1 files changed, 33 insertions, 5 deletions

diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index 3c68fe2d46c..f3f2104408d 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -41,6 +41,32 @@ ENTRY(phys_startup_64)
 jiffies_64 = jiffies;
 #endif
 
+#if defined(CONFIG_X86_64) && defined(CONFIG_DEBUG_RODATA)
+/*
+ * On 64-bit, align RODATA to 2MB so that even with CONFIG_DEBUG_RODATA
+ * we retain large page mappings for boundaries spanning kernel text, rodata
+ * and data sections.
+ *
+ * However, kernel identity mappings will have different RWX permissions
+ * to the pages mapping to text and to the pages padding (which are freed) the
+ * text section. Hence kernel identity mappings will be broken to smaller
+ * pages. For 64-bit, kernel text and kernel identity mappings are different,
+ * so we can enable protection checks that come with CONFIG_DEBUG_RODATA,
+ * as well as retain 2MB large page mappings for kernel text.
+ */
+#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 +116,9 @@ 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) {
@@ -107,13 +135,13 @@ SECTIONS
 
 		PAGE_ALIGNED_DATA(PAGE_SIZE)
 
-		CACHELINE_ALIGNED_DATA(CONFIG_X86_L1_CACHE_BYTES)
+		CACHELINE_ALIGNED_DATA(L1_CACHE_BYTES)
 
 		DATA_DATA
 		CONSTRUCTORS
 
 		/* rarely changed data like cpu maps */
-		READ_MOSTLY_DATA(CONFIG_X86_INTERNODE_CACHE_BYTES)
+		READ_MOSTLY_DATA(INTERNODE_CACHE_BYTES)
 
 		/* End of data section */
 		_edata = .;
@@ -137,12 +165,12 @@ SECTIONS
 		*(.vsyscall_0)
 	} :user
 
-	. = ALIGN(CONFIG_X86_L1_CACHE_BYTES);
+	. = ALIGN(L1_CACHE_BYTES);
 	.vsyscall_fn : AT(VLOAD(.vsyscall_fn)) {
 		*(.vsyscall_fn)
 	}
 
-	. = ALIGN(CONFIG_X86_L1_CACHE_BYTES);
+	. = ALIGN(L1_CACHE_BYTES);
 	.vsyscall_gtod_data : AT(VLOAD(.vsyscall_gtod_data)) {
 		*(.vsyscall_gtod_data)
 	}
@@ -166,7 +194,7 @@ SECTIONS
 	}
 	vgetcpu_mode = VVIRT(.vgetcpu_mode);
 
-	. = ALIGN(CONFIG_X86_L1_CACHE_BYTES);
+	. = ALIGN(L1_CACHE_BYTES);
 	.jiffies : AT(VLOAD(.jiffies)) {
 		*(.jiffies)
 	}