The main principle of this patch,is to get slave cpus polling for flag
to change,
thus waiting for master cpu to set it with non-zero cpu number(see misc_32.S).
This flag is placed in kexec control page,so it would not be
overlapped when copying kimage.
The master cpu put flag's physical address in r28 as a parameter
passed to second kernel,
so the latter knows how to wake slave cpus up in smp_85xx_kick_cpu.
The pseudo-code may be like:
void slave_cpu_spin(void)
{
int cpu = smp_processor_id();
while (*kexec_poll != cpu)
;
/*slave wakeup and jump*/
jump(*(kexec_poll+1));
}
void master_cpu_wakeup(unsigned long *kexec_poll, int cpu)
{
*(kexec_poll+1) = __early_start;
mb();
*kexec_poll = cpu;
}
However,after applied this patch,we got some kernel exception during
booting second kernel,
I'm not sure if it's caused by improper treament of cache,or tlb,or
other.So I put this
patch here hoping someone can check and review it.
Signed-off-by: Yu Chen <chenyu...@gmail.com>
---
arch/powerpc/kernel/head_fsl_booke.S | 7 ++
arch/powerpc/kernel/misc_32.S | 66 +++++++++++++-
arch/powerpc/platforms/85xx/smp.c | 166 ++++++++++++++++++++++++++++++----
3 files changed, 222 insertions(+), 17 deletions(-)
mode change 100644 => 100755 arch/powerpc/kernel/head_fsl_booke.S
mode change 100644 => 100755 arch/powerpc/kernel/misc_32.S
mode change 100644 => 100755 arch/powerpc/platforms/85xx/smp.c
diff --git a/arch/powerpc/kernel/head_fsl_booke.S
b/arch/powerpc/kernel/head_fsl_booke.S
old mode 100644
new mode 100755
index d10a7ca..63c8392
--- a/arch/powerpc/kernel/head_fsl_booke.S
+++ b/arch/powerpc/kernel/head_fsl_booke.S
@@ -178,6 +178,13 @@ _ENTRY(__early_start)
* This is where the main kernel code starts.
*/
+#if defined(CONFIG_KEXEC) && defined(CONFIG_SMP)
+ /* r28 contain position where slave cpus spin*/
+ lis r1,kexec_poll_phy@h
+ ori r1,r1,kexec_poll_phy@l
+ stw r28,0(r1)
+#endif
+
/* ptr to current */
lis r2,init_task@h
ori r2,r2,init_task@l
diff --git a/arch/powerpc/kernel/misc_32.S b/arch/powerpc/kernel/misc_32.S
old mode 100644
new mode 100755
index e469f30..d9eefc2
--- a/arch/powerpc/kernel/misc_32.S
+++ b/arch/powerpc/kernel/misc_32.S
@@ -120,7 +120,7 @@ _GLOBAL(reloc_got2)
addi r4,r4,1b@l
subf r0,r4,r0
add r7,r0,r7
-2: lwz r0,0(r7)
+ 2: lwz r0,0(r7)
add r0,r0,r3
stw r0,0(r7)
addi r7,r7,4
@@ -692,6 +692,7 @@ _GLOBAL(__main)
blr
#ifdef CONFIG_KEXEC
+#define KEXEC_MAGIC 0xdeadbeef
/*
* Must be relocatable PIC code callable as a C function.
