From: Heiko Carstens hca@linux.ibm.com
[ Upstream commit 41e1992665a2701fa025a8b76970c43b4148446f ]
GCC 11.1.0 and 11.2.0 generate a wrong warning when compiling the kernel e.g. with allmodconfig:
arch/s390/kernel/setup.c: In function ‘setup_lowcore_dat_on’: ./include/linux/fortify-string.h:57:33: error: ‘__builtin_memcpy’ reading 128 bytes from a region of size 0 [-Werror=stringop-overread] ... arch/s390/kernel/setup.c:526:9: note: in expansion of macro ‘memcpy’ 526 | memcpy(abs_lc->cregs_save_area, S390_lowcore.cregs_save_area, | ^~~~~~
This could be addressed by using absolute_pointer() with the S390_lowcore macro, but this is not a good idea since this generates worse code for performance critical paths.
Therefore simply use a for loop to copy the array in question and get rid of the warning.
Reported-by: Geert Uytterhoeven geert@linux-m68k.org Signed-off-by: Heiko Carstens hca@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/s390/kernel/setup.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c index ab19ddb09d65..2ec5f1e0312f 100644 --- a/arch/s390/kernel/setup.c +++ b/arch/s390/kernel/setup.c @@ -507,6 +507,7 @@ static void __init setup_lowcore_dat_on(void) { struct lowcore *abs_lc; unsigned long flags; + int i;
__ctl_clear_bit(0, 28); S390_lowcore.external_new_psw.mask |= PSW_MASK_DAT; @@ -521,8 +522,8 @@ static void __init setup_lowcore_dat_on(void) abs_lc = get_abs_lowcore(&flags); abs_lc->restart_flags = RESTART_FLAG_CTLREGS; abs_lc->program_new_psw = S390_lowcore.program_new_psw; - memcpy(abs_lc->cregs_save_area, S390_lowcore.cregs_save_area, - sizeof(abs_lc->cregs_save_area)); + for (i = 0; i < 16; i++) + abs_lc->cregs_save_area[i] = S390_lowcore.cregs_save_area[i]; put_abs_lowcore(abs_lc, flags); }