From: Joe Perches <joe@perches.com>
To: Michael Ellerman <mpe@ellerman.id.au>,
Christophe Leroy <christophe.leroy@csgroup.eu>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH] powerpc/xmon: Change printk() to pr_cont()
Date: Fri, 04 Dec 2020 07:55:21 -0800 [thread overview]
Message-ID: <189ad2584d80d915d3c9f76c044947f83ca5ebf8.camel@perches.com> (raw)
In-Reply-To: <87h7p1vnym.fsf@mpe.ellerman.id.au>
On Fri, 2020-12-04 at 21:56 +1100, Michael Ellerman wrote:
> Christophe Leroy <christophe.leroy@csgroup.eu> writes:
> > Since some time now, printk() adds carriage return, leading to
> > unusable xmon output:
> >
> > [ 54.288722] sysrq: Entering xmon
> > [ 54.292209] Vector: 0 at [cace3d2c]
> > [ 54.292274] pc:
> > [ 54.292331] c0023650
>
> ...
>
> > diff --git a/arch/powerpc/xmon/nonstdio.c b/arch/powerpc/xmon/nonstdio.c
> > index 5c1a50912229..9b0d85bff021 100644
> > --- a/arch/powerpc/xmon/nonstdio.c
> > +++ b/arch/powerpc/xmon/nonstdio.c
> > @@ -178,7 +178,7 @@ void xmon_printf(const char *format, ...)
> >
> >
> > if (n && rc == 0) {
> > /* No udbg hooks, fallback to printk() - dangerous */
> > - printk("%s", xmon_outbuf);
> > + pr_cont("%s", xmon_outbuf);
> > }
>
> Ah OK, in the case where there's no udbg backend. We basically always
> have a udbg backend on 64-bit, via hvc console. Which explains why we
> haven't noticed it.
>
> Will pick up the patch.
>
> cheers
Perhaps all of these bare printks should be inspected for defects:
$ git grep -P -n '\bprintk\s*\(\s*(?!KERN_\w+)"[^\\n]*"' arch/powerpc
arch/powerpc/kernel/process.c:1475: printk("NIP: "REG" LR: "REG" CTR: "REG"\n",
arch/powerpc/kernel/process.c:1479: printk("MSR: "REG" ", regs->msr);
arch/powerpc/kernel/process.c:1513: printk("NIP ["REG"] %pS\n", regs->nip, (void *)regs->nip);
arch/powerpc/kernel/process.c:1514: printk("LR ["REG"] %pS\n", regs->link, (void *)regs->link);
arch/powerpc/kernel/process.c:2157: printk("%s["REG"] ["REG"] %pS",
arch/powerpc/kernel/traps.c:621: printk("Caused by (from MCSR=%lx): ", reason);
arch/powerpc/kernel/traps.c:726: printk("Caused by (from MCSR=%lx): ", reason);
arch/powerpc/kernel/traps.c:766: printk("Caused by (from MCSR=%lx): ", reason);
arch/powerpc/kernel/traps.c:791: printk("Caused by (from SRR1=%lx): ", reason);
arch/powerpc/kernel/udbg.c:95: printk("%s", s);
arch/powerpc/math-emu/fabs.c:13: printk("%s: D %p, B %p: ", __func__, frD, frB);
arch/powerpc/math-emu/fctiw.c:22: printk("%s: D %p, B %p: ", __func__, frD, frB);
arch/powerpc/math-emu/fctiwz.c:29: printk("%s: D %p, B %p: ", __func__, frD, frB);
arch/powerpc/math-emu/fmr.c:13: printk("%s: D %p, B %p: ", __func__, frD, frB);
arch/powerpc/math-emu/fnabs.c:13: printk("%s: D %p, B %p: ", __func__, frD, frB);
arch/powerpc/math-emu/fneg.c:13: printk("%s: D %p, B %p: ", __func__, frD, frB);
arch/powerpc/math-emu/lfd.c:15: printk("%s: D %p, ea %p: ", __func__, frD, ea);
arch/powerpc/math-emu/stfd.c:11: printk("%s: S %p, ea %p: ", __func__, frS, ea);
arch/powerpc/mm/nohash/44x.c:192: printk("%d ", i);
arch/powerpc/platforms/4xx/machine_check.c:19: printk("Data");
arch/powerpc/platforms/chrp/pci.c:256: printk(" at %llx", (unsigned long long)r.start);
arch/powerpc/platforms/embedded6xx/ls_uart.c:47: printk("%c", in_8(avr_addr + UART_RX));
arch/powerpc/platforms/powermac/pfunc_core.c:83: printk("%s", title);
arch/powerpc/platforms/powermac/pfunc_core.c:85: printk("%02x ", *((u8 *)blob));
arch/powerpc/platforms/powernv/pci-ioda.c:81: printk("%spci %s: [PE# %.2x] %pV",
arch/powerpc/sysdev/tsi108_pci.c:63: printk("PCI CFG write : ");
arch/powerpc/sysdev/tsi108_pci.c:64: printk("%d:0x%x:0x%x ", bus->number, devfunc, offset);
arch/powerpc/sysdev/tsi108_pci.c:65: printk("%d ADDR=0x%08x ", len, (uint) cfg_addr);
arch/powerpc/sysdev/tsi108_pci.c:164: printk("PCI CFG read : ");
arch/powerpc/sysdev/tsi108_pci.c:165: printk("%d:0x%x:0x%x ", bus->number, devfn, offset);
arch/powerpc/sysdev/tsi108_pci.c:166: printk("%d ADDR=0x%08x ", len, (uint) cfg_addr);
arch/powerpc/sysdev/tsi108_pci.c:315: printk("cfg_ctl=0x%08x ", temp);
arch/powerpc/xmon/nonstdio.c:181: printk("%s", xmon_outbuf);
next prev parent reply other threads:[~2020-12-04 15:56 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-04 10:35 [PATCH] powerpc/xmon: Change printk() to pr_cont() Christophe Leroy
2020-12-04 10:56 ` Michael Ellerman
2020-12-04 15:55 ` Joe Perches [this message]
2020-12-10 11:29 ` Michael Ellerman
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