This is a note to let you know that I've just added the patch titled
s390/vdso64: add sigreturn,rt_sigreturn and restart_syscall
to the 5.13-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-vdso64-add-sigreturn-rt_sigreturn-and-restart_syscall.patch
and it can be found in the queue-5.13 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 686341f2548b5a4c4ab1ee22427e046027ae1c9c Mon Sep 17 00:00:00 2001
From: Sven Schnelle <svens@xxxxxxxxxxxxx>
Date: Fri, 25 Jun 2021 14:48:28 +0200
Subject: s390/vdso64: add sigreturn,rt_sigreturn and restart_syscall
From: Sven Schnelle <svens@xxxxxxxxxxxxx>
commit 686341f2548b5a4c4ab1ee22427e046027ae1c9c upstream.
Add minimalistic trampolines to vdso64 so we can return from signal
without using the stack which requires pgm check handler hacks when
NX is enabled.
restart_syscall will be called from vdso to work around the architectural
limitation that the syscall number might be encoded in the svc instruction,
and therefore can not be changed.
Signed-off-by: Sven Schnelle <svens@xxxxxxxxxxxxx>
Reviewed-by: Heiko Carstens <hca@xxxxxxxxxxxxx>
Signed-off-by: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/s390/kernel/vdso64/vdso64.lds.S | 3 +++
arch/s390/kernel/vdso64/vdso_user_wrapper.S | 17 +++++++++++++++++
2 files changed, 20 insertions(+)
--- a/arch/s390/kernel/vdso64/vdso64.lds.S
+++ b/arch/s390/kernel/vdso64/vdso64.lds.S
@@ -137,6 +137,9 @@ VERSION
__kernel_clock_gettime;
__kernel_clock_getres;
__kernel_getcpu;
+ __kernel_restart_syscall;
+ __kernel_rt_sigreturn;
+ __kernel_sigreturn;
local: *;
};
}
--- a/arch/s390/kernel/vdso64/vdso_user_wrapper.S
+++ b/arch/s390/kernel/vdso64/vdso_user_wrapper.S
@@ -37,3 +37,20 @@ vdso_func gettimeofday
vdso_func clock_getres
vdso_func clock_gettime
vdso_func getcpu
+
+.macro vdso_syscall func,syscall
+ .globl __kernel_\func
+ .type __kernel_\func,@function
+ .align 8
+__kernel_\func:
+ CFI_STARTPROC
+ svc \syscall
+ /* Make sure we notice when a syscall returns, which shouldn't happen */
+ .word 0
+ CFI_ENDPROC
+ .size __kernel_\func,.-__kernel_\func
+.endm
+
+vdso_syscall restart_syscall,__NR_restart_syscall
+vdso_syscall sigreturn,__NR_sigreturn
+vdso_syscall rt_sigreturn,__NR_rt_sigreturn
Patches currently in stable-queue which might be from svens@xxxxxxxxxxxxx are
queue-5.13/s390-vdso-rename-vdso64_lbase-to-vdso_lbase.patch
queue-5.13/s390-vdso64-add-sigreturn-rt_sigreturn-and-restart_syscall.patch
queue-5.13/s390-signal-switch-to-using-vdso-for-sigreturn-and-syscall-restart.patch
queue-5.13/s390-vdso-add-minimal-compat-vdso.patch
queue-5.13/s390-vdso-always-enable-vdso.patch
