x86: allow extend_brk users to reserve brk space

[linux-2.6-omap-h63xx.git] / arch / x86 / include / asm / setup.h

diff --git a/arch/x86/include/asm/setup.h b/arch/x86/include/asm/setup.h
index 366d366399407328dabe262b441a4b99801b071a..61b126b97885954a3008ede83fa33f11efc50df9 100644 (file)
--- a/arch/x86/include/asm/setup.h
+++ b/arch/x86/include/asm/setup.h
@@ -104,6 +104,29 @@ extern struct boot_params boot_params;
 extern unsigned long _brk_end;
 void *extend_brk(size_t size, size_t align);
 
+/*
+ * Reserve space in the brk section.  The name must be unique within
+ * the file, and somewhat descriptive.  The size is in bytes.  Must be
+ * used at file scope.
+ *
+ * (This uses a temp function to wrap the asm so we can pass it the
+ * size parameter; otherwise we wouldn't be able to.  We can't use a
+ * "section" attribute on a normal variable because it always ends up
+ * being @progbits, which ends up allocating space in the vmlinux
+ * executable.)
+ */
+#define RESERVE_BRK(name,sz)                                           \
+       static void __section(.discard) __used                  \
+       __brk_reservation_fn_##name##__(void) {                         \
+               asm volatile (                                          \
+                       ".pushsection .brk_reservation,\"aw\",@nobits;" \
+                       "__brk_reservation_" #name "__:"                \
+                       " 1:.skip %c0;"                                 \
+                       " .size __brk_reservation_" #name "__, . - 1b;" \
+                       " .popsection"                                  \
+                       : : "i" (sz));                                  \
+       }
+
 #ifdef __i386__
 
 void __init i386_start_kernel(void);
@@ -115,6 +138,13 @@ void __init x86_64_start_reservations(char *real_mode_data);
 
 #endif /* __i386__ */
 #endif /* _SETUP */
+#else
+#define RESERVE_BRK(name,sz)                           \
+       .pushsection .brk_reservation,"aw",@nobits;     \
+__brk_reservation_##name##__:                          \
+1:     .skip sz;                                       \
+       .size __brk_reservation_##name##__,.-1b;        \
+       .popsection
 #endif /* __ASSEMBLY__ */
 #endif  /*  __KERNEL__  */