powerpc/kuap: KUAP enabling/disabling functions must be __always_inline

Objtool reports following warnings:

  arch/powerpc/kernel/signal_32.o: warning: objtool:
    __prevent_user_access.constprop.0+0x4 (.text+0x4):
    redundant UACCESS disable

  arch/powerpc/kernel/signal_32.o: warning: objtool: user_access_begin+0x2c
    (.text+0x4c): return with UACCESS enabled

  arch/powerpc/kernel/signal_32.o: warning: objtool: handle_rt_signal32+0x188
    (.text+0x360): call to __prevent_user_access.constprop.0() with UACCESS enabled

  arch/powerpc/kernel/signal_32.o: warning: objtool: handle_signal32+0x150
    (.text+0x4d4): call to __prevent_user_access.constprop.0() with UACCESS enabled

This is due to some KUAP enabling/disabling functions being outline
allthough they are marked inline. Use __always_inline instead.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/ca5e50ddbec3867db5146ebddbc9a1dc0e443bc8.1689091022.git.christophe.leroy@csgroup.eu

arch/powerpc/include/asm/book3s/32/kup.h

@@ -15,19 +15,19 @@
 
 #define KUAP_NONE	(~0UL)
 
-static inline void kuap_lock_one(unsigned long addr)
+static __always_inline void kuap_lock_one(unsigned long addr)
 {
 	mtsr(mfsr(addr) | SR_KS, addr);
 	isync();	/* Context sync required after mtsr() */
 }
 
-static inline void kuap_unlock_one(unsigned long addr)
+static __always_inline void kuap_unlock_one(unsigned long addr)
 {
 	mtsr(mfsr(addr) & ~SR_KS, addr);
 	isync();	/* Context sync required after mtsr() */
 }
 
-static inline void __kuap_save_and_lock(struct pt_regs *regs)
+static __always_inline void __kuap_save_and_lock(struct pt_regs *regs)
 {
 	unsigned long kuap = current->thread.kuap;
 
@@ -40,11 +40,11 @@ static inline void __kuap_save_and_lock(struct pt_regs *regs)
 }
 #define __kuap_save_and_lock __kuap_save_and_lock
 
-static inline void kuap_user_restore(struct pt_regs *regs)
+static __always_inline void kuap_user_restore(struct pt_regs *regs)
 {
 }
 
-static inline void __kuap_kernel_restore(struct pt_regs *regs, unsigned long kuap)
+static __always_inline void __kuap_kernel_restore(struct pt_regs *regs, unsigned long kuap)
 {
 	if (unlikely(kuap != KUAP_NONE)) {
 		current->thread.kuap = KUAP_NONE;
@@ -59,7 +59,7 @@ static inline void __kuap_kernel_restore(struct pt_regs *regs, unsigned long kua
 	kuap_unlock_one(regs->kuap);
 }
 
-static inline unsigned long __kuap_get_and_assert_locked(void)
+static __always_inline unsigned long __kuap_get_and_assert_locked(void)
 {
 	unsigned long kuap = current->thread.kuap;
 
@@ -94,7 +94,7 @@ static __always_inline void __prevent_user_access(unsigned long dir)
 	kuap_lock_one(kuap);
 }
 
-static inline unsigned long __prevent_user_access_return(void)
+static __always_inline unsigned long __prevent_user_access_return(void)
 {
 	unsigned long flags = current->thread.kuap;
 
@@ -106,7 +106,7 @@ static inline unsigned long __prevent_user_access_return(void)
 	return flags;
 }
 
-static inline void __restore_user_access(unsigned long flags)
+static __always_inline void __restore_user_access(unsigned long flags)
 {
 	if (flags != KUAP_NONE) {
 		current->thread.kuap = flags;
@@ -114,7 +114,7 @@ static inline void __restore_user_access(unsigned long flags)
 	}
 }
 
-static inline bool
+static __always_inline bool
 __bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write)
 {
 	unsigned long kuap = regs->kuap;

arch/powerpc/include/asm/book3s/64/kup.h

@@ -213,14 +213,14 @@ extern u64 __ro_after_init default_iamr;
  * access restrictions. Because of this ignore AMR value when accessing
  * userspace via kernel thread.
  */
-static inline u64 current_thread_amr(void)
+static __always_inline u64 current_thread_amr(void)
 {
 	if (current->thread.regs)
 		return current->thread.regs->amr;
 	return default_amr;
 }
 
