2021-08-03 15:56:35

by Lee Jones

[permalink] [raw]
Subject: [PATCH 0/3] power: reset: Convert Power-Off driver to tristate

Provide support to compile the Power-Off driver as a module.

Elliot Berman (2):
reboot: Export reboot_mode
power: reset: Enable tristate on restart power-off driver

Lee Jones (1):
arch: Export machine_restart() instances so they can be called from
modules

arch/arc/kernel/reset.c | 1 +
arch/arm/kernel/reboot.c | 1 +
arch/arm64/kernel/process.c | 1 +
arch/csky/kernel/power.c | 1 +
arch/h8300/kernel/process.c | 1 +
arch/hexagon/kernel/reset.c | 1 +
arch/m68k/kernel/process.c | 1 +
arch/microblaze/kernel/reset.c | 1 +
arch/mips/kernel/reset.c | 1 +
arch/mips/lantiq/falcon/reset.c | 1 +
arch/mips/sgi-ip27/ip27-reset.c | 1 +
arch/nios2/kernel/process.c | 1 +
arch/openrisc/kernel/process.c | 1 +
arch/parisc/kernel/process.c | 1 +
arch/powerpc/kernel/setup-common.c | 1 +
arch/riscv/kernel/reset.c | 1 +
arch/s390/kernel/setup.c | 1 +
arch/sh/kernel/reboot.c | 1 +
arch/sparc/kernel/process_32.c | 1 +
arch/sparc/kernel/reboot.c | 1 +
arch/um/kernel/reboot.c | 1 +
arch/x86/kernel/reboot.c | 1 +
arch/xtensa/kernel/setup.c | 1 +
drivers/power/reset/Kconfig | 2 +-
kernel/reboot.c | 2 ++
25 files changed, 26 insertions(+), 1 deletion(-)


--
2.32.0.554.ge1b32706d8-goog



2021-08-03 15:56:39

by Lee Jones

[permalink] [raw]
Subject: [PATCH 2/3] reboot: Export reboot_mode

From: Elliot Berman <[email protected]>

Export reboot_mode to support kernel modules wishing to modify reboot_mode.

Signed-off-by: Elliot Berman <[email protected]>
Reviewed-by: Bjorn Andersson <[email protected]>
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Lee Jones <[email protected]>
---
kernel/reboot.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/kernel/reboot.c b/kernel/reboot.c
index a6ad5eb2fa733..7ca414aa070b6 100644
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -32,7 +32,9 @@ EXPORT_SYMBOL(cad_pid);
#define DEFAULT_REBOOT_MODE
#endif
enum reboot_mode reboot_mode DEFAULT_REBOOT_MODE;
+EXPORT_SYMBOL_GPL(reboot_mode);
enum reboot_mode panic_reboot_mode = REBOOT_UNDEFINED;
+EXPORT_SYMBOL_GPL(panic_reboot_mode);

/*
* This variable is used privately to keep track of whether or not
--
2.32.0.554.ge1b32706d8-goog


2021-08-03 15:56:46

by Lee Jones

[permalink] [raw]
Subject: [PATCH 1/3] arch: Export machine_restart() instances so they can be called from modules

A recent attempt to convert the Power Reset Restart driver to tristate
failed because of the following compile error (reported once merged by
Stephen Rothwell via Linux Next):

ERROR: "machine_restart" [drivers/power/reset/restart-poweroff.ko] undefined!

This error occurs since some of the machine_restart() instances are
not currently exported for use in modules. This patch aims to rectify
that.

Signed-off-by: Lee Jones <[email protected]>
---

NB: If it's safe to omit some of these, let me know and I'll revise the patch.

arch/arc/kernel/reset.c | 1 +
arch/arm/kernel/reboot.c | 1 +
arch/arm64/kernel/process.c | 1 +
arch/csky/kernel/power.c | 1 +
arch/h8300/kernel/process.c | 1 +
arch/hexagon/kernel/reset.c | 1 +
arch/m68k/kernel/process.c | 1 +
arch/microblaze/kernel/reset.c | 1 +
arch/mips/kernel/reset.c | 1 +
arch/mips/lantiq/falcon/reset.c | 1 +
arch/mips/sgi-ip27/ip27-reset.c | 1 +
arch/nios2/kernel/process.c | 1 +
arch/openrisc/kernel/process.c | 1 +
arch/parisc/kernel/process.c | 1 +
arch/powerpc/kernel/setup-common.c | 1 +
arch/riscv/kernel/reset.c | 1 +
arch/s390/kernel/setup.c | 1 +
arch/sh/kernel/reboot.c | 1 +
arch/sparc/kernel/process_32.c | 1 +
arch/sparc/kernel/reboot.c | 1 +
arch/um/kernel/reboot.c | 1 +
arch/x86/kernel/reboot.c | 1 +
arch/xtensa/kernel/setup.c | 1 +
23 files changed, 23 insertions(+)

diff --git a/arch/arc/kernel/reset.c b/arch/arc/kernel/reset.c
index fd6c3eb930bad..ae4f8a43b0af4 100644
--- a/arch/arc/kernel/reset.c
+++ b/arch/arc/kernel/reset.c
@@ -20,6 +20,7 @@ void machine_restart(char *__unused)
pr_info("Put your restart handler here\n");
machine_halt();
}
+EXPORT_SYMBOL(machine_restart);

void machine_power_off(void)
{
diff --git a/arch/arm/kernel/reboot.c b/arch/arm/kernel/reboot.c
index 0ce388f154226..2878260efd130 100644
--- a/arch/arm/kernel/reboot.c
+++ b/arch/arm/kernel/reboot.c
@@ -150,3 +150,4 @@ void machine_restart(char *cmd)
printk("Reboot failed -- System halted\n");
while (1);
}
+EXPORT_SYMBOL(machine_restart);
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index b4bb67f17a2ca..cf89ce91d7145 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -212,6 +212,7 @@ void machine_restart(char *cmd)
printk("Reboot failed -- System halted\n");
while (1);
}
+EXPORT_SYMBOL(machine_restart);

#define bstr(suffix, str) [PSR_BTYPE_ ## suffix >> PSR_BTYPE_SHIFT] = str
static const char *const btypes[] = {
diff --git a/arch/csky/kernel/power.c b/arch/csky/kernel/power.c
index 923ee4e381b81..b466c825cbb3c 100644
--- a/arch/csky/kernel/power.c
+++ b/arch/csky/kernel/power.c
@@ -28,3 +28,4 @@ void machine_restart(char *cmd)
do_kernel_restart(cmd);
asm volatile ("bkpt");
}
+EXPORT_SYMBOL(machine_restart);
diff --git a/arch/h8300/kernel/process.c b/arch/h8300/kernel/process.c
index 46b1342ce515b..8203ac5cd33ec 100644
--- a/arch/h8300/kernel/process.c
+++ b/arch/h8300/kernel/process.c
@@ -66,6 +66,7 @@ void machine_restart(char *__unused)
local_irq_disable();
__asm__("jmp @@0");
}
+EXPORT_SYMBOL(machine_restart);

void machine_halt(void)
{
diff --git a/arch/hexagon/kernel/reset.c b/arch/hexagon/kernel/reset.c
index da36114d928f0..433378d52063c 100644
--- a/arch/hexagon/kernel/reset.c
+++ b/arch/hexagon/kernel/reset.c
@@ -19,6 +19,7 @@ void machine_halt(void)
void machine_restart(char *cmd)
{
}
+EXPORT_SYMBOL(machine_restart);

void (*pm_power_off)(void) = NULL;
EXPORT_SYMBOL(pm_power_off);
diff --git a/arch/m68k/kernel/process.c b/arch/m68k/kernel/process.c
index da83cc83e7912..e0264704686e9 100644
--- a/arch/m68k/kernel/process.c
+++ b/arch/m68k/kernel/process.c
@@ -57,6 +57,7 @@ void machine_restart(char * __unused)
mach_reset();
for (;;);
}
+EXPORT_SYMBOL(machine_restart);

void machine_halt(void)
{
diff --git a/arch/microblaze/kernel/reset.c b/arch/microblaze/kernel/reset.c
index 5f4722908164d..902fbe3777846 100644
--- a/arch/microblaze/kernel/reset.c
+++ b/arch/microblaze/kernel/reset.c
@@ -41,3 +41,4 @@ void machine_restart(char *cmd)
pr_emerg("Reboot failed -- System halted\n");
while (1);
}
+EXPORT_SYMBOL(machine_restart);
diff --git a/arch/mips/kernel/reset.c b/arch/mips/kernel/reset.c
index 6288780b779e7..2d3193a3cf68b 100644
--- a/arch/mips/kernel/reset.c
+++ b/arch/mips/kernel/reset.c
@@ -99,6 +99,7 @@ void machine_restart(char *command)
pr_emerg("Reboot failed -- System halted\n");
machine_hang();
}
+EXPORT_SYMBOL(machine_restart);

void machine_halt(void)
{
diff --git a/arch/mips/lantiq/falcon/reset.c b/arch/mips/lantiq/falcon/reset.c
index 261996c230cf6..80dd9759ffa55 100644
--- a/arch/mips/lantiq/falcon/reset.c
+++ b/arch/mips/lantiq/falcon/reset.c
@@ -51,6 +51,7 @@ static void machine_restart(char *command)
(void *)WDT_REG_BASE);
unreachable();
}
+EXPORT_SYMBOL(machine_restart);

static void machine_halt(void)
{
diff --git a/arch/mips/sgi-ip27/ip27-reset.c b/arch/mips/sgi-ip27/ip27-reset.c
index 5ac5ad6387343..a3f8f4498b7c5 100644
--- a/arch/mips/sgi-ip27/ip27-reset.c
+++ b/arch/mips/sgi-ip27/ip27-reset.c
@@ -29,6 +29,7 @@
#include "ip27-common.h"

void machine_restart(char *command) __noreturn;
+EXPORT_SYMBOL(machine_restart);
void machine_halt(void) __noreturn;
void machine_power_off(void) __noreturn;

diff --git a/arch/nios2/kernel/process.c b/arch/nios2/kernel/process.c
index c5f916ca6845f..6f9459e8ae4ed 100644
--- a/arch/nios2/kernel/process.c
+++ b/arch/nios2/kernel/process.c
@@ -51,6 +51,7 @@ void machine_restart(char *__unused)
: "r" (cpuinfo.reset_addr)
: "r4");
}
+EXPORT_SYMBOL(machine_restart);

void machine_halt(void)
{
diff --git a/arch/openrisc/kernel/process.c b/arch/openrisc/kernel/process.c
index eb62429681fc8..12c3022c46387 100644
--- a/arch/openrisc/kernel/process.c
+++ b/arch/openrisc/kernel/process.c
@@ -61,6 +61,7 @@ void machine_restart(char *cmd)
pr_emerg("Reboot failed -- System halted\n");
while (1);
}
+EXPORT_SYMBOL(machine_restart);

/*
* Similar to machine_power_off, but don't shut off power. Add code
diff --git a/arch/parisc/kernel/process.c b/arch/parisc/kernel/process.c
index b144fbe29bc16..05e9f03124b64 100644
--- a/arch/parisc/kernel/process.c
+++ b/arch/parisc/kernel/process.c
@@ -96,6 +96,7 @@ void machine_restart(char *cmd)
while (1) ;

