From: Seung-Woo Kim <sw0312.kim@samsung.com>
Date: Wed, 2 Dec 2020 04:35:32 +0000 (+0900)
Subject: Revert "fs/proc: make cmdline writable"
X-Git-Tag: accepted/tizen/unified/20201211.124320~30
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=755516e8c0f4865be933e64f0f2890c1bcb226b2;p=platform%2Fkernel%2Flinux-amlogic.git

Revert "fs/proc: make cmdline writable"

This reverts commit 341b13d1ba7f5d10830a7236b257bed780602917
and commit 7970fede1d941cbda83ac6f875b1f99b9af5a8f9 and commit
129e951a369446eb40d23264caf20bddcd1929e3.

Writing /proc/cmdline is not required and the feature causes too
much stack frame usage. To remove the FRAME_WARN issue for
frame-larger-than, revert writing /proc/cmdline feature commits.

Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com>
---

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 708e27f..4471e0b 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -1140,12 +1140,20 @@ int __init early_init_dt_scan_chosen(unsigned long node, const char *uname,
 		p = of_get_flat_dt_prop(node, "bootargs", &l);
 
 	if (p != NULL && l > 0) {
-		strlcpy(cmdline, p, min((int)l, COMMAND_LINE_SIZE));
+		if (concat_cmdline) {
+			int cmdline_len;
+			int copy_len;
+			strlcat(cmdline, " ", COMMAND_LINE_SIZE);
+			cmdline_len = strlen(cmdline);
+			copy_len = COMMAND_LINE_SIZE - cmdline_len - 1;
+			copy_len = min((int)l, copy_len);
+			strncpy(cmdline + cmdline_len, p, copy_len);
+			cmdline[cmdline_len + copy_len] = '\0';
+		} else {
+			strlcpy(cmdline, p, min((int)l, COMMAND_LINE_SIZE));
+		}
 	}
 
-	if (concat_cmdline)
-		strlcat(cmdline, config_cmdline, COMMAND_LINE_SIZE);
-
 	pr_debug("Command line is: %s\n", (char*)data);
 
 	/* break now */
diff --git a/fs/proc/cmdline.c b/fs/proc/cmdline.c
index c59ed26..cbd82df 100644
--- a/fs/proc/cmdline.c
+++ b/fs/proc/cmdline.c
@@ -3,14 +3,9 @@
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
 
-#include <asm/setup.h>  /* for COMMAND_LINE_SIZE */
-#include <asm/uaccess.h>    /* copy_from_user */
-
-char proc_cmdline[COMMAND_LINE_SIZE];
-
 static int cmdline_proc_show(struct seq_file *m, void *v)
 {
-	seq_printf(m, "%s\n", proc_cmdline);
+	seq_printf(m, "%s\n", saved_command_line);
 	return 0;
 }
 
@@ -19,31 +14,15 @@ static int cmdline_proc_open(struct inode *inode, struct file *file)
 	return single_open(file, cmdline_proc_show, NULL);
 }
 
-static ssize_t cmdline_proc_write(struct file *file, const char __user *buf,
-				size_t len, loff_t *ppos)
-{
-	char str[COMMAND_LINE_SIZE];
-	if (copy_from_user(str, buf, len)) {
-	   printk( KERN_INFO "[cmdline] copy_from_user failed.\n");
-	   return -EFAULT;
-	}
-	str[len] = '\0';
-	strlcpy(proc_cmdline, str, min((int)len, COMMAND_LINE_SIZE));
-
-	return len;
-}
-
 static const struct file_operations cmdline_proc_fops = {
 	.open		= cmdline_proc_open,
 	.read		= seq_read,
-	.write		= cmdline_proc_write,
 	.llseek		= seq_lseek,
 	.release	= single_release,
 };
 
 static int __init proc_cmdline_init(void)
 {
-	strcpy(proc_cmdline, saved_command_line);
 	proc_create("cmdline", 0, NULL, &cmdline_proc_fops);
 	return 0;
 }