Patchwork [v2,4/7] book3e/kexec/kdump: introduce a kexec kernel flag

login
register
mail settings
Submitter Tiejun Chen
Date June 20, 2013, 7:53 a.m.
Message ID <1371714797-7898-5-git-send-email-tiejun.chen@windriver.com>
Download mbox | patch
Permalink /patch/252782/
State Superseded
Headers show

Comments

Tiejun Chen - June 20, 2013, 7:53 a.m.
We need to introduce a flag to indicate we're already running
a kexec kernel then we can go proper path. For example, We
shouldn't access spin_table from the bootloader to up any secondary
cpu for kexec kernel, and kexec kernel already know how to jump to
generic_secondary_smp_init.

Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com>
---
 arch/powerpc/include/asm/smp.h    |    3 +++
 arch/powerpc/kernel/head_64.S     |   12 ++++++++++++
 arch/powerpc/kernel/misc_64.S     |    6 ++++++
 arch/powerpc/platforms/85xx/smp.c |   14 ++++++++++++++
 4 files changed, 35 insertions(+)
Bharat Bhushan - July 2, 2013, 5:37 a.m.
> -----Original Message-----
> From: Linuxppc-dev [mailto:linuxppc-dev-
> bounces+bharat.bhushan=freescale.com@lists.ozlabs.org] On Behalf Of Tiejun Chen
> Sent: Thursday, June 20, 2013 1:23 PM
> To: benh@kernel.crashing.org
> Cc: linuxppc-dev@lists.ozlabs.org; linux-kernel@vger.kernel.org
> Subject: [v2][PATCH 4/7] book3e/kexec/kdump: introduce a kexec kernel flag
> 
> We need to introduce a flag to indicate we're already running
> a kexec kernel then we can go proper path. For example, We
> shouldn't access spin_table from the bootloader to up any secondary
> cpu for kexec kernel, and kexec kernel already know how to jump to
> generic_secondary_smp_init.
> 
> Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com>
> ---
>  arch/powerpc/include/asm/smp.h    |    3 +++
>  arch/powerpc/kernel/head_64.S     |   12 ++++++++++++
>  arch/powerpc/kernel/misc_64.S     |    6 ++++++
>  arch/powerpc/platforms/85xx/smp.c |   14 ++++++++++++++
>  4 files changed, 35 insertions(+)
> 
> diff --git a/arch/powerpc/include/asm/smp.h b/arch/powerpc/include/asm/smp.h
> index ffbaabe..fbc3d9b 100644
> --- a/arch/powerpc/include/asm/smp.h
> +++ b/arch/powerpc/include/asm/smp.h
> @@ -200,6 +200,9 @@ extern void generic_secondary_thread_init(void);
>  extern unsigned long __secondary_hold_spinloop;
>  extern unsigned long __secondary_hold_acknowledge;
