linux-dev/arch/s390/kernel/vdso.c, branch linus/master

s390/vdso: add vdso randomization

2022-04-25T11:54:15Z

Randomize the address of vdso if randomize_va_space is enabled. Note that this keeps the vdso address on the same PMD as the stack to avoid allocating an extra page table just for vdso. Signed-off-by: Sven Schnelle Reviewed-by: Heiko Carstens Signed-off-by: Heiko Carstens

s390/vdso: map vdso above stack

2022-04-25T11:54:14Z

In the current code vdso is mapped below the stack. This is problematic when programs mapped to the top of the address space are allocating a lot of memory, because the heap will clash with the vdso. To avoid this map the vdso above the stack and move STACK_TOP so that it all fits into three level paging. Signed-off-by: Sven Schnelle Reviewed-by: Heiko Carstens Signed-off-by: Heiko Carstens

s390/vdso: move vdso mapping to its own function

2022-04-25T11:54:14Z

This is a preparation patch for adding vdso randomization to s390. It adds a function vdso_size(), which will be used later in calculating the STACK_TOP value. It also moves the vdso mapping into a new function vdso_map(), to keep the code similar to other architectures. Signed-off-by: Sven Schnelle Reviewed-by: Heiko Carstens Signed-off-by: Heiko Carstens

s390/vdso: add minimal compat vdso

2021-07-08T13:37:28Z

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 Reviewed-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/vdso: always enable vdso

2021-07-08T13:37:28Z

With the upcoming move of the svc sigreturn instruction from the signal frame to vdso we need to have vdso always enabled. Signed-off-by: Sven Schnelle Reviewed-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/vdso: on timens page fault prefault also VVAR page

2021-02-09T14:57:05Z

This is the s390 variant of commit e6b28ec65b6d ("x86/vdso: On timens page fault prefault also VVAR page"). Reviewed-by: Alexander Gordeev Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/vdso: implement generic vdso time namespace support

2021-02-09T14:57:05Z

Implement generic vdso time namespace support which also enables time namespaces for s390. This is quite similar to what arm64 has. Reviewed-by: Alexander Gordeev Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/vdso: move data page before code pages

2021-02-09T14:57:05Z

For consistency with x86 and arm64 move the data page before code pages. Similar to commit 601255ae3c98 ("arm64: vdso: move data page before code pages"). Reviewed-by: Alexander Gordeev Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/vdso: put vdso datapage in a separate vma

2021-02-09T14:57:05Z

Add a separate "[vvar]" mapping for the vdso datapage, since it doesn't need to be executable or COW-able. This is actually the s390 implementation of commit 871549385278 ("arm64: vdso: put vdso datapage in a separate vma") Reviewed-by: Alexander Gordeev Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/vdso: get rid of vdso_fault

2021-02-09T14:57:05Z

Implement vdso mapping similar to arm64 and powerpc. Reviewed-by: Alexander Gordeev Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik