From: Alexander Egorenkov Date: Wed, 9 Feb 2022 10:25:09 +0000 (+0100) Subject: s390/setup: preserve memory at OLDMEM_BASE and OLDMEM_SIZE X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=a29c71f3a4b17ce49feacc6e610e953ef70d7dfc;p=linux.git s390/setup: preserve memory at OLDMEM_BASE and OLDMEM_SIZE [ Upstream commit 6b4b54c7ca347bcb4aa7a3cc01aa16e84ac7fbe4 ] We need to preserve the values at OLDMEM_BASE and OLDMEM_SIZE which are used by zgetdump in case when kdump crashes. In that case zgetdump will attempt to read OLDMEM_BASE and OLDMEM_SIZE in order to find out where the memory range [0 - OLDMEM_SIZE] belonging to the production kernel is. Fixes: f1a546947431 ("s390/setup: don't reserve memory that occupied decompressor's head") Cc: stable@vger.kernel.org # 5.15+ Signed-off-by: Alexander Egorenkov Acked-by: Vasily Gorbik Signed-off-by: Vasily Gorbik Signed-off-by: Sasha Levin --- diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c index 2ebde341d057a..36c1f31dfd66f 100644 --- a/arch/s390/kernel/setup.c +++ b/arch/s390/kernel/setup.c @@ -798,6 +798,8 @@ static void __init check_initrd(void) static void __init reserve_kernel(void) { memblock_reserve(0, STARTUP_NORMAL_OFFSET); + memblock_reserve(OLDMEM_BASE, sizeof(unsigned long)); + memblock_reserve(OLDMEM_SIZE, sizeof(unsigned long)); memblock_reserve(__amode31_base, __eamode31 - __samode31); memblock_reserve(__pa(sclp_early_sccb), EXT_SCCB_READ_SCP); memblock_reserve(__pa(_stext), _end - _stext);