Re: [PATCH] powerpc/4xx: Fix setup_kuep() on SMP
Le 29/06/2021 à 13:58, Michael Ellerman a écrit :
Christophe Leroy writes:
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
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
---
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
Seems like we need when we don't have CONFIG_SMP.
I tested it with akebono_defconfig, looks like it has CONFIG_SMP.
Re: [PATCH] powerpc/4xx: Fix setup_kuep() on SMP
Christophe Leroy writes:
> 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
> 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
> ---
> 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
cheers
[PATCH] powerpc/4xx: Fix setup_kuep() on SMP
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
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
---
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
--
2.25.0
