[PATCH v3 0/2] powerpc/xmon: Paged output for paca display

[PATCH v3 0/2] powerpc/xmon: Paged output for paca display

[Sam Bobroff]

Changes v2 -> v3:

Moved the pagination implementation from xmon.c to nonstdio.c where it's much
easier to do and the code is significantly simplified.

As it's now trivial to do, add the capability to truncate the output or to stop
pagination and dump the rest of the output.

Changed function naming scheme to read more easily (e.g.
xmon_start_pagination()).


Changes v1 -> v2:

* Removed pagination parameters from commands, replaced with new command to set
  page size. This works better for multiple commands and produces simpler code.
* Switched from encoding the page position in the command buffer to using some
  globals. Saves some memory and is less invasive to the command code.
* Added a patch to paginate the kernel log buffer display.


Sam Bobroff (2):
  powerpc/xmon: Paged output for paca display
  powerpc/xmon: Paginate kernel log buffer display

 arch/powerpc/xmon/nonstdio.c | 57 ++++++++++++++++++++++++++++++++++++++++++--
 arch/powerpc/xmon/nonstdio.h |  3 +++
 arch/powerpc/xmon/xmon.c     | 18 ++++++++++++++
 3 files changed, 76 insertions(+), 2 deletions(-)

-- 
2.1.4

[PATCH v3 1/2] powerpc/xmon: Paged output for paca display

[Sam Bobroff]

The paca display is already more than 24 lines, which can be problematic
if you have an old school 80x24 terminal, or more likely you are on a
virtual terminal which does not scroll for whatever reason.

This patch adds a new command ".", which takes a single (hex) numeric
argument: lines per page. It will cause the output of "dp" and "dpa"
to be broken into pages, if necessary.

Sample output:

0:mon> .10
0:mon> dp1
paca for cpu 0x1 @ c00000000fdc0480:
 possible         = yes
 present          = yes
 online           = yes
 lock_token       = 0x8000            	(0x8)
 paca_index       = 0x1               	(0xa)
 kernel_toc       = 0xc000000000eb2400	(0x10)
 kernelbase       = 0xc000000000000000	(0x18)
 kernel_msr       = 0xb000000000001032	(0x20)
 emergency_sp     = 0xc00000003ffe8000	(0x28)
 mc_emergency_sp  = 0xc00000003ffe4000	(0x2e0)
 in_mce           = 0x0               	(0x2e8)
 data_offset      = 0x7f170000        	(0x30)
 hw_cpu_id        = 0x8               	(0x38)
 cpu_start        = 0x1               	(0x3a)
 kexec_state      = 0x0               	(0x3b)
[Hit a key (a:all, q:truncate, any:next page)]
0:mon>
 __current        = 0xc00000007e696620	(0x290)
 kstack           = 0xc00000007e6ebe30	(0x298)
 stab_rr          = 0xb               	(0x2a0)
 saved_r1         = 0xc00000007ef37860	(0x2a8)
 trap_save        = 0x0               	(0x2b8)
 soft_enabled     = 0x0               	(0x2ba)
 irq_happened     = 0x1               	(0x2bb)
 io_sync          = 0x0               	(0x2bc)
 irq_work_pending = 0x0               	(0x2bd)
 nap_state_lost   = 0x0               	(0x2be)
0:mon>

(Based on a similar patch by Michael Ellerman <mpe@ellerman.id.au>
"[v2] powerpc/xmon: Allow limiting the size of the paca display".
This patch is an alternative and cannot coexist with the original.)

Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com>
---
 arch/powerpc/xmon/nonstdio.c | 57 ++++++++++++++++++++++++++++++++++++++++++--
 arch/powerpc/xmon/nonstdio.h |  3 +++
 arch/powerpc/xmon/xmon.c     | 18 ++++++++++++++
 3 files changed, 76 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/xmon/nonstdio.c b/arch/powerpc/xmon/nonstdio.c
index c987486..18819d7 100644
--- a/arch/powerpc/xmon/nonstdio.c
+++ b/arch/powerpc/xmon/nonstdio.c
@@ -11,10 +11,25 @@
 #include <asm/time.h>
 #include "nonstdio.h"
 
+int paginating = 0, paginate_skipping = 0;
+unsigned long paginate_lpp = 0 /* Lines Per Page */;
+unsigned long paginate_pos;
 
