[PATCH] kdump ppc64: fix htab-size for non-lpar

[Michael Ellerman]

On Fri, 17 Feb 2006 01:26, Olof Johansson wrote:
> On Thu, Feb 16, 2006 at 07:45:06PM +0530, R Sharada wrote:
> > Hello,
> > 	The htab-size calculated for kexec/kdump on 2.6 kernels was broken,
> > leading to wrong value being exported to /proc/device-tree
> > Here is a patch fixing it up.
>
> Why you don't use htab_hash_mask in kexec instead of introducing a
> global variable?

Separation of concerns? We currently do the calculation in the kexec code, but 
that's gotten out of sync with the htab code, so just do it in one place and 
export it.

> Saves a new global and a bunch of #ifdefs.

I agree the patch could be a bit simpler, eg (totally untested):

Index: to-merge/arch/powerpc/kernel/machine_kexec_64.c
===================================================================
--- to-merge.orig/arch/powerpc/kernel/machine_kexec_64.c
+++ to-merge/arch/powerpc/kernel/machine_kexec_64.c
@@ -26,8 +26,6 @@
 #include <asm/prom.h>
 #include <asm/smp.h>
 
-#define HASH_GROUP_SIZE 0x80	/* size of each hash group, asm/mmu.h */
-
 int default_machine_kexec_prepare(struct kimage *image)
 {
 	int i;
@@ -61,7 +59,7 @@ int default_machine_kexec_prepare(struct
 	 */
 	if (htab_address) {
 		low = __pa(htab_address);
-		high = low + (htab_hash_mask + 1) * HASH_GROUP_SIZE;
+		high = low + htab_size_bytes;
 
 		for (i = 0; i < image->nr_segments; i++) {
 			begin = image->segment[i].mem;
@@ -294,7 +292,7 @@ void default_machine_kexec(struct kimage
 }
 
 /* Values we need to export to the second kernel via the device tree. */
-static unsigned long htab_base, htab_size, kernel_end;
+static unsigned long htab_base, kernel_end;
 
 static struct property htab_base_prop = {
 	.name = "linux,htab-base",
@@ -305,7 +303,7 @@ static struct property htab_base_prop = 
 static struct property htab_size_prop = {
 	.name = "linux,htab-size",
 	.length = sizeof(unsigned long),
-	.value = (unsigned char *)&htab_size,
+	.value = (unsigned char *)&htab_size_bytes,
 };
 
 static struct property kernel_end_prop = {
@@ -331,8 +329,6 @@ static void __init export_htab_values(vo
 
 	htab_base = __pa(htab_address);
 	prom_add_property(node, &htab_base_prop);
-
-	htab_size = 1UL << ppc64_pft_size;
 	prom_add_property(node, &htab_size_prop);
 
  out:
Index: to-merge/arch/powerpc/mm/hash_utils_64.c
===================================================================
--- to-merge.orig/arch/powerpc/mm/hash_utils_64.c
+++ to-merge/arch/powerpc/mm/hash_utils_64.c
@@ -88,6 +88,7 @@ static unsigned long _SDR1;
 struct mmu_psize_def mmu_psize_defs[MMU_PAGE_COUNT];
 
 hpte_t *htab_address;
+unsigned long htab_size_bytes;
 unsigned long htab_hash_mask;
 int mmu_linear_psize = MMU_PAGE_4K;
 int mmu_virtual_psize = MMU_PAGE_4K;
@@ -399,7 +400,7 @@ void create_section_mapping(unsigned lon
 
 void __init htab_initialize(void)
 {
-	unsigned long table, htab_size_bytes;
+	unsigned long table;
 	unsigned long pteg_count;
 	unsigned long mode_rw;
 	unsigned long base = 0, size = 0;
Index: to-merge/include/asm-powerpc/mmu.h
===================================================================
--- to-merge.orig/include/asm-powerpc/mmu.h
+++ to-merge/include/asm-powerpc/mmu.h
@@ -112,6 +112,7 @@ typedef struct {
 } hpte_t;
 
 extern hpte_t *htab_address;
+extern unsigned long htab_size_bytes;
 extern unsigned long htab_hash_mask;
 
 /*
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