5 files changed, 40 insertions, 2 deletions

diff --git a/arch/x86/include/asm/setup.h b/arch/x86/include/asm/setup.h
index 366d36639940..61b126b97885 100644
--- 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__  */
 
diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index 3ce5456dfbe6..9e89f2a14b90 100644
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -75,6 +75,8 @@ ALLOCATOR_SLOP = 4
 
 INIT_MAP_BEYOND_END = BOOTBITMAP_SIZE + (PAGE_TABLE_SIZE + ALLOCATOR_SLOP)*PAGE_SIZE_asm
 
+RESERVE_BRK(pagetables, PAGE_TABLE_SIZE * PAGE_SIZE)
+
 /*
  * 32-bit kernel entrypoint; only used by the boot CPU.  On entry,
  * %esi points to the real-mode code as a 32-bit pointer.
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index e894f36335f2..a0d26237d7cf 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -112,6 +112,8 @@
 #define ARCH_SETUP
 #endif
 
+RESERVE_BRK(dmi_alloc, 65536);
+
 unsigned int boot_cpu_id __read_mostly;
 
 static __initdata unsigned long _brk_start = (unsigned long)__brk_base;
diff --git a/arch/x86/kernel/vmlinux_32.lds.S b/arch/x86/kernel/vmlinux_32.lds.S
index 1063fbe93c73..a1f28b85fb34 100644
--- a/arch/x86/kernel/vmlinux_32.lds.S
+++ b/arch/x86/kernel/vmlinux_32.lds.S
@@ -192,7 +192,8 @@ SECTIONS
 
         . = ALIGN(PAGE_SIZE);
         __brk_base = . ;
-        . += 1024 * 1024 ;
+        . += 64 * 1024 ;        /* 64k slop space */
+        *(.brk_reservation)     /* areas brk users have reserved */
         __brk_limit = . ;
 
         _end = . ;
@@ -201,6 +202,7 @@ SECTIONS
   /* Sections to be discarded */
   /DISCARD/ : {
         *(.exitcall.exit)
+        *(.discard)
         }
 
   STABS_DEBUG
diff --git a/arch/x86/kernel/vmlinux_64.lds.S b/arch/x86/kernel/vmlinux_64.lds.S
index ff373423138c..7996687663a2 100644
--- a/arch/x86/kernel/vmlinux_64.lds.S
+++ b/arch/x86/kernel/vmlinux_64.lds.S
@@ -250,7 +250,8 @@ SECTIONS
 
         . = ALIGN(PAGE_SIZE);
         __brk_base = . ;
-        . += 1024 * 1024 ;
+        . += 64 * 1024;         /* 64k slop space */
+        *(.brk_reservation)     /* areas brk users have reserved */
         __brk_limit = . ;
   }
 
@@ -260,6 +261,7 @@ SECTIONS
   /DISCARD/ : {
         *(.exitcall.exit)
         *(.eh_frame)
+        *(.discard)
         }
 
   STABS_DEBUG