diff mbox series

mips: Implement "current_stack_pointer"

Message ID 20220224060432.1855897-1-keescook@chromium.org (mailing list archive)
State Mainlined
Commit 200ed341b8646ea893d5466974d6e107c46237ba
Headers show
Series mips: Implement "current_stack_pointer" | expand

Commit Message

Kees Cook Feb. 24, 2022, 6:04 a.m. UTC
To follow the existing per-arch conventions replace open-coded uses
of asm "sp" as "current_stack_pointer". This will let it be used in
non-arch places (like HARDENED_USERCOPY).

Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Yanteng Si <siyanteng01@gmail.com>
Cc: linux-mips@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 arch/mips/Kconfig                   | 1 +
 arch/mips/include/asm/thread_info.h | 2 ++
 arch/mips/kernel/irq.c              | 3 +--
 arch/mips/lib/uncached.c            | 4 +---
 4 files changed, 5 insertions(+), 5 deletions(-)

Comments

Thomas Bogendoerfer March 1, 2022, 4:30 p.m. UTC | #1
On Wed, Feb 23, 2022 at 10:04:32PM -0800, Kees Cook wrote:
> To follow the existing per-arch conventions replace open-coded uses
> of asm "sp" as "current_stack_pointer". This will let it be used in
> non-arch places (like HARDENED_USERCOPY).
> 
> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
> Cc: Marc Zyngier <maz@kernel.org>
> Cc: Guenter Roeck <linux@roeck-us.net>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: Yanteng Si <siyanteng01@gmail.com>
> Cc: linux-mips@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
>  arch/mips/Kconfig                   | 1 +
>  arch/mips/include/asm/thread_info.h | 2 ++
>  arch/mips/kernel/irq.c              | 3 +--
>  arch/mips/lib/uncached.c            | 4 +---
>  4 files changed, 5 insertions(+), 5 deletions(-)

applied to mips-next.

Thomas.
diff mbox series

Patch

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 058446f01487..6781f87e2218 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -4,6 +4,7 @@  config MIPS
 	default y
 	select ARCH_32BIT_OFF_T if !64BIT
 	select ARCH_BINFMT_ELF_STATE if MIPS_FP_SUPPORT
+	select ARCH_HAS_CURRENT_STACK_POINTER
 	select ARCH_HAS_DEBUG_VIRTUAL if !64BIT
 	select ARCH_HAS_FORTIFY_SOURCE
 	select ARCH_HAS_KCOV
diff --git a/arch/mips/include/asm/thread_info.h b/arch/mips/include/asm/thread_info.h
index 0b17aaa9e012..4463348d2372 100644
--- a/arch/mips/include/asm/thread_info.h
+++ b/arch/mips/include/asm/thread_info.h
@@ -69,6 +69,8 @@  static inline struct thread_info *current_thread_info(void)
 	return __current_thread_info;
 }
 
+register unsigned long current_stack_pointer __asm__("sp");
+
 #endif /* !__ASSEMBLY__ */
 
 /* thread information allocation */
diff --git a/arch/mips/kernel/irq.c b/arch/mips/kernel/irq.c
index 5e11582fe308..fc313c49a417 100644
--- a/arch/mips/kernel/irq.c
+++ b/arch/mips/kernel/irq.c
@@ -75,9 +75,8 @@  void __init init_IRQ(void)
 #ifdef CONFIG_DEBUG_STACKOVERFLOW
 static inline void check_stack_overflow(void)
 {
-	unsigned long sp;
+	unsigned long sp = current_stack_pointer;
 
-	__asm__ __volatile__("move %0, $sp" : "=r" (sp));
 	sp &= THREAD_MASK;
 
 	/*
diff --git a/arch/mips/lib/uncached.c b/arch/mips/lib/uncached.c
index f80a67c092b6..f8d4ca046c3e 100644
--- a/arch/mips/lib/uncached.c
+++ b/arch/mips/lib/uncached.c
@@ -40,9 +40,7 @@  unsigned long run_uncached(void *func)
 	register long ret __asm__("$2");
 	long lfunc = (long)func, ufunc;
 	long usp;
-	long sp;
-
-	__asm__("move %0, $sp" : "=r" (sp));
+	long sp = current_stack_pointer;
 
 	if (sp >= (long)CKSEG0 && sp < (long)CKSEG2)
 		usp = CKSEG1ADDR(sp);