diff options
| author | Christophe Leroy <christophe.leroy@csgroup.eu> | 2021-06-03 08:41:42 +0000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2021-06-17 00:09:08 +1000 |
| commit | 50d2f104cd9572af476579eae9aa1b38de602ec7 (patch) | |
| tree | 91fd88774d6ed6efb0cbbbc8fdbb24d8f357fe6f /arch | |
| parent | 86f46f3432727933be82f64b739712a6edb9d704 (diff) | |
powerpc/32s: Allow disabling KUEP at boot time
PPC64 uses MMU features to enable/disable KUEP at boot time.
But feature fixups are applied way too early on PPC32.
Now that all KUEP related actions are in C following the
conversion of KUEP initial setup and context switch in C,
static branches can be used to enable/disable KUEP.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/7745a2c3a08ec46302920a3f48d1cb9b5469dbbb.1622708530.git.christophe.leroy@csgroup.eu
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/powerpc/include/asm/book3s/32/kup.h | 6 | ||||
| -rw-r--r-- | arch/powerpc/mm/book3s32/kuep.c | 11 |
2 files changed, 12 insertions, 5 deletions
diff --git a/arch/powerpc/include/asm/book3s/32/kup.h b/arch/powerpc/include/asm/book3s/32/kup.h index 618ffc8e4ee9..2854d970dabe 100644 --- a/arch/powerpc/include/asm/book3s/32/kup.h +++ b/arch/powerpc/include/asm/book3s/32/kup.h @@ -7,6 +7,10 @@ #ifndef __ASSEMBLY__ +#include <linux/jump_label.h> + +extern struct static_key_false disable_kuep_key; + static __always_inline bool kuap_is_disabled(void) { return !IS_ENABLED(CONFIG_PPC_KUAP); @@ -14,7 +18,7 @@ static __always_inline bool kuap_is_disabled(void) static __always_inline bool kuep_is_disabled(void) { - return !IS_ENABLED(CONFIG_PPC_KUEP); + return !IS_ENABLED(CONFIG_PPC_KUEP) || static_branch_unlikely(&disable_kuep_key); } static inline void kuep_lock(void) diff --git a/arch/powerpc/mm/book3s32/kuep.c b/arch/powerpc/mm/book3s32/kuep.c index 3147e2edcf63..3f6eb6e23fca 100644 --- a/arch/powerpc/mm/book3s32/kuep.c +++ b/arch/powerpc/mm/book3s32/kuep.c @@ -3,15 +3,18 @@ #include <asm/kup.h> #include <asm/smp.h> +struct static_key_false disable_kuep_key; + void __init setup_kuep(bool disabled) { - kuep_lock(); + if (!disabled) + kuep_lock(); if (smp_processor_id() != boot_cpuid) return; - pr_info("Activating Kernel Userspace Execution Prevention\n"); - if (disabled) - pr_warn("KUEP cannot be disabled yet on 6xx when compiled in\n"); + static_branch_enable(&disable_kuep_key); + else + pr_info("Activating Kernel Userspace Execution Prevention\n"); } |