-static inline u64 current_thread_iamr(void)
+static __always_inline u64 current_thread_iamr(void)
 {
 	if (current->thread.regs)
 		return current->thread.regs->iamr;
@@ -230,7 +230,7 @@ static inline u64 current_thread_iamr(void)
 
 #ifdef CONFIG_PPC_KUAP
 
-static inline void kuap_user_restore(struct pt_regs *regs)
+static __always_inline void kuap_user_restore(struct pt_regs *regs)
 {
 	bool restore_amr = false, restore_iamr = false;
 	unsigned long amr, iamr;
@@ -269,7 +269,7 @@ static inline void kuap_user_restore(struct pt_regs *regs)
 	 */
 }
 
-static inline void __kuap_kernel_restore(struct pt_regs *regs, unsigned long amr)
+static __always_inline void __kuap_kernel_restore(struct pt_regs *regs, unsigned long amr)
 {
 	if (likely(regs->amr == amr))
 		return;
@@ -285,7 +285,7 @@ static inline void __kuap_kernel_restore(struct pt_regs *regs, unsigned long amr
 	 */
 }
 
-static inline unsigned long __kuap_get_and_assert_locked(void)
+static __always_inline unsigned long __kuap_get_and_assert_locked(void)
 {
 	unsigned long amr = mfspr(SPRN_AMR);
 
@@ -302,7 +302,7 @@ static inline unsigned long __kuap_get_and_assert_locked(void)
  * because that would require an expensive read/modify write of the AMR.
  */
 
-static inline unsigned long get_kuap(void)
+static __always_inline unsigned long get_kuap(void)
 {
 	/*
 	 * We return AMR_KUAP_BLOCKED when we don't support KUAP because
@@ -332,7 +332,8 @@ static __always_inline void set_kuap(unsigned long value)
 	isync();
 }
 
-static inline bool __bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write)
+static __always_inline bool
+__bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write)
 {
 	/*
 	 * For radix this will be a storage protection fault (DSISR_PROTFAULT).
@@ -375,12 +376,12 @@ static __always_inline void allow_user_access(void __user *to, const void __user
 
 #else /* CONFIG_PPC_KUAP */
 
-static inline unsigned long get_kuap(void)
+static __always_inline unsigned long get_kuap(void)
 {
 	return AMR_KUAP_BLOCKED;
 }
 
-static inline void set_kuap(unsigned long value) { }
+static __always_inline void set_kuap(unsigned long value) { }
 
 static __always_inline void allow_user_access(void __user *to, const void __user *from,
 					      unsigned long size, unsigned long dir)
@@ -395,7 +396,7 @@ static __always_inline void prevent_user_access(unsigned long dir)
 		do_uaccess_flush();
 }
 
-static inline unsigned long prevent_user_access_return(void)
+static __always_inline unsigned long prevent_user_access_return(void)
 {
 	unsigned long flags = get_kuap();
 
@@ -406,7 +407,7 @@ static inline unsigned long prevent_user_access_return(void)
 	return flags;
 }
 
-static inline void restore_user_access(unsigned long flags)
+static __always_inline void restore_user_access(unsigned long flags)
 {
 	set_kuap(flags);
 	if (static_branch_unlikely(&uaccess_flush_key) && flags == AMR_KUAP_BLOCKED)

arch/powerpc/include/asm/kup.h

@@ -57,14 +57,14 @@ static inline void setup_kuap(bool disabled) { }
 
 static __always_inline bool kuap_is_disabled(void) { return true; }
 
-static inline bool
+static __always_inline bool
 __bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write)
 {
 	return false;
 }
 
-static inline void kuap_user_restore(struct pt_regs *regs) { }
-static inline void __kuap_kernel_restore(struct pt_regs *regs, unsigned long amr) { }
+static __always_inline void kuap_user_restore(struct pt_regs *regs) { }
+static __always_inline void __kuap_kernel_restore(struct pt_regs *regs, unsigned long amr) { }
 