*/
@@ -707,6 +708,16 @@ relocate_new_kernel:
mr r30, r4
mr r31, r5
+#ifdef CONFIG_SMP
+ bl 1f
+1: mflr r8
+ addi r8,r8,kexec_flag-1b
+ lis r7,PAGE_OFFSET@h
+ ori r7,r7,PAGE_OFFSET@l
+ /*r28 contain slave cpu spin physical address */
+ subf r28, r7, r8
+#endif
+
#define ENTRY_MAPPING_KEXEC_SETUP
#include "fsl_booke_entry_mapping.S"
#undef ENTRY_MAPPING_KEXEC_SETUP
@@ -1172,4 +1183,57 @@ relocate_new_kernel_end:
.globl relocate_new_kernel_size
relocate_new_kernel_size:
.long relocate_new_kernel_end - relocate_new_kernel
+#ifdef CONFIG_FSL_BOOKE
+ /**
+ * Slave cpus wait for kexec_flag to change
+ */
+ .globl relocate_smp_cpu_offset
+relocate_smp_cpu_offset:
+ .long relocate_smp_cpu_wait-relocate_new_kernel
+
+ .globl relocate_smp_cpu_wait
+relocate_smp_cpu_wait:
+
+ bl 1f
+1: mflr r5
+ addi r5,r5,kexec_flag-1b
+ /*see if anyone calls me?*/
+ mfspr r24,SPRN_PIR
+99: lwz r4,4(r5)
+ cmpw r4,r24
+ msync
+ bne 99b
+
+ msync
+ /*r4 contains jump address*/
+ lwz r4,8(r5)
+ msync
+ lis r5,MSR_KERNEL@h
+ ori r5,r5,MSR_KERNEL@l
+ msync
+ isync
+ mtspr SPRN_SRR1, r5
+ mtspr SPRN_SRR0, r4
+ msync
+ isync
+ rfi
+ isync
+1: b 1b
+
+ /**
+ * kexec_flag indicates a kexec magic
+ * kexec_flag+4 bytes supposed to be set with cpu number
+ * kexec_flag+8 countain addr for slave cpu to jump into
+ */
+ .globl kexec_flag
+kexec_flag:
+ .long KEXEC_MAGIC
+ .long 0
+ .long 0
+relocate_smp_cpu_wait_end:
+ .globl relocate_smp_cpu_size
+relocate_smp_cpu_size:
+ .long relocate_smp_cpu_wait_end-relocate_smp_cpu_wait
+#endif
+
#endif
diff --git a/arch/powerpc/platforms/85xx/smp.c
b/arch/powerpc/platforms/85xx/smp.c
old mode 100644
new mode 100755
index 5ced4f5..c4f5c4c
--- a/arch/powerpc/platforms/85xx/smp.c
+++ b/arch/powerpc/platforms/85xx/smp.c
@@ -140,6 +140,70 @@ static inline u32 read_spin_table_addr_l(void *spin_table)
(ulong)spin_table + sizeof(struct epapr_spin_table));
return in_be32(&((struct epapr_spin_table *)spin_table)->addr_l);
}
+#ifdef CONFIG_KEXEC
+
+#define KEXEC_MAGIC 0xdeadbeef
+#define KEXEC_RESERVE_LIMIT 0x10
+unsigned long kexec_poll_phy;
+extern void reserve_kexec_bootmem(unsigned long poll_phy, int size);
+
+/*
+ * Reserved bootmem for slave cpus kexec spin area.
+ */
+void mpc85xx_smp_reserve_kexec(void)
+{
+ unsigned long kexec_poll_virt;
+ unsigned long *kexec_magic_virt;
+
+ if (!kexec_poll_phy ||
+ kexec_poll_phy >= __max_low_memory)
+ return;
+
+ kexec_poll_virt = (unsigned long)phys_to_virt(kexec_poll_phy);
+ kexec_magic_virt = (unsigned long *)kexec_poll_virt;
+
+ if (*kexec_magic_virt == KEXEC_MAGIC)
+ reserve_kexec_bootmem(kexec_poll_phy, KEXEC_RESERVE_LIMIT);
+}
+
+/*
+ * Kick slave cpus from kexec spin area.
