Patch "s390/early: fix sclp_early_sccb variable lifetime" has been added to the 6.2-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    s390/early: fix sclp_early_sccb variable lifetime

to the 6.2-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     s390-early-fix-sclp_early_sccb-variable-lifetime.patch
and it can be found in the queue-6.2 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 64f86d47e4394b9c7c241a03e7e9da91a4a28edf
Author: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>
Date:   Thu Dec 15 08:00:34 2022 +0100

    s390/early: fix sclp_early_sccb variable lifetime
    
    [ Upstream commit 639886b71ddef085a0e7bb1f225b8ae3eda5c06f ]
    
    Commit ada1da31ce34 ("s390/sclp: sort out physical vs
    virtual pointers usage") fixed the notion of virtual
    address for sclp_early_sccb pointer. However, it did
    not take into account that kasan_early_init() can also
    output messages and sclp_early_sccb should be adjusted
    by the time kasan_early_init() is called.
    
    Currently it is not a problem, since virtual and physical
    addresses on s390 are the same. Nevertheless, should they
    ever differ, this would cause an invalid pointer access.
    
    Fixes: ada1da31ce34 ("s390/sclp: sort out physical vs virtual pointers usage")
    Reviewed-by: Heiko Carstens <hca@xxxxxxxxxxxxx>
    Signed-off-by: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>
    Signed-off-by: Heiko Carstens <hca@xxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c
index 6030fdd6997bc..9693c8630e73f 100644
--- a/arch/s390/kernel/early.c
+++ b/arch/s390/kernel/early.c
@@ -288,7 +288,6 @@ static void __init sort_amode31_extable(void)
 
 void __init startup_init(void)
 {
-	sclp_early_adjust_va();
 	reset_tod_clock();
 	check_image_bootable();
 	time_early_init();
diff --git a/arch/s390/kernel/head64.S b/arch/s390/kernel/head64.S
index d7b8b6ad574dc..3b3bf8329e6c1 100644
--- a/arch/s390/kernel/head64.S
+++ b/arch/s390/kernel/head64.S
@@ -25,6 +25,7 @@ ENTRY(startup_continue)
 	larl	%r14,init_task
 	stg	%r14,__LC_CURRENT
 	larl	%r15,init_thread_union+THREAD_SIZE-STACK_FRAME_OVERHEAD-__PT_SIZE
+	brasl	%r14,sclp_early_adjust_va	# allow sclp_early_printk
 #ifdef CONFIG_KASAN
 	brasl	%r14,kasan_early_init
 #endif
diff --git a/drivers/s390/char/sclp_early.c b/drivers/s390/char/sclp_early.c
index c1c70a161c0e2..f480d6c7fd399 100644
--- a/drivers/s390/char/sclp_early.c
+++ b/drivers/s390/char/sclp_early.c
@@ -163,7 +163,7 @@ static void __init sclp_early_console_detect(struct init_sccb *sccb)
 		sclp.has_linemode = 1;
 }
 
-void __init sclp_early_adjust_va(void)
+void __init __no_sanitize_address sclp_early_adjust_va(void)
 {
 	sclp_early_sccb = __va((unsigned long)sclp_early_sccb);
 }