* [PATCH v2] powerpc/fadump: return error when fadump registration fails
@ 2017-05-27 15:46 Michal Suchanek
2017-05-30 4:41 ` Mahesh Jagannath Salgaonkar
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: Michal Suchanek @ 2017-05-27 15:46 UTC (permalink / raw)
To: Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman,
Mahesh Salgaonkar, Hari Bathini, Andrew Morton, Michal Suchanek,
Colin Ian King, linuxppc-dev, linux-kernel
- log an error message when registration fails and no error code listed
in the switch is returned
- translate the hv error code to posix error code and return it from
fw_register
- return the posix error code from fw_register to the process writing
to sysfs
- return EEXIST on re-registration
- return success on deregistration when fadump is not registered
- return ENODEV when no memory is reserved for fadump
Signed-off-by: Michal Suchanek <msuchanek@suse.de>
---
v2: fix return in register_fadump()
---
arch/powerpc/kernel/fadump.c | 24 ++++++++++++++++--------
1 file changed, 16 insertions(+), 8 deletions(-)
diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
index 2fa582092d42..83421e0a774b 100644
--- a/arch/powerpc/kernel/fadump.c
+++ b/arch/powerpc/kernel/fadump.c
@@ -398,9 +398,9 @@ static int __init early_fadump_param(char *p)
}
early_param("fadump", early_fadump_param);
-static void register_fw_dump(struct fadump_mem_struct *fdm)
+static int register_fw_dump(struct fadump_mem_struct *fdm)
{
- int rc;
+ int rc, err;
unsigned int wait_time;
pr_debug("Registering for firmware-assisted kernel dump...\n");
@@ -417,7 +417,12 @@ static void register_fw_dump(struct fadump_mem_struct *fdm)
} while (wait_time);
+ err = -EIO;
switch (rc) {
+ default:
+ printk(KERN_ERR "Failed to register firmware-assisted kernel"
+ " dump. Unknown Error(%d).\n", rc);
+ break;
case -1:
printk(KERN_ERR "Failed to register firmware-assisted kernel"
" dump. Hardware Error(%d).\n", rc);
@@ -425,18 +430,22 @@ static void register_fw_dump(struct fadump_mem_struct *fdm)
case -3:
printk(KERN_ERR "Failed to register firmware-assisted kernel"
" dump. Parameter Error(%d).\n", rc);
+ err = -EINVAL;
break;
case -9:
printk(KERN_ERR "firmware-assisted kernel dump is already "
" registered.");
fw_dump.dump_registered = 1;
+ err = -EEXIST;
break;
case 0:
printk(KERN_INFO "firmware-assisted kernel dump registration"
" is successful\n");
fw_dump.dump_registered = 1;
+ err = 0;
break;
}
+ return err;
}
void crash_fadump(struct pt_regs *regs, const char *str)
@@ -977,7 +986,7 @@ static unsigned long init_fadump_header(unsigned long addr)
return addr;
}
-static void register_fadump(void)
+static int register_fadump(void)
{
unsigned long addr;
void *vaddr;
@@ -987,7 +996,7 @@ static void register_fadump(void)
* assisted dump.
*/
if (!fw_dump.reserve_dump_area_size)
- return;
+ return -ENODEV;
fadump_setup_crash_memory_ranges();
@@ -1000,7 +1009,7 @@ static void register_fadump(void)
fadump_create_elfcore_headers(vaddr);
/* register the future kernel dump with firmware. */
- register_fw_dump(&fdm);
+ return register_fw_dump(&fdm);
}
static int fadump_unregister_dump(struct fadump_mem_struct *fdm)
@@ -1182,7 +1191,6 @@ static ssize_t fadump_register_store(struct kobject *kobj,
switch (buf[0]) {
case '0':
if (fw_dump.dump_registered == 0) {
- ret = -EINVAL;
goto unlock_out;
}
/* Un-register Firmware-assisted dump */
@@ -1190,11 +1198,11 @@ static ssize_t fadump_register_store(struct kobject *kobj,
break;
case '1':
if (fw_dump.dump_registered == 1) {
- ret = -EINVAL;
+ ret = -EEXIST;
goto unlock_out;
}
/* Register Firmware-assisted dump */
- register_fadump();
+ ret = register_fadump();
break;
default:
ret = -EINVAL;
--
2.10.2
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH v2] powerpc/fadump: return error when fadump registration fails
2017-05-27 15:46 [PATCH v2] powerpc/fadump: return error when fadump registration fails Michal Suchanek
@ 2017-05-30 4:41 ` Mahesh Jagannath Salgaonkar
2017-05-30 10:45 ` Michael Ellerman
2017-06-01 10:00 ` Hari Bathini
2017-06-05 10:21 ` [v2] " Michael Ellerman
2 siblings, 1 reply; 5+ messages in thread
From: Mahesh Jagannath Salgaonkar @ 2017-05-30 4:41 UTC (permalink / raw)
To: Michal Suchanek, Benjamin Herrenschmidt, Paul Mackerras,
Michael Ellerman, Hari Bathini, Andrew Morton, Colin Ian King,
linuxppc-dev, linux-kernel
On 05/27/2017 09:16 PM, Michal Suchanek wrote:
> - log an error message when registration fails and no error code listed
> in the switch is returned
> - translate the hv error code to posix error code and return it from
> fw_register
> - return the posix error code from fw_register to the process writing
> to sysfs
> - return EEXIST on re-registration
> - return success on deregistration when fadump is not registered
> - return ENODEV when no memory is reserved for fadump
Why do we need this ? Userspace can always read back the fadump
registration status from /sys/kernel/fadump_registered (after echo 1 to
it) to find out whether fadump registration succeeded or not.
