Messages in this thread | | | Date | Sat, 18 Feb 2023 17:20:28 -0600 | From | Samuel Holland <> | Subject | Re: [PATCH 1/3] kernel/reboot: Use the static sys-off handler for any priority |
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On 2/14/23 18:17, Palmer Dabbelt wrote: > On Wed, 28 Dec 2022 08:19:13 PST (-0800), samuel@sholland.org 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 and SBI on >> RISC-V, which should 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 drivers) >> do not need any per-instance data, so .cb_data could be NULL. >> >> Reviewed-by: Dmitry Osipenko <dmitry.osipenko@collabora.com> >> 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); > > Sorry for being slow here, I'd been assuming someone would Ack this but > it looks like maybe there's nobody in the maintainers file for > kernel/reboot.c? I'm fine taking this via the RISC-V tree if that's OK > with people, but the cover letter suggests the patch is necessary for > multiple patch sets.
See also Dmitry's reply[0] to the PSCI thread. (Maybe I should have sent both conversions as one series?)
I am happy with the patches going through any tree. The kernel/reboot.c patch is exactly the same between the two series, so it should not hurt if it gets merged twice. Though if you take this series through the RISC-V tree, maybe you want to create a tag for it?
I am not sure exactly what needs to be done here; I am happy to do anything that would assist getting both series merged for v6.3, to avoid a regression with axp20x[1].
Regards, Samuel
[0]: https://lore.kernel.org/lkml/0a180849-ba1b-2a82-ab06-ed1b8155d5ca@collabora.com/ [1]: https://lore.kernel.org/lkml/e38d29f5-cd3c-4a2b-b355-2bcfad00a24b@sholland.org/
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