All of lore.kernel.org
 help / color / mirror / Atom feed
* [PATCH] powerpc/64: Force inlining of prevent_user_access() and set_kuap()
@ 2022-02-11 14:16 ` Christophe Leroy
  0 siblings, 0 replies; 3+ messages in thread
From: Christophe Leroy @ 2022-02-11 14:16 UTC (permalink / raw)
  To: Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman
  Cc: Christophe Leroy, linux-kernel, linuxppc-dev

A ppc64_defconfig build exhibits about 10 copied of
prevent_user_access(). It also have one copy of set_kuap().

	c000000000017340 <.prevent_user_access.constprop.0>:
	c00000000001a038:	4b ff d3 09 	bl      c000000000017340 <.prevent_user_access.constprop.0>
	c00000000001aabc:	4b ff c8 85 	bl      c000000000017340 <.prevent_user_access.constprop.0>
	c00000000001ab38:	4b ff c8 09 	bl      c000000000017340 <.prevent_user_access.constprop.0>
	c00000000001ade0:	4b ff c5 61 	bl      c000000000017340 <.prevent_user_access.constprop.0>
	c000000000039b90 <.prevent_user_access.constprop.0>:
	c00000000003ac08:	4b ff ef 89 	bl      c000000000039b90 <.prevent_user_access.constprop.0>
	c00000000003b9d0:	4b ff e1 c1 	bl      c000000000039b90 <.prevent_user_access.constprop.0>
	c00000000003ba54:	4b ff e1 3d 	bl      c000000000039b90 <.prevent_user_access.constprop.0>
	c00000000003bbfc:	4b ff df 95 	bl      c000000000039b90 <.prevent_user_access.constprop.0>
	c00000000015dde0 <.prevent_user_access.constprop.0>:
	c0000000001612c0:	4b ff cb 21 	bl      c00000000015dde0 <.prevent_user_access.constprop.0>
	c000000000161b54:	4b ff c2 8d 	bl      c00000000015dde0 <.prevent_user_access.constprop.0>
	c000000000188cf0 <.prevent_user_access.constprop.0>:
	c00000000018d658:	4b ff b6 99 	bl      c000000000188cf0 <.prevent_user_access.constprop.0>
	c00000000030fe20 <.prevent_user_access.constprop.0>:
	c0000000003123d4:	4b ff da 4d 	bl      c00000000030fe20 <.prevent_user_access.constprop.0>
	c000000000313970:	4b ff c4 b1 	bl      c00000000030fe20 <.prevent_user_access.constprop.0>
	c0000000005e6bd0 <.prevent_user_access.constprop.0>:
	c0000000005e7d8c:	4b ff ee 45 	bl      c0000000005e6bd0 <.prevent_user_access.constprop.0>
	c0000000007bcae0 <.prevent_user_access.constprop.0>:
	c0000000007bda10:	4b ff f0 d1 	bl      c0000000007bcae0 <.prevent_user_access.constprop.0>
	c0000000007bda54:	4b ff f0 8d 	bl      c0000000007bcae0 <.prevent_user_access.constprop.0>
	c0000000007bdd28:	4b ff ed b9 	bl      c0000000007bcae0 <.prevent_user_access.constprop.0>
	c0000000007c0390:	4b ff c7 51 	bl      c0000000007bcae0 <.prevent_user_access.constprop.0>
	c00000000094e4f0 <.prevent_user_access.constprop.0>:
	c000000000950e40:	4b ff d6 b1 	bl      c00000000094e4f0 <.prevent_user_access.constprop.0>
	c00000000097d2d0 <.prevent_user_access.constprop.0>:
	c0000000009813fc:	4b ff be d5 	bl      c00000000097d2d0 <.prevent_user_access.constprop.0>
	c000000000acd540 <.prevent_user_access.constprop.0>:
	c000000000ad1d60:	4b ff b7 e1 	bl      c000000000acd540 <.prevent_user_access.constprop.0>
	c000000000e5d680 <.prevent_user_access.constprop.0>:
	c000000000e64b60:	4b ff 8b 21 	bl      c000000000e5d680 <.prevent_user_access.constprop.0>
	c000000000e64b6c:	4b ff 8b 15 	bl      c000000000e5d680 <.prevent_user_access.constprop.0>
	c000000000e64c38:	4b ff 8a 49 	bl      c000000000e5d680 <.prevent_user_access.constprop.0>

When building signal_64.c with -Winline the following messages appear:

	./arch/powerpc/include/asm/book3s/64/kup.h:331:20: error: inlining failed in call to 'set_kuap': call is unlikely and code size would grow [-Werror=inline]
	./arch/powerpc/include/asm/book3s/64/kup.h:401:20: error: inlining failed in call to 'prevent_user_access.constprop': call is unlikely and code size would grow [-Werror=inline]

Those functions are used on hot pathes and have been
expected to be inlined at all time.

