Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 209 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/pseries/rtas-work-area.c b/arch/powerpc/platforms/pseries/rtas-work-area.c
new file mode 100644
index 0000000000..b37d52f403
--- /dev/null
+++ b/arch/powerpc/platforms/pseries/rtas-work-area.c
@@ -0,0 +1,209 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#define pr_fmt(fmt)	"rtas-work-area: " fmt
+
+#include <linux/genalloc.h>
+#include <linux/log2.h>
+#include <linux/kernel.h>
+#include <linux/memblock.h>
+#include <linux/mempool.h>
+#include <linux/minmax.h>
+#include <linux/mutex.h>
+#include <linux/numa.h>
+#include <linux/sizes.h>
+#include <linux/wait.h>
+
+#include <asm/machdep.h>
+#include <asm/rtas-work-area.h>
+#include <asm/rtas.h>
+
+enum {
+	/*
+	 * Ensure the pool is page-aligned.
+	 */
+	RTAS_WORK_AREA_ARENA_ALIGN = PAGE_SIZE,
+	/*
+	 * Don't let a single allocation claim the whole arena.
+	 */
+	RTAS_WORK_AREA_ARENA_SZ = RTAS_WORK_AREA_MAX_ALLOC_SZ * 2,
+	/*
+	 * The smallest known work area size is for ibm,get-vpd's
+	 * location code argument, which is limited to 79 characters
+	 * plus 1 nul terminator.
+	 *
+	 * PAPR+ 7.3.20 ibm,get-vpd RTAS Call
+	 * PAPR+ 12.3.2.4 Converged Location Code Rules - Length Restrictions
+	 */
+	RTAS_WORK_AREA_MIN_ALLOC_SZ = roundup_pow_of_two(80),
+};
+
+static struct {
+	struct gen_pool *gen_pool;
+	char *arena;
+	struct mutex mutex; /* serializes allocations */
+	struct wait_queue_head wqh;
+	mempool_t descriptor_pool;
+	bool available;
+} rwa_state = {
+	.mutex = __MUTEX_INITIALIZER(rwa_state.mutex),
+	.wqh = __WAIT_QUEUE_HEAD_INITIALIZER(rwa_state.wqh),
+};
+
+/*
+ * A single work area buffer and descriptor to serve requests early in
+ * boot before the allocator is fully initialized. We know 4KB is the
+ * most any boot time user needs (they all call ibm,get-system-parameter).
+ */
+static bool early_work_area_in_use __initdata;
+static char early_work_area_buf[SZ_4K] __initdata __aligned(SZ_4K);
+static struct rtas_work_area early_work_area __initdata = {
+	.buf = early_work_area_buf,
+	.size = sizeof(early_work_area_buf),
+};
+
+
+static struct rtas_work_area * __init rtas_work_area_alloc_early(size_t size)
+{
+	WARN_ON(size > early_work_area.size);
+	WARN_ON(early_work_area_in_use);
+	early_work_area_in_use = true;
+	memset(early_work_area.buf, 0, early_work_area.size);
+	return &early_work_area;
+}
+
+static void __init rtas_work_area_free_early(struct rtas_work_area *work_area)
+{
+	WARN_ON(work_area != &early_work_area);
+	WARN_ON(!early_work_area_in_use);
+	early_work_area_in_use = false;
+}
+
+struct rtas_work_area * __ref __rtas_work_area_alloc(size_t size)
+{
+	struct rtas_work_area *area;
+	unsigned long addr;
+
+	might_sleep();
+
+	/*
+	 * The rtas_work_area_alloc() wrapper enforces this at build
+	 * time. Requests that exceed the arena size will block
+	 * indefinitely.
+	 */
+	WARN_ON(size > RTAS_WORK_AREA_MAX_ALLOC_SZ);
+
+	if (!rwa_state.available)
+		return rtas_work_area_alloc_early(size);
+	/*
+	 * To ensure FCFS behavior and prevent a high rate of smaller
+	 * requests from starving larger ones, use the mutex to queue
+	 * allocations.