-static int xmon_write(const void *ptr, int nb)
+void xmon_start_pagination(void)
 {
-	return udbg_write(ptr, nb);
+	paginating = 1;
+	paginate_skipping = 0;
+	paginate_pos = 0;
+}
+
+void xmon_end_pagination(void)
+{
+	paginating = 0;
+}
+
+void xmon_set_pagination_lpp(unsigned long lpp)
+{
+	paginate_lpp = lpp;
 }
 
 static int xmon_readchar(void)
@@ -24,6 +39,44 @@ static int xmon_readchar(void)
 	return -1;
 }
 
+static int xmon_write(const char *ptr, int nb)
+{
+	int rv = 0;
+	const char *p = ptr, *q;
+	const char msg[] = "[Hit a key (a:all, q:truncate, any:next page)]";
+
+	if (nb <= 0)
+		return rv;
+	if (paginating && paginate_skipping)
+		return nb;
+	if (paginate_lpp) {
+		while (paginating && (q = strchr(p, '\n'))) {
+			rv += udbg_write(p, q - p + 1);
+			p = q + 1;
+			paginate_pos++;
+			if (paginate_pos >= paginate_lpp) {
+				udbg_write(msg, strlen(msg));
+				switch (xmon_readchar()) {
+				case 'a':
+					paginating = 0;
+					break;
+				case 'q':
+					paginate_skipping = 1;
+					break;
+				default:
+					/* nothing */
+					break;
+				}
+				paginate_pos = 0;
+				udbg_write("\r\n", 2);
+				if (paginate_skipping)
+					return nb;
+			}
+		}
+	}
+	return rv + udbg_write(p, nb - (p - ptr));
+}
+
 int xmon_putchar(int c)
 {
 	char ch = c;
diff --git a/arch/powerpc/xmon/nonstdio.h b/arch/powerpc/xmon/nonstdio.h
index 18a51de..f865336 100644
--- a/arch/powerpc/xmon/nonstdio.h
+++ b/arch/powerpc/xmon/nonstdio.h
@@ -3,6 +3,9 @@
 #define printf	xmon_printf
 #define putchar	xmon_putchar
 
+extern void xmon_set_pagination_lpp(unsigned long lpp);
+extern void xmon_start_pagination(void);
+extern void xmon_end_pagination(void);
 extern int xmon_putchar(int c);
 extern void xmon_puts(const char *);
 extern char *xmon_gets(char *, int);
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index 6ef1231..cc070c3 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -242,6 +242,9 @@ Commands:\n\
 "  u	dump TLB\n"
 #endif
 "  ?	help\n"
+#ifdef CONFIG_PPC64
+"  .#	limit output to # lines per page (dump paca only)\n"
+#endif
 "  zr	reboot\n\
   zh	halt\n"
 ;
@@ -833,6 +836,16 @@ static void remove_cpu_bpts(void)
 	write_ciabr(0);
 }
 
+static void set_lpp_cmd(void)
+{
+	unsigned long lpp;
+
+	if (!scanhex(&lpp)) {
+		printf("Invalid number.\n");
+		lpp = 0;
+	}
+	xmon_set_pagination_lpp(lpp);
+}
 /* Command interpreting routine */
 static char *last_cmd;
 
@@ -924,6 +937,9 @@ cmds(struct pt_regs *excp)
 		case '?':
 			xmon_puts(help_string);
 			break;
+		case '.':
+			set_lpp_cmd();
+			break;
 		case 'b':
 			bpt_cmds();
 			break;
@@ -2166,7 +2182,9 @@ dump(void)
 
 #ifdef CONFIG_PPC64
 	if (c == 'p') {
+		xmon_start_pagination();
 		dump_pacas();
+		xmon_end_pagination();
 		return;
 	}
 #endif
-- 
2.1.4

[PATCH v3 2/2] powerpc/xmon: Paginate kernel log buffer display

[Sam Bobroff]

The kernel log buffer is often much longer than the size of a terminal
so paginate it's output.

Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com>
---
 arch/powerpc/xmon/xmon.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index cc070c3..8ba8ea7 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -242,9 +242,7 @@ Commands:\n\
 "  u	dump TLB\n"
 #endif
 "  ?	help\n"
-#ifdef CONFIG_PPC64
-"  .#	limit output to # lines per page (dump paca only)\n"
-#endif
+"  .#	limit output to # lines per page (for dp#, dpa, dl)\n"
 "  zr	reboot\n\
   zh	halt\n"
 ;
@@ -2333,10 +2331,12 @@ dump_log_buf(void)
 	sync();
 
 	kmsg_dump_rewind_nolock(&dumper);
+	xmon_start_pagination();
 	while (kmsg_dump_get_line_nolock(&dumper, false, buf, sizeof(buf), &len)) {
 		buf[len] = '\0';
 		printf("%s", buf);
 	}
+	xmon_end_pagination();
 
 	sync();
 	/* wait a little while to see if we get a machine check */
-- 
2.1.4

Re: [PATCH v3 1/2] powerpc/xmon: Paged output for paca display

[Michael Ellerman]

On Thu, 2015-10-08 at 11:50 +1100, Sam Bobroff wrote:
> The paca display is already more than 24 lines, which can be problematic
> if you have an old school 80x24 terminal, or more likely you are on a
> virtual terminal which does not scroll for whatever reason.
> 
> This patch adds a new command ".", which takes a single (hex) numeric
> argument: lines per page. It will cause the output of "dp" and "dpa"
> to be broken into pages, if necessary.
> 
> Sample output:
> 
> 0:mon> .10

So what about making it "#" rather than "." ?

cheers

Re: [PATCH v3 1/2] powerpc/xmon: Paged output for paca display

[Sam Bobroff]

On Wed, Oct 14, 2015 at 08:39:09PM +1100, Michael Ellerman wrote:
> On Thu, 2015-10-08 at 11:50 +1100, Sam Bobroff wrote:
> > The paca display is already more than 24 lines, which can be problematic
> > if you have an old school 80x24 terminal, or more likely you are on a
> > virtual terminal which does not scroll for whatever reason.
> > 
> > This patch adds a new command ".", which takes a single (hex) numeric
> > argument: lines per page. It will cause the output of "dp" and "dpa"
> > to be broken into pages, if necessary.
> > 
> > Sample output:
> > 
> > 0:mon> .10
> 
> So what about making it "#" rather than "." ?
> 
> cheers

Sure, although we'll have to do a better job than the other commands in the help text ;-)
(They use "#" to indicate a hex number and "##" is just going to be confusing.)

Do you want me to respin? (I'm happy for you to just adjust the patch.)

Cheers,
Sam.

Re: [PATCH v3 1/2] powerpc/xmon: Paged output for paca display

[Michael Ellerman]

On Thu, 2015-10-15 at 09:24 +1100, Sam Bobroff wrote:
> On Wed, Oct 14, 2015 at 08:39:09PM +1100, Michael Ellerman wrote:
> > On Thu, 2015-10-08 at 11:50 +1100, Sam Bobroff wrote:
> > > The paca display is already more than 24 lines, which can be problematic
> > > if you have an old school 80x24 terminal, or more likely you are on a
> > > virtual terminal which does not scroll for whatever reason.
> > > 
> > > This patch adds a new command ".", which takes a single (hex) numeric
> > > argument: lines per page. It will cause the output of "dp" and "dpa"
> > > to be broken into pages, if necessary.
> > > 
> > > Sample output:
> > > 
> > > 0:mon> .10
> > 
> > So what about making it "#" rather than "." ?
> > 
> > cheers
> 
> Sure, although we'll have to do a better job than the other commands in the help text ;-)
> (They use "#" to indicate a hex number and "##" is just going to be confusing.)
> 
> Do you want me to respin? (I'm happy for you to just adjust the patch.)

Not that's fine I'll fix it up here.

