From 30de14b1884ba609fc1acfba5b40309e3a6ccefe Mon Sep 17 00:00:00 2001 From: Sven Schnelle Date: Fri, 8 Apr 2022 14:51:26 +0200 Subject: [PATCH] s390: current_stack_pointer shouldn't be a function s390 defines current_stack_pointer as function while all other architectures use 'register unsigned long asm(""). This make codes like the following from check_stack_object() fail: if (IS_ENABLED(CONFIG_STACK_GROWSUP)) { if ((void *)current_stack_pointer < obj + len) return BAD_STACK; } else { if (obj < (void *)current_stack_pointer) return BAD_STACK; } because this would compare the address of current_stack_pointer() and not the stackpointer value. Reported-by: Karsten Graul Fixes: 2792d84e6da5 ("usercopy: Check valid lifetime via stack depth") Cc: Kees Cook Cc: Vasily Gorbik Cc: Alexander Gordeev Signed-off-by: Sven Schnelle Reviewed-by: Heiko Carstens Signed-off-by: Heiko Carstens --- arch/s390/include/asm/entry-common.h | 2 +- arch/s390/include/asm/processor.h | 8 +------- arch/s390/include/asm/stacktrace.h | 2 +- arch/s390/lib/test_unwind.c | 2 +- 4 files changed, 4 insertions(+), 10 deletions(-) diff --git a/arch/s390/include/asm/entry-common.h b/arch/s390/include/asm/entry-common.h index eabab24b71dd..2f0a1cacdf85 100644 --- a/arch/s390/include/asm/entry-common.h +++ b/arch/s390/include/asm/entry-common.h @@ -58,7 +58,7 @@ static inline void arch_exit_to_user_mode_prepare(struct pt_regs *regs, static inline bool on_thread_stack(void) { - return !(((unsigned long)(current->stack) ^ current_stack_pointer()) & ~(THREAD_SIZE - 1)); + return !(((unsigned long)(current->stack) ^ current_stack_pointer) & ~(THREAD_SIZE - 1)); } #endif diff --git a/arch/s390/include/asm/processor.h b/arch/s390/include/asm/processor.h index eee8d96fb38e..ff1e25d515a8 100644 --- a/arch/s390/include/asm/processor.h +++ b/arch/s390/include/asm/processor.h @@ -200,13 +200,7 @@ unsigned long __get_wchan(struct task_struct *p); /* Has task runtime instrumentation enabled ? */ #define is_ri_task(tsk) (!!(tsk)->thread.ri_cb) -static __always_inline unsigned long current_stack_pointer(void) -{ - unsigned long sp; - - asm volatile("la %0,0(15)" : "=a" (sp)); - return sp; -} +register unsigned long current_stack_pointer asm("r15"); static __always_inline unsigned short stap(void) { diff --git a/arch/s390/include/asm/stacktrace.h b/arch/s390/include/asm/stacktrace.h index 275f4258fbd5..f8500191993d 100644 --- a/arch/s390/include/asm/stacktrace.h +++ b/arch/s390/include/asm/stacktrace.h @@ -46,7 +46,7 @@ struct stack_frame { }; /* - * Unlike current_stack_pointer() which simply returns current value of %r15 + * Unlike current_stack_pointer which simply contains the current value of %r15 * current_frame_address() returns function stack frame address, which matches * %r15 upon function invocation. It may differ from %r15 later if function * allocates stack for local variables or new stack frame to call other diff --git a/arch/s390/lib/test_unwind.c b/arch/s390/lib/test_unwind.c index 9bb067321ab4..5a053b393d5c 100644 --- a/arch/s390/lib/test_unwind.c +++ b/arch/s390/lib/test_unwind.c @@ -147,7 +147,7 @@ static __always_inline struct pt_regs fake_pt_regs(void) struct pt_regs regs; memset(®s, 0, sizeof(regs)); - regs.gprs[15] = current_stack_pointer(); + regs.gprs[15] = current_stack_pointer; asm volatile( "basr %[psw_addr],0\n"