+ */
+int mpc85xx_smp_kick_kexec_cpus(int nr)
+{
+ unsigned long kexec_poll_virt;
+ unsigned long *kexec_flag_virt;
+ unsigned long *kexec_magic_virt;
+ unsigned long *kexec_jump_virt;
+
+ /*verify accessible*/
+ if (!kexec_poll_phy ||
+ kexec_poll_phy >= __max_low_memory)
+ return -EBUSY;
+
+ kexec_poll_virt = (unsigned long)phys_to_virt(kexec_poll_phy);
+
+ kexec_magic_virt = (unsigned long *)kexec_poll_virt;
+ kexec_flag_virt = (unsigned long *)kexec_poll_virt + 1;
+ kexec_jump_virt = (unsigned long *)kexec_poll_virt + 2;
+
+ /*verify a valid kexec kick*/
+ if (*kexec_magic_virt == KEXEC_MAGIC) {
+ flush_dcache_range((ulong)kexec_poll_virt,
+ (ulong)kexec_poll_virt + L1_CACHE_BYTES-1);
+ *kexec_jump_virt = (unsigned long)__early_start;
+ mb();
+ /*kick cpu[nr] up*/
+ *kexec_flag_virt = nr;
+ mb();
+ flush_dcache_range((ulong)kexec_poll_virt,
+ (ulong)kexec_poll_virt + L1_CACHE_BYTES-1);
+
+ return 0;
+ }
+ return -EBUSY;
+}
+#endif
static int smp_85xx_kick_cpu(int nr)
{
@@ -181,6 +245,10 @@ static int smp_85xx_kick_cpu(int nr)
local_irq_save(flags);
#ifdef CONFIG_PPC32
+#ifdef CONFIG_KEXEC
+ if (!mpc85xx_smp_kick_kexec_cpus(nr))
+ goto kexec_kick_done;
+#endif
#ifdef CONFIG_HOTPLUG_CPU
/* Corresponding to generic_set_cpu_dead() */
generic_set_cpu_up(nr);
@@ -225,7 +293,9 @@ static int smp_85xx_kick_cpu(int nr)
out_be32(&spin_table->pir, hw_cpu);
out_be32(&spin_table->addr_l, __pa(__early_start));
flush_spin_table(spin_table);
-
+#ifdef CONFIG_KEXEC
+kexec_kick_done:
+#endif
/* Wait a bit for the CPU to ack. */
if (!spin_event_timeout(__secondary_hold_acknowledge == hw_cpu,
10000, 100)) {
@@ -266,7 +336,13 @@ struct smp_ops_t smp_85xx_ops = {
};
#ifdef CONFIG_KEXEC
+
atomic_t kexec_down_cpus = ATOMIC_INIT(0);
+atomic_t kexec_ready_to_reboot = ATOMIC_INIT(0);
+atomic_t kexec_slave_finish = ATOMIC_INIT(0);
+unsigned long wait_code_buffer;
+static struct kimage *save_image;
+extern const unsigned int relocate_smp_cpu_size;
void mpc85xx_smp_kexec_cpu_down(int crash_shutdown, int secondary)
{
@@ -274,8 +350,29 @@ void mpc85xx_smp_kexec_cpu_down(int
crash_shutdown, int secondary)
if (secondary) {
atomic_inc(&kexec_down_cpus);
- /* loop forever */
- while (1);
+ mb();
+
+ if (crash_shutdown) {
+ /* loop forever */
+ while (1)
+ ;
+ } else {
+ while (!atomic_read(&kexec_ready_to_reboot))
+ cpu_relax();
+ /*flush destination*/
+ if (save_image)
+ mpc85xx_smp_flush_dcache_kexec(save_image, 1);
+
+ flush_icache_range(wait_code_buffer,
+ wait_code_buffer + relocate_smp_cpu_size);
+ flush_dcache_range(wait_code_buffer,
+ wait_code_buffer + relocate_smp_cpu_size);
+
+ atomic_inc(&kexec_slave_finish);
+
+ ((void (*)(void)) wait_code_buffer)();
+ /* NOTREACHED */
+ }
}
}
@@ -285,13 +382,23 @@ static void mpc85xx_smp_kexec_down(void *arg)
ppc_md.kexec_cpu_down(0,1);
}
-static void map_and_flush(unsigned long paddr)
+static void map_and_flush(unsigned long paddr, int atomic)
{
struct page *page = pfn_to_page(paddr >> PAGE_SHIFT);
- unsigned long kaddr = (unsigned long)kmap(page);
+ unsigned long kaddr;
+
+ if (atomic)
+ kaddr = (unsigned long)kmap_atomic(page);
+ else
+ kaddr = (unsigned long)kmap(page);
flush_dcache_range(kaddr, kaddr + PAGE_SIZE);
- kunmap(page);
+ flush_icache_range(kaddr, kaddr + PAGE_SIZE);
+
+ if (atomic)
+ kunmap_atomic((void *)kaddr);
+ else
+ kunmap(page);
}
/**
@@ -300,7 +407,7 @@ static void map_and_flush(unsigned long paddr)
* are performed out of an overabundance of caution as interrupts are not
* disabled yet and we can switch cores
*/
-static void mpc85xx_smp_flush_dcache_kexec(struct kimage *image)
+static void mpc85xx_smp_flush_dcache_kexec(struct kimage *image, int atomic)
{
kimage_entry_t *ptr, entry;
unsigned long paddr;
@@ -312,18 +419,18 @@ static void
mpc85xx_smp_flush_dcache_kexec(struct kimage *image)
ptr = (entry & IND_INDIRECTION) ?