}
+EXPORT_SYMBOL(machine_restart);

void (*chassis_power_off)(void);

diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index 74a98fff2c2f9..54ebae540dd7d 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -159,6 +159,7 @@ void machine_restart(char *cmd)

machine_hang();
}
+EXPORT_SYMBOL(machine_restart);

void machine_power_off(void)
{
diff --git a/arch/riscv/kernel/reset.c b/arch/riscv/kernel/reset.c
index ee5878d968cc1..596a36b91eaa2 100644
--- a/arch/riscv/kernel/reset.c
+++ b/arch/riscv/kernel/reset.c
@@ -20,6 +20,7 @@ void machine_restart(char *cmd)
do_kernel_restart(cmd);
while (1);
}
+EXPORT_SYMBOL(machine_restart);

void machine_halt(void)
{
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index 5aab59ad56881..fd2394af0d43a 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -276,6 +276,7 @@ void machine_restart(char *command)
console_unblank();
_machine_restart(command);
}
+EXPORT_SYMBOL(machine_restart);

void machine_halt(void)
{
diff --git a/arch/sh/kernel/reboot.c b/arch/sh/kernel/reboot.c
index 5c33f036418be..36b6c61f3b129 100644
--- a/arch/sh/kernel/reboot.c
+++ b/arch/sh/kernel/reboot.c
@@ -83,6 +83,7 @@ void machine_restart(char *cmd)
{
machine_ops.restart(cmd);
}
+EXPORT_SYMBOL(machine_restart);

void machine_halt(void)
{
diff --git a/arch/sparc/kernel/process_32.c b/arch/sparc/kernel/process_32.c
index 3b9794978e5bc..30a1674683946 100644
--- a/arch/sparc/kernel/process_32.c
+++ b/arch/sparc/kernel/process_32.c
@@ -104,6 +104,7 @@ void machine_restart(char * cmd)
prom_feval ("reset");
panic("Reboot failed!");
}
+EXPORT_SYMBOL(machine_restart);

void machine_power_off(void)
{
diff --git a/arch/sparc/kernel/reboot.c b/arch/sparc/kernel/reboot.c
index 69c1b6c047d53..53adef425d7de 100644
--- a/arch/sparc/kernel/reboot.c
+++ b/arch/sparc/kernel/reboot.c
@@ -52,4 +52,5 @@ void machine_restart(char *cmd)
prom_reboot("");
panic("Reboot failed!");
}
+EXPORT_SYMBOL(machine_restart);

diff --git a/arch/um/kernel/reboot.c b/arch/um/kernel/reboot.c
index 48c0610d506e0..4b764311efb89 100644
--- a/arch/um/kernel/reboot.c
+++ b/arch/um/kernel/reboot.c
@@ -47,6 +47,7 @@ void machine_restart(char * __unused)
uml_cleanup();
reboot_skas();
}
+EXPORT_SYMBOL(machine_restart);

void machine_power_off(void)
{
diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index b29657b76e3fa..b48c30ead7167 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -733,6 +733,7 @@ static void native_machine_restart(char *__unused)
machine_shutdown();
__machine_emergency_restart(0);
}
+EXPORT_SYMBOL(machine_restart);

static void native_machine_halt(void)
{
diff --git a/arch/xtensa/kernel/setup.c b/arch/xtensa/kernel/setup.c
index ed184106e4cf9..a84cc934300d5 100644
--- a/arch/xtensa/kernel/setup.c
+++ b/arch/xtensa/kernel/setup.c
@@ -564,6 +564,7 @@ void machine_restart(char * cmd)
{
platform_restart();
}
+EXPORT_SYMBOL(machine_restart);

void machine_halt(void)
{
--
2.32.0.554.ge1b32706d8-goog


2021-08-03 15:57:47

by Lee Jones

[permalink] [raw]
Subject: [PATCH 3/3] power: reset: Enable tristate on restart power-off driver

From: Elliot Berman <[email protected]>

Since reboot_mode is an exported symbol, restart power-off driver can be
compiled as module.

