From: Rafael J. Wysocki <rjw@xxxxxxx>
Subject: x86: Change static allocation of trampoline area
Impact: Improvement
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@xxxxxxx>
---
arch/x86/include/asm/trampoline.h | 7 +++++++
arch/x86/kernel/e820.c | 16 ----------------
arch/x86/kernel/head32.c | 3 +++
arch/x86/kernel/head64.c | 3 +++
arch/x86/kernel/trampoline.c | 19 +++++++++++++++++--
5 files changed, 30 insertions(+), 18 deletions(-)
Index: linux-2.6/arch/x86/include/asm/trampoline.h
===================================================================
--- linux-2.6.orig/arch/x86/include/asm/trampoline.h
+++ linux-2.6/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__ */
Index: linux-2.6/arch/x86/kernel/e820.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/e820.c
+++ linux-2.6/arch/x86/kernel/e820.c
@@ -698,22 +698,6 @@ struct early_res {
};
static struct early_res early_res[MAX_EARLY_RES] __initdata = {
{ 0, PAGE_SIZE, "BIOS data page" }, /* BIOS data page */
-#if defined(CONFIG_X86_64) && defined(CONFIG_X86_TRAMPOLINE)
- { TRAMPOLINE_BASE, TRAMPOLINE_BASE + 2 * PAGE_SIZE, "TRAMPOLINE" },
-#endif
-#if defined(CONFIG_X86_32) && defined(CONFIG_SMP)
- /*
- * But first pinch a few for the stack/trampoline stuff
- * FIXME: Don't need the extra page at 4K, but need to fix
- * trampoline before removing it. (see the GDT stuff)
- */
- { PAGE_SIZE, PAGE_SIZE + PAGE_SIZE, "EX TRAMPOLINE" },
- /*
- * Has to be in very low memory so we can execute
- * real-mode AP code.
- */
- { TRAMPOLINE_BASE, TRAMPOLINE_BASE + PAGE_SIZE, "TRAMPOLINE" },
-#endif
{}
};
Index: linux-2.6/arch/x86/kernel/trampoline.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/trampoline.c
+++ linux-2.6/arch/x86/kernel/trampoline.c
@@ -1,10 +1,26 @@
#include <linux/io.h>
#include <asm/trampoline.h>
+#include <asm/e820.h>
/* ready for x86_64 and x86 */
unsigned char *trampoline_base = __va(TRAMPOLINE_BASE);
+void __init reserve_trampoline_memory(void)
+{
+#ifdef CONFIG_X86_32
+ /*
+ * But first pinch a few for the stack/trampoline stuff
+ * FIXME: Don't need the extra page at 4K, but need to fix
+ * trampoline before removing it. (see the GDT stuff)
+ */
+ reserve_early(PAGE_SIZE, PAGE_SIZE + PAGE_SIZE, "EX TRAMPOLINE");
+#endif
+ /* Has to be in very low memory so we can execute real-mode AP code. */
+ reserve_early(TRAMPOLINE_BASE, TRAMPOLINE_BASE + TRAMPOLINE_SIZE,
+ "TRAMPOLINE");
+}
+
/*
* Currently trivial. Write the real->protected mode
* bootstrap into the page concerned. The caller
@@ -12,7 +28,6 @@ unsigned char *trampoline_base = __va(TR
*/
unsigned long setup_trampoline(void)
{
- memcpy(trampoline_base, trampoline_data,
- trampoline_end - trampoline_data);
+ memcpy(trampoline_base, trampoline_data, TRAMPOLINE_SIZE);
return virt_to_phys(trampoline_base);
}
Index: linux-2.6/arch/x86/kernel/head32.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/head32.c
+++ linux-2.6/arch/x86/kernel/head32.c
@@ -12,9 +12,12 @@
#include <asm/sections.h>
#include <asm/e820.h>
#include <asm/bios_ebda.h>
+#include <asm/trampoline.h>
void __init i386_start_kernel(void)
{
+ reserve_trampoline_memory();
+
reserve_early(__pa_symbol(&_text), __pa_symbol(&_end), "TEXT DATA BSS");
#ifdef CONFIG_BLK_DEV_INITRD
Index: linux-2.6/arch/x86/kernel/head64.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/head64.c
+++ linux-2.6/arch/x86/kernel/head64.c
@@ -24,6 +24,7 @@
#include <asm/kdebug.h>
#include <asm/e820.h>
#include <asm/bios_ebda.h>
+#include <asm/trampoline.h>
/* boot cpu pda */
static struct x8664_pda _boot_cpu_pda __read_mostly;
@@ -120,6 +121,8 @@ void __init x86_64_start_reservations(ch
{
copy_bootdata(__va(real_mode_data));
+ reserve_trampoline_memory();
+
reserve_early(__pa_symbol(&_text), __pa_symbol(&_end), "TEXT DATA BSS");
#ifdef CONFIG_BLK_DEV_INITRD
--
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