Force them inline.

This patch reduces the kernel text size by 700 bytes, confirming
that not inlining those functions is not worth it.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/include/asm/book3s/64/kup.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/kup.h b/arch/powerpc/include/asm/book3s/64/kup.h
index 69fcf63eec94..54cf46808157 100644
--- a/arch/powerpc/include/asm/book3s/64/kup.h
+++ b/arch/powerpc/include/asm/book3s/64/kup.h
@@ -328,7 +328,7 @@ static inline unsigned long get_kuap(void)
 	return mfspr(SPRN_AMR);
 }
 
-static inline void set_kuap(unsigned long value)
+static __always_inline void set_kuap(unsigned long value)
 {
 	if (!mmu_has_feature(MMU_FTR_BOOK3S_KUAP))
 		return;
@@ -398,7 +398,7 @@ static __always_inline void allow_user_access(void __user *to, const void __user
 
 #endif /* !CONFIG_PPC_KUAP */
 
-static inline void prevent_user_access(unsigned long dir)
+static __always_inline void prevent_user_access(unsigned long dir)
 {
 	set_kuap(AMR_KUAP_BLOCKED);
 	if (static_branch_unlikely(&uaccess_flush_key))
-- 
2.34.1


^ permalink raw reply related	[flat|nested] 3+ messages in thread
* [PATCH] powerpc/64: Force inlining of prevent_user_access() and set_kuap()
@ 2022-02-11 14:16 ` Christophe Leroy
  0 siblings, 0 replies; 3+ messages in thread
From: Christophe Leroy @ 2022-02-11 14:16 UTC (permalink / raw)
  To: Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman
  Cc: linuxppc-dev, linux-kernel

A ppc64_defconfig build exhibits about 10 copied of
prevent_user_access(). It also have one copy of set_kuap().

	c000000000017340 <.prevent_user_access.constprop.0>:
	c00000000001a038:	4b ff d3 09 	bl      c000000000017340 <.prevent_user_access.constprop.0>
	c00000000001aabc:	4b ff c8 85 	bl      c000000000017340 <.prevent_user_access.constprop.0>
	c00000000001ab38:	4b ff c8 09 	bl      c000000000017340 <.prevent_user_access.constprop.0>
	c00000000001ade0:	4b ff c5 61 	bl      c000000000017340 <.prevent_user_access.constprop.0>
	c000000000039b90 <.prevent_user_access.constprop.0>:
	c00000000003ac08:	4b ff ef 89 	bl      c000000000039b90 <.prevent_user_access.constprop.0>
	c00000000003b9d0:	4b ff e1 c1 	bl      c000000000039b90 <.prevent_user_access.constprop.0>
	c00000000003ba54:	4b ff e1 3d 	bl      c000000000039b90 <.prevent_user_access.constprop.0>
	c00000000003bbfc:	4b ff df 95 	bl      c000000000039b90 <.prevent_user_access.constprop.0>
	c00000000015dde0 <.prevent_user_access.constprop.0>:
	c0000000001612c0:	4b ff cb 21 	bl      c00000000015dde0 <.prevent_user_access.constprop.0>
	c000000000161b54:	4b ff c2 8d 	bl      c00000000015dde0 <.prevent_user_access.constprop.0>
	c000000000188cf0 <.prevent_user_access.constprop.0>:
	c00000000018d658:	4b ff b6 99 	bl      c000000000188cf0 <.prevent_user_access.constprop.0>
	c00000000030fe20 <.prevent_user_access.constprop.0>:
	c0000000003123d4:	4b ff da 4d 	bl      c00000000030fe20 <.prevent_user_access.constprop.0>
	c000000000313970:	4b ff c4 b1 	bl      c00000000030fe20 <.prevent_user_access.constprop.0>
	c0000000005e6bd0 <.prevent_user_access.constprop.0>:
	c0000000005e7d8c:	4b ff ee 45 	bl      c0000000005e6bd0 <.prevent_user_access.constprop.0>
	c0000000007bcae0 <.prevent_user_access.constprop.0>:
	c0000000007bda10:	4b ff f0 d1 	bl      c0000000007bcae0 <.prevent_user_access.constprop.0>
	c0000000007bda54:	4b ff f0 8d 	bl      c0000000007bcae0 <.prevent_user_access.constprop.0>
	c0000000007bdd28:	4b ff ed b9 	bl      c0000000007bcae0 <.prevent_user_access.constprop.0>
	c0000000007c0390:	4b ff c7 51 	bl      c0000000007bcae0 <.prevent_user_access.constprop.0>
	c00000000094e4f0 <.prevent_user_access.constprop.0>:
	c000000000950e40:	4b ff d6 b1 	bl      c00000000094e4f0 <.prevent_user_access.constprop.0>
	c00000000097d2d0 <.prevent_user_access.constprop.0>:
	c0000000009813fc:	4b ff be d5 	bl      c00000000097d2d0 <.prevent_user_access.constprop.0>
	c000000000acd540 <.prevent_user_access.constprop.0>:
	c000000000ad1d60:	4b ff b7 e1 	bl      c000000000acd540 <.prevent_user_access.constprop.0>
	c000000000e5d680 <.prevent_user_access.constprop.0>:
	c000000000e64b60:	4b ff 8b 21 	bl      c000000000e5d680 <.prevent_user_access.constprop.0>
	c000000000e64b6c:	4b ff 8b 15 	bl      c000000000e5d680 <.prevent_user_access.constprop.0>
	c000000000e64c38:	4b ff 8a 49 	bl      c000000000e5d680 <.prevent_user_access.constprop.0>

