Messages in this thread | | | From | Kees Cook <> | Date | Fri, 8 Feb 2019 01:05:46 +0000 | Subject | Re: [PATCH] panic/reboot: allow specifying reboot_mode for panic only |
| |
On Thu, Feb 7, 2019 at 8:59 PM Aaro Koskinen <aaro.koskinen@iki.fi> wrote: > > From: Aaro Koskinen <aaro.koskinen@nokia.com> > > Allow specifying reboot_mode for panic only. This is needed on systems > where ramoops is used to store panic logs, and user wants to use warm > reset to preserve those, while still having cold reset on normal reboots.
Seems reasonable to me. I'd make the "-1" be a specific #define, though. Open-coded literals should generally be avoided.
-Kees
> > Signed-off-by: Aaro Koskinen <aaro.koskinen@nokia.com> > --- > .../admin-guide/kernel-parameters.txt | 4 +++- > include/linux/reboot.h | 1 + > kernel/panic.c | 2 ++ > kernel/reboot.c | 20 ++++++++++++++----- > 4 files changed, 21 insertions(+), 6 deletions(-) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index b799bcf67d7b..033c93048a95 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -3950,7 +3950,9 @@ > [[,]s[mp]#### \ > [[,]b[ios] | a[cpi] | k[bd] | t[riple] | e[fi] | p[ci]] \ > [[,]f[orce] > - Where reboot_mode is one of warm (soft) or cold (hard) or gpio, > + Where reboot_mode is one of warm (soft) or cold (hard) or gpio > + (prefix with 'panic_' to set mode for panic > + reboot only), > reboot_type is one of bios, acpi, kbd, triple, efi, or pci, > reboot_force is either force or not specified, > reboot_cpu is s[mp]#### with #### being the processor > diff --git a/include/linux/reboot.h b/include/linux/reboot.h > index e63799a6e895..61962f9826fa 100644 > --- a/include/linux/reboot.h > +++ b/include/linux/reboot.h > @@ -21,6 +21,7 @@ enum reboot_mode { > REBOOT_GPIO, > }; > extern enum reboot_mode reboot_mode; > +extern enum reboot_mode panic_reboot_mode; > > enum reboot_type { > BOOT_TRIPLE = 't', > diff --git a/kernel/panic.c b/kernel/panic.c > index f121e6ba7e11..c4285e3a27ef 100644 > --- a/kernel/panic.c > +++ b/kernel/panic.c > @@ -306,6 +306,8 @@ void panic(const char *fmt, ...) > * shutting down. But if there is a chance of > * rebooting the system it will be rebooted. > */ > + if (panic_reboot_mode != -1) > + reboot_mode = panic_reboot_mode; > emergency_restart(); > } > #ifdef __sparc__ > diff --git a/kernel/reboot.c b/kernel/reboot.c > index e1b79b6a2735..d5627a92508d 100644 > --- a/kernel/reboot.c > +++ b/kernel/reboot.c > @@ -31,6 +31,7 @@ EXPORT_SYMBOL(cad_pid); > #define DEFAULT_REBOOT_MODE > #endif > enum reboot_mode reboot_mode DEFAULT_REBOOT_MODE; > +enum reboot_mode panic_reboot_mode = -1; > > /* > * This variable is used privately to keep track of whether or not > @@ -519,6 +520,8 @@ EXPORT_SYMBOL_GPL(orderly_reboot); > static int __init reboot_setup(char *str) > { > for (;;) { > + enum reboot_mode *mode; > + > /* > * Having anything passed on the command line via > * reboot= will cause us to disable DMI checking > @@ -526,17 +529,24 @@ static int __init reboot_setup(char *str) > */ > reboot_default = 0; > > + if (!strncmp(str, "panic_", 6)) { > + mode = &panic_reboot_mode; > + str += 6; > + } else { > + mode = &reboot_mode; > + } > + > switch (*str) { > case 'w': > - reboot_mode = REBOOT_WARM; > + *mode = REBOOT_WARM; > break; > > case 'c': > - reboot_mode = REBOOT_COLD; > + *mode = REBOOT_COLD; > break; > > case 'h': > - reboot_mode = REBOOT_HARD; > + *mode = REBOOT_HARD; > break; > > case 's': > @@ -553,11 +563,11 @@ static int __init reboot_setup(char *str) > if (rc) > return rc; > } else > - reboot_mode = REBOOT_SOFT; > + *mode = REBOOT_SOFT; > break; > } > case 'g': > - reboot_mode = REBOOT_GPIO; > + *mode = REBOOT_GPIO; > break; > > case 'b': > -- > 2.17.0 >
-- Kees Cook
| |