Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...

[sfrench/cifs-2.6.git] / arch / x86 / kernel / vmlinux.lds.S

diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index 3c68fe2d46cfad42b22c2011c6de4cced838bd7f..f3f2104408d932ab05172fe4edb42cba420ec7d4 100644 (file)
--- 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)
        }