From c6c26fb55e8e4b3fc376be5611685990a17de27a Mon Sep 17 00:00:00 2001 From: Aravinda Prasad Date: Tue, 16 Oct 2018 17:20:05 +0530 Subject: [PATCH] powerpc/pseries: Export raw per-CPU VPA data via debugfs This patch exports the raw per-CPU VPA data via debugfs. A per-CPU file is created which exports the VPA data of that CPU to help debug some of the VPA related issues or to analyze the per-CPU VPA related statistics. v3: Removed offline CPU check. v2: Included offline CPU check and other review comments. Signed-off-by: Aravinda Prasad Signed-off-by: Michael Ellerman --- arch/powerpc/platforms/pseries/lpar.c | 54 +++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c index 0b5081085a44..32d4452973e7 100644 --- a/arch/powerpc/platforms/pseries/lpar.c +++ b/arch/powerpc/platforms/pseries/lpar.c @@ -48,6 +48,7 @@ #include #include #include +#include #include "pseries.h" @@ -1239,3 +1240,56 @@ static int __init reserve_vrma_context_id(void) return 0; } machine_device_initcall(pseries, reserve_vrma_context_id); + +#ifdef CONFIG_DEBUG_FS +/* debugfs file interface for vpa data */ +static ssize_t vpa_file_read(struct file *filp, char __user *buf, size_t len, + loff_t *pos) +{ + int cpu = (long)filp->private_data; + struct lppaca *lppaca = &lppaca_of(cpu); + + return simple_read_from_buffer(buf, len, pos, lppaca, + sizeof(struct lppaca)); +} + +static const struct file_operations vpa_fops = { + .open = simple_open, + .read = vpa_file_read, + .llseek = default_llseek, +}; + +static int __init vpa_debugfs_init(void) +{ + char name[16]; + long i; + static struct dentry *vpa_dir; + + if (!firmware_has_feature(FW_FEATURE_SPLPAR)) + return 0; + + vpa_dir = debugfs_create_dir("vpa", powerpc_debugfs_root); + if (!vpa_dir) { + pr_warn("%s: can't create vpa root dir\n", __func__); + return -ENOMEM; + } + + /* set up the per-cpu vpa file*/ + for_each_possible_cpu(i) { + struct dentry *d; + + sprintf(name, "cpu-%ld", i); + + d = debugfs_create_file(name, 0400, vpa_dir, (void *)i, + &vpa_fops); + if (!d) { + pr_warn("%s: can't create per-cpu vpa file\n", + __func__); + return -ENOMEM; + } + } + + return 0; +} +machine_arch_initcall(pseries, vpa_debugfs_init); +#endif /* CONFIG_DEBUG_FS */ -- 2.30.2