When building signal_64.c with -Winline the following messages appear:

	./arch/powerpc/include/asm/book3s/64/kup.h:331:20: error: inlining failed in call to 'set_kuap': call is unlikely and code size would grow [-Werror=inline]
	./arch/powerpc/include/asm/book3s/64/kup.h:401:20: error: inlining failed in call to 'prevent_user_access.constprop': call is unlikely and code size would grow [-Werror=inline]

Those functions are used on hot pathes and have been
expected to be inlined at all time.

Force them inline.

This patch reduces the kernel text size by 700 bytes, confirming
that not inlining those functions is not worth it.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/include/asm/book3s/64/kup.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/kup.h b/arch/powerpc/include/asm/book3s/64/kup.h
index 69fcf63eec94..54cf46808157 100644
--- a/arch/powerpc/include/asm/book3s/64/kup.h
+++ b/arch/powerpc/include/asm/book3s/64/kup.h
@@ -328,7 +328,7 @@ static inline unsigned long get_kuap(void)
 	return mfspr(SPRN_AMR);
 }
 
-static inline void set_kuap(unsigned long value)
+static __always_inline void set_kuap(unsigned long value)
 {
 	if (!mmu_has_feature(MMU_FTR_BOOK3S_KUAP))
 		return;
@@ -398,7 +398,7 @@ static __always_inline void allow_user_access(void __user *to, const void __user
 
 #endif /* !CONFIG_PPC_KUAP */
 
-static inline void prevent_user_access(unsigned long dir)
+static __always_inline void prevent_user_access(unsigned long dir)
 {
 	set_kuap(AMR_KUAP_BLOCKED);
 	if (static_branch_unlikely(&uaccess_flush_key))
-- 
2.34.1


^ permalink raw reply related	[flat|nested] 3+ messages in thread
* Re: [PATCH] powerpc/64: Force inlining of prevent_user_access() and set_kuap()
  2022-02-11 14:16 ` Christophe Leroy
  (?)
@ 2022-03-12 10:29 ` Michael Ellerman
  -1 siblings, 0 replies; 3+ messages in thread
From: Michael Ellerman @ 2022-03-12 10:29 UTC (permalink / raw)
  To: Christophe Leroy, Michael Ellerman, Paul Mackerras,
	Benjamin Herrenschmidt
  Cc: linuxppc-dev, linux-kernel

