x86: change static allocation of trampoline area

Impact: fix trampoline sizing bug, save space

While debugging a suspend-to-RAM related issue it occured to me that
if the trampoline code had grown past 4 KB, we would have been
allocating too little memory for it, since the 4 KB size of the
trampoline is hardcoded into arch/x86/kernel/e820.c .  Change that
by making the kernel compute the trampoline size and allocate as much
memory as necessary.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 7 insertions, 0 deletions

diff --git a/arch/x86/include/asm/trampoline.h b/arch/x86/include/asm/trampoline.h
index fa0d79facdbc..780ba0ab94f9 100644
--- a/arch/x86/include/asm/trampoline.h
+++ b/arch/x86/include/asm/trampoline.h
@@ -3,6 +3,7 @@
 
 #ifndef __ASSEMBLY__
 
+#ifdef CONFIG_X86_TRAMPOLINE
 /*
  * Trampoline 80x86 program as an array.
  */
@@ -13,8 +14,14 @@ extern unsigned char *trampoline_base;
 extern unsigned long init_rsp;
 extern unsigned long initial_code;
 
+#define TRAMPOLINE_SIZE roundup(trampoline_end - trampoline_data, PAGE_SIZE)
 #define TRAMPOLINE_BASE 0x6000
+
 extern unsigned long setup_trampoline(void);
+extern void __init reserve_trampoline_memory(void);
+#else
+static inline void reserve_trampoline_memory(void) {};
+#endif /* CONFIG_X86_TRAMPOLINE */
 
 #endif /* __ASSEMBLY__ */