The patch titled
mips: cacheflush system call not returning -EINVAL
has been added to the -mm tree. Its filename is
mips-cacheflush-system-call-not-returning-einval.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: mips: cacheflush system call not returning -EINVAL
From: Maxin John <maxin.john@xxxxxxxxx>
cacheflush man page states that cacheflush() will set EINVAL if cache
parameter is not one of ICACHE, DCACHE, or BCACHE. In order to confirm
this behavior, I have executed the below listed program
(cacheflush_check.c) in Toshiba RBTX4937 board (MIPS) with 2.6.29.1
kernel.
=================================================================
/*
* cacheflush_check.c
*
* Description:
* Tests EINVAL error of cacheflush system call
*
* Expected behaviour:
* cacheflush() should return -EINVAL when cache parameter is not one of ICACHE, DCACHE, or BCACHE.
*
*/
#include <sys/syscall.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#if defined __mips__
#include <asm/cachectl.h>
int cacheflush(char *addr, int nbytes, int cache)
{
return syscall(__NR_cacheflush, addr, nbytes, cache);
}
#endif /* __mips__ */
int main()
{
/* cacheflush man page states that cacheflush() is only
applicable to MIPS architecture */
char *addr = NULL;
/* Create some user address range */
addr = malloc(getpagesize());
if (addr == NULL) {
printf("Malloc error\n");
exit(-1);
}
/* Invokes cacheflush() with proper parameters */
cacheflush(addr, getpagesize(), ICACHE);
cacheflush(addr, getpagesize(), DCACHE);
cacheflush(addr, getpagesize(), BCACHE);
/* Tests whether cacheflush() returns -EINVAL */
if (cacheflush(addr, getpagesize(), 0) < 0) {
if (errno == EINVAL) {
printf("cacheflush EINVAL : TEST PASS\n");
exit(0);
} else {
printf("cacheflush EINVAL : TEST FAIL\n");
}
}
printf("cacheflush EINVAL : TEST FAIL\n");
return -1;
}
=======================================================
I have observed that the test failed when executed in target board.
-bash-3.2# ./cacheflush_err_check
cacheflush EINVAL : TEST FAIL
I have checked the 'arch/mips/mm/cache.c' and observed that the
cacheflush() implementation is not setting EINVAL.
So, I have modified this file by including these two lines for EINVAL.
if ( (cache != ICACHE) && (cache != DCACHE) && (cache != BCACHE) )
return -EINVAL;
After this modification, I have straced the cacheflush_check program
with the modified kernel:
strace ./cacheflush_check
....
set_thread_area(0x2aacd3e0) = 0
mprotect(0x2ac1a000, 28672, PROT_READ) = 0
mprotect(0x2aad4000, 4096, PROT_READ) = 0
brk(0) = 0x411000
brk(0x432000) = 0x432000
syscall(0x1033, 0x411050, 0x1000, 0x1, 0x418e90, 0x2aac5280, 0x418e90,
0x2aad4ef0) = 0
syscall(0x1033, 0x411050, 0x1000, 0x2, 0x418e90, 0x2aac5280, 0x418e90,
0x2aad4ef0) = 0
syscall(0x1033, 0x411050, 0x1000, 0x3, 0x418e90, 0x2aac5280, 0x418e90,
0x2aad4ef0) = 0
syscall(0x1033, 0x411050, 0x1000, 0, 0x418e90, 0x2aac5280, 0x418e90,
0x2aad4ef0) = -1 EINVAL (Invalid argument)
fstat64(1, {st_mode=S_IFCHR|0600, st_rdev=makedev(136, 0), ...}) = 0
old_mmap(NULL, 65536, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS,
-1, 0) = 0x2ac2a000
....
The test passes when executed in the modified kernel.I have tested this
patch and seen no adverse effects.
Signed-off-by: Maxin B. John <maxinbjohn@xxxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/mips/mm/cache.c | 4 ++++
1 file changed, 4 insertions(+)
diff -puN arch/mips/mm/cache.c~mips-cacheflush-system-call-not-returning-einval arch/mips/mm/cache.c
--- a/arch/mips/mm/cache.c~mips-cacheflush-system-call-not-returning-einval
+++ a/arch/mips/mm/cache.c
@@ -64,6 +64,10 @@ SYSCALL_DEFINE3(cacheflush, unsigned lon
{
if (bytes == 0)
return 0;
+
+ if ( (cache != ICACHE) && (cache != DCACHE) && (cache != BCACHE) )
+ return -EINVAL;
+
if (!access_ok(VERIFY_WRITE, (void __user *) addr, bytes))
return -EFAULT;
_
Patches currently in -mm which might be from maxin.john@xxxxxxxxx are
mips-cacheflush-system-call-not-returning-einval.patch
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