>  extern char __secondary_hold;
> +#if defined(CONFIG_KEXEC) || defined(CONFIG_CRASH_DUMP)
> +extern unsigned long __run_at_kexec;
> +#endif
> 
>  extern void __early_start(void);
>  #endif /* __ASSEMBLY__ */
> diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
> index 3e19ba2..ffa4b18 100644
> --- a/arch/powerpc/kernel/head_64.S
> +++ b/arch/powerpc/kernel/head_64.S
> @@ -89,6 +89,12 @@ __secondary_hold_spinloop:
>  __secondary_hold_acknowledge:
>  	.llong	0x0
> 
> +#if defined(CONFIG_KEXEC) || defined(CONFIG_CRASH_DUMP)
> +	.globl	__run_at_kexec
> +__run_at_kexec:
> +	.llong	0x0	/* Flag for the secondary kernel from kexec. */
> +#endif
> +
>  #ifdef CONFIG_RELOCATABLE
>  	/* This flag is set to 1 by a loader if the kernel should run
>  	 * at the loaded address instead of the linked address.  This
> @@ -417,6 +423,12 @@ _STATIC(__after_prom_start)
>  #if defined(CONFIG_PPC_BOOK3E)
>  	tovirt(r26,r26)			/* on booke, we already run at
> PAGE_OFFSET */
>  #endif
> +#if defined(CONFIG_KEXEC) || defined(CONFIG_CRASH_DUMP)
> +	/* If relocated we need to restore this flag on that relocated address. */
> +	ld	r7,__run_at_kexec-_stext(r26)
> +	std	r7,__run_at_kexec-_stext(r26)
> +#endif
> +
>  	lwz	r7,__run_at_load-_stext(r26)
>  #if defined(CONFIG_PPC_BOOK3E)
>  	tophys(r26,r26)			/* Restore for the remains. */
> diff --git a/arch/powerpc/kernel/misc_64.S b/arch/powerpc/kernel/misc_64.S
> index 20cbb98..c89aead 100644
> --- a/arch/powerpc/kernel/misc_64.S
> +++ b/arch/powerpc/kernel/misc_64.S
> @@ -619,6 +619,12 @@ _GLOBAL(kexec_sequence)
>  	bl	.copy_and_flush	/* (dest, src, copy limit, start offset) */
>  1:	/* assume normal blr return */
> 
> +	/* notify we're going into kexec kernel for SMP. */
> +	LOAD_REG_ADDR(r3,__run_at_kexec)
> +	li	r4,1
> +	std	r4,0(r3)
> +	sync
> +
>  	/* release other cpus to the new kernel secondary start at 0x60 */
>  	mflr	r5
>  	li	r6,1
> diff --git a/arch/powerpc/platforms/85xx/smp.c
> b/arch/powerpc/platforms/85xx/smp.c
> index 6a17599..b308373 100644
> --- a/arch/powerpc/platforms/85xx/smp.c
> +++ b/arch/powerpc/platforms/85xx/smp.c
> @@ -150,6 +150,9 @@ static int __cpuinit smp_85xx_kick_cpu(int nr)
>  	int hw_cpu = get_hard_smp_processor_id(nr);
>  	int ioremappable;
>  	int ret = 0;
> +#if defined(CONFIG_KEXEC) || defined(CONFIG_CRASH_DUMP)
> +	unsigned long *ptr;
> +#endif

