From: Grazvydas Ignotas <notasas@gmail.com>
Date: Sun, 7 Jun 2015 00:18:58 +0000 (+0300)
Subject: Revert "pagemap: do not leak physical addresses to non-privileged userspace"
X-Git-Tag: sz_173~52
X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=commitdiff_plain;h=f35aaa5471cbf312917c102a99d8e2f7943a0654;hp=0b469f06d09bd6579639fda2ea3db1bca363b2db;ds=inline

Revert "pagemap: do not leak physical addresses to non-privileged userspace"

This reverts commit 1ffc3cd9a36b504c20ce98fe5eeb5463f389e1ac.

Don't need it on pandora - even if rowhammer worked, pandora is almost
never a multiuser system, and cache invalidate is a privileged instruction
already on ARM.

pagemap may also be useful for use c64_tools and such.
---

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index ff29db991467..bc02b6b966dc 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1089,19 +1089,9 @@ out:
 	return ret;
 }
 
-static int pagemap_open(struct inode *inode, struct file *file)
-{
-	/* do not disclose physical addresses to unprivileged
-	   userspace (closes a rowhammer attack vector) */
-	if (!capable(CAP_SYS_ADMIN))
-		return -EPERM;
-	return 0;
-}
-
 const struct file_operations proc_pagemap_operations = {
 	.llseek		= mem_lseek, /* borrow this */
 	.read		= pagemap_read,
-	.open		= pagemap_open,
 };
 #endif /* CONFIG_PROC_PAGE_MONITOR */