diff options
| author | Christophe Leroy <christophe.leroy@csgroup.eu> | 2023-07-11 17:59:21 +0200 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2023-08-02 22:22:18 +1000 |
| commit | 3a24ea0df83e32355d897a18bbd82e05986dcdc3 (patch) | |
| tree | 7475f41263f21546c960ad4e10d26d2fa12a5c59 /arch/powerpc/include/asm/nohash/32 | |
| parent | eb52f66f0abd468caf8be4e690d7fdef96250c2f (diff) | |
powerpc/kuap: Use ASM feature fixups instead of static branches
To avoid a useless nop on top of every uaccess enable/disable and
make life easier for objtool, replace static branches by ASM feature
fixups that will nop KUAP enabling instructions out in the unlikely
case KUAP is disabled at boottime.
Leave it as is on book3s/64 for now, it will be handled later when
objtool is activated on PPC64.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/671948788024fd890ec4ed175bc332dab8664ea5.1689091022.git.christophe.leroy@csgroup.eu
Diffstat (limited to 'arch/powerpc/include/asm/nohash/32')
| -rw-r--r-- | arch/powerpc/include/asm/nohash/32/kup-8xx.h | 30 |
1 files changed, 21 insertions, 9 deletions
diff --git a/arch/powerpc/include/asm/nohash/32/kup-8xx.h b/arch/powerpc/include/asm/nohash/32/kup-8xx.h index e231b3afed98..46bc5925e5fd 100644 --- a/arch/powerpc/include/asm/nohash/32/kup-8xx.h +++ b/arch/powerpc/include/asm/nohash/32/kup-8xx.h @@ -37,31 +37,43 @@ static __always_inline unsigned long __kuap_get_and_assert_locked(void) #define __kuap_get_and_assert_locked __kuap_get_and_assert_locked #endif -static __always_inline void __allow_user_access(void __user *to, const void __user *from, - unsigned long size, unsigned long dir) +static __always_inline void uaccess_begin_8xx(unsigned long val) { - mtspr(SPRN_MD_AP, MD_APG_INIT); + asm(ASM_MMU_FTR_IFSET("mtspr %0, %1", "", %2) : : + "i"(SPRN_MD_AP), "r"(val), "i"(MMU_FTR_KUAP) : "memory"); } -static __always_inline void __prevent_user_access(unsigned long dir) +static __always_inline void uaccess_end_8xx(void) { - mtspr(SPRN_MD_AP, MD_APG_KUAP); + asm(ASM_MMU_FTR_IFSET("mtspr %0, %1", "", %2) : : + "i"(SPRN_MD_AP), "r"(MD_APG_KUAP), "i"(MMU_FTR_KUAP) : "memory"); +} + +static __always_inline void allow_user_access(void __user *to, const void __user *from, + unsigned long size, unsigned long dir) +{ + uaccess_begin_8xx(MD_APG_INIT); } -static __always_inline unsigned long __prevent_user_access_return(void) +static __always_inline void prevent_user_access(unsigned long dir) +{ + uaccess_end_8xx(); +} + +static __always_inline unsigned long prevent_user_access_return(void) { unsigned long flags; flags = mfspr(SPRN_MD_AP); - mtspr(SPRN_MD_AP, MD_APG_KUAP); + uaccess_end_8xx(); return flags; } -static __always_inline void __restore_user_access(unsigned long flags) +static __always_inline void restore_user_access(unsigned long flags) { - mtspr(SPRN_MD_AP, flags); + uaccess_begin_8xx(flags); } static __always_inline bool |