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[PATCH v9 10/20] x86/reboot: Add ljmp instructions to stackvalidate whitelist

From Josh Poimboeuf <jpoimboe@redhat.com>
Newsgroups linux.kernel
Subject [PATCH v9 10/20] x86/reboot: Add ljmp instructions to stackvalidate whitelist
Date 2015-08-07 19:00 +0200
Message-ID <pUT9X-5pP-63@gated-at.bofh.it> (permalink)
References <pUT9U-5pP-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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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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Thread

[PATCH v9 00/20] Compile-time stack validation Josh Poimboeuf <jpoimboe@redhat.com> - 2015-08-07 19:00 +0200
  [PATCH v9 05/20] x86/stackvalidate: Add ignore macros Josh Poimboeuf <jpoimboe@redhat.com> - 2015-08-07 19:00 +0200
  [PATCH v9 03/20] x86/stackvalidate: Compile-time stack validation Josh Poimboeuf <jpoimboe@redhat.com> - 2015-08-07 19:00 +0200
  [PATCH v9 18/20] x86/asm: Create stack frames in rwsem functions Josh Poimboeuf <jpoimboe@redhat.com> - 2015-08-07 19:00 +0200
  [PATCH v9 16/20] x86/asm/entry: Create stack frames in thunk functions Josh Poimboeuf <jpoimboe@redhat.com> - 2015-08-07 19:00 +0200
  [PATCH v9 13/20] x86/asm/crypto: Move .Lbswap_mask data to .rodata section Josh Poimboeuf <jpoimboe@redhat.com> - 2015-08-07 19:00 +0200
  [PATCH v9 01/20] x86/asm: Frame pointer macro cleanup Josh Poimboeuf <jpoimboe@redhat.com> - 2015-08-07 19:00 +0200
  [PATCH v9 08/20] x86/paravirt: Create a stack frame in PV_CALLEE_SAVE_REGS_THUNK Josh Poimboeuf <jpoimboe@redhat.com> - 2015-08-07 19:00 +0200
  [PATCH v9 11/20] x86/xen: Add xen_cpuid() and xen_setup_gdt() to stackvalidate whitelists Josh Poimboeuf <jpoimboe@redhat.com> - 2015-08-07 19:00 +0200
  [PATCH v9 09/20] x86/amd: Set ELF function type for vide() Josh Poimboeuf <jpoimboe@redhat.com> - 2015-08-07 19:00 +0200
  [PATCH v9 14/20] x86/asm/crypto: Move jump_table to .rodata section Josh Poimboeuf <jpoimboe@redhat.com> - 2015-08-07 19:00 +0200
  [PATCH v9 15/20] x86/asm/crypto: Create stack frames in clmul_ghash_mul/update() Josh Poimboeuf <jpoimboe@redhat.com> - 2015-08-07 19:00 +0200
  [PATCH v9 20/20] x86/asm/power: Create stack frames in hibernate_asm_64.S Josh Poimboeuf <jpoimboe@redhat.com> - 2015-08-07 19:00 +0200
    Re: [PATCH v9 20/20] x86/asm/power: Create stack frames in  hibernate_asm_64.S Pavel Machek <pavel@ucw.cz> - 2015-08-09 21:20 +0200
  [PATCH v9 10/20] x86/reboot: Add ljmp instructions to stackvalidate whitelist Josh Poimboeuf <jpoimboe@redhat.com> - 2015-08-07 19:00 +0200
  [PATCH v9 04/20] x86/stackvalidate: Add file and directory ignores Josh Poimboeuf <jpoimboe@redhat.com> - 2015-08-07 19:00 +0200

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