 /*
  * book3s/64/kup-radix.h defines these functions for the !KUAP case to flush
@@ -72,11 +72,11 @@ static inline void __kuap_kernel_restore(struct pt_regs *regs, unsigned long amr
  * platforms.
  */
 #ifndef CONFIG_PPC_BOOK3S_64
-static inline void __allow_user_access(void __user *to, const void __user *from,
-				       unsigned long size, unsigned long dir) { }
-static inline void __prevent_user_access(unsigned long dir) { }
-static inline unsigned long __prevent_user_access_return(void) { return 0UL; }
-static inline void __restore_user_access(unsigned long flags) { }
+static __always_inline void __allow_user_access(void __user *to, const void __user *from,
+						unsigned long size, unsigned long dir) { }
+static __always_inline void __prevent_user_access(unsigned long dir) { }
+static __always_inline unsigned long __prevent_user_access_return(void) { return 0UL; }
+static __always_inline void __restore_user_access(unsigned long flags) { }
 #endif /* CONFIG_PPC_BOOK3S_64 */
 #endif /* CONFIG_PPC_KUAP */
 

arch/powerpc/include/asm/nohash/32/kup-8xx.h

@@ -11,24 +11,24 @@
 
 #include <asm/reg.h>
 
-static inline void __kuap_save_and_lock(struct pt_regs *regs)
+static __always_inline void __kuap_save_and_lock(struct pt_regs *regs)
 {
 	regs->kuap = mfspr(SPRN_MD_AP);
 	mtspr(SPRN_MD_AP, MD_APG_KUAP);
 }
 #define __kuap_save_and_lock __kuap_save_and_lock
 
-static inline void kuap_user_restore(struct pt_regs *regs)
+static __always_inline void kuap_user_restore(struct pt_regs *regs)
 {
 }
 
-static inline void __kuap_kernel_restore(struct pt_regs *regs, unsigned long kuap)
+static __always_inline void __kuap_kernel_restore(struct pt_regs *regs, unsigned long kuap)
 {
 	mtspr(SPRN_MD_AP, regs->kuap);
 }
 
 #ifdef CONFIG_PPC_KUAP_DEBUG
-static inline unsigned long __kuap_get_and_assert_locked(void)
+static __always_inline unsigned long __kuap_get_and_assert_locked(void)
 {
 	WARN_ON_ONCE(mfspr(SPRN_MD_AP) >> 16 != MD_APG_KUAP >> 16);
 
@@ -37,18 +37,18 @@ static inline unsigned long __kuap_get_and_assert_locked(void)
 #define __kuap_get_and_assert_locked __kuap_get_and_assert_locked
 #endif
 
-static inline void __allow_user_access(void __user *to, const void __user *from,
-				       unsigned long size, unsigned long dir)
+static __always_inline void __allow_user_access(void __user *to, const void __user *from,
+						unsigned long size, unsigned long dir)
 {
 	mtspr(SPRN_MD_AP, MD_APG_INIT);
 }
 
-static inline void __prevent_user_access(unsigned long dir)
+static __always_inline void __prevent_user_access(unsigned long dir)
 {
 	mtspr(SPRN_MD_AP, MD_APG_KUAP);
 }
 
-static inline unsigned long __prevent_user_access_return(void)
+static __always_inline unsigned long __prevent_user_access_return(void)
 {
 	unsigned long flags;
 
@@ -59,12 +59,12 @@ static inline unsigned long __prevent_user_access_return(void)
 	return flags;
 }
 
-static inline void __restore_user_access(unsigned long flags)
+static __always_inline void __restore_user_access(unsigned long flags)
 {
 	mtspr(SPRN_MD_AP, flags);
 }
 
-static inline bool
+static __always_inline bool
 __bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write)
 {
 	return !((regs->kuap ^ MD_APG_KUAP) & 0xff000000);

arch/powerpc/include/asm/nohash/kup-booke.h

@@ -17,14 +17,14 @@
 
 #include <asm/reg.h>
 
-static inline void __kuap_lock(void)
+static __always_inline void __kuap_lock(void)
 {
 	mtspr(SPRN_PID, 0);
 	isync();
 }
 #define __kuap_lock __kuap_lock
 
