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From: Ard Biesheuvel <ardb@kernel.org>
To: linux@armlinux.org.uk, linux-arm-kernel@lists.infradead.org
Cc: linux-hardening@vger.kernel.org, Ard Biesheuvel <ardb@kernel.org>,
	Arnd Bergmann <arnd@arndb.de>, Kees Cook <keescook@chromium.org>,
	Keith Packard <keithpac@amazon.com>,
	Linus Walleij <linus.walleij@linaro.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Marc Zyngier <maz@kernel.org>
Subject: [PATCH v6 8/8] ARM: make get_current() and __my_cpu_offset() __always_inline
Date: Tue, 25 Jan 2022 10:14:53 +0100	[thread overview]
Message-ID: <20220125091453.1475246-9-ardb@kernel.org> (raw)
In-Reply-To: <20220125091453.1475246-1-ardb@kernel.org>

The get_current() and __my_cpu_offset() accessors evaluate to only a
single instruction emitted inline, but due to the size of the asm string
that is created for SMP+v6 configurations, the compiler assumes
otherwise, and may emit the functions out of line instead.

So use __always_inline to avoid this.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/arm/include/asm/current.h | 2 +-
 arch/arm/include/asm/percpu.h  | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm/include/asm/current.h b/arch/arm/include/asm/current.h
index 131a89bbec6b..1e1178bf176d 100644
--- a/arch/arm/include/asm/current.h
+++ b/arch/arm/include/asm/current.h
@@ -14,7 +14,7 @@ struct task_struct;
 
 extern struct task_struct *__current;
 
-static inline __attribute_const__ struct task_struct *get_current(void)
+static __always_inline __attribute_const__ struct task_struct *get_current(void)
 {
 	struct task_struct *cur;
 
diff --git a/arch/arm/include/asm/percpu.h b/arch/arm/include/asm/percpu.h
index a09034ae45a1..7545c87c251f 100644
--- a/arch/arm/include/asm/percpu.h
+++ b/arch/arm/include/asm/percpu.h
@@ -25,7 +25,7 @@ static inline void set_my_cpu_offset(unsigned long off)
 	asm volatile("mcr p15, 0, %0, c13, c0, 4" : : "r" (off) : "memory");
 }
 
-static inline unsigned long __my_cpu_offset(void)
+static __always_inline unsigned long __my_cpu_offset(void)
 {
 	unsigned long off;
 
-- 
2.30.2


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  parent reply	other threads:[~2022-01-25  9:45 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-25  9:14 [PATCH v6 0/8] ARM vmap'ed and IRQ stacks roundup Ard Biesheuvel
2022-01-25  9:14 ` [PATCH v6 1/8] ARM: mm: switch to swapper_pg_dir early for vmap'ed stack Ard Biesheuvel
2022-01-25  9:14 ` [PATCH v6 2/8] ARM: assembler: define a Kconfig symbol for group relocation support Ard Biesheuvel
2022-01-25  9:14 ` [PATCH v6 3/8] ARM: smp: elide HWCAP_TLS checks or __entry_task updates on SMP+v6 Ard Biesheuvel
2022-01-25  9:14 ` [PATCH v6 4/8] ARM: entry: avoid clobbering R9 in IRQ handler Ard Biesheuvel
2022-01-25  9:14 ` [PATCH v6 5/8] ARM: mm: make vmalloc_seq handling SMP safe Ard Biesheuvel
2022-01-25  9:14 ` [PATCH v6 6/8] ARM: iop: make iop_handle_irq() static Ard Biesheuvel
2022-01-25  9:14 ` [PATCH v6 7/8] ARM: drop pointless SMP check on secondary startup path Ard Biesheuvel
2022-01-25  9:14 ` Ard Biesheuvel [this message]
2022-01-25 20:48   ` [PATCH v6 8/8] ARM: make get_current() and __my_cpu_offset() __always_inline Nick Desaulniers

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