mips: Implement "current_stack_pointer"

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 <[email protected]> Cc: Marc Zyngier <[email protected]> Cc: Guenter Roeck <[email protected]> Cc: Mark Rutland <[email protected]> Cc: Yanteng Si <[email protected]> Cc: [email protected] Signed-off-by: Kees Cook <[email protected]> Signed-off-by: Thomas Bogendoerfer <[email protected]>
LoveHeat · Mar 1, 2022 · 200ed34 · 200ed34
1 parent 455481f
commit 200ed34
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Showing 4 changed files with 5 additions and 5 deletions.
diff --git 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
@@ -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
@@ -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
@@ -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);