-static inline void __kuap_save_and_lock(struct pt_regs *regs)
+static __always_inline void __kuap_save_and_lock(struct pt_regs *regs)
 {
 	regs->kuap = mfspr(SPRN_PID);
 	mtspr(SPRN_PID, 0);
@@ -32,7 +32,7 @@ static inline void __kuap_save_and_lock(struct pt_regs *regs)
 }
 #define __kuap_save_and_lock __kuap_save_and_lock
 
-static inline void kuap_user_restore(struct pt_regs *regs)
+static __always_inline void kuap_user_restore(struct pt_regs *regs)
 {
 	if (kuap_is_disabled())
 		return;
@@ -42,7 +42,7 @@ static inline void kuap_user_restore(struct pt_regs *regs)
 	/* Context synchronisation is performed by rfi */
 }
 
-static inline void __kuap_kernel_restore(struct pt_regs *regs, unsigned long kuap)
+static __always_inline void __kuap_kernel_restore(struct pt_regs *regs, unsigned long kuap)
 {
 	if (regs->kuap)
 		mtspr(SPRN_PID, current->thread.pid);
@@ -51,7 +51,7 @@ static inline void __kuap_kernel_restore(struct pt_regs *regs, unsigned long kua
 }
 
 #ifdef CONFIG_PPC_KUAP_DEBUG
-static inline unsigned long __kuap_get_and_assert_locked(void)
+static __always_inline unsigned long __kuap_get_and_assert_locked(void)
 {
 	WARN_ON_ONCE(mfspr(SPRN_PID));
 
@@ -60,20 +60,20 @@ static inline unsigned long __kuap_get_and_assert_locked(void)
 #define __kuap_get_and_assert_locked __kuap_get_and_assert_locked
 #endif
 
-static inline void __allow_user_access(void __user *to, const void __user *from,
-				       unsigned long size, unsigned long dir)
+static __always_inline void __allow_user_access(void __user *to, const void __user *from,
+						unsigned long size, unsigned long dir)
 {
 	mtspr(SPRN_PID, current->thread.pid);
 	isync();
 }
 
-static inline void __prevent_user_access(unsigned long dir)
+static __always_inline void __prevent_user_access(unsigned long dir)
 {
 	mtspr(SPRN_PID, 0);
 	isync();
 }
 
-static inline unsigned long __prevent_user_access_return(void)
+static __always_inline unsigned long __prevent_user_access_return(void)
 {
 	unsigned long flags = mfspr(SPRN_PID);
 
@@ -83,7 +83,7 @@ static inline unsigned long __prevent_user_access_return(void)
 	return flags;
 }
 
-static inline void __restore_user_access(unsigned long flags)
+static __always_inline void __restore_user_access(unsigned long flags)
 {
 	if (flags) {
 		mtspr(SPRN_PID, current->thread.pid);
@@ -91,7 +91,7 @@ static inline void __restore_user_access(unsigned long flags)
 	}
 }
 
-static inline bool
+static __always_inline bool
 __bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write)
 {
 	return !regs->kuap;

arch/powerpc/include/asm/uaccess.h

@@ -386,7 +386,7 @@ copy_mc_to_user(void __user *to, const void *from, unsigned long n)
 extern long __copy_from_user_flushcache(void *dst, const void __user *src,
 		unsigned size);
 
-static __must_check inline bool user_access_begin(const void __user *ptr, size_t len)
+static __must_check __always_inline bool user_access_begin(const void __user *ptr, size_t len)
 {
 	if (unlikely(!access_ok(ptr, len)))
 		return false;
@@ -401,7 +401,7 @@ static __must_check inline bool user_access_begin(const void __user *ptr, size_t
 #define user_access_save	prevent_user_access_return
 #define user_access_restore	restore_user_access
 
-static __must_check inline bool
+static __must_check __always_inline bool
 user_read_access_begin(const void __user *ptr, size_t len)
 {
 	if (unlikely(!access_ok(ptr, len)))
@@ -415,7 +415,7 @@ user_read_access_begin(const void __user *ptr, size_t len)
 #define user_read_access_begin	user_read_access_begin
 #define user_read_access_end		prevent_current_read_from_user
 
-static __must_check inline bool
+static __must_check __always_inline bool
 user_write_access_begin(const void __user *ptr, size_t len)
 {
 	if (unlikely(!access_ok(ptr, len)))