| Message ID | 20221105214841.7828-2-samuel@sholland.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | firmware/psci: Switch to the sys-off handler API | expand |
On 11/6/22 00:48, Samuel Holland wrote: > commit 587b9bfe0668 ("kernel/reboot: Use static handler for > register_platform_power_off()") addded a statically-allocated handler > so register_sys_off_handler() could be called before the slab allocator > is available. > > That behavior was limited to the SYS_OFF_PRIO_PLATFORM priority. > However, it is also required for handlers such as PSCI on ARM, which > needs to be registered at SYS_OFF_PRIO_FIRMWARE. Currently, this call > stack crashes: > > start_kernel() > setup_arch() > psci_dt_init() > psci_0_2_init() > register_sys_off_handler() > kmem_cache_alloc() > > Generalize the code to use the statically-allocated handler for the > first registration, regardless of priority. Check .sys_off_cb for > conflicts instead of .cb_data; some callbacks (e.g. firmware) do not > need any per-instance data, so .cb_data could be NULL. > > Signed-off-by: Samuel Holland <samuel@sholland.org> > --- > > kernel/reboot.c | 10 ++++------ > 1 file changed, 4 insertions(+), 6 deletions(-) > > diff --git a/kernel/reboot.c b/kernel/reboot.c > index 3bba88c7ffc6..38c18d4f0a36 100644 > --- a/kernel/reboot.c > +++ b/kernel/reboot.c > @@ -327,7 +327,7 @@ static int sys_off_notify(struct notifier_block *nb, > return handler->sys_off_cb(&data); > } > > -static struct sys_off_handler platform_sys_off_handler; > +static struct sys_off_handler early_sys_off_handler; > > static struct sys_off_handler *alloc_sys_off_handler(int priority) > { > @@ -338,10 +338,8 @@ static struct sys_off_handler *alloc_sys_off_handler(int priority) > * Platforms like m68k can't allocate sys_off handler dynamically > * at the early boot time because memory allocator isn't available yet. > */ > - if (priority == SYS_OFF_PRIO_PLATFORM) { > - handler = &platform_sys_off_handler; > - if (handler->cb_data) > - return ERR_PTR(-EBUSY); > + if (!early_sys_off_handler.sys_off_cb) { > + handler = &early_sys_off_handler; > } else { > if (system_state > SYSTEM_RUNNING) > flags = GFP_ATOMIC; > @@ -358,7 +356,7 @@ static struct sys_off_handler *alloc_sys_off_handler(int priority) > > static void free_sys_off_handler(struct sys_off_handler *handler) > { > - if (handler == &platform_sys_off_handler) > + if (handler == &early_sys_off_handler) > memset(handler, 0, sizeof(*handler)); > else > kfree(handler); Reviewed-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
diff --git a/kernel/reboot.c b/kernel/reboot.c index 3bba88c7ffc6..38c18d4f0a36 100644 --- a/kernel/reboot.c +++ b/kernel/reboot.c @@ -327,7 +327,7 @@ static int sys_off_notify(struct notifier_block *nb, return handler->sys_off_cb(&data); } -static struct sys_off_handler platform_sys_off_handler; +static struct sys_off_handler early_sys_off_handler; static struct sys_off_handler *alloc_sys_off_handler(int priority) { @@ -338,10 +338,8 @@ static struct sys_off_handler *alloc_sys_off_handler(int priority) * Platforms like m68k can't allocate sys_off handler dynamically * at the early boot time because memory allocator isn't available yet. */ - if (priority == SYS_OFF_PRIO_PLATFORM) { - handler = &platform_sys_off_handler; - if (handler->cb_data) - return ERR_PTR(-EBUSY); + if (!early_sys_off_handler.sys_off_cb) { + handler = &early_sys_off_handler; } else { if (system_state > SYSTEM_RUNNING) flags = GFP_ATOMIC; @@ -358,7 +356,7 @@ static struct sys_off_handler *alloc_sys_off_handler(int priority) static void free_sys_off_handler(struct sys_off_handler *handler) { - if (handler == &platform_sys_off_handler) + if (handler == &early_sys_off_handler) memset(handler, 0, sizeof(*handler)); else kfree(handler);
commit 587b9bfe0668 ("kernel/reboot: Use static handler for register_platform_power_off()") addded a statically-allocated handler so register_sys_off_handler() could be called before the slab allocator is available. That behavior was limited to the SYS_OFF_PRIO_PLATFORM priority. However, it is also required for handlers such as PSCI on ARM, which needs to be registered at SYS_OFF_PRIO_FIRMWARE. Currently, this call stack crashes: start_kernel() setup_arch() psci_dt_init() psci_0_2_init() register_sys_off_handler() kmem_cache_alloc() Generalize the code to use the statically-allocated handler for the first registration, regardless of priority. Check .sys_off_cb for conflicts instead of .cb_data; some callbacks (e.g. firmware) do not need any per-instance data, so .cb_data could be NULL. Signed-off-by: Samuel Holland <samuel@sholland.org> --- kernel/reboot.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-)