From: Michael D Labriola <mlabriol@gdeb.com>
To: Michael D Labriola <mlabriol@gdeb.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>,
"H. Peter Anvin" <hpa@zytor.com>,
Kushal Koolwal <kushalkoolwal@gmail.com>,
linux-kernel@vger.kernel.org, michael.d.labriola@gmail.com,
Ingo Molnar <mingo@elte.hu>,
Matthew Garrett <mjg59@srcf.ucam.org>,
support@versalogic.com, Thomas Gleixner <tglx@linutronix.de>,
x86@kernel.org
Subject: Re: [PATCH] x86, reboot: skip DMI checks if reboot set by user
Date: Thu, 19 Jan 2012 12:46:55 -0500 [thread overview]
Message-ID: <OF2B909250.6078896E-ON8525798A.0058FF49-8525798A.0061AEA1@gdeb.com> (raw)
In-Reply-To: <OF8642E997.5ED041E1-ON8525798A.0056983A-8525798A.0056E05B@LocalDomain>
Michael D Labriola/EB/GDYN wrote on 01/19/2012 10:48:53 AM:
> Alan Cox <alan@lxorguk.ukuu.org.uk> wrote on 01/19/2012 10:45:04 AM:
>
> > > checking if reboot_type's value is anything other than BOOT_ACPI
(which
> > > is the default), but that does assume BOOT_ACPI is the default. What
if
> > > that's ever changed? Seems likely to me that whoever changes the
default
> > > in the future could very easily re-break this at that point.
> > >
> > > Thoughts?
> >
> > Fair point - how about a BOOT_DEFAULT define value if it hasn't been
set
> > and we can just make it do the same as ACPI in the switch ?
>
> Sounds good to me. I'll whip that up and resubmit.
Well, how about this. Using a #define won't do as far as I can tell.
But I can reduce the size of the diff considerably like this.
Random question... why do we have a reboot_init function that does DMI
checking with reboot_dmi_table (callbacks are mostly set_bios_reboot, but
there is a single set_kbd_reboot) and also a pci_reboot_init which does
the DMI check again using a separate pci_reboot_dmi_table (all callbacks
are to set_pci_reboot)?
Wouldn't it make more sense to do a single DMI scan using one big table?
diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index 37a458b..0fc5b31 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -39,6 +39,14 @@ static int reboot_mode;
enum reboot_type reboot_type = BOOT_ACPI;
int reboot_force;
+/* This variable is used privately to keep track of whether or not
+ * reboot_type is still set to its default value (i.e., reboot= hasn't
+ * been set on the command line). This is needed so that we can
+ * suppress DMI scanning for reboot quirks. Without it, it's
+ * impossible to override a faulty reboot quirk without recompiling.
+ */
+static int reboot_default = 1;
+
#if defined(CONFIG_X86_32) && defined(CONFIG_SMP)
static int reboot_cpu = -1;
#endif
@@ -67,6 +75,12 @@ bool port_cf9_safe = false;
static int __init reboot_setup(char *str)
{
for (;;) {
+ /* Having anything passed on the command line via
+ * reboot= will cause us to disable DMI checking
+ * below.
+ */
+ reboot_default = 0;
+
switch (*str) {
case 'w':
reboot_mode = 0x1234;
@@ -316,7 +330,12 @@ static struct dmi_system_id __initdata
reboot_dmi_table[] = {
static int __init reboot_init(void)
{
- dmi_check_system(reboot_dmi_table);
+ /* Only do the DMI check if reboot_type hasn't been overridden
+ * on the command line
+ */
+ if (reboot_default) {
+ dmi_check_system(reboot_dmi_table);
+ }
return 0;
}
core_initcall(reboot_init);
@@ -465,7 +484,12 @@ static struct dmi_system_id __initdata
pci_reboot_dmi_table[] = {
static int __init pci_reboot_init(void)
{
- dmi_check_system(pci_reboot_dmi_table);
+ /* Only do the DMI check if reboot_type hasn't been overridden
+ * on the command line
+ */
+ if (reboot_default) {
+ dmi_check_system(pci_reboot_dmi_table);
+ }
return 0;
}
core_initcall(pci_reboot_init);
next prev parent reply other threads:[~2012-01-19 17:47 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-17 15:16 [PATCH] x86, reboot: skip DMI checks if reboot set by user Michael D Labriola
2012-01-17 19:58 ` Alan Cox
2012-01-19 15:32 ` Michael D Labriola
2012-01-19 15:45 ` Alan Cox
2012-01-19 15:48 ` Michael D Labriola
[not found] ` <OF8642E997.5ED041E1-ON8525798A.0056983A-8525798A.0056E05B@LocalDomain>
2012-01-19 17:46 ` Michael D Labriola [this message]
2012-01-19 17:52 ` H. Peter Anvin
2012-01-19 19:14 ` Michael D Labriola
2012-01-19 19:17 ` H. Peter Anvin
2012-01-19 19:34 ` Michael D Labriola
2012-01-19 19:41 ` Ingo Molnar
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