[POWERPC] Add code for removing HPTEs for parts of the linear mapping

For memory remove, we need to clean up htab mappings for the
section of the memory we are removing.

This implements support for removing htab bolted mappings for pSeries
logical partitions.  Other sub-archs may need to implement similar
functionality for hotplug memory remove to work on them.

Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 23 insertions, 0 deletions

diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 73b78486abf..4cc53f92377 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -192,6 +192,24 @@ int htab_bolt_mapping(unsigned long vstart, unsigned long vend,
 	return ret < 0 ? ret : 0;
 }
 
+static void htab_remove_mapping(unsigned long vstart, unsigned long vend,
+		      int psize, int ssize)
+{
+	unsigned long vaddr;
+	unsigned int step, shift;
+
+	shift = mmu_psize_defs[psize].shift;
+	step = 1 << shift;
+
+	if (!ppc_md.hpte_removebolted) {
+		printk("Sub-arch doesn't implement hpte_removebolted\n");
+		return;
+	}
+
+	for (vaddr = vstart; vaddr < vend; vaddr += step)
+		ppc_md.hpte_removebolted(vaddr, psize, ssize);
+}
+
 static int __init htab_dt_scan_seg_sizes(unsigned long node,
 					 const char *uname, int depth,
 					 void *data)
@@ -430,6 +448,11 @@ void create_section_mapping(unsigned long start, unsigned long end)
 			_PAGE_ACCESSED | _PAGE_DIRTY | _PAGE_COHERENT | PP_RWXX,
 			mmu_linear_psize, mmu_kernel_ssize));
 }
+
+void remove_section_mapping(unsigned long start, unsigned long end)
+{
+	htab_remove_mapping(start, end, mmu_linear_psize, mmu_kernel_ssize);
+}
 #endif /* CONFIG_MEMORY_HOTPLUG */
 
 static inline void make_bl(unsigned int *insn_addr, void *func)