[PATCH 1/2] powerpc/kdump: Add missing optional dummy functions

If KEXEC_CORE is not enabled, PowerNV builds fail as follows.

arch/powerpc/platforms/powernv/smp.c: In function 'pnv_smp_cpu_kill_self':
arch/powerpc/platforms/powernv/smp.c:236:4: error:
	implicit declaration of function 'crash_ipi_callback'

Add dummy function calls, similar to kdump_in_progress(), to solve the
problem.

Fixes: 4145f358644b ("powernv/kdump: Fix cases where the kdump kernel ...")
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
 arch/powerpc/include/asm/kexec.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/powerpc/include/asm/kexec.h b/arch/powerpc/include/asm/kexec.h
index 9dcbfa6bbb91..d8b1e8e7e035 100644
--- a/arch/powerpc/include/asm/kexec.h
+++ b/arch/powerpc/include/asm/kexec.h

@@ -140,6 +140,12 @@ static inline bool kdump_in_progress(void)
 	return false;
 }
 
+static inline void crash_ipi_callback(struct pt_regs *regs) { }
+
+static inline void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *))
+{
+}
+
 #endif /* CONFIG_KEXEC_CORE */
 #endif /* ! __ASSEMBLY__ */
 #endif /* __KERNEL__ */

-- 
2.7.4

Commit e67e02a544e9 ("powerpc/pseries: Fix cpu hotplug crash with
memoryless nodes") adds an unconditional call to find_and_online_cpu_nid(),
which is only declared if CONFIG_PPC_SPLPAR is enabled. This results in
the following build error if this is not the case.

arch/powerpc/platforms/pseries/hotplug-cpu.o: In function `dlpar_online_cpu':
arch/powerpc/platforms/pseries/hotplug-cpu.c:369:
			undefined reference to `.find_and_online_cpu_nid'

Follow the guideline provided by similar functions and provide a dummy
function if CONFIG_PPC_SPLPAR is not enabled. This also moves the external
function declaration into an include file where it should be.

Fixes: e67e02a544e9 ("powerpc/pseries: Fix cpu hotplug crash with ...")
Cc: Michael Bringmann <redacted>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nathan Fontenot <redacted>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
 arch/powerpc/include/asm/topology.h          | 5 +++++
 arch/powerpc/platforms/pseries/hotplug-cpu.c | 2 --
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/include/asm/topology.h b/arch/powerpc/include/asm/topology.h
index 88187c285c70..52815982436f 100644
--- a/arch/powerpc/include/asm/topology.h
+++ b/arch/powerpc/include/asm/topology.h

@@ -82,6 +82,7 @@ static inline int numa_update_cpu_topology(bool cpus_locked)
 extern int start_topology_update(void);
 extern int stop_topology_update(void);
 extern int prrn_is_enabled(void);
+extern int find_and_online_cpu_nid(int cpu);
 #else
 static inline int start_topology_update(void)
 {

@@ -95,6 +96,10 @@ static inline int prrn_is_enabled(void)
 {
 	return 0;
 }
+static inline int find_and_online_cpu_nid(int cpu)
+{
+	return 0;
+}
 #endif /* CONFIG_NUMA && CONFIG_PPC_SPLPAR */
 
 #if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_NEED_MULTIPLE_NODES)

diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c
index dceb51454d8d..f5c6a8cd2926 100644
--- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
+++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c

@@ -340,8 +340,6 @@ static void pseries_remove_processor(struct device_node *np)
 	cpu_maps_update_done();
 }
 
-extern int find_and_online_cpu_nid(int cpu);
-
 static int dlpar_online_cpu(struct device_node *dn)
 {
 	int rc = 0;

-- 
2.7.4

On Tue, Feb 13, 2018 at 9:34 AM, Guenter Roeck [off-list ref] wrote:

If KEXEC_CORE is not enabled, PowerNV builds fail as follows.

arch/powerpc/platforms/powernv/smp.c: In function 'pnv_smp_cpu_kill_self':
arch/powerpc/platforms/powernv/smp.c:236:4: error:
        implicit declaration of function 'crash_ipi_callback'

Add dummy function calls, similar to kdump_in_progress(), to solve the
problem.

Fixes: 4145f358644b ("powernv/kdump: Fix cases where the kdump kernel ...")
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---

Thanks for working on this.

You've added two functions, I understand the crash_send_ipi() bits
that I broke. Looks like crash_ipi_callback broken without KEXEC_CORE?

I am going to test these patches, for now

Acked-by: Balbir Singh <bsingharora@gmail.com>

Balbir Singh

On Tue, Feb 13, 2018 at 10:01:57AM +1100, Balbir Singh wrote:

On Tue, Feb 13, 2018 at 9:34 AM, Guenter Roeck [off-list ref] wrote:

quoted

If KEXEC_CORE is not enabled, PowerNV builds fail as follows.

arch/powerpc/platforms/powernv/smp.c: In function 'pnv_smp_cpu_kill_self':
arch/powerpc/platforms/powernv/smp.c:236:4: error:
        implicit declaration of function 'crash_ipi_callback'

Add dummy function calls, similar to kdump_in_progress(), to solve the
problem.

Fixes: 4145f358644b ("powernv/kdump: Fix cases where the kdump kernel ...")
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---

Thanks for working on this.

You've added two functions, I understand the crash_send_ipi() bits
that I broke. Looks like crash_ipi_callback broken without KEXEC_CORE?

