summaryrefslogtreecommitdiffstats
path: root/arch/s390/boot
diff options
context:
space:
mode:
authorGerald Schaefer <gerald.schaefer@de.ibm.com>2019-11-19 12:30:53 +0100
committerVasily Gorbik <gor@linux.ibm.com>2019-11-30 10:52:45 +0100
commita9f2f6865d784477e1c7b59269d3a384abafd9ca (patch)
tree2c79590ce114bb6436fab466d58303ad974094e5 /arch/s390/boot
parente76e69611e944ecc38aaf8fe3a7bebdc3c5daf84 (diff)
downloadlinux-a9f2f6865d784477e1c7b59269d3a384abafd9ca.tar.bz2
s390/kaslr: store KASLR offset for early dumps
The KASLR offset is added to vmcoreinfo in arch_crash_save_vmcoreinfo(), so that it can be found by crash when processing kernel dumps. However, arch_crash_save_vmcoreinfo() is called during a subsys_initcall, so if the kernel crashes before that, we have no vmcoreinfo and no KASLR offset. Fix this by storing the KASLR offset in the lowcore, where the vmcore_info pointer will be stored, and where it can be found by crash. In order to make it distinguishable from a real vmcore_info pointer, mark it as uneven (KASLR offset itself is aligned to THREAD_SIZE). When arch_crash_save_vmcoreinfo() stores the real vmcore_info pointer in the lowcore, it overwrites the KASLR offset. At that point, the KASLR offset is not yet added to vmcoreinfo, so we also need to move the mem_assign_absolute() behind the vmcoreinfo_append_str(). Fixes: b2d24b97b2a9 ("s390/kernel: add support for kernel address space layout randomization (KASLR)") Cc: <stable@vger.kernel.org> # v5.2+ Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diffstat (limited to 'arch/s390/boot')
-rw-r--r--arch/s390/boot/startup.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/s390/boot/startup.c b/arch/s390/boot/startup.c
index fbd341ea03b8..3b3a11f95269 100644
--- a/arch/s390/boot/startup.c
+++ b/arch/s390/boot/startup.c
@@ -170,6 +170,11 @@ void startup_kernel(void)
handle_relocs(__kaslr_offset);
if (__kaslr_offset) {
+ /*
+ * Save KASLR offset for early dumps, before vmcore_info is set.
+ * Mark as uneven to distinguish from real vmcore_info pointer.
+ */
+ S390_lowcore.vmcore_info = __kaslr_offset | 0x1UL;
/* Clear non-relocated kernel */
if (IS_ENABLED(CONFIG_KERNEL_UNCOMPRESSED))
memset(img, 0, vmlinux.image_size);