/sys/kernel/fadump_registered
This is used to display the fadump registration status as well
as to control (start/stop) the fadump registration.
0 = fadump is not registered.
1 = fadump is registered and ready to handle system crash.
-Mahesh.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2] powerpc/fadump: return error when fadump registration fails
2017-05-30 4:41 ` Mahesh Jagannath Salgaonkar
@ 2017-05-30 10:45 ` Michael Ellerman
0 siblings, 0 replies; 5+ messages in thread
From: Michael Ellerman @ 2017-05-30 10:45 UTC (permalink / raw)
To: Mahesh Jagannath Salgaonkar, Michal Suchanek,
Benjamin Herrenschmidt, Paul Mackerras, Hari Bathini,
Andrew Morton, Colin Ian King, linuxppc-dev, linux-kernel
Mahesh Jagannath Salgaonkar <mahesh@linux.vnet.ibm.com> writes:
> On 05/27/2017 09:16 PM, Michal Suchanek wrote:
>> - log an error message when registration fails and no error code listed
>> in the switch is returned
>> - translate the hv error code to posix error code and return it from
>> fw_register
>> - return the posix error code from fw_register to the process writing
>> to sysfs
>> - return EEXIST on re-registration
>> - return success on deregistration when fadump is not registered
>> - return ENODEV when no memory is reserved for fadump
>
> Why do we need this ?
Because that's how we do error handling.
> Userspace can always read back the fadump registration status from
> /sys/kernel/fadump_registered (after echo 1 to it) to find out
> whether fadump registration succeeded or not.
That's a terrible API.
If we followed that example, open() wouldn't return a value, you'd have
to do another syscall to check if it worked.
I'd appreciate if someone could test this and give me a Tested-by.
cheers
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2] powerpc/fadump: return error when fadump registration fails
2017-05-27 15:46 [PATCH v2] powerpc/fadump: return error when fadump registration fails Michal Suchanek
2017-05-30 4:41 ` Mahesh Jagannath Salgaonkar
@ 2017-06-01 10:00 ` Hari Bathini
2017-06-05 10:21 ` [v2] " Michael Ellerman
2 siblings, 0 replies; 5+ messages in thread
From: Hari Bathini @ 2017-06-01 10:00 UTC (permalink / raw)
To: Michal Suchanek, Benjamin Herrenschmidt, Paul Mackerras,
Michael Ellerman, Mahesh Salgaonkar, Andrew Morton,
Colin Ian King, linuxppc-dev, linux-kernel
On Saturday 27 May 2017 09:16 PM, Michal Suchanek wrote:
> - log an error message when registration fails and no error code listed
> in the switch is returned
> - translate the hv error code to posix error code and return it from
> fw_register
> - return the posix error code from fw_register to the process writing
> to sysfs
> - return EEXIST on re-registration
> - return success on deregistration when fadump is not registered
> - return ENODEV when no memory is reserved for fadump
>
> Signed-off-by: Michal Suchanek <msuchanek@suse.de>
With the below change write to /sys/kernel/fadump_registered returns
error appropriately.