What about if we can remove the ifdef around *ptr ...

> 
>  	WARN_ON(nr < 0 || nr >= NR_CPUS);
>  	WARN_ON(hw_cpu < 0 || hw_cpu >= NR_CPUS);
> @@ -238,11 +241,22 @@ out:
>  #else
>  	smp_generic_kick_cpu(nr);
> 
> +#if defined(CONFIG_KEXEC) || defined(CONFIG_CRASH_DUMP)
> +	ptr  = (unsigned long *)((unsigned long)&__run_at_kexec);

... #endif here ...

> +	/* We shouldn't access spin_table from the bootloader to up any
> +	 * secondary cpu for kexec kernel, and kexec kernel already
> +	 * know how to jump to generic_secondary_smp_init.
> +	 */
> +	if (!*ptr) {
> +#endif

... remove #endif ...

>  	flush_spin_table(spin_table);
>  	out_be32(&spin_table->pir, hw_cpu);
>  	out_be64((u64 *)(&spin_table->addr_h),
>  	  __pa((u64)*((unsigned long long *)generic_secondary_smp_init)));
>  	flush_spin_table(spin_table);
> +#if defined(CONFIG_KEXEC) || defined(CONFIG_CRASH_DUMP)
> +	}
> +#endif

--- remove above 3 lines

-Bharat

>  #endif
> 
>  	local_irq_restore(flags);
> --
> 1.7.9.5
> 
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@lists.ozlabs.org
> https://lists.ozlabs.org/listinfo/linuxppc-dev
Tiejun Chen - July 9, 2013, 7:51 a.m.
On 07/02/2013 01:37 PM, Bhushan Bharat-R65777 wrote:
>
>
>> -----Original Message-----
>> From: Linuxppc-dev [mailto:linuxppc-dev-
>> bounces+bharat.bhushan=freescale.com@lists.ozlabs.org] On Behalf Of Tiejun Chen
>> Sent: Thursday, June 20, 2013 1:23 PM
>> To: benh@kernel.crashing.org
>> Cc: linuxppc-dev@lists.ozlabs.org; linux-kernel@vger.kernel.org
>> Subject: [v2][PATCH 4/7] book3e/kexec/kdump: introduce a kexec kernel flag
>>
>> We need to introduce a flag to indicate we're already running
>> a kexec kernel then we can go proper path. For example, We
>> shouldn't access spin_table from the bootloader to up any secondary
>> cpu for kexec kernel, and kexec kernel already know how to jump to
>> generic_secondary_smp_init.
>>
>> Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com>
>> ---

[snip]

>> +++ b/arch/powerpc/platforms/85xx/smp.c
>> @@ -150,6 +150,9 @@ static int __cpuinit smp_85xx_kick_cpu(int nr)
>>   	int hw_cpu = get_hard_smp_processor_id(nr);
>>   	int ioremappable;
>>   	int ret = 0;
>> +#if defined(CONFIG_KEXEC) || defined(CONFIG_CRASH_DUMP)
>> +	unsigned long *ptr;
>> +#endif
>
> What about if we can remove the ifdef around *ptr ...
>
>>
>>   	WARN_ON(nr < 0 || nr >= NR_CPUS);
>>   	WARN_ON(hw_cpu < 0 || hw_cpu >= NR_CPUS);
>> @@ -238,11 +241,22 @@ out:
>>   #else
>>   	smp_generic_kick_cpu(nr);
>>
>> +#if defined(CONFIG_KEXEC) || defined(CONFIG_CRASH_DUMP)
>> +	ptr  = (unsigned long *)((unsigned long)&__run_at_kexec);
>
> ... #endif here ...
>
>> +	/* We shouldn't access spin_table from the bootloader to up any
>> +	 * secondary cpu for kexec kernel, and kexec kernel already
>> +	 * know how to jump to generic_secondary_smp_init.
>> +	 */
>> +	if (!*ptr) {
>> +#endif
>
> ... remove #endif ...
>
>>   	flush_spin_table(spin_table);
>>   	out_be32(&spin_table->pir, hw_cpu);
>>   	out_be64((u64 *)(&spin_table->addr_h),
>>   	  __pa((u64)*((unsigned long long *)generic_secondary_smp_init)));
>>   	flush_spin_table(spin_table);
>> +#if defined(CONFIG_KEXEC) || defined(CONFIG_CRASH_DUMP)
>> +	}
>> +#endif
>
> --- remove above 3 lines

I'd like to try to address your comments next version.

Thanks

Tiejun

Patch

diff --git a/arch/powerpc/include/asm/smp.h b/arch/powerpc/include/asm/smp.h
index ffbaabe..fbc3d9b 100644
--- a/arch/powerpc/include/asm/smp.h
+++ b/arch/powerpc/include/asm/smp.h
@@ -200,6 +200,9 @@  extern void generic_secondary_thread_init(void);
 extern unsigned long __secondary_hold_spinloop;
 extern unsigned long __secondary_hold_acknowledge;
 extern char __secondary_hold;
+#if defined(CONFIG_KEXEC) || defined(CONFIG_CRASH_DUMP)
+extern unsigned long __run_at_kexec;
+#endif
 
 extern void __early_start(void);
 #endif /* __ASSEMBLY__ */
diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
index 3e19ba2..ffa4b18 100644
--- a/arch/powerpc/kernel/head_64.S
+++ b/arch/powerpc/kernel/head_64.S
@@ -89,6 +89,12 @@  __secondary_hold_spinloop:
 __secondary_hold_acknowledge:
 	.llong	0x0
 