+	 */
+	mutex_lock(&rwa_state.mutex);
+	wait_event(rwa_state.wqh,
+		   (addr = gen_pool_alloc(rwa_state.gen_pool, size)) != 0);
+	mutex_unlock(&rwa_state.mutex);
+
+	area = mempool_alloc(&rwa_state.descriptor_pool, GFP_KERNEL);
+	area->buf = (char *)addr;
+	area->size = size;
+
+	return area;
+}
+
+void __ref rtas_work_area_free(struct rtas_work_area *area)
+{
+	if (!rwa_state.available) {
+		rtas_work_area_free_early(area);
+		return;
+	}
+
+	gen_pool_free(rwa_state.gen_pool, (unsigned long)area->buf, area->size);
+	mempool_free(area, &rwa_state.descriptor_pool);
+	wake_up(&rwa_state.wqh);
+}
+
+/*
+ * Initialization of the work area allocator happens in two parts. To
+ * reliably reserve an arena that satisfies RTAS addressing
+ * requirements, we must perform a memblock allocation early,
+ * immmediately after RTAS instantiation. Then we have to wait until
+ * the slab allocator is up before setting up the descriptor mempool
+ * and adding the arena to a gen_pool.
+ */
+static __init int rtas_work_area_allocator_init(void)
+{
+	const unsigned int order = ilog2(RTAS_WORK_AREA_MIN_ALLOC_SZ);
+	const phys_addr_t pa_start = __pa(rwa_state.arena);
+	const phys_addr_t pa_end = pa_start + RTAS_WORK_AREA_ARENA_SZ - 1;
+	struct gen_pool *pool;
+	const int nid = NUMA_NO_NODE;
+	int err;
+
+	err = -ENOMEM;
+	if (!rwa_state.arena)
+		goto err_out;
+
+	pool = gen_pool_create(order, nid);
+	if (!pool)
+		goto err_out;
+	/*
+	 * All RTAS functions that consume work areas are OK with
+	 * natural alignment, when they have alignment requirements at
+	 * all.
+	 */
+	gen_pool_set_algo(pool, gen_pool_first_fit_order_align, NULL);
+
+	err = gen_pool_add(pool, (unsigned long)rwa_state.arena,
+			   RTAS_WORK_AREA_ARENA_SZ, nid);
+	if (err)
+		goto err_destroy;
+
+	err = mempool_init_kmalloc_pool(&rwa_state.descriptor_pool, 1,
+					sizeof(struct rtas_work_area));
+	if (err)
+		goto err_destroy;
+
+	rwa_state.gen_pool = pool;
+	rwa_state.available = true;
+
+	pr_debug("arena [%pa-%pa] (%uK), min/max alloc sizes %u/%u\n",
+		 &pa_start, &pa_end,
+		 RTAS_WORK_AREA_ARENA_SZ / SZ_1K,
+		 RTAS_WORK_AREA_MIN_ALLOC_SZ,
+		 RTAS_WORK_AREA_MAX_ALLOC_SZ);
+
+	return 0;
+
+err_destroy:
+	gen_pool_destroy(pool);
+err_out:
+	return err;
+}
+machine_arch_initcall(pseries, rtas_work_area_allocator_init);
+
+/**
+ * rtas_work_area_reserve_arena() - Reserve memory suitable for RTAS work areas.
+ */
+void __init rtas_work_area_reserve_arena(const phys_addr_t limit)
+{
+	const phys_addr_t align = RTAS_WORK_AREA_ARENA_ALIGN;
+	const phys_addr_t size = RTAS_WORK_AREA_ARENA_SZ;
+	const phys_addr_t min = MEMBLOCK_LOW_LIMIT;
+	const int nid = NUMA_NO_NODE;
+
+	/*
+	 * Too early for a machine_is(pseries) check. But PAPR
+	 * effectively mandates that ibm,get-system-parameter is
+	 * present:
+	 *
+	 * R1–7.3.16–1. All platforms must support the System
+	 * Parameters option.
+	 *
+	 * So set up the arena if we find that, with a fallback to
+	 * ibm,configure-connector, just in case.
+	 */
+	if (rtas_function_implemented(RTAS_FN_IBM_GET_SYSTEM_PARAMETER) ||
+	    rtas_function_implemented(RTAS_FN_IBM_CONFIGURE_CONNECTOR))
+		rwa_state.arena = memblock_alloc_try_nid(size, align, min, limit, nid);
+}