Tested-by: Hari Bathini <hbathini@linux.vnet.ibm.com>
> ---
> v2: fix return in register_fadump()
> ---
> arch/powerpc/kernel/fadump.c | 24 ++++++++++++++++--------
> 1 file changed, 16 insertions(+), 8 deletions(-)
>
> diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
> index 2fa582092d42..83421e0a774b 100644
> --- a/arch/powerpc/kernel/fadump.c
> +++ b/arch/powerpc/kernel/fadump.c
> @@ -398,9 +398,9 @@ static int __init early_fadump_param(char *p)
> }
> early_param("fadump", early_fadump_param);
>
> -static void register_fw_dump(struct fadump_mem_struct *fdm)
> +static int register_fw_dump(struct fadump_mem_struct *fdm)
> {
> - int rc;
> + int rc, err;
> unsigned int wait_time;
>
> pr_debug("Registering for firmware-assisted kernel dump...\n");
> @@ -417,7 +417,12 @@ static void register_fw_dump(struct fadump_mem_struct *fdm)
>
> } while (wait_time);
>
> + err = -EIO;
> switch (rc) {
> + default:
> + printk(KERN_ERR "Failed to register firmware-assisted kernel"
> + " dump. Unknown Error(%d).\n", rc);
> + break;
> case -1:
> printk(KERN_ERR "Failed to register firmware-assisted kernel"
> " dump. Hardware Error(%d).\n", rc);
> @@ -425,18 +430,22 @@ static void register_fw_dump(struct fadump_mem_struct *fdm)
> case -3:
> printk(KERN_ERR "Failed to register firmware-assisted kernel"
> " dump. Parameter Error(%d).\n", rc);
> + err = -EINVAL;
> break;
> case -9:
> printk(KERN_ERR "firmware-assisted kernel dump is already "
> " registered.");
> fw_dump.dump_registered = 1;
> + err = -EEXIST;
> break;
> case 0:
> printk(KERN_INFO "firmware-assisted kernel dump registration"
> " is successful\n");
> fw_dump.dump_registered = 1;
> + err = 0;
> break;
> }
> + return err;
> }
>
> void crash_fadump(struct pt_regs *regs, const char *str)
> @@ -977,7 +986,7 @@ static unsigned long init_fadump_header(unsigned long addr)
> return addr;
> }
>
> -static void register_fadump(void)
> +static int register_fadump(void)
> {
> unsigned long addr;
> void *vaddr;
> @@ -987,7 +996,7 @@ static void register_fadump(void)
> * assisted dump.
> */
> if (!fw_dump.reserve_dump_area_size)
> - return;
> + return -ENODEV;
>
> fadump_setup_crash_memory_ranges();
>
> @@ -1000,7 +1009,7 @@ static void register_fadump(void)
> fadump_create_elfcore_headers(vaddr);
>
> /* register the future kernel dump with firmware. */
> - register_fw_dump(&fdm);
> + return register_fw_dump(&fdm);
> }
>
> static int fadump_unregister_dump(struct fadump_mem_struct *fdm)
> @@ -1182,7 +1191,6 @@ static ssize_t fadump_register_store(struct kobject *kobj,
> switch (buf[0]) {
> case '0':
> if (fw_dump.dump_registered == 0) {
> - ret = -EINVAL;
> goto unlock_out;
> }
> /* Un-register Firmware-assisted dump */
> @@ -1190,11 +1198,11 @@ static ssize_t fadump_register_store(struct kobject *kobj,
> break;
> case '1':
> if (fw_dump.dump_registered == 1) {
> - ret = -EINVAL;
> + ret = -EEXIST;
> goto unlock_out;
> }
> /* Register Firmware-assisted dump */
> - register_fadump();
> + ret = register_fadump();
> break;
> default:
> ret = -EINVAL;
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [v2] powerpc/fadump: return error when fadump registration fails
2017-05-27 15:46 [PATCH v2] powerpc/fadump: return error when fadump registration fails Michal Suchanek
2017-05-30 4:41 ` Mahesh Jagannath Salgaonkar
2017-06-01 10:00 ` Hari Bathini
@ 2017-06-05 10:21 ` Michael Ellerman
2 siblings, 0 replies; 5+ messages in thread
From: Michael Ellerman @ 2017-06-05 10:21 UTC (permalink / raw)
To: Michal Suchanek, Benjamin Herrenschmidt, Paul Mackerras,
Mahesh Salgaonkar, Hari Bathini, Andrew Morton, Michal Suchanek,
Colin Ian King, linuxppc-dev, linux-kernel
On Sat, 2017-05-27 at 15:46:15 UTC, Michal Suchanek wrote:
> - log an error message when registration fails and no error code listed
> in the switch is returned
> - translate the hv error code to posix error code and return it from
> fw_register
> - return the posix error code from fw_register to the process writing
> to sysfs
> - return EEXIST on re-registration
> - return success on deregistration when fadump is not registered
> - return ENODEV when no memory is reserved for fadump
>
> Signed-off-by: Michal Suchanek <msuchanek@suse.de>
Applied to powerpc next, thanks.
https://git.kernel.org/powerpc/c/98b8cd7f75643e0a442d7a4c1cef2c
cheers
^ permalink raw reply [flat|nested] 5+ messages in thread
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2017-05-27 15:46 [PATCH v2] powerpc/fadump: return error when fadump registration fails Michal Suchanek
2017-05-30 4:41 ` Mahesh Jagannath Salgaonkar
2017-05-30 10:45 ` Michael Ellerman
2017-06-01 10:00 ` Hari Bathini
2017-06-05 10:21 ` [v2] " Michael Ellerman
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