Subject: [PATCH] powerpc xmon: drop the option `i` in cacheflush

From: Balamuruhan S <[email-masked]>
Date: Mon, 23 Mar 2020 16:55:48 +0530

Data Cache Block Invalidate (dcbi) instruction implemented in 32-bit
designs prior to PowerPC architecture version 2.01 and got obsolete
from version 2.01. Attempt to use of this illegal instruction results
in a hypervisor emulation assistance interrupt. So, drop the option
`i` in cacheflush xmon and continue using `dcbf`.

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 <[email-masked]>
---
 arch/powerpc/xmon/xmon.c | 22 ++--------------------
 1 file changed, 2 insertions(+), 20 deletions(-)

diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index 0ec9640335bb..d287bf2a54be 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -335,11 +335,6 @@ static inline void cflush(void *p)
 	asm volatile ("dcbf 0,%0; icbi 0,%0" : : "r" (p));
 }
 
-static inline void cinval(void *p)
-{
-	asm volatile ("dcbi 0,%0; icbi 0,%0" : : "r" (p));
-}
-
 /**
  * write_ciabr() - write the CIABR SPR
  * @ciabr:	The value to write.
@@ -1791,29 +1786,16 @@ static void prregs(struct pt_regs *fp)
 
 static void cacheflush(void)
 {
-	int cmd;
 	unsigned long nflush;
 
-	cmd = inchar();
-	if (cmd != 'i')
-		termch = cmd;
-	scanhex((void *)&adrs);
-	if (termch != '\n')
-		termch = 0;
 	nflush = 1;
 	scanhex(&nflush);
 	nflush = (nflush + L1_CACHE_BYTES - 1) / L1_CACHE_BYTES;
 	if (setjmp(bus_error_jmp) == 0) {
 		catch_memory_errors = 1;
 		sync();
-
-		if (cmd != 'i') {
-			for (; nflush > 0; --nflush, adrs += L1_CACHE_BYTES)
-				cflush((void *) adrs);
-		} else {
-			for (; nflush > 0; --nflush, adrs += L1_CACHE_BYTES)
-				cinval((void *) adrs);
-		}
+		for (; nflush > 0; --nflush, adrs += L1_CACHE_BYTES)
+			cflush((void *)adrs);
 		sync();
 		/* wait a little while to see if we get a machine check */
 		__delay(200);

base-commit: a87b93bdf800a4d7a42d95683624a4516e516b4f
-- 
2.24.1