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

Tiejun Chen
2013-06-20T07:53:18Z

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

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);
--
1.7.9.5