Signed-off-by: Elliot Berman <[email protected]>
Signed-off-by: Lee Jones <[email protected]>
---
drivers/power/reset/Kconfig | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
index 4d1192062508d..e155b2e2a75c4 100644
--- a/drivers/power/reset/Kconfig
+++ b/drivers/power/reset/Kconfig
@@ -192,7 +192,7 @@ config POWER_RESET_REGULATOR
power regulator defined in the devicetree.

config POWER_RESET_RESTART
- bool "Restart power-off driver"
+ tristate "Restart power-off driver"
help
Some boards don't actually have the ability to power off.
Instead they restart, and u-boot holds the SoC until the
--
2.32.0.554.ge1b32706d8-goog


2021-08-03 16:16:46

by Sebastian Reichel

[permalink] [raw]
Subject: Re: [PATCH 3/3] power: reset: Enable tristate on restart power-off driver

Hi,

On Tue, Aug 03, 2021 at 04:54:52PM +0100, Lee Jones wrote:
> From: Elliot Berman <[email protected]>
>
> Since reboot_mode is an exported symbol, restart power-off driver can be
> compiled as module.
>
> Signed-off-by: Elliot Berman <[email protected]>
> Signed-off-by: Lee Jones <[email protected]>
> ---

Acked-by: Sebastian Reichel <[email protected]>

-- Sebastian

> drivers/power/reset/Kconfig | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
> index 4d1192062508d..e155b2e2a75c4 100644
> --- a/drivers/power/reset/Kconfig
> +++ b/drivers/power/reset/Kconfig
> @@ -192,7 +192,7 @@ config POWER_RESET_REGULATOR
> power regulator defined in the devicetree.
>
> config POWER_RESET_RESTART
> - bool "Restart power-off driver"
> + tristate "Restart power-off driver"
> help
> Some boards don't actually have the ability to power off.
> Instead they restart, and u-boot holds the SoC until the
> --
> 2.32.0.554.ge1b32706d8-goog
>


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2021-08-09 15:21:59

by Geert Uytterhoeven

[permalink] [raw]
Subject: Re: [PATCH 1/3] arch: Export machine_restart() instances so they can be called from modules

On Tue, Aug 3, 2021 at 5:56 PM Lee Jones <[email protected]> wrote:
> A recent attempt to convert the Power Reset Restart driver to tristate
> failed because of the following compile error (reported once merged by
> Stephen Rothwell via Linux Next):
>
> ERROR: "machine_restart" [drivers/power/reset/restart-poweroff.ko] undefined!
>
> This error occurs since some of the machine_restart() instances are
> not currently exported for use in modules. This patch aims to rectify
> that.
>
> Signed-off-by: Lee Jones <[email protected]>

> NB: If it's safe to omit some of these, let me know and I'll revise the patch.

How do you plan to handle that? Isn't this an all-or-nothing export?

> arch/m68k/kernel/process.c | 1 +

Acked-by: Geert Uytterhoeven <[email protected]>

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds

2021-08-10 09:35:11

by Lee Jones

[permalink] [raw]
Subject: Re: [PATCH 1/3] arch: Export machine_restart() instances so they can be called from modules

On Mon, 09 Aug 2021, Geert Uytterhoeven wrote:

> On Tue, Aug 3, 2021 at 5:56 PM Lee Jones <[email protected]> wrote:
> > A recent attempt to convert the Power Reset Restart driver to tristate
> > failed because of the following compile error (reported once merged by
> > Stephen Rothwell via Linux Next):
> >
> > ERROR: "machine_restart" [drivers/power/reset/restart-poweroff.ko] undefined!
> >
> > This error occurs since some of the machine_restart() instances are
> > not currently exported for use in modules. This patch aims to rectify
> > that.
> >
> > Signed-off-by: Lee Jones <[email protected]>
>
> > NB: If it's safe to omit some of these, let me know and I'll revise the patch.
>
> How do you plan to handle that? Isn't this an all-or-nothing export?

That's the way I see it, but I don't have an in-depth knowledge of all
of the architectures. There may be a method there that isn't part of
the core API. If that's the case, I can drop the export.

> > arch/m68k/kernel/process.c | 1 +
>
> Acked-by: Geert Uytterhoeven <[email protected]>

Thanks Geert.

I'll pick this up when I do the re-spin shortly.

--
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
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