On Fri, Dec 18, 2015 at 06:39:27AM -0600, Josh Poimboeuf wrote:
> stacktool 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 stacktool to ignore them.
>
> Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
> ---
> 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 02693dd..1ea1c5e 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/stacktool.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(STACKTOOL_IGNORE_INSN
> + "jmpl *%0;" : :
> "rm" (real_mode_header->machine_real_restart_asm),
> "a" (type));
> #else
> - asm volatile("ljmpl *%0" : :
> + asm volatile(STACKTOOL_IGNORE_INSN
> + "ljmpl *%0" : :
> "m" (real_mode_header->machine_real_restart_asm),
> "D" (type));
> #endif
Well, I can't say that I'm crazy about all those new tools adding
markers to unrelated kernel code.
Can't you teach stacktool to ignore the whole machine_real_restart()
function simply?
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
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