+#if defined(CONFIG_KEXEC) || defined(CONFIG_CRASH_DUMP)
+	.globl	__run_at_kexec
+__run_at_kexec:
+	.llong	0x0	/* Flag for the secondary kernel from kexec. */
+#endif
+
 #ifdef CONFIG_RELOCATABLE
 	/* This flag is set to 1 by a loader if the kernel should run
 	 * at the loaded address instead of the linked address.  This
@@ -417,6 +423,12 @@  _STATIC(__after_prom_start)
 #if defined(CONFIG_PPC_BOOK3E)
 	tovirt(r26,r26)			/* on booke, we already run at PAGE_OFFSET */
 #endif
+#if defined(CONFIG_KEXEC) || defined(CONFIG_CRASH_DUMP)
+	/* If relocated we need to restore this flag on that relocated address. */
+	ld	r7,__run_at_kexec-_stext(r26)
+	std	r7,__run_at_kexec-_stext(r26)
+#endif
+
 	lwz	r7,__run_at_load-_stext(r26)
 #if defined(CONFIG_PPC_BOOK3E)
 	tophys(r26,r26)			/* Restore for the remains. */
diff --git a/arch/powerpc/kernel/misc_64.S b/arch/powerpc/kernel/misc_64.S
index 20cbb98..c89aead 100644
--- a/arch/powerpc/kernel/misc_64.S
+++ b/arch/powerpc/kernel/misc_64.S
@@ -619,6 +619,12 @@  _GLOBAL(kexec_sequence)
 	bl	.copy_and_flush	/* (dest, src, copy limit, start offset) */
 1:	/* assume normal blr return */
 
+	/* notify we're going into kexec kernel for SMP. */
+	LOAD_REG_ADDR(r3,__run_at_kexec)
+	li	r4,1
+	std	r4,0(r3)
+	sync
+
 	/* release other cpus to the new kernel secondary start at 0x60 */
 	mflr	r5
 	li	r6,1
diff --git a/arch/powerpc/platforms/85xx/smp.c b/arch/powerpc/platforms/85xx/smp.c
index 6a17599..b308373 100644
--- a/arch/powerpc/platforms/85xx/smp.c
+++ b/arch/powerpc/platforms/85xx/smp.c
@@ -150,6 +150,9 @@  static int __cpuinit smp_85xx_kick_cpu(int nr)
 	int hw_cpu = get_hard_smp_processor_id(nr);
 	int ioremappable;
 	int ret = 0;
+#if defined(CONFIG_KEXEC) || defined(CONFIG_CRASH_DUMP)
+	unsigned long *ptr;
+#endif
 
 	WARN_ON(nr < 0 || nr >= NR_CPUS);
 	WARN_ON(hw_cpu < 0 || hw_cpu >= NR_CPUS);
@@ -238,11 +241,22 @@  out:
 #else
 	smp_generic_kick_cpu(nr);
 
+#if defined(CONFIG_KEXEC) || defined(CONFIG_CRASH_DUMP)
+	ptr  = (unsigned long *)((unsigned long)&__run_at_kexec);
+	/* We shouldn't access spin_table from the bootloader to up any
+	 * secondary cpu for kexec kernel, and kexec kernel already
+	 * know how to jump to generic_secondary_smp_init.
+	 */
+	if (!*ptr) {
+#endif
 	flush_spin_table(spin_table);
 	out_be32(&spin_table->pir, hw_cpu);
 	out_be64((u64 *)(&spin_table->addr_h),
 	  __pa((u64)*((unsigned long long *)generic_secondary_smp_init)));
 	flush_spin_table(spin_table);
+#if defined(CONFIG_KEXEC) || defined(CONFIG_CRASH_DUMP)
+	}
+#endif
 #endif
 
 	local_irq_restore(flags);