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authorMohan Kumar M <mohan@in.ibm.com>2008-10-21 17:38:10 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2008-10-22 15:01:22 +1100
commit54622f10a6aabb8bb2bdacf3dd070046f03dc246 (patch)
tree73eb5ad4eeb7174b8c0ae1904bbe80602c5e295d /arch/powerpc/kernel/iommu.c
parent4792adbac9eb41cea77a45ab76258ea10d411173 (diff)
powerpc: Support for relocatable kdump kernel
This adds relocatable kernel support for kdump. With this one can use the same regular kernel to capture the kdump. A signature (0xfeed1234) is passed in r6 from panic code to the next kernel through kexec_sequence and purgatory code. The signature is used to differentiate between kdump kernel and non-kdump kernels. The purgatory code compares the signature and sets the __kdump_flag in head_64.S. During the boot up, kernel code checks __kdump_flag and if it is set, the kernel will behave as relocatable kdump kernel. This kernel will boot at the address where it was loaded by kexec-tools ie. at the address reserved through crashkernel boot parameter. CONFIG_CRASH_DUMP depends on CONFIG_RELOCATABLE option to build kdump kernel as relocatable. So the same kernel can be used as production and kdump kernel. This patch incorporates the changes suggested by Paul Mackerras to avoid GOT use and to avoid two copies of the code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Mohan Kumar M <mohan@in.ibm.com> Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/kernel/iommu.c')
-rw-r--r--arch/powerpc/kernel/iommu.c69
1 files changed, 37 insertions, 32 deletions
diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index ea1ba89f9c9..3857d7e2af0 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -458,6 +458,42 @@ void iommu_unmap_sg(struct iommu_table *tbl, struct scatterlist *sglist,
spin_unlock_irqrestore(&(tbl->it_lock), flags);
}
+static void iommu_table_clear(struct iommu_table *tbl)
+{
+ if (!__kdump_flag) {
+ /* Clear the table in case firmware left allocations in it */
+ ppc_md.tce_free(tbl, tbl->it_offset, tbl->it_size);
+ return;
+ }
+
+#ifdef CONFIG_CRASH_DUMP
+ if (ppc_md.tce_get) {
+ unsigned long index, tceval, tcecount = 0;
+
+ /* Reserve the existing mappings left by the first kernel. */
+ for (index = 0; index < tbl->it_size; index++) {
+ tceval = ppc_md.tce_get(tbl, index + tbl->it_offset);
+ /*
+ * Freed TCE entry contains 0x7fffffffffffffff on JS20
+ */
+ if (tceval && (tceval != 0x7fffffffffffffffUL)) {
+ __set_bit(index, tbl->it_map);
+ tcecount++;
+ }
+ }
+
+ if ((tbl->it_size - tcecount) < KDUMP_MIN_TCE_ENTRIES) {
+ printk(KERN_WARNING "TCE table is full; freeing ");
+ printk(KERN_WARNING "%d entries for the kdump boot\n",
+ KDUMP_MIN_TCE_ENTRIES);
+ for (index = tbl->it_size - KDUMP_MIN_TCE_ENTRIES;
+ index < tbl->it_size; index++)
+ __clear_bit(index, tbl->it_map);
+ }
+ }
+#endif
+}
+
/*
* Build a iommu_table structure. This contains a bit map which
* is used to manage allocation of the tce space.
@@ -484,38 +520,7 @@ struct iommu_table *iommu_init_table(struct iommu_table *tbl, int nid)
tbl->it_largehint = tbl->it_halfpoint;
spin_lock_init(&tbl->it_lock);
-#ifdef CONFIG_CRASH_DUMP
- if (ppc_md.tce_get) {
- unsigned long index;
- unsigned long tceval;
- unsigned long tcecount = 0;
-
- /*
- * Reserve the existing mappings left by the first kernel.
- */
- for (index = 0; index < tbl->it_size; index++) {
- tceval = ppc_md.tce_get(tbl, index + tbl->it_offset);
- /*
- * Freed TCE entry contains 0x7fffffffffffffff on JS20
- */
- if (tceval && (tceval != 0x7fffffffffffffffUL)) {
- __set_bit(index, tbl->it_map);
- tcecount++;
- }
- }
- if ((tbl->it_size - tcecount) < KDUMP_MIN_TCE_ENTRIES) {
- printk(KERN_WARNING "TCE table is full; ");
- printk(KERN_WARNING "freeing %d entries for the kdump boot\n",
- KDUMP_MIN_TCE_ENTRIES);
- for (index = tbl->it_size - KDUMP_MIN_TCE_ENTRIES;
- index < tbl->it_size; index++)
- __clear_bit(index, tbl->it_map);
- }
- }
-#else
- /* Clear the hardware table in case firmware left allocations in it */
- ppc_md.tce_free(tbl, tbl->it_offset, tbl->it_size);
-#endif
+ iommu_table_clear(tbl);
if (!welcomed) {
printk(KERN_INFO "IOMMU table initialized, virtual merging %s\n",