Re: [PATCH] prctl: implement PR_GET_ENDIAN for all architectures
From: Andrew Morton <akpm@linux-foundation.org>
Date: 2017-02-01 00:26:27
Also in:
lkml
On Sat, 28 Jan 2017 12:13:10 +0100 Helge Deller [off-list ref] wrote:
The prctl(PR_GET_ENDIAN) syscall was added to Kernel 2.6.18, but implemented for PowerPC only. This trivial patch adds support for this syscall for all other architectures.
Seems reasonable. I guess. Why is this needed? The man page will need updating. It says "PowerPC only".
quoted hunk
diff --git a/kernel/sys.c b/kernel/sys.c index 842914e..5818e5e 100644 --- a/kernel/sys.c +++ b/kernel/sys.c@@ -79,9 +79,6 @@ #ifndef GET_FPEXC_CTL # define GET_FPEXC_CTL(a, b) (-EINVAL) #endif -#ifndef GET_ENDIAN -# define GET_ENDIAN(a, b) (-EINVAL) -#endif #ifndef SET_ENDIAN # define SET_ENDIAN(a, b) (-EINVAL) #endif@@ -2136,7 +2133,13 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, return -EFAULT; break; case PR_GET_ENDIAN: +#ifdef GET_ENDIAN error = GET_ENDIAN(me, arg2); +#elif defined(__BIG_ENDIAN) + error = put_user(PR_ENDIAN_BIG, (unsigned int __user *)arg2); +#else + error = put_user(PR_ENDIAN_LITTLE, (unsigned int __user *)arg2); +#endif break; case PR_SET_ENDIAN: error = SET_ENDIAN(me, arg2);