book3s64/hash: Make kernel_map_linear_page() generic

Currently kernel_map_linear_page() function assumes to be working on
linear_map_hash_slots array. But since in later patches we need a
separate linear map array for kfence, hence make
kernel_map_linear_page() take a linear map array and lock in it's
function argument.

This is needed to separate out kfence from debug_pagealloc
infrastructure.

Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://patch.msgid.link/5b67df7b29e68d7c78d6fc1f42d41137299bac6b.1729271995.git.ritesh.list@gmail.com

arch/powerpc/mm/book3s64/hash_utils.c

@@ -272,11 +272,8 @@ void hash__tlbiel_all(unsigned int action)
 }
 
 #ifdef CONFIG_DEBUG_PAGEALLOC
-static u8 *linear_map_hash_slots;
-static unsigned long linear_map_hash_count;
-static DEFINE_RAW_SPINLOCK(linear_map_hash_lock);
-
-static void kernel_map_linear_page(unsigned long vaddr, unsigned long lmi)
+static void kernel_map_linear_page(unsigned long vaddr, unsigned long idx,
+				   u8 *slots, raw_spinlock_t *lock)
 {
 	unsigned long hash;
 	unsigned long vsid = get_kernel_vsid(vaddr, mmu_kernel_ssize);
@@ -290,44 +287,48 @@ static void kernel_map_linear_page(unsigned long vaddr, unsigned long lmi)
 	if (!vsid)
 		return;
 
-	if (linear_map_hash_slots[lmi] & 0x80)
+	if (slots[idx] & 0x80)
 		return;
 
 	ret = hpte_insert_repeating(hash, vpn, __pa(vaddr), mode,
 				    HPTE_V_BOLTED,
 				    mmu_linear_psize, mmu_kernel_ssize);
 
 	BUG_ON (ret < 0);
-	raw_spin_lock(&linear_map_hash_lock);
-	BUG_ON(linear_map_hash_slots[lmi] & 0x80);
-	linear_map_hash_slots[lmi] = ret | 0x80;
-	raw_spin_unlock(&linear_map_hash_lock);
+	raw_spin_lock(lock);
+	BUG_ON(slots[idx] & 0x80);
+	slots[idx] = ret | 0x80;
+	raw_spin_unlock(lock);
 }
 
-static void kernel_unmap_linear_page(unsigned long vaddr, unsigned long lmi)
+static void kernel_unmap_linear_page(unsigned long vaddr, unsigned long idx,
+				     u8 *slots, raw_spinlock_t *lock)
 {
-	unsigned long hash, hidx, slot;
+	unsigned long hash, hslot, slot;
 	unsigned long vsid = get_kernel_vsid(vaddr, mmu_kernel_ssize);
 	unsigned long vpn = hpt_vpn(vaddr, vsid, mmu_kernel_ssize);
 
 	hash = hpt_hash(vpn, PAGE_SHIFT, mmu_kernel_ssize);
-	raw_spin_lock(&linear_map_hash_lock);
-	if (!(linear_map_hash_slots[lmi] & 0x80)) {
-		raw_spin_unlock(&linear_map_hash_lock);
+	raw_spin_lock(lock);
+	if (!(slots[idx] & 0x80)) {
+		raw_spin_unlock(lock);
 		return;
 	}
-	hidx = linear_map_hash_slots[lmi] & 0x7f;
-	linear_map_hash_slots[lmi] = 0;
-	raw_spin_unlock(&linear_map_hash_lock);
-	if (hidx & _PTEIDX_SECONDARY)
+	hslot = slots[idx] & 0x7f;
+	slots[idx] = 0;
+	raw_spin_unlock(lock);
+	if (hslot & _PTEIDX_SECONDARY)
 		hash = ~hash;
 	slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
-	slot += hidx & _PTEIDX_GROUP_IX;
+	slot += hslot & _PTEIDX_GROUP_IX;
 	mmu_hash_ops.hpte_invalidate(slot, vpn, mmu_linear_psize,
 				     mmu_linear_psize,
 				     mmu_kernel_ssize, 0);
 }
 
+static u8 *linear_map_hash_slots;
+static unsigned long linear_map_hash_count;
+static DEFINE_RAW_SPINLOCK(linear_map_hash_lock);
 static inline void hash_debug_pagealloc_alloc_slots(void)
 {
 	if (!debug_pagealloc_enabled())
@@ -362,9 +363,11 @@ static int hash_debug_pagealloc_map_pages(struct page *page, int numpages,
 		if (lmi >= linear_map_hash_count)
 			continue;
 		if (enable)
-			kernel_map_linear_page(vaddr, lmi);
+			kernel_map_linear_page(vaddr, lmi,
+				linear_map_hash_slots, &linear_map_hash_lock);
 		else
-			kernel_unmap_linear_page(vaddr, lmi);
+			kernel_unmap_linear_page(vaddr, lmi,
+				linear_map_hash_slots, &linear_map_hash_lock);
 	}
 	local_irq_restore(flags);
 	return 0;