Messages in this thread Patch in this message | | | Subject | Re: [PATCH] powerpc/xmon: Fix an unexpected xmon onoff state change | From | Pan Xinhui <> | Date | Thu, 16 Feb 2017 19:51:27 +0800 |
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在 2017/2/16 18:57, Guilherme G. Piccoli 写道: > On 16/02/2017 03:09, Michael Ellerman wrote: >> Pan Xinhui <xinhui.pan@linux.vnet.ibm.com> writes: >> >>> Once xmon is triggered by sysrq-x, it is enabled always afterwards even >>> if it is disabled during boot. This will cause a system reset interrut >>> fail to dump. So keep xmon in its original state after exit. >>> >>> Signed-off-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com> >>> --- >>> arch/powerpc/xmon/xmon.c | 5 ++++- >>> 1 file changed, 4 insertions(+), 1 deletion(-) >>> >>> diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c >>> index 9c0e17c..721212f 100644 >>> --- a/arch/powerpc/xmon/xmon.c >>> +++ b/arch/powerpc/xmon/xmon.c >>> @@ -76,6 +76,7 @@ static int xmon_gate; >>> #endif /* CONFIG_SMP */ >>> >>> static unsigned long in_xmon __read_mostly = 0; >>> +static int xmon_off = 0; >>> >>> static unsigned long adrs; >>> static int size = 1; >>> @@ -3250,6 +3251,8 @@ static void sysrq_handle_xmon(int key) >>> /* ensure xmon is enabled */ >>> xmon_init(1); >>> debugger(get_irq_regs()); >>> + if (xmon_off) >>> + xmon_init(0); >>> } >> >> I don't think this is right. >> >> xmon_off is only true if you boot with xmon=off on the command line. >> >> So if you boot with CONFIG_XMON_DEFAULT=n, and nothing on the command >> line, then enter xmon via sysrq, then exit, xmon will still be enabled. >> > > Agreed, noticed it after some work in V2 of my patch. I'm addressing it > there, so maybe no harm in keeping this way here.. > Hi, mpe I cooked a new patch. And as Paul mentioned in slack, we need keep xmon on too if xmon=early is set in cmdline.
hi, Guilherme feel free to include it in your new patchset. :)
thanks xinhui
--------patch----- powerpc/xmon: Fix an unexpected xmon onoff state change
Once xmon is triggered by sysrq-x, it is enabled always afterwards even if it is disabled during boot. This will cause a system reset interrupt fail to dump. So keep xmon in its original state after exit.
We have several ways to set xmon on or off. 1) by a build config CONFIG_XMON_DEFAULT. 2) by a boot cmdline with xmon or xmon=early or xmon=on to enable xmon and xmon=off to disable xmon. This value will override that in step 1. 3) by a debugfs interface. We need someone implement it in the future. And this value can override those in step 1 and 2.
Signed-off-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com> --- arch/powerpc/xmon/xmon.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-)
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c index 9c0e17c..f6e5c3d 100644 --- a/arch/powerpc/xmon/xmon.c +++ b/arch/powerpc/xmon/xmon.c @@ -76,6 +76,7 @@ static int xmon_gate; #endif /* CONFIG_SMP */ static unsigned long in_xmon __read_mostly = 0; +static int xmon_off = !IS_ENABLED(CONFIG_XMON_DEFAULT); static unsigned long adrs; static int size = 1; @@ -3250,6 +3251,8 @@ static void sysrq_handle_xmon(int key) /* ensure xmon is enabled */ xmon_init(1); debugger(get_irq_regs()); + if (xmon_off) + xmon_init(0); } static struct sysrq_key_op sysrq_xmon_op = { @@ -3266,16 +3269,16 @@ static int __init setup_xmon_sysrq(void) __initcall(setup_xmon_sysrq); #endif /* CONFIG_MAGIC_SYSRQ */ -static int __initdata xmon_early, xmon_off; +static int __initdata xmon_early; static int __init early_parse_xmon(char *p) { if (!p || strncmp(p, "early", 5) == 0) { /* just "xmon" is equivalent to "xmon=early" */ - xmon_init(1); xmon_early = 1; + xmon_off = 0; } else if (strncmp(p, "on", 2) == 0) - xmon_init(1); + xmon_off = 0; else if (strncmp(p, "off", 3) == 0) xmon_off = 1; else if (strncmp(p, "nobt", 4) == 0) @@ -3289,10 +3292,9 @@ early_param("xmon", early_parse_xmon); void __init xmon_setup(void) { -#ifdef CONFIG_XMON_DEFAULT - if (!xmon_off) - xmon_init(1); -#endif + if (xmon_off) + return; + xmon_init(1); if (xmon_early) debugger(NULL); } -- 2.9.3
> Thanks, > > > Guilherme > > > >> cheers >> >
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