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[PATCH v11 10/20] x86/reboot: Add ljmp instructions to stackvalidate whitelist

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  [PATCH v11 10/20] x86/reboot: Add ljmp instructions to stackvalidate whitelist Josh Poimboeuf <jpoimboe@redhat.com> - 2015-08-24 16:50 +0200

#1212271 — [PATCH v11 10/20] x86/reboot: Add ljmp instructions to stackvalidate whitelist

stackvalidate reports a false positive warning for the ljmp instruction
in machine_real_restart().  Normally, ljmp isn't allowed in a function,
but this is a special case where it's jumping into real mode.

Add the jumps to a whitelist which tells stackvalidate to ignore them.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
 arch/x86/kernel/reboot.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index 86db4bc..0931d87 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -9,6 +9,7 @@
 #include <linux/sched.h>
 #include <linux/tboot.h>
 #include <linux/delay.h>
+#include <linux/stackvalidate.h>
 #include <acpi/reboot.h>
 #include <asm/io.h>
 #include <asm/apic.h>
@@ -97,11 +98,13 @@ void __noreturn machine_real_restart(unsigned int type)
 
 	/* Jump to the identity-mapped low memory code */
 #ifdef CONFIG_X86_32
-	asm volatile("jmpl *%0" : :
+	asm volatile(STACKVALIDATE_IGNORE_INSN
+		     "jmpl *%0;" : :
 		     "rm" (real_mode_header->machine_real_restart_asm),
 		     "a" (type));
 #else
-	asm volatile("ljmpl *%0" : :
+	asm volatile(STACKVALIDATE_IGNORE_INSN
+		     "ljmpl *%0" : :
 		     "m" (real_mode_header->machine_real_restart_asm),
 		     "D" (type));
 #endif
-- 
2.4.3

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