ARM: use linker magic for vectors and vector stubs
Russell King [Thu, 4 Jul 2013 11:03:31 +0000 (12:03 +0100)]
commit b9b32bf70f2fb710b07c94e13afbc729afe221da upstream.

Use linker magic to create the vectors and vector stubs: we can tell the
linker to place them at an appropriate VMA, but keep the LMA within the
kernel.  This gets rid of some unnecessary symbol manipulation, and
have the linker calculate the relocations appropriately.

Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arch/arm/kernel/entry-armv.S
arch/arm/kernel/vmlinux.lds.S

index bc2180d..12ac1e3 100644 (file)
@@ -992,7 +992,7 @@ ENDPROC(vector_\name)
 1:
        .endm
 
-       .globl  __stubs_start
+       .section .stubs, "ax", %progbits
 __stubs_start:
        @ This must be the first word
        .word   vector_swi
@@ -1119,24 +1119,16 @@ vector_addrexcptn:
 vector_fiq:
        subs    pc, lr, #4
 
-       .globl  __stubs_end
-__stubs_end:
-
-       .equ    stubs_offset, __vectors_start + 0x1000 - __stubs_start
-
-       .globl  __vectors_start
+       .section .vectors, "ax", %progbits
 __vectors_start:
-       W(b)    vector_rst + stubs_offset
-       W(b)    vector_und + stubs_offset
-       W(ldr)  pc, .LCvswi + stubs_offset
-       W(b)    vector_pabt + stubs_offset
-       W(b)    vector_dabt + stubs_offset
-       W(b)    vector_addrexcptn + stubs_offset
-       W(b)    vector_irq + stubs_offset
-       W(b)    vector_fiq + stubs_offset
-
-       .globl  __vectors_end
-__vectors_end:
+       W(b)    vector_rst
+       W(b)    vector_und
+       W(ldr)  pc, __vectors_start + 0x1000
+       W(b)    vector_pabt
+       W(b)    vector_dabt
+       W(b)    vector_addrexcptn
+       W(b)    vector_irq
+       W(b)    vector_fiq
 
        .data
 
index a871b8e..33f2ea3 100644 (file)
@@ -152,6 +152,23 @@ SECTIONS
        . = ALIGN(PAGE_SIZE);
        __init_begin = .;
 #endif
+       /*
+        * The vectors and stubs are relocatable code, and the
+        * only thing that matters is their relative offsets
+        */
+       __vectors_start = .;
+       .vectors 0 : AT(__vectors_start) {
+               *(.vectors)
+       }
+       . = __vectors_start + SIZEOF(.vectors);
+       __vectors_end = .;
+
+       __stubs_start = .;
+       .stubs 0x1000 : AT(__stubs_start) {
+               *(.stubs)
+       }
+       . = __stubs_start + SIZEOF(.stubs);
+       __stubs_end = .;
 
        INIT_TEXT_SECTION(8)
        .exit.text : {