On Tue, Aug 31, 2021 at 02:13:08PM +0200, Thomas Gleixner wrote: > On Tue, Aug 31 2021 at 04:13, Guenter Roeck wrote: > > On Mon, Aug 09, 2021 at 10:12:15AM +0800, Xiaoming Ni wrote: > >> Semaphore is sleeping lock. Add might_sleep() to down*() family > >> (with exception of down_trylock()) to detect atomic context sleep. > >> > >> Previously discussed with Peter Zijlstra, see link: > >> https://lore.kernel.org/lkml/20210806082320.GD22037@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx > >> > >> Signed-off-by: Xiaoming Ni <nixiaoming@xxxxxxxxxx> > >> Acked-by: Will Deacon <will@xxxxxxxxxx> > > > > This patch results in the following traceback on all arm64 boots with > > EFI BIOS. > > That's what this change was supposed to catch :) > > > The problem is only seen with CONFIG_ACPI_PPTT=y, and thus only on arm64. > > The below should fix this. > > Thanks, > > tglx > --- > Subject: drivers: base: cacheinfo: Get rid of DEFINE_SMP_CALL_CACHE_FUNCTION() > From: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > Date: Tue, 31 Aug 2021 13:48:34 +0200 > > DEFINE_SMP_CALL_CACHE_FUNCTION() was usefel before the CPU hotplug rework typo: "usefel" > to ensure that the cache related functions are called on the upcoming CPU > because the notifier itself could run on any online CPU. > > The hotplug state machine guarantees that the callbacks are invoked on the > upcoming CPU. So there is no need to have this SMP function call > obfuscation. That indirection was missed when the hotplug notifiers were > converted. > > This also solves the problem of ARM64 init_cache_level() invoking ACPI > functions which take a semaphore in that context. That's invalid as SMP > function calls run with interrupts disabled. Running it just from the > callback in context of the CPU hotplug thread solves this. > > Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx> > Fixes: 8571890e1513 ("arm64: Add support for ACPI based firmware tables") > Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > --- > arch/arm64/kernel/cacheinfo.c | 7 ++----- > arch/mips/kernel/cacheinfo.c | 7 ++----- > arch/riscv/kernel/cacheinfo.c | 7 ++----- > arch/x86/kernel/cpu/cacheinfo.c | 7 ++----- > include/linux/cacheinfo.h | 18 ------------------ > 5 files changed, 8 insertions(+), 38 deletions(-) > > --- a/arch/arm64/kernel/cacheinfo.c > +++ b/arch/arm64/kernel/cacheinfo.c > @@ -43,7 +43,7 @@ static void ci_leaf_init(struct cacheinf > this_leaf->type = type; > } > > -static int __init_cache_level(unsigned int cpu) > +int init_cache_level(unsigned int cpu) > { > unsigned int ctype, level, leaves, fw_level; > struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu); > @@ -78,7 +78,7 @@ static int __init_cache_level(unsigned i > return 0; > } > > -static int __populate_cache_leaves(unsigned int cpu) > +int populate_cache_leaves(unsigned int cpu) > { > unsigned int level, idx; > enum cache_type type; > @@ -97,6 +97,3 @@ static int __populate_cache_leaves(unsig > } > return 0; > } > - > -DEFINE_SMP_CALL_CACHE_FUNCTION(init_cache_level) > -DEFINE_SMP_CALL_CACHE_FUNCTION(populate_cache_leaves) Glad to see the back of this: Acked-by: Will Deacon <will@xxxxxxxxxx> Will