On Fri, 11 Feb 2022 15:16:51 +0100, Christophe Leroy wrote:
> A ppc64_defconfig build exhibits about 10 copied of
> prevent_user_access(). It also have one copy of set_kuap().
> 
> 	c000000000017340 <.prevent_user_access.constprop.0>:
> 	c00000000001a038:	4b ff d3 09 	bl      c000000000017340 <.prevent_user_access.constprop.0>
> 	c00000000001aabc:	4b ff c8 85 	bl      c000000000017340 <.prevent_user_access.constprop.0>
> 	c00000000001ab38:	4b ff c8 09 	bl      c000000000017340 <.prevent_user_access.constprop.0>
> 	c00000000001ade0:	4b ff c5 61 	bl      c000000000017340 <.prevent_user_access.constprop.0>
> 	c000000000039b90 <.prevent_user_access.constprop.0>:
> 	c00000000003ac08:	4b ff ef 89 	bl      c000000000039b90 <.prevent_user_access.constprop.0>
> 	c00000000003b9d0:	4b ff e1 c1 	bl      c000000000039b90 <.prevent_user_access.constprop.0>
> 	c00000000003ba54:	4b ff e1 3d 	bl      c000000000039b90 <.prevent_user_access.constprop.0>
> 	c00000000003bbfc:	4b ff df 95 	bl      c000000000039b90 <.prevent_user_access.constprop.0>
> 	c00000000015dde0 <.prevent_user_access.constprop.0>:
> 	c0000000001612c0:	4b ff cb 21 	bl      c00000000015dde0 <.prevent_user_access.constprop.0>
> 	c000000000161b54:	4b ff c2 8d 	bl      c00000000015dde0 <.prevent_user_access.constprop.0>
> 	c000000000188cf0 <.prevent_user_access.constprop.0>:
> 	c00000000018d658:	4b ff b6 99 	bl      c000000000188cf0 <.prevent_user_access.constprop.0>
> 	c00000000030fe20 <.prevent_user_access.constprop.0>:
> 	c0000000003123d4:	4b ff da 4d 	bl      c00000000030fe20 <.prevent_user_access.constprop.0>
> 	c000000000313970:	4b ff c4 b1 	bl      c00000000030fe20 <.prevent_user_access.constprop.0>
> 	c0000000005e6bd0 <.prevent_user_access.constprop.0>:
> 	c0000000005e7d8c:	4b ff ee 45 	bl      c0000000005e6bd0 <.prevent_user_access.constprop.0>
> 	c0000000007bcae0 <.prevent_user_access.constprop.0>:
> 	c0000000007bda10:	4b ff f0 d1 	bl      c0000000007bcae0 <.prevent_user_access.constprop.0>
> 	c0000000007bda54:	4b ff f0 8d 	bl      c0000000007bcae0 <.prevent_user_access.constprop.0>
> 	c0000000007bdd28:	4b ff ed b9 	bl      c0000000007bcae0 <.prevent_user_access.constprop.0>
> 	c0000000007c0390:	4b ff c7 51 	bl      c0000000007bcae0 <.prevent_user_access.constprop.0>
> 	c00000000094e4f0 <.prevent_user_access.constprop.0>:
> 	c000000000950e40:	4b ff d6 b1 	bl      c00000000094e4f0 <.prevent_user_access.constprop.0>
> 	c00000000097d2d0 <.prevent_user_access.constprop.0>:
> 	c0000000009813fc:	4b ff be d5 	bl      c00000000097d2d0 <.prevent_user_access.constprop.0>
> 	c000000000acd540 <.prevent_user_access.constprop.0>:
> 	c000000000ad1d60:	4b ff b7 e1 	bl      c000000000acd540 <.prevent_user_access.constprop.0>
> 	c000000000e5d680 <.prevent_user_access.constprop.0>:
> 	c000000000e64b60:	4b ff 8b 21 	bl      c000000000e5d680 <.prevent_user_access.constprop.0>
> 	c000000000e64b6c:	4b ff 8b 15 	bl      c000000000e5d680 <.prevent_user_access.constprop.0>
> 	c000000000e64c38:	4b ff 8a 49 	bl      c000000000e5d680 <.prevent_user_access.constprop.0>
> 
> [...]

Applied to powerpc/next.

[1/1] powerpc/64: Force inlining of prevent_user_access() and set_kuap()
      https://git.kernel.org/powerpc/c/792993919349fefba20f58ae4843c80e8b01f518

cheers

^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2022-03-12 10:31 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-02-11 14:16 [PATCH] powerpc/64: Force inlining of prevent_user_access() and set_kuap() Christophe Leroy
2022-02-11 14:16 ` Christophe Leroy
2022-03-12 10:29 ` Michael Ellerman

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.