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authorSven Schnelle <svens@linux.ibm.com>2021-06-25 14:48:28 +0200
committerVasily Gorbik <gor@linux.ibm.com>2021-07-08 15:37:28 +0200
commit686341f2548b5a4c4ab1ee22427e046027ae1c9c (patch)
tree8b660e0f6bf87f85253d6a2211eaa5d1661139c3 /arch/s390
parentd57778feb9878aa6b79c615fd029c2112d40a747 (diff)
s390/vdso64: add sigreturn,rt_sigreturn and restart_syscall
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@linux.ibm.com> Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diffstat (limited to 'arch/s390')
-rw-r--r--arch/s390/kernel/vdso64/vdso64.lds.S3
-rw-r--r--arch/s390/kernel/vdso64/vdso_user_wrapper.S17
2 files changed, 20 insertions, 0 deletions
diff --git a/arch/s390/kernel/vdso64/vdso64.lds.S b/arch/s390/kernel/vdso64/vdso64.lds.S
index 518f1ea405f4..489a72a69594 100644
--- 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: *;
};
}
diff --git a/arch/s390/kernel/vdso64/vdso_user_wrapper.S b/arch/s390/kernel/vdso64/vdso_user_wrapper.S
index f773505c7e63..97f0c0a669a5 100644
--- 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