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| author |   Sven Schnelle <svens@linux.ibm.com> | 2021-06-25 14:48:28 +0200 |
|---|---|---|
| committer |   Vasily Gorbik <gor@linux.ibm.com> | 2021-07-08 15:37:28 +0200 |
| commit | 686341f2548b5a4c4ab1ee22427e046027ae1c9c (patch) | |
| tree | 8b660e0f6bf87f85253d6a2211eaa5d1661139c3 /arch/s390/kernel/vdso64 | |
| parent | s390/vdso: always enable vdso (diff) | |
| download | linux-dev-686341f2548b5a4c4ab1ee22427e046027ae1c9c.tar.xz linux-dev-686341f2548b5a4c4ab1ee22427e046027ae1c9c.zip | |
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/kernel/vdso64')
| -rw-r--r-- | arch/s390/kernel/vdso64/vdso64.lds.S | 3 | ||||
| -rw-r--r-- | arch/s390/kernel/vdso64/vdso_user_wrapper.S | 17 |
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 |