[PATCH] powerpc/powernv: Expose OPAL firmware symbol map
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Date: 2014-12-05 02:36:50
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
Newer versions of OPAL will provide this, so let's expose it to user space so tools like perf can use it to properly decode samples in firmware space. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> ---
diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index 06d9076..6427959 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c@@ -61,6 +61,8 @@ static DEFINE_SPINLOCK(opal_notifier_lock); static uint64_t last_notified_mask = 0x0ul; static atomic_t opal_notifier_hold = ATOMIC_INIT(0); static uint32_t opal_heartbeat; +static void *opal_symmap; +static uint64_t opal_symmap_size; static void opal_reinit_cores(void) {
@@ -604,10 +606,49 @@ static int opal_sysfs_init(void) pr_warn("kobject_create_and_add opal failed\n"); return -ENOMEM; } - return 0; } +static ssize_t symbol_map_read(struct file *fp, struct kobject *kobj, + struct bin_attribute *bin_attr, + char *buf, loff_t off, size_t count) +{ + ssize_t chunk; + + if (off >= opal_symmap_size) + return 0; + chunk = min_t(ssize_t, opal_symmap_size - off, count); + memcpy(buf, opal_symmap + off, chunk); + + return chunk; +} + +static BIN_ATTR_RO(symbol_map, 0); + +static void opal_export_symmap(void) +{ + const __be64 *syms; + unsigned int size; + struct device_node *fw; + int rc; + + fw = of_find_node_by_path("/ibm,opal/firmware"); + if (!fw) + return; + syms = of_get_property(fw, "symbol-map", &size); + if (!syms || size != 2 * sizeof(__be64)) + return; + + opal_symmap = __va(be64_to_cpu(syms[0])); + opal_symmap_size = be64_to_cpu(syms[1]); + + /* Setup attributes */ + bin_attr_symbol_map.size = opal_symmap_size; + rc = sysfs_create_bin_file(opal_kobj, &bin_attr_symbol_map); + if (rc) + pr_warn("Error %d creating OPAL symbols file\n", rc); +} + static void __init opal_dump_region_init(void) { void *addr;
@@ -738,6 +779,8 @@ static int __init opal_init(void) /* Create "opal" kobject under /sys/firmware */ rc = opal_sysfs_init(); if (rc == 0) { + /* Export symbol map to userspace */ + opal_export_symmap(); /* Setup dump region interface */ opal_dump_region_init(); /* Setup error log interface */