diff mbox

[v3,2/2] powerpc/xmon: Disable tracing when entering xmon

Message ID 1501704846-22625-2-git-send-email-leitao@debian.org (mailing list archive)
State Accepted
Commit ed49f7fd6438dcc8c93fa7d1d7d815e47c7115dd
Headers show

Commit Message

Breno Leitao Aug. 2, 2017, 8:14 p.m. UTC 
If tracing is enabled and you get into xmon, the tracing buffer
continues to be updated, causing possible loss of data and unnecessary
tracing information coming from xmon functions.

This patch simple disables tracing when entering xmon, and re-enables it
if the kernel is resumed (with 'x').

Signed-off-by: Breno Leitao <leitao@debian.org>
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
---
 arch/powerpc/xmon/xmon.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

Comments

Michael Ellerman Aug. 16, 2017, 12:29 p.m. UTC | #1 
On Wed, 2017-08-02 at 20:14:06 UTC, Breno Leitao wrote:
> If tracing is enabled and you get into xmon, the tracing buffer
> continues to be updated, causing possible loss of data and unnecessary
> tracing information coming from xmon functions.
> 
> This patch simple disables tracing when entering xmon, and re-enables it
> if the kernel is resumed (with 'x').
> 
> Signed-off-by: Breno Leitao <leitao@debian.org>
> Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/ed49f7fd6438dcc8c93fa7d1d7d815

cheers
diff mbox

Patch

diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index e0522f60f0ee..d038e7db44c4 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -89,6 +89,7 @@  static unsigned long nidump = 16;
 static unsigned long ncsum = 4096;
 static int termch;
 static char tmpstr[128];
+static int tracing_enabled;
 
 static long bus_error_jmp[JMP_BUF_LEN];
 static int catch_memory_errors;
@@ -462,6 +463,9 @@  static int xmon_core(struct pt_regs *regs, int fromipi)
 	local_irq_save(flags);
 	hard_irq_disable();
 
+	tracing_enabled = tracing_is_on();
+	tracing_off();
+
 	bp = in_breakpoint_table(regs->nip, &offset);
 	if (bp != NULL) {
 		regs->nip = bp->address + offset;
@@ -982,6 +986,8 @@  cmds(struct pt_regs *excp)
 			break;
 		case 'x':
 		case 'X':
+			if (tracing_enabled)
+				tracing_on();
 			return cmd;
 		case EOF:
 			printf(" <no input ...>\n");
@@ -2241,8 +2247,6 @@  static void dump_tracing(void)
 		ftrace_dump(DUMP_ORIG);
 	else
 		ftrace_dump(DUMP_ALL);
-
-	tracing_on();
 }
 
 #ifdef CONFIG_PPC64