If I recall correctly, 4145f358644b introduced the call to crash_ipi_callback().
After I declared the dummy function for that, I got an error about the missing
crash_send_ipi(). I didn't spend more time on it but just added another dummy
function. It may well be that another problem was introduced in the same time
frame. On the other side, maybe I got it all wrong, and my patch is not worth
the computer it was written on.

Thanks,
Guenter

Guenter Roeck [off-list ref] writes:

If KEXEC_CORE is not enabled, PowerNV builds fail as follows.

arch/powerpc/platforms/powernv/smp.c: In function 'pnv_smp_cpu_kill_self':
arch/powerpc/platforms/powernv/smp.c:236:4: error:
	implicit declaration of function 'crash_ipi_callback'

Add dummy function calls, similar to kdump_in_progress(), to solve the
problem.

Fixes: 4145f358644b ("powernv/kdump: Fix cases where the kdump kernel ...")

Personally I prefer these untruncated.

Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
 arch/powerpc/include/asm/kexec.h | 6 ++++++
 1 file changed, 6 insertions(+)

Thanks. Nathan sent a fix for this a few days ago, but I like this
version because it uses the existing #ifdefs.

I've taken this version but used the subject from his patch.

cheers

On 02/12/2018 02:34 PM, Guenter Roeck wrote:

Commit e67e02a544e9 ("powerpc/pseries: Fix cpu hotplug crash with
memoryless nodes") adds an unconditional call to find_and_online_cpu_nid(),
which is only declared if CONFIG_PPC_SPLPAR is enabled. This results in
the following build error if this is not the case.

arch/powerpc/platforms/pseries/hotplug-cpu.o: In function `dlpar_online_cpu':
arch/powerpc/platforms/pseries/hotplug-cpu.c:369:
			undefined reference to `.find_and_online_cpu_nid'

Follow the guideline provided by similar functions and provide a dummy
function if CONFIG_PPC_SPLPAR is not enabled. This also moves the external
function declaration into an include file where it should be.

Fixes: e67e02a544e9 ("powerpc/pseries: Fix cpu hotplug crash with ...")
Cc: Michael Bringmann <redacted>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nathan Fontenot <redacted>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Nathan already sent a patch on the 9th for this issue to the list.

-Tyrel

On Mon, 12 Feb 2018 15:25:51 -0800
Guenter Roeck [off-list ref] wrote:

On Tue, Feb 13, 2018 at 10:01:57AM +1100, Balbir Singh wrote:

quoted

On Tue, Feb 13, 2018 at 9:34 AM, Guenter Roeck [off-list ref] wrote:  

quoted

If KEXEC_CORE is not enabled, PowerNV builds fail as follows.

arch/powerpc/platforms/powernv/smp.c: In function 'pnv_smp_cpu_kill_self':
arch/powerpc/platforms/powernv/smp.c:236:4: error:
        implicit declaration of function 'crash_ipi_callback'

Add dummy function calls, similar to kdump_in_progress(), to solve the
problem.

Fixes: 4145f358644b ("powernv/kdump: Fix cases where the kdump kernel ...")
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---  

Thanks for working on this.

You've added two functions, I understand the crash_send_ipi() bits
that I broke. Looks like crash_ipi_callback broken without KEXEC_CORE?
  

If I recall correctly, 4145f358644b introduced the call to crash_ipi_callback().
After I declared the dummy function for that, I got an error about the missing
crash_send_ipi(). I didn't spend more time on it but just added another dummy
function. It may well be that another problem was introduced in the same time
frame. On the other side, maybe I got it all wrong, and my patch is not worth
the computer it was written on.

The patches worked for me with CONFIG_KEXEC=n and CONFIG_KEXEC_CORE=n

Tested-by: Balbir Singh <bsingharora@gmail.com>

Balbir Singh

On Mon, 2018-02-12 at 22:34:07 UTC, Guenter Roeck wrote:

If KEXEC_CORE is not enabled, PowerNV builds fail as follows.

arch/powerpc/platforms/powernv/smp.c: In function 'pnv_smp_cpu_kill_self':
arch/powerpc/platforms/powernv/smp.c:236:4: error:
	implicit declaration of function 'crash_ipi_callback'

Add dummy function calls, similar to kdump_in_progress(), to solve the
problem.

Fixes: 4145f358644b ("powernv/kdump: Fix cases where the kdump kernel ...")
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Balbir Singh <bsingharora@gmail.com>

Applied to powerpc fixes, thanks.

https://git.kernel.org/powerpc/c/910961754572a2f4c83ad7e610d180

cheers

On Mon, 2018-02-12 at 22:34:08 UTC, Guenter Roeck wrote:

Commit e67e02a544e9 ("powerpc/pseries: Fix cpu hotplug crash with
memoryless nodes") adds an unconditional call to find_and_online_cpu_nid(),
which is only declared if CONFIG_PPC_SPLPAR is enabled. This results in
the following build error if this is not the case.

arch/powerpc/platforms/pseries/hotplug-cpu.o: In function `dlpar_online_cpu':
arch/powerpc/platforms/pseries/hotplug-cpu.c:369:
			undefined reference to `.find_and_online_cpu_nid'

Follow the guideline provided by similar functions and provide a dummy
function if CONFIG_PPC_SPLPAR is not enabled. This also moves the external
function declaration into an include file where it should be.

Fixes: e67e02a544e9 ("powerpc/pseries: Fix cpu hotplug crash with ...")
Cc: Michael Bringmann <redacted>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nathan Fontenot <redacted>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Applied to powerpc fixes, thanks.

https://git.kernel.org/powerpc/c/82343484a2d4c97a03bfd81303b549

cheers