_data = {
@@ -924,6 +949,13 @@ void __init setup_arch(char **cmdline_p)
 
 	mpx_mm_init(&init_mm);
 
+	code_resource.start = __pa_symbol(_text);
+	code_resource.end = __pa_symbol(_etext)-1;
+	data_resource.start = __pa_symbol(_etext);
+	data_resource.end = __pa_symbol(_edata)-1;
+	bss_resource.start = __pa_symbol(__bss_start);
+	bss_resource.end = __pa_symbol(__bss_stop)-1;
+
 #ifdef CONFIG_CMDLINE_BOOL
 #ifdef CONFIG_CMDLINE_OVERRIDE
 	strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
@@ -987,6 +1019,11 @@ void __init setup_arch(char **cmdline_p)
 
 	x86_init.resources.probe_roms();
 
+	/* after parse_early_param, so could debug it */
+	insert_resource(&iomem_resource, &code_resource);
+	insert_resource(&iomem_resource, &data_resource);
+	insert_resource(&iomem_resource, &bss_resource);
+
 	e820_add_kernel_range();
 	trim_bios_range();
 #ifdef CONFIG_X86_32