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| author | Thomas Gleixner <tglx@linutronix.de> | 2024-03-04 13:12:23 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2024-03-04 14:09:07 +0300 |
| commit | 71eb4893cfaf37f8884515c8f71717044b97bf44 (patch) | |
| tree | c5bcb3cb3ddae2cf99e55aba7cbd2221e7f3b287 /arch/x86/kernel/cpu/common.c | |
| parent | 712610725c48c829e42bebfc9908cd92468e2731 (diff) | |
| download | linux-71eb4893cfaf37f8884515c8f71717044b97bf44.tar.xz | |
x86/percpu: Cure per CPU madness on UP
On UP builds Sparse complains rightfully about accesses to cpu_info with
per CPU accessors:
cacheinfo.c:282:30: sparse: warning: incorrect type in initializer (different address spaces)
cacheinfo.c:282:30: sparse: expected void const [noderef] __percpu *__vpp_verify
cacheinfo.c:282:30: sparse: got unsigned int *
The reason is that on UP builds cpu_info which is a per CPU variable on SMP
is mapped to boot_cpu_info which is a regular variable. There is a hideous
accessor cpu_data() which tries to hide this, but it's not sufficient as
some places require raw accessors and generates worse code than the regular
per CPU accessors.
Waste sizeof(struct x86_cpuinfo) memory on UP and provide the per CPU
cpu_info unconditionally. This requires to update the CPU info on the boot
CPU as SMP does. (Ab)use the weakly defined smp_prepare_boot_cpu() function
and implement exactly that.
This allows to use regular per CPU accessors uncoditionally and paves the
way to remove the cpu_data() hackery.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20240304005104.622511517@linutronix.de
Diffstat (limited to 'arch/x86/kernel/cpu/common.c')
| -rw-r--r-- | arch/x86/kernel/cpu/common.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index fbc4e60d027c..6057a9ecac93 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -70,6 +70,9 @@ #include "cpu.h" +DEFINE_PER_CPU_READ_MOSTLY(struct cpuinfo_x86, cpu_info); +EXPORT_PER_CPU_SYMBOL(cpu_info); + u32 elf_hwcap2 __read_mostly; /* Number of siblings per CPU package */ |