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| author |   Sven Schnelle <svens@linux.ibm.com> | 2021-06-25 14:50:08 +0200 |
|---|---|---|
| committer |   Vasily Gorbik <gor@linux.ibm.com> | 2021-07-08 15:37:28 +0200 |
| commit | 779df2248739b6308c03b354c99e4c352141e3bc (patch) | |
| tree | 952ac56aee397e3d16bdecf4e4d9afa866b48978 /arch/s390/kernel/vdso64 | |
| parent | s390/vdso: rename VDSO64_LBASE to VDSO_LBASE (diff) | |
| download | linux-dev-779df2248739b6308c03b354c99e4c352141e3bc.tar.xz linux-dev-779df2248739b6308c03b354c99e4c352141e3bc.zip | |
s390/vdso: add minimal compat vdso
Add a small vdso for 31 bit compat application that provides
trampolines for calls to sigreturn,rt_sigreturn,syscall_restart.
This is requird for moving these syscalls away from the signal
frame to the vdso. Note that this patch effectively disables
CONFIG_COMPAT when using clang to compile the kernel. clang
doesn't support 31 bit mode.
We want to redirect sigreturn and restart_syscall to the vdso. However,
the kernel cannot parse the ELF vdso file, so we need to generate header
files which contain the offsets of the syscall instructions in the vdso
page.
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/Makefile | 8 | ||||
| -rwxr-xr-x | arch/s390/kernel/vdso64/gen_vdso_offsets.sh | 15 |
2 files changed, 23 insertions, 0 deletions
diff --git a/arch/s390/kernel/vdso64/Makefile b/arch/s390/kernel/vdso64/Makefile index a6e0fb6b91d6..2a2092ce19f1 100644 --- a/arch/s390/kernel/vdso64/Makefile +++ b/arch/s390/kernel/vdso64/Makefile @@ -74,3 +74,11 @@ vdso64.so: $(obj)/vdso64.so.dbg $(call cmd,vdso_install) vdso_install: vdso64.so + +# Generate VDSO offsets using helper script +gen-vdsosym := $(srctree)/$(src)/gen_vdso_offsets.sh +quiet_cmd_vdsosym = VDSOSYM $@ + cmd_vdsosym = $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@ + +include/generated/vdso64-offsets.h: $(obj)/vdso64.so.dbg FORCE + $(call if_changed,vdsosym) diff --git a/arch/s390/kernel/vdso64/gen_vdso_offsets.sh b/arch/s390/kernel/vdso64/gen_vdso_offsets.sh new file mode 100755 index 000000000000..37f05cb38dad --- /dev/null +++ b/arch/s390/kernel/vdso64/gen_vdso_offsets.sh @@ -0,0 +1,15 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 + +# +# Match symbols in the DSO that look like VDSO_*; produce a header file +# of constant offsets into the shared object. +# +# Doing this inside the Makefile will break the $(filter-out) function, +# causing Kbuild to rebuild the vdso-offsets header file every time. +# +# Inspired by arm64 version. +# + +LC_ALL=C +sed -n 's/\([0-9a-f]*\) . __kernel_\(.*\)/\#define vdso64_offset_\2\t0x\1/p' |