Re: [PATCH] powerpc/4xx: Fix setup_kuep() on SMP
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From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2021-06-29 11:58:55
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Christophe Leroy [off-list ref] writes:
quoted hunk ↗ jump to hunk
On SMP, setup_kuep() is also called from start_secondary() since commit 86f46f343272 ("powerpc/32s: Initialise KUAP and KUEP in C"). start_secondary() is not an __init function. Remove the __init marker from setup_kuep() and bail out when not caller on the first CPU as the work is already done. Reported-by: kernel test robot <redacted> Fixes: 10248dcba120 ("powerpc/44x: Implement Kernel Userspace Exec Protection (KUEP)") Fixes: 86f46f343272 ("powerpc/32s: Initialise KUAP and KUEP in C"). Signed-off-by: Christophe Leroy <redacted> --- arch/powerpc/mm/nohash/44x.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)diff --git a/arch/powerpc/mm/nohash/44x.c b/arch/powerpc/mm/nohash/44x.c index 7da6d1e9fc9b..20c18bd5b9a0 100644 --- a/arch/powerpc/mm/nohash/44x.c +++ b/arch/powerpc/mm/nohash/44x.c@@ -241,8 +241,11 @@ void __init mmu_init_secondary(int cpu) #endif /* CONFIG_SMP */ #ifdef CONFIG_PPC_KUEP -void __init setup_kuep(bool disabled) +void setup_kuep(bool disabled) { + if (smp_processor_id() != boot_cpuid) + return; + if (disabled) patch_instruction_site(&patch__tlb_44x_kuep, ppc_inst(PPC_RAW_NOP())); else
Building ppc44x_defconfig gives me:
/linux/arch/powerpc/mm/nohash/44x.c: In function 'setup_kuep':
/linux/arch/powerpc/mm/nohash/44x.c:246:35: error: 'boot_cpuid' undeclared (first use in this function); did you mean 'boot_cpu_init'?
246 | if (smp_processor_id() != boot_cpuid)
| ^~~~~~~~~~
| boot_cpu_init
/linux/arch/powerpc/mm/nohash/44x.c:246:35: note: each undeclared identifier is reported only once for each function it appears in
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