phys_to_virt(entry & PAGE_MASK) : ptr + 1) {
if (!(entry & IND_DESTINATION)) {
- map_and_flush(entry);
+ map_and_flush(entry, atomic);
}
}
/* flush out last IND_DONE page */
- map_and_flush(entry);
+ map_and_flush(entry, atomic);
} else {
/* crash type kexec images are copied to the crash region */
for (i = 0; i < image->nr_segments; i++) {
struct kexec_segment *seg = &image->segment[i];
for (paddr = seg->mem; paddr < seg->mem + seg->memsz;
paddr += PAGE_SIZE) {
- map_and_flush(paddr);
+ map_and_flush(paddr, atomic);
}
}
}
@@ -335,13 +442,18 @@ static void
mpc85xx_smp_flush_dcache_kexec(struct kimage *image)
static void mpc85xx_smp_machine_kexec(struct kimage *image)
{
+ extern const unsigned char relocate_smp_cpu_wait[];
+ extern const unsigned int relocate_smp_cpu_offset;
int timeout = INT_MAX;
int i, num_cpus = num_present_cpus();
mpc85xx_smp_flush_dcache_kexec(image);
- if (image->type == KEXEC_TYPE_DEFAULT)
+ if (image->type == KEXEC_TYPE_DEFAULT) {
+ save_image = image;
+ mb();
smp_call_function(mpc85xx_smp_kexec_down, NULL, 0);
+ }
while ( (atomic_read(&kexec_down_cpus) != (num_cpus - 1)) &&
( timeout > 0 ) )
@@ -352,12 +464,34 @@ static void mpc85xx_smp_machine_kexec(struct
kimage *image)
if ( !timeout )
printk(KERN_ERR "Unable to bring down secondary cpu(s)");
- for_each_online_cpu(i)
- {
- if ( i == smp_processor_id() ) continue;
- mpic_reset_core(i);
- }
+ if (image->type == KEXEC_TYPE_DEFAULT) {
+ wait_code_buffer =
+ (unsigned long)page_address(image->control_code_page)+
+ relocate_smp_cpu_offset;
+
+ /* copy slave cpu spin code to the control code page */
+ memcpy((void *)wait_code_buffer, relocate_smp_cpu_wait,
+ relocate_smp_cpu_size);
+ atomic_set(&kexec_ready_to_reboot, 1);
+ mb();
+ timeout = INT_MAX;
+
+ while ((atomic_read(&kexec_slave_finish) != (num_cpus-1)) &&
+ (timeout > 0))
+ timeout--;
+
+ if (!timeout)
+ printk(KERN_ERR "Unable to wait for secondary cpu(s) to
flush caches\n");
+
+ } else {
+ for_each_online_cpu(i)
+ {
+ if (i == smp_processor_id())
+ continue;
+ mpic_reset_core(i);
+ }
+ }
default_machine_kexec(image);
}
#endif /* CONFIG_KEXEC */
