---

yaml --- r: 173036 b: refs/heads/master c: 74e0817 h: refs/heads/master v: v3
git-mirror · Oct 20, 2009 · dcd473f · dcd473f
1 parent 6ff35e2
commit dcd473f
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Showing 5 changed files with 51 additions and 2 deletions.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: b9af7c0d44b8bb71e3af5e94688d076414aa8c87
+refs/heads/master: 74e081797bd9d2a7d8005fe519e719df343a2ba8
diff --git a/trunk/arch/x86/include/asm/sections.h b/trunk/arch/x86/include/asm/sections.h
@@ -2,7 +2,13 @@
 #define _ASM_X86_SECTIONS_H
 
 #include <asm-generic/sections.h>
+#include <asm/uaccess.h>
 
 extern char __brk_base[], __brk_limit[];
+extern struct exception_table_entry __stop___ex_table[];
+
+#if defined(CONFIG_X86_64) && defined(CONFIG_DEBUG_RODATA)
+extern char __end_rodata_hpage_align[];
+#endif
 
 #endif	/* _ASM_X86_SECTIONS_H */
diff --git a/trunk/arch/x86/kernel/vmlinux.lds.S b/trunk/arch/x86/kernel/vmlinux.lds.S
@@ -41,6 +41,21 @@ ENTRY(phys_startup_64)
 jiffies_64 = jiffies;
 #endif
 
+#if defined(CONFIG_X86_64) && defined(CONFIG_DEBUG_RODATA)
+
+#define X64_ALIGN_DEBUG_RODATA_BEGIN	. = ALIGN(HPAGE_SIZE);
+
+#define X64_ALIGN_DEBUG_RODATA_END				\
+		. = ALIGN(HPAGE_SIZE);				\
+		__end_rodata_hpage_align = .;
+
+#else
+
+#define X64_ALIGN_DEBUG_RODATA_BEGIN
+#define X64_ALIGN_DEBUG_RODATA_END
+
+#endif
+
 PHDRS {
 	text PT_LOAD FLAGS(5);          /* R_E */
 	data PT_LOAD FLAGS(7);          /* RWE */
@@ -90,7 +105,9 @@ SECTIONS
 
 	EXCEPTION_TABLE(16) :text = 0x9090
 
+	X64_ALIGN_DEBUG_RODATA_BEGIN
 	RO_DATA(PAGE_SIZE)
+	X64_ALIGN_DEBUG_RODATA_END
 
 	/* Data */
 	.data : AT(ADDR(.data) - LOAD_OFFSET) {

diff --git a/trunk/arch/x86/mm/init_64.c b/trunk/arch/x86/mm/init_64.c
@@ -727,9 +727,13 @@ void set_kernel_text_ro(void)
 
 void mark_rodata_ro(void)
 {
-	unsigned long start = PFN_ALIGN(_text), end = PFN_ALIGN(__end_rodata);
+	unsigned long start = PFN_ALIGN(_text);
 	unsigned long rodata_start =
 		((unsigned long)__start_rodata + PAGE_SIZE - 1) & PAGE_MASK;
+	unsigned long end = (unsigned long) &__end_rodata_hpage_align;
+	unsigned long text_end = PAGE_ALIGN((unsigned long) &__stop___ex_table);
+	unsigned long rodata_end = PAGE_ALIGN((unsigned long) &__end_rodata);
+	unsigned long data_start = (unsigned long) &_sdata;
 
 	printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
 	       (end - start) >> 10);
@@ -752,6 +756,14 @@ void mark_rodata_ro(void)
 	printk(KERN_INFO "Testing CPA: again\n");
 	set_memory_ro(start, (end-start) >> PAGE_SHIFT);
 #endif
+
+	free_init_pages("unused kernel memory",
+			(unsigned long) page_address(virt_to_page(text_end)),
+			(unsigned long)
+				 page_address(virt_to_page(rodata_start)));
+	free_init_pages("unused kernel memory",
+			(unsigned long) page_address(virt_to_page(rodata_end)),
+			(unsigned long) page_address(virt_to_page(data_start)));
 }
 
 #endif

diff --git a/trunk/arch/x86/mm/pageattr.c b/trunk/arch/x86/mm/pageattr.c
@@ -279,6 +279,20 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long address,
 		   __pa((unsigned long)__end_rodata) >> PAGE_SHIFT))
 		pgprot_val(forbidden) |= _PAGE_RW;
 
+#if defined(CONFIG_X86_64) && defined(CONFIG_DEBUG_RODATA)
+	/*
+	 * Kernel text mappings for the large page aligned .rodata section
+	 * will be read-only. For the kernel identity mappings covering
+	 * the holes caused by this alignment can be anything.
+	 *
+	 * This will preserve the large page mappings for kernel text/data
+	 * at no extra cost.
+	 */
+	if (within(address, (unsigned long)_text,
+		   (unsigned long)__end_rodata_hpage_align))
+		pgprot_val(forbidden) |= _PAGE_RW;
+#endif
+
 	prot = __pgprot(pgprot_val(prot) & ~pgprot_val(forbidden));
 
 	return prot;