Le 14/12/2020 à 13:30, Michael Ellerman a écrit :
setup_kup() is used by both 64-bit and 32-bit code. However on 64-bit it must not be __init, because it's used for CPU hotplug, whereas on 32-bit it should be __init because it calls setup_kuap/kuep() which are __init. We worked around that problem in the past by marking it __ref, see commit 67d53f30e23e ("powerpc/mm: fix section mismatch for setup_kup()"). Marking it __ref basically just omits it from section mismatch checking, which can lead to bugs, and in fact it did, see commit 44b4c4450f8d ("powerpc/64s: Mark the kuap/kuep functions non __init") We can avoid all these problems by just making it static inline. Because all it does is call other functions, making it inline actually shrinks the 32-bit vmlinux by ~76 bytes. Signed-off-by: Michael Ellerman <m...@ellerman.id.au> --- arch/powerpc/include/asm/kup.h | 8 ++++++-- arch/powerpc/mm/init-common.c | 6 ------ 2 files changed, 6 insertions(+), 8 deletions(-) diff --git a/arch/powerpc/include/asm/kup.h b/arch/powerpc/include/asm/kup.h index 5a9820c54da9..46b12c6dc728 100644 --- a/arch/powerpc/include/asm/kup.h +++ b/arch/powerpc/include/asm/kup.h @@ -49,8 +49,6 @@ extern bool disable_kuap;#include <linux/pgtable.h> -void setup_kup(void);- #ifdef CONFIG_PPC_KUEP void setup_kuep(bool disabled); #else @@ -85,6 +83,12 @@ static inline void restore_user_access(unsigned long flags) { } #endif /* CONFIG_PPC_BOOK3S_64 */ #endif /* CONFIG_PPC_KUAP */+static inline void setup_kup(void)
Should it be __always_inline ? Christophe
+{ + setup_kuep(disable_kuep); + setup_kuap(disable_kuap); +} + static inline void allow_read_from_user(const void __user *from, unsigned long size) { allow_user_access(NULL, from, size, KUAP_READ); diff --git a/arch/powerpc/mm/init-common.c b/arch/powerpc/mm/init-common.c index afdebb95bcae..3a82f89827a5 100644 --- a/arch/powerpc/mm/init-common.c +++ b/arch/powerpc/mm/init-common.c @@ -47,12 +47,6 @@ static int __init parse_nosmap(char *p) } early_param("nosmap", parse_nosmap);-void __ref setup_kup(void)-{ - setup_kuep(disable_kuep); - setup_kuap(disable_kuap); -} - #define CTOR(shift) static void ctor_##shift(void *addr) \ { \ memset(addr, 0, sizeof(void *) << (shift)); \
