6.10-stable review patch. If anyone has any objections, please let me know.
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From: Alexander Gordeev agordeev@linux.ibm.com
[ Upstream commit b798b685b42c9dbe508e59a74250d97c41bec35e ]
When allocating a random memory range for .amode31 sections the minimal randomization address is 0. That does not lead to a possible overlap with the decompressor image (which also starts from 0) since by that time the image range is already reserved.
Do not assume the decompressor range is reserved and always provide the minimal randomization address for .amode31 sections beyond the decompressor. That is a prerequisite for moving the lowcore memory address from NULL elsewhere.
Signed-off-by: Alexander Gordeev agordeev@linux.ibm.com Signed-off-by: Sven Schnelle svens@linux.ibm.com Signed-off-by: Vasily Gorbik gor@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/s390/boot/startup.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/arch/s390/boot/startup.c b/arch/s390/boot/startup.c index 6d88f241dd43..66ee97ac803d 100644 --- a/arch/s390/boot/startup.c +++ b/arch/s390/boot/startup.c @@ -476,8 +476,12 @@ void startup_kernel(void) * before the kernel started. Therefore, in case the two sections * overlap there is no risk of corrupting any data. */ - if (kaslr_enabled()) - amode31_lma = randomize_within_range(vmlinux.amode31_size, PAGE_SIZE, 0, SZ_2G); + if (kaslr_enabled()) { + unsigned long amode31_min; + + amode31_min = (unsigned long)_decompressor_end; + amode31_lma = randomize_within_range(vmlinux.amode31_size, PAGE_SIZE, amode31_min, SZ_2G); + } if (!amode31_lma) amode31_lma = text_lma - vmlinux.amode31_size; physmem_reserve(RR_AMODE31, amode31_lma, vmlinux.amode31_size);