Merge branch 'akpm' (patches from Andrew)

[cascardo/linux.git] / arch / powerpc / kernel / vmlinux.lds.S

diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S
index 7ed59f0..8295f51 100644 (file)
--- a/arch/powerpc/kernel/vmlinux.lds.S
+++ b/arch/powerpc/kernel/vmlinux.lds.S
@@ -44,11 +44,58 @@ SECTIONS
  * Text, read only data and other permanent read-only sections
  */
 
-       /* Text and gots */
+       _text = .;
+       _stext = .;
+
+       /*
+        * Head text.
+        * This needs to be in its own output section to avoid ld placing
+        * branch trampoline stubs randomly throughout the fixed sections,
+        * which it will do (even if the branch comes from another section)
+        * in order to optimize stub generation.
+        */
+       .head.text : AT(ADDR(.head.text) - LOAD_OFFSET) {
+#ifdef CONFIG_PPC64
+               KEEP(*(.head.text.first_256B));
+#ifdef CONFIG_PPC_BOOK3E
+# define END_FIXED     0x100
+#else
+               KEEP(*(.head.text.real_vectors));
+               *(.head.text.real_trampolines);
+               KEEP(*(.head.text.virt_vectors));
+               *(.head.text.virt_trampolines);
+# if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_PPC_POWERNV)
+               KEEP(*(.head.data.fwnmi_page));
+#  define END_FIXED    0x8000
+# else
+#  define END_FIXED    0x7000
+# endif
+#endif
+               ASSERT((. == END_FIXED), "vmlinux.lds.S: fixed section overflow error");
+#else /* !CONFIG_PPC64 */
+               HEAD_TEXT
+#endif
+       } :kernel
+
+       /*
+        * If the build dies here, it's likely code in head_64.S is referencing
+        * labels it can't reach, and the linker inserting stubs without the
+        * assembler's knowledge. To debug, remove the above assert and
+        * rebuild. Look for branch stubs in the fixed section region.
+        *
+        * Linker stub generation could be allowed in "trampoline"
+        * sections if absolutely necessary, but this would require
+        * some rework of the fixed sections. Before resorting to this,
+        * consider references that have sufficient addressing range,
+        * (e.g., hand coded trampolines) so the linker does not have
+        * to add stubs.
+        *
+        * Linker stubs at the top of the main text section are currently not
+        * detected, and will result in a crash at boot due to offsets being
+        * wrong.
+        */
        .text : AT(ADDR(.text) - LOAD_OFFSET) {
                ALIGN_FUNCTION();
-               HEAD_TEXT
-               _text = .;
                /* careful! __ftr_alt_* sections need to be close to .text */
                *(.text .fixup __ftr_alt_* .ref.text)
                SCHED_TEXT
@@ -57,6 +104,8 @@ SECTIONS
                KPROBES_TEXT
                IRQENTRY_TEXT
                SOFTIRQENTRY_TEXT
+               MEM_KEEP(init.text)
+               MEM_KEEP(exit.text)
 
 #ifdef CONFIG_PPC32
                *(.got1)