powerpc/kuap: Add kuap_lock()

Add kuap_lock() and call it when entering interrupts from user.

It is called kuap_lock() as it is similar to kuap_save_and_lock()
without the save.

However book3s/32 already have a kuap_lock(). Rename it
kuap_lock_addr().

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/4437e2deb9f6f549f7089d45e9c6f96a7e77905a.1634627931.git.christophe.leroy@csgroup.eu

diff --git a/arch/powerpc/include/asm/book3s/32/kup.h b/arch/powerpc/include/asm/book3s/32/kup.h
index bc245e9f0bcc04d9782ea24bc9321c92b6a091a5..678f9c9d89b6ab75fab7abc68b87d764d83eb4d1 100644 (file)
--- a/arch/powerpc/include/asm/book3s/32/kup.h
+++ b/arch/powerpc/include/asm/book3s/32/kup.h
@@ -57,7 +57,7 @@ static inline void kuap_unlock_all(void)
 void kuap_lock_all_ool(void);
 void kuap_unlock_all_ool(void);
 
-static inline void kuap_lock(unsigned long addr, bool ool)
+static inline void kuap_lock_addr(unsigned long addr, bool ool)
 {
        if (likely(addr != KUAP_ALL))
                kuap_lock_one(addr);
@@ -77,6 +77,10 @@ static inline void kuap_unlock(unsigned long addr, bool ool)
                kuap_unlock_all_ool();
 }
 
+static inline void __kuap_lock(void)
+{
+}
+
 static inline void __kuap_save_and_lock(struct pt_regs *regs)
 {
        unsigned long kuap = current->thread.kuap;
@@ -86,7 +90,7 @@ static inline void __kuap_save_and_lock(struct pt_regs *regs)
                return;
 
        current->thread.kuap = KUAP_NONE;
-       kuap_lock(kuap, false);
+       kuap_lock_addr(kuap, false);
 }
 
 static inline void kuap_user_restore(struct pt_regs *regs)
@@ -97,7 +101,7 @@ static inline void __kuap_kernel_restore(struct pt_regs *regs, unsigned long kua
 {
        if (unlikely(kuap != KUAP_NONE)) {
                current->thread.kuap = KUAP_NONE;
-               kuap_lock(kuap, false);
+               kuap_lock_addr(kuap, false);
        }
 
        if (likely(regs->kuap == KUAP_NONE))
@@ -139,7 +143,7 @@ static __always_inline void __prevent_user_access(unsigned long dir)
                return;
 
        current->thread.kuap = KUAP_NONE;
-       kuap_lock(kuap, true);
+       kuap_lock_addr(kuap, true);
 }
 
 static inline unsigned long __prevent_user_access_return(void)
@@ -148,7 +152,7 @@ static inline unsigned long __prevent_user_access_return(void)
 
        if (flags != KUAP_NONE) {
                current->thread.kuap = KUAP_NONE;
-               kuap_lock(flags, true);
+               kuap_lock_addr(flags, true);
        }
 
        return flags;

diff --git a/arch/powerpc/include/asm/interrupt.h b/arch/powerpc/include/asm/interrupt.h
index 94cc9366f3f02c5751221707002fd04023acb184..50d891e4c08c4e700a81a63b78a0320d97b10be2 100644 (file)
--- a/arch/powerpc/include/asm/interrupt.h
+++ b/arch/powerpc/include/asm/interrupt.h
@@ -140,9 +140,12 @@ static inline void interrupt_enter_prepare(struct pt_regs *regs, struct interrup
                trace_hardirqs_off();
 
        if (user_mode(regs))
-               account_cpu_user_entry();
+               kuap_lock();
        else
                kuap_save_and_lock(regs);
+
+       if (user_mode(regs))
+               account_cpu_user_entry();
 #endif
 
 #ifdef CONFIG_PPC64

diff --git a/arch/powerpc/include/asm/kup.h b/arch/powerpc/include/asm/kup.h
index 5d3c1e8060f93bb784a4ebb7422b301b04ed48cb..34574a7455cee83c8790dd98de28c91254f603e5 100644 (file)
--- a/arch/powerpc/include/asm/kup.h
+++ b/arch/powerpc/include/asm/kup.h
@@ -49,6 +49,7 @@ __bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write)
 }
 
 static inline void __kuap_assert_locked(void) { }
+static inline void __kuap_lock(void) { }
 static inline void __kuap_save_and_lock(struct pt_regs *regs) { }
 static inline void kuap_user_restore(struct pt_regs *regs) { }
 static inline void __kuap_kernel_restore(struct pt_regs *regs, unsigned long amr) { }
@@ -91,6 +92,14 @@ static __always_inline void kuap_assert_locked(void)
 }
 
 #ifdef CONFIG_PPC32
+static __always_inline void kuap_lock(void)
+{
+       if (kuap_is_disabled())
+               return;
+
+       __kuap_lock();
+}
+
 static __always_inline void kuap_save_and_lock(struct pt_regs *regs)
 {
        if (kuap_is_disabled())

diff --git a/arch/powerpc/include/asm/nohash/32/kup-8xx.h b/arch/powerpc/include/asm/nohash/32/kup-8xx.h
index 37fe4b32b658d47222e32b68e38d89bb09363f0d..c44d97751723cfa30756f3622a691b1b5d3f0f66 100644 (file)
--- a/arch/powerpc/include/asm/nohash/32/kup-8xx.h
+++ b/arch/powerpc/include/asm/nohash/32/kup-8xx.h
@@ -20,6 +20,10 @@ static __always_inline bool kuap_is_disabled(void)
        return static_branch_unlikely(&disable_kuap_key);
 }
 
+static inline void __kuap_lock(void)
+{
+}
+
 static inline void __kuap_save_and_lock(struct pt_regs *regs)
 {
        regs->kuap = mfspr(SPRN_MD_AP);

diff --git a/arch/powerpc/kernel/interrupt.c b/arch/powerpc/kernel/interrupt.c
index 75dc045bdcb839e7ecb76ee50114ef68543d461e..beb55bc92ffe1db96636ba88609554b0d7e0d4a6 100644 (file)
--- a/arch/powerpc/kernel/interrupt.c
+++ b/arch/powerpc/kernel/interrupt.c
@@ -81,6 +81,8 @@ notrace long system_call_exception(long r3, long r4, long r5,
 {
        syscall_fn f;
 
+       kuap_lock();
+
        regs->orig_gpr3 = r3;
 
        if (IS_ENABLED(CONFIG_PPC_IRQ_SOFT_MASK_DEBUG))