I also converted some things to bool that could be, final patch is below.

cheers


diff --git a/arch/powerpc/xmon/nonstdio.c b/arch/powerpc/xmon/nonstdio.c
index c98748617896..d00123421e00 100644
--- a/arch/powerpc/xmon/nonstdio.c
+++ b/arch/powerpc/xmon/nonstdio.c
@@ -11,10 +11,25 @@
 #include <asm/time.h>
 #include "nonstdio.h"
 
+static bool paginating, paginate_skipping;
+static unsigned long paginate_lpp; /* Lines Per Page */
+static unsigned long paginate_pos;
 
-static int xmon_write(const void *ptr, int nb)
+void xmon_start_pagination(void)
 {
-	return udbg_write(ptr, nb);
+	paginating = true;
+	paginate_skipping = false;
+	paginate_pos = 0;
+}
+
+void xmon_end_pagination(void)
+{
+	paginating = false;
+}
+
+void xmon_set_pagination_lpp(unsigned long lpp)
+{
+	paginate_lpp = lpp;
 }
 
 static int xmon_readchar(void)
@@ -24,6 +39,51 @@ static int xmon_readchar(void)
 	return -1;
 }
 
+static int xmon_write(const char *ptr, int nb)
+{
+	int rv = 0;
+	const char *p = ptr, *q;
+	const char msg[] = "[Hit a key (a:all, q:truncate, any:next page)]";
+
+	if (nb <= 0)
+		return rv;
+
+	if (paginating && paginate_skipping)
+		return nb;
+
+	if (paginate_lpp) {
+		while (paginating && (q = strchr(p, '\n'))) {
+			rv += udbg_write(p, q - p + 1);
+			p = q + 1;
+			paginate_pos++;
+
+			if (paginate_pos >= paginate_lpp) {
+				udbg_write(msg, strlen(msg));
+
+				switch (xmon_readchar()) {
+				case 'a':
+					paginating = false;
+					break;
+				case 'q':
+					paginate_skipping = true;
+					break;
+				default:
+					/* nothing */
+					break;
+				}
+
+				paginate_pos = 0;
+				udbg_write("\r\n", 2);
+
+				if (paginate_skipping)
+					return nb;
+			}
+		}
+	}
+
+	return rv + udbg_write(p, nb - (p - ptr));
+}
+
 int xmon_putchar(int c)
 {
 	char ch = c;
diff --git a/arch/powerpc/xmon/nonstdio.h b/arch/powerpc/xmon/nonstdio.h
index 18a51ded4ffd..f8653365667e 100644
--- a/arch/powerpc/xmon/nonstdio.h
+++ b/arch/powerpc/xmon/nonstdio.h
@@ -3,6 +3,9 @@
 #define printf	xmon_printf
 #define putchar	xmon_putchar
 
+extern void xmon_set_pagination_lpp(unsigned long lpp);
+extern void xmon_start_pagination(void);
+extern void xmon_end_pagination(void);
 extern int xmon_putchar(int c);
 extern void xmon_puts(const char *);
 extern char *xmon_gets(char *, int);
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index 6ef1231c6e9c..f829baf45fd7 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -242,6 +242,9 @@ Commands:\n\
 "  u	dump TLB\n"
 #endif
 "  ?	help\n"
+#ifdef CONFIG_PPC64
+"  # n	limit output to n lines per page (dump paca only)\n"
+#endif
 "  zr	reboot\n\
   zh	halt\n"
 ;
@@ -833,6 +836,16 @@ static void remove_cpu_bpts(void)
 	write_ciabr(0);
 }
 
+static void set_lpp_cmd(void)
+{
+	unsigned long lpp;
+
+	if (!scanhex(&lpp)) {
+		printf("Invalid number.\n");
+		lpp = 0;
+	}
+	xmon_set_pagination_lpp(lpp);
+}
 /* Command interpreting routine */
 static char *last_cmd;
 
@@ -924,6 +937,9 @@ cmds(struct pt_regs *excp)
 		case '?':
 			xmon_puts(help_string);
 			break;
+		case '#':
+			set_lpp_cmd();
+			break;
 		case 'b':
 			bpt_cmds();
 			break;
@@ -2166,7 +2182,9 @@ dump(void)
 
 #ifdef CONFIG_PPC64
 	if (c == 'p') {
+		xmon_start_pagination();
 		dump_pacas();
+		xmon_end_pagination();
 		return;
 	}
 #endif

Re: [v3,1/2] powerpc/xmon: Paged output for paca display

[Michael Ellerman]

On Thu, 2015-08-10 at 00:50:23 UTC, Sam bobroff wrote:
> The paca display is already more than 24 lines, which can be problematic
> if you have an old school 80x24 terminal, or more likely you are on a
> virtual terminal which does not scroll for whatever reason.
...
> Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com>

Series applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/958b7c80507a6eb847777b0d

cheers