[PATCH] i386: move startup_32() in text.head section
o Entry startup_32 was in .text section but it was accessing some init
data too and it prompts MODPOST to generate compilation warnings.
WARNING: vmlinux - Section mismatch: reference to .init.data:boot_params from
.text between '_text' (at offset 0xc0100029) and 'startup_32_smp'
WARNING: vmlinux - Section mismatch: reference to .init.data:boot_params from
.text between '_text' (at offset 0xc0100037) and 'startup_32_smp'
WARNING: vmlinux - Section mismatch: reference to
.init.data:init_pg_tables_end from .text between '_text' (at offset
0xc0100099) and 'startup_32_smp'
o Can't move startup_32 to .init.text as this entry point has to be at the
start of bzImage. Hence moved startup_32 to a new section .text.head and
instructed MODPOST to not to generate warnings if init data is being
accessed from .text.head section. This code has been audited.
o SMP boot up code (startup_32_smp) can go into .init.text if CPU hotplug
is not supported. Otherwise it generates more warnings
WARNING: vmlinux - Section mismatch: reference to .init.data:new_cpu_data from
.text between 'checkCPUtype' (at offset 0xc0100126) and 'is486'
WARNING: vmlinux - Section mismatch: reference to .init.data:new_cpu_data from
.text between 'checkCPUtype' (at offset 0xc0100130) and 'is486'
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Andi Kleen <ak@suse.de>
diff --git a/arch/i386/kernel/head.S b/arch/i386/kernel/head.S
index 6c7f711..734be55 100644
--- a/arch/i386/kernel/head.S
+++ b/arch/i386/kernel/head.S
@@ -53,6 +53,7 @@
* any particular GDT layout, because we load our own as soon as we
* can.
*/
+.section .text.head,"ax",@progbits
ENTRY(startup_32)
#ifdef CONFIG_PARAVIRT
@@ -141,16 +142,25 @@
jb 10b
movl %edi,(init_pg_tables_end - __PAGE_OFFSET)
-#ifdef CONFIG_SMP
xorl %ebx,%ebx /* This is the boot CPU (BSP) */
jmp 3f
-
/*
* Non-boot CPU entry point; entered from trampoline.S
* We can't lgdt here, because lgdt itself uses a data segment, but
* we know the trampoline has already loaded the boot_gdt_table GDT
* for us.
+ *
+ * If cpu hotplug is not supported then this code can go in init section
+ * which will be freed later
*/
+
+#ifdef CONFIG_HOTPLUG_CPU
+.section .text,"ax",@progbits
+#else
+.section .init.text,"ax",@progbits
+#endif
+
+#ifdef CONFIG_SMP
ENTRY(startup_32_smp)
cld
movl $(__BOOT_DS),%eax
@@ -208,8 +218,8 @@
xorl %ebx,%ebx
incl %ebx
-3:
#endif /* CONFIG_SMP */
+3:
/*
* Enable paging
@@ -492,6 +502,7 @@
#endif
iret
+.section .text
#ifdef CONFIG_PARAVIRT
startup_paravirt:
cld
diff --git a/arch/i386/kernel/vmlinux.lds.S b/arch/i386/kernel/vmlinux.lds.S
index 5038a73..ca516109 100644
--- a/arch/i386/kernel/vmlinux.lds.S
+++ b/arch/i386/kernel/vmlinux.lds.S
@@ -37,9 +37,14 @@
{
. = LOAD_OFFSET + LOAD_PHYSICAL_ADDR;
phys_startup_32 = startup_32 - LOAD_OFFSET;
+
+ .text.head : AT(ADDR(.text.head) - LOAD_OFFSET) {
+ _text = .; /* Text and read-only data */
+ *(.text.head)
+ } :text = 0x9090
+
/* read-only */
.text : AT(ADDR(.text) - LOAD_OFFSET) {
- _text = .; /* Text and read-only data */
*(.text)
SCHED_TEXT
LOCK_TEXT
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 2aa4762..569e684 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -641,12 +641,20 @@
if (f1 && f2)
return 1;
- /* Whitelist all references from .pci_fixup section if vmlinux */
+ /* Whitelist all references from .pci_fixup section if vmlinux
+ * Whitelist all refereces from .text.head to .init.data if vmlinux
+ * Whitelist all refereces from .text.head to .init.text if vmlinux
+ */
if (is_vmlinux(modname)) {
if ((strcmp(fromsec, ".pci_fixup") == 0) &&
(strcmp(tosec, ".init.text") == 0))
return 1;
+ if ((strcmp(fromsec, ".text.head") == 0) &&
+ ((strcmp(tosec, ".init.data") == 0) ||
+ (strcmp(tosec, ".init.text") == 0)))
+ return 1;
+
/* Check for pattern 3 */
for (s = pat3refsym; *s; s++)
if (strcmp(refsymname, *s) == 0)