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-rw-r--r--kernel/printk/printk.c34
1 files changed, 34 insertions, 0 deletions
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index db290be32984..f855ec36dff9 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -266,6 +266,7 @@ static u32 clear_idx;
#define LOG_ALIGN __alignof__(struct printk_log)
#endif
#define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT)
+#define __LOG_CPU_MAX_BUF_LEN (1 << CONFIG_LOG_CPU_MAX_BUF_SHIFT)
static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN);
static char *log_buf = __log_buf;
static u32 log_buf_len = __LOG_BUF_LEN;
@@ -848,12 +849,45 @@ static int __init log_buf_len_setup(char *str)
}
early_param("log_buf_len", log_buf_len_setup);
+static void __init log_buf_add_cpu(void)
+{
+ unsigned int cpu_extra;
+
+ /*
+ * archs should set up cpu_possible_bits properly with
+ * set_cpu_possible() after setup_arch() but just in
+ * case lets ensure this is valid.
+ */
+ if (num_possible_cpus() == 1)
+ return;
+
+ cpu_extra = (num_possible_cpus() - 1) * __LOG_CPU_MAX_BUF_LEN;
+
+ /* by default this will only continue through for large > 64 CPUs */
+ if (cpu_extra <= __LOG_BUF_LEN / 2)
+ return;
+
+ pr_info("log_buf_len individual max cpu contribution: %d bytes\n",
+ __LOG_CPU_MAX_BUF_LEN);
+ pr_info("log_buf_len total cpu_extra contributions: %d bytes\n",
+ cpu_extra);
+ pr_info("log_buf_len min size: %d bytes\n", __LOG_BUF_LEN);
+
+ log_buf_len_update(cpu_extra + __LOG_BUF_LEN);
+}
+
void __init setup_log_buf(int early)
{
unsigned long flags;
char *new_log_buf;
int free;
+ if (log_buf != __log_buf)
+ return;
+
+ if (!early && !new_log_buf_len)
+ log_buf_add_cpu();
+
if (!new_log_buf_len)
return;