From: Prarit Bhargava <prarit@redhat.com>
Subject: [RHEL5.1 PATCH] BZ 226824 226874: Fix boot_params and .pci_fixup warnings
Date: Thu, 1 Feb 2007 18:01:08 -0500
Bugzilla: 226824 226874
Message-Id: <20070201230108.27497.74928.sendpatchset@prarit.boston.redhat.com>
Changelog: [x86] Fix boot_params and .pci_fixup warnings


Backport of

http://marc.theaimsgroup.com/?l=linux-kernel&m=116650542300200&w=2

This resolves BZ 226824.

This also required a backport of upstream secref_whitelist which resolves
BZ 226874.

Tested successfully by me.

P.

--- linux-2.6.18.i386.orig/arch/i386/kernel/head.S	2007-02-01 17:32:53.000000000 -0500
+++ linux-2.6.18.i386/arch/i386/kernel/head.S	2007-02-01 17:33:10.000000000 -0500
@@ -53,6 +53,7 @@
  * any particular GDT layout, because we load our own as soon as we
  * can.
  */
+.section .text.head
 ENTRY(startup_32)
 
 /*
@@ -135,16 +136,25 @@ page_pde_offset = (__PAGE_OFFSET >> 20);
 	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
+#else
+.section .init.text
+#endif
+
+#ifdef CONFIG_SMP
 ENTRY(startup_32_smp)
 	cld
 	movl $(__BOOT_DS),%eax
@@ -202,8 +212,8 @@ ENTRY(startup_32_smp)
 	xorl %ebx,%ebx
 	incl %ebx
 
-3:
 #endif /* CONFIG_SMP */
+3:
 
 /*
  * Enable paging
@@ -405,6 +415,7 @@ ignore_int:
 #endif
 	iret
 
+.section .text
 /*
  * Real beginning of normal "text" segment
  */
--- linux-2.6.18.i386.orig/arch/i386/kernel/vmlinux.lds.S	2007-02-01 16:08:21.000000000 -0500
+++ linux-2.6.18.i386/arch/i386/kernel/vmlinux.lds.S	2007-02-01 16:35:53.000000000 -0500
@@ -30,9 +30,14 @@ SECTIONS
   . = LOAD_OFFSET + LOAD_PHYSICAL_ADDR;
 #endif
   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
--- linux-2.6.18.i386.orig/scripts/mod/modpost.c	2007-02-01 16:08:21.000000000 -0500
+++ linux-2.6.18.i386/scripts/mod/modpost.c	2007-02-01 17:18:11.000000000 -0500
@@ -580,9 +580,19 @@ static int strrcmp(const char *s, const 
  *   tosec   = .init.text | .exit.text | .init.data
  *   fromsec = .data
  *   atsym = *driver, *_template, *_sht, *_ops, *_probe, *probe_one
- **/
-static int secref_whitelist(const char *tosec, const char *fromsec,
-			    const char *atsym)
+ *
+ * Pattern 3:
+ *   Some symbols belong to init section but still it is ok to reference
+ *   these from non-init sections as these symbols don't have any memory
+ *   allocated for them and symbol address and value are same. So even
+ *   if init section is freed, its ok to reference those symbols.
+ *   For ex. symbols marking the init section boundaries.
+ *   This pattern is identified by
+ *   refsymname = __init_begin, _sinittext, _einittext
+ **/
+static int secref_whitelist(const char *modname, const char *tosec,
+			    const char *fromsec, const char *atsym,
+			    const char *refsymname)
 {
 	int f1 = 1, f2 = 1;
 	const char **s;
@@ -593,6 +603,14 @@ static int secref_whitelist(const char *
 		"_ops",
 		"_probe",
 		"_probe_one",
+		"_console",
+		NULL
+	};
+
+	const char *pat3refsym[] = {
+		"__init_begin",
+		"_sinittext",
+		"_einittext",
 		NULL
 	};
 
@@ -618,8 +636,29 @@ static int secref_whitelist(const char *
 	for (s = pat2sym; *s; s++)
 		if (strrcmp(atsym, *s) == 0)
 			f1 = 1;
+	if (f1 && f2)
+		return 1;
 
-	return f1 && f2;
+	/* 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)
+				return 1;
+	}
+	return 0;
 }
 
 /**
@@ -726,7 +765,8 @@ static void warn_sec_mismatch(const char
 
 	/* check whitelist - we may ignore it */
 	if (before &&
-	    secref_whitelist(secname, fromsec, elf->strtab + before->st_name))
+	    secref_whitelist(modname, secname, fromsec,
+			     elf->strtab + before->st_name, refsymname))
 		return;
 
 	if (before && after) {