Messages in this thread | | | Date | Fri, 24 Jul 2020 10:13:52 +0100 | From | Mark Rutland <> | Subject | Re: [PATCH -next] arm64: Export __cpu_logical_map |
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On Fri, Jul 24, 2020 at 01:46:18PM +0530, Anshuman Khandual wrote: > > On 07/24/2020 08:38 AM, Kefeng Wang wrote: > > +maillist > > This does not seem to be a correct method of posting any patch. > > > > > On 2020/7/24 11:04, Kefeng Wang wrote: > >> ERROR: modpost: "__cpu_logical_map" [drivers/cpufreq/tegra194-cpufreq.ko] undefined! > > > >> > >> ARM64 tegra194-cpufreq driver use cpu_logical_map, export > >> __cpu_logical_map to fix build issue. > > Commit 887d5fc82cb4 ("cpufreq: Add Tegra194 cpufreq driver") which adds > this particular driver is present just on linux-next. But as expected, > the driver does not use __cpu_logical_map directly but instead accesses > it via cpu_logical_map() wrapper. Wondering, how did you even trigger > the modpost error ?
The wrapper in <asm/smp.h> is:
| /* | * Logical CPU mapping. | */ | extern u64 __cpu_logical_map[NR_CPUS]; | #define cpu_logical_map(cpu) __cpu_logical_map[cpu]
... and use of that would blow up as described.
> >> > >> Reported-by: Hulk Robot <hulkci@huawei.com> > >> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> > >> --- > >> arch/arm64/kernel/setup.c | 1 + > >> 1 file changed, 1 insertion(+) > >> > >> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c > >> index c793276ec7ad9..3aea05fbb9998 100644 > >> --- a/arch/arm64/kernel/setup.c > >> +++ b/arch/arm64/kernel/setup.c > >> @@ -275,6 +275,7 @@ static int __init reserve_memblock_reserved_regions(void) > >> arch_initcall(reserve_memblock_reserved_regions); > >> u64 __cpu_logical_map[NR_CPUS] = { [0 ... NR_CPUS-1] = INVALID_HWID }; > >> +EXPORT_SYMBOL(__cpu_logical_map);
If modules are using cpu_logical_map(), this looks sane ot me, but I wonder if we should instead turn cpu_logical_map() into a C wrapper in smp.c, or at least mark __cpu_logical_map as __ro_after_init lest someone have the bright idea to fiddle with it.
Mark.
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