From: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Date: Wed, 19 Oct 2005 10:57:14 +0000 (+0900)
Subject: Fix zero length sys_cacheflush
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=750ccf687ff9adbf2a16066a3a2757d0f761384c;p=GitHub%2FLineageOS%2Fandroid_kernel_samsung_universal7580.git

Fix zero length sys_cacheflush

Cacheflush(0, 0, 0) was crashing the system.  This is because
flush_icache_range(start, end) tries to flushing whole address space
(0 - ~0UL) if both start and end are zero.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
---

diff --git a/arch/mips/mm/cache.c b/arch/mips/mm/cache.c
index 611b48dde73..314701a66b1 100644
--- a/arch/mips/mm/cache.c
+++ b/arch/mips/mm/cache.c
@@ -56,6 +56,8 @@ EXPORT_SYMBOL(_dma_cache_inv);
 asmlinkage int sys_cacheflush(unsigned long __user addr,
 	unsigned long bytes, unsigned int cache)
 {
+	if (bytes == 0)
+		return 0;
 	if (!access_ok(VERIFY_WRITE, (void __user *) addr, bytes))
 		return -EFAULT;