Data Cache Block Invalidate (dcbi) instruction implemented back in PowerPC architecture version 2.03. But as per Power Processor Users Manual it is obsolete and not supported by POWER8/POWER9 core. Attempt to use of this illegal instruction results in a hypervisor emulation assistance interrupt. So, ifdef it out the option `i` in xmon for 64bit Book3S.
0:mon> fi cpu 0x0: Vector: 700 (Program Check) at [c000000003be74a0] pc: c000000000102030: cacheflush+0x180/0x1a0 lr: c000000000101f3c: cacheflush+0x8c/0x1a0 sp: c000000003be7730 msr: 8000000000081033 current = 0xc0000000035e5c00 paca = 0xc000000001910000 irqmask: 0x03 irq_happened: 0x01 pid = 1025, comm = bash Linux version 5.6.0-rc5-g5aa19adac (root@ltc-wspoon6) (gcc version 7.4.0 (Ubuntu 7.4.0-1ubuntu1~18.04.1)) #1 SMP Tue Mar 10 04:38:41 CDT 2020 cpu 0x0: Exception 700 (Program Check) in xmon, returning to main loop [c000000003be7c50] c00000000084abb0 __handle_sysrq+0xf0/0x2a0 [c000000003be7d00] c00000000084b3c0 write_sysrq_trigger+0xb0/0xe0 [c000000003be7d30] c0000000004d1edc proc_reg_write+0x8c/0x130 [c000000003be7d60] c00000000040dc7c __vfs_write+0x3c/0x70 [c000000003be7d80] c000000000410e70 vfs_write+0xd0/0x210 [c000000003be7dd0] c00000000041126c ksys_write+0xdc/0x130 [c000000003be7e20] c00000000000b9d0 system_call+0x5c/0x68 --- Exception: c01 (System Call) at 00007fffa345e420 SP (7ffff0b08ab0) is in userspace Signed-off-by: Balamuruhan S <bal...@linux.ibm.com> --- arch/powerpc/xmon/xmon.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- changes in v3: ------------- Fix Christophe's review comments and rebase it on latest mpe's merge tree, * mention the dcbi obsolete statement based on Power processor users manual in commit message. * make #ifdef in a more simple way. changes in v2: ------------- Fix review comments from Segher and Michael, * change incorrect architecture version 2.01 to 2.03 in commit message. * ifdef it out the option `i` for PPC_BOOK3S_64 instead to drop it and change the commit message accordingly. diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c index ea303b7e4e29..7b62d5dcc4a1 100644 --- a/arch/powerpc/xmon/xmon.c +++ b/arch/powerpc/xmon/xmon.c @@ -1808,7 +1808,7 @@ static void cacheflush(void) catch_memory_errors = 1; sync(); - if (cmd != 'i') { + if (cmd != 'i' || IS_ENABLED(CONFIG_PPC_BOOK3S_64)) { for (; nflush > 0; --nflush, adrs += L1_CACHE_BYTES) cflush((void *) adrs); } else { base-commit: 1ad3b5ebe084246ad593a22707cd91ef6418c31e -- 2.24.1