[tip:x86/urgent] x86: Use find_e820() instead of hard coded trampoline address

tip-bot for Yinghai Lu
2009-12-11T08:56:48Z

Commit-ID: 893f38d144a4d96d2483cd7c3801d26e1b2c23e9
Gitweb: http://git.kernel.org/tip/893f38d144a4d96d2483cd7c3801d26e1b2c23e9
Author: Yinghai Lu <yinghai@kernel.org>
AuthorDate: Thu, 10 Dec 2009 13:07:22 -0800
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Fri, 11 Dec 2009 09:28:22 +0100

x86: Use find_e820() instead of hard coded trampoline address

Jens found the following crash/regression:

[ 0.000000] found SMP MP-table at [ffff8800000fdd80] fdd80
[ 0.000000] Kernel panic - not syncing: Overlapping early reservations 12-f011 MP-table mpc to 0-fff BIOS data page

and

[ 0.000000] Kernel panic - not syncing: Overlapping early reservations 12-f011 MP-table mpc to 6000-7fff TRAMPOLINE

and bisected it to b24c2a9 ("x86: Move find_smp_config()
earlier and avoid bootmem usage").

It turns out the BIOS is using the first 64k for mptable,
without reserving it.

So try to find good range for the real-mode trampoline instead of
hard coding it, in case some bios tries to use that range for sth.

Reported-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Tested-by: Jens Axboe <jens.axboe@oracle.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
LKML-Reference: <4B21630A.6000308@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
arch/x86/include/asm/trampoline.h | 1 -
arch/x86/kernel/e820.c | 11 ++++++++++-
arch/x86/kernel/head32.c | 2 --
arch/x86/kernel/head64.c | 2 --
arch/x86/kernel/mpparse.c | 3 ---
arch/x86/kernel/setup.c | 13 ++++++++-----
arch/x86/kernel/trampoline.c | 20 +++++++++-----------
7 files changed, 27 insertions(+), 25 deletions(-)

diff --git a/arch/x86/include/asm/trampoline.h b/arch/x86/include/asm/trampoline.h
index 90f06c2..cb507bb 100644
--- a/arch/x86/include/asm/trampoline.h
+++ b/arch/x86/include/asm/trampoline.h
@@ -16,7 +16,6 @@ extern unsigned long initial_code;
extern unsigned long initial_gs;

#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);
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index d17d482..f50447d 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -732,7 +732,16 @@ struct early_res {
char overlap_ok;
};
static struct early_res early_res[MAX_EARLY_RES] __initdata = {
- { 0, PAGE_SIZE, "BIOS data page" }, /* BIOS data page */
+ { 0, PAGE_SIZE, "BIOS data page", 1 }, /* BIOS data page */
+#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)
+ */
+ { PAGE_SIZE, PAGE_SIZE, "EX TRAMPOLINE", 1 },
+#endif
+
{}
};

diff --git a/arch/x86/kernel/head32.c b/arch/x86/kernel/head32.c
index 4f8e250..5051b94 100644
--- a/arch/x86/kernel/head32.c
+++ b/arch/x86/kernel/head32.c
@@ -29,8 +29,6 @@ static void __init i386_default_early_setup(void)

void __init i386_start_kernel(void)
{
- reserve_trampoline_memory();
-
reserve_early(__pa_symbol(&_text), __pa_symbol(&__bss_stop), "TEXT DATA BSS");

#ifdef CONFIG_BLK_DEV_INITRD
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 0b06cd7..b5a9896 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -98,8 +98,6 @@ void __init x86_64_start_reservations(char *real_mode_data)
{
copy_bootdata(__va(real_mode_data));

- reserve_trampoline_memory();
-
reserve_early(__pa_symbol(&_text), __pa_symbol(&__bss_stop), "TEXT DATA BSS");

#ifdef CONFIG_BLK_DEV_INITRD
diff --git a/arch/x86/kernel/mpparse.c b/arch/x86/kernel/mpparse.c
index 35a57c9..40b54ce 100644
--- a/arch/x86/kernel/mpparse.c
+++ b/arch/x86/kernel/mpparse.c
@@ -945,9 +945,6 @@ void __init early_reserve_e820_mpc_new(void)
{
if (enable_update_mptable && alloc_mptable) {
u64 startt = 0;
-#ifdef CONFIG_X86_TRAMPOLINE
- startt = TRAMPOLINE_BASE;
-#endif
mpc_new_phys = early_reserve_e820(startt, mpc_new_length, 4);
}
}
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 946a311..f7b8b98 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -73,6 +73,7 @@

#include <asm/mtrr.h>
#include <asm/apic.h>
+#include <asm/trampoline.h>
#include <asm/e820.h>
#include <asm/mpspec.h>
#include <asm/setup.h>
@@ -875,6 +876,13 @@ void __init setup_arch(char **cmdline_p)

reserve_brk();

+ /*
+ * Find and reserve possible boot-time SMP configuration:
+ */
+ find_smp_config();
+
+ reserve_trampoline_memory();
+
#ifdef CONFIG_ACPI_SLEEP
/*
* Reserve low memory region for sleep support.
@@ -921,11 +929,6 @@ void __init setup_arch(char **cmdline_p)

early_acpi_boot_init();

- /*
- * Find and reserve possible boot-time SMP configuration:
- */
- find_smp_config();
-
#ifdef CONFIG_ACPI_NUMA
/*
* Parse SRAT to discover nodes.
diff --git a/arch/x86/kernel/trampoline.c b/arch/x86/kernel/trampoline.c
index cd02212..c652ef6 100644
--- a/arch/x86/kernel/trampoline.c
+++ b/arch/x86/kernel/trampoline.c
@@ -12,21 +12,19 @@
#endif

/* ready for x86_64 and x86 */
-unsigned char *__trampinitdata trampoline_base = __va(TRAMPOLINE_BASE);
+unsigned char *__trampinitdata 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
+ unsigned long mem;
+
/* Has to be in very low memory so we can execute real-mode AP code. */
- reserve_early(TRAMPOLINE_BASE, TRAMPOLINE_BASE + TRAMPOLINE_SIZE,
- "TRAMPOLINE");
+ mem = find_e820_area(0, 1<<20, TRAMPOLINE_SIZE, PAGE_SIZE);
+ if (mem == -1L)
+ panic("Cannot allocate trampoline\n");
+
+ trampoline_base = __va(mem);
+ reserve_early(mem, mem + TRAMPOLINE_SIZE, "TRAMPOLINE");
}

/*