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authorH. Peter Anvin <hpa@linux.intel.com>2011-02-14 15:34:57 -0800
committerH. Peter Anvin <hpa@linux.intel.com>2011-02-17 21:02:43 -0800
commit4822b7fc6d4870685a9feadfc348d48f5e47460a (patch)
tree52a482fde76ff8bae64fc09761967a33b9b7b08b /arch/x86/kernel/trampoline_32.S
parent85e2efbb1db9a18d218006706d6e4fbeb0216213 (diff)
x86, trampoline: Common infrastructure for low memory trampolines
Common infrastructure for low memory trampolines. This code installs the trampolines permanently in low memory very early. It also permits multiple pieces of code to be used for this purpose. This code also introduces a standard infrastructure for computing symbol addresses in the trampoline code. The only change to the actual SMP trampolines themselves is that the 64-bit trampoline has been made reusable -- the previous version would overwrite the code with a status variable; this moves the status variable to a separate location. Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> LKML-Reference: <4D5DFBE4.7090104@intel.com> Cc: Rafael J. Wysocki <rjw@sisk.pl> Cc: Matthieu Castet <castet.matthieu@free.fr> Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Diffstat (limited to 'arch/x86/kernel/trampoline_32.S')
-rw-r--r--arch/x86/kernel/trampoline_32.S15
1 files changed, 11 insertions, 4 deletions
diff --git a/arch/x86/kernel/trampoline_32.S b/arch/x86/kernel/trampoline_32.S
index 8508237e8e4..451c0a7ef7f 100644
--- a/arch/x86/kernel/trampoline_32.S
+++ b/arch/x86/kernel/trampoline_32.S
@@ -32,9 +32,11 @@
#include <asm/segment.h>
#include <asm/page_types.h>
-/* We can free up trampoline after bootup if cpu hotplug is not supported. */
-__CPUINITRODATA
-.code16
+#ifdef CONFIG_SMP
+
+ .section ".x86_trampoline","a"
+ .balign PAGE_SIZE
+ .code16
ENTRY(trampoline_data)
r_base = .
@@ -44,7 +46,7 @@ r_base = .
cli # We should be safe anyway
- movl $0xA5A5A5A5, trampoline_data - r_base
+ movl $0xA5A5A5A5, trampoline_status - r_base
# write marker for master knows we're running
/* GDT tables in non default location kernel can be beyond 16MB and
@@ -72,5 +74,10 @@ boot_idt_descr:
.word 0 # idt limit = 0
.long 0 # idt base = 0L
+ENTRY(trampoline_status)
+ .long 0
+
.globl trampoline_end
trampoline_end:
+
+#endif /* CONFIG_SMP */