linux-kernel - [PATCH] tile 32-bit big-endian: fix bugs in syscall argument order

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Date:	Wed, 15 Jun 2016 15:33:39 -0400
From:	Chris Metcalf <cmetcalf@...lanox.com>
To:	<linux-kernel@...r.kernel.org>
CC:	Chris Metcalf <cmetcalf@...lanox.com>
Subject: [PATCH] tile 32-bit big-endian: fix bugs in syscall argument order

The glibc __LONG_LONG_PAIR passes arguments in a different
order for BE platforms vs LE platforms.  Adjust the expectations
in the kernel 32-bit syscall routines for BE to match.

Signed-off-by: Chris Metcalf <cmetcalf@...lanox.com>
---
 arch/tile/kernel/compat.c | 35 ++++++++++++++++++++++-------------
 arch/tile/kernel/sys.c    | 13 ++++++++++---
 2 files changed, 32 insertions(+), 16 deletions(-)

diff --git a/arch/tile/kernel/compat.c b/arch/tile/kernel/compat.c
index 49120843ff96..bdaf71d31a4a 100644
--- a/arch/tile/kernel/compat.c
+++ b/arch/tile/kernel/compat.c
@@ -23,42 +23,50 @@
 #include <linux/uaccess.h>
 #include <linux/signal.h>
 #include <asm/syscalls.h>
+#include <asm/byteorder.h>
 
 /*
  * Syscalls that take 64-bit numbers traditionally take them in 32-bit
  * "high" and "low" value parts on 32-bit architectures.
  * In principle, one could imagine passing some register arguments as
  * fully 64-bit on TILE-Gx in 32-bit mode, but it seems easier to
- * adapt the usual convention.
+ * adopt the usual convention.
  */
 
+#ifdef __BIG_ENDIAN
+#define SYSCALL_PAIR(name) u32, name ## _hi, u32, name ## _lo
+#else
+#define SYSCALL_PAIR(name) u32, name ## _lo, u32, name ## _hi
+#endif
+
 COMPAT_SYSCALL_DEFINE4(truncate64, char __user *, filename, u32, dummy,
-                       u32, low, u32, high)
+		       SYSCALL_PAIR(length))
 {
-	return sys_truncate(filename, ((loff_t)high << 32) | low);
+	return sys_truncate(filename, ((loff_t)length_hi << 32) | length_lo);
 }
 
 COMPAT_SYSCALL_DEFINE4(ftruncate64, unsigned int, fd, u32, dummy,
-                       u32, low, u32, high)
+		       SYSCALL_PAIR(length))
 {
-	return sys_ftruncate(fd, ((loff_t)high << 32) | low);
+	return sys_ftruncate(fd, ((loff_t)length_hi << 32) | length_lo);
 }
 
 COMPAT_SYSCALL_DEFINE6(pread64, unsigned int, fd, char __user *, ubuf,
-                       size_t, count, u32, dummy, u32, low, u32, high)
+		       size_t, count, u32, dummy, SYSCALL_PAIR(offset))
 {
-	return sys_pread64(fd, ubuf, count, ((loff_t)high << 32) | low);
+	return sys_pread64(fd, ubuf, count,
+			   ((loff_t)offset_hi << 32) | offset_lo);
 }
 
 COMPAT_SYSCALL_DEFINE6(pwrite64, unsigned int, fd, char __user *, ubuf,
-                       size_t, count, u32, dummy, u32, low, u32, high)
+		       size_t, count, u32, dummy, SYSCALL_PAIR(offset))
 {
-	return sys_pwrite64(fd, ubuf, count, ((loff_t)high << 32) | low);
+	return sys_pwrite64(fd, ubuf, count,
+			    ((loff_t)offset_hi << 32) | offset_lo);
 }
 
 COMPAT_SYSCALL_DEFINE6(sync_file_range2, int, fd, unsigned int, flags,
-                       u32, offset_lo, u32, offset_hi,
-                       u32, nbytes_lo, u32, nbytes_hi)
+		       SYSCALL_PAIR(offset), SYSCALL_PAIR(nbytes))
 {
 	return sys_sync_file_range(fd, ((loff_t)offset_hi << 32) | offset_lo,
 				   ((loff_t)nbytes_hi << 32) | nbytes_lo,
@@ -66,8 +74,7 @@ COMPAT_SYSCALL_DEFINE6(sync_file_range2, int, fd, unsigned int, flags,
 }
 
 COMPAT_SYSCALL_DEFINE6(fallocate, int, fd, int, mode,
-                       u32, offset_lo, u32, offset_hi,
-                       u32, len_lo, u32, len_hi)
+		       SYSCALL_PAIR(offset), SYSCALL_PAIR(len))
 {
 	return sys_fallocate(fd, mode, ((loff_t)offset_hi << 32) | offset_lo,
 			     ((loff_t)len_hi << 32) | len_lo);
@@ -77,6 +84,8 @@ COMPAT_SYSCALL_DEFINE6(fallocate, int, fd, int, mode,
  * Avoid bug in generic sys_llseek() that specifies offset_high and
  * offset_low as "unsigned long", thus making it possible to pass
  * a sign-extended high 32 bits in offset_low.
+ * Note that we do not use SYSCALL_PAIR here since glibc passes the
+ * high and low parts explicitly in that order.
  */
 COMPAT_SYSCALL_DEFINE5(llseek, unsigned int, fd, unsigned int, offset_high,
 		       unsigned int, offset_low, loff_t __user *, result,
diff --git a/arch/tile/kernel/sys.c b/arch/tile/kernel/sys.c
index 38debe706061..c7418dcbbb08 100644
--- a/arch/tile/kernel/sys.c
+++ b/arch/tile/kernel/sys.c
@@ -33,6 +33,7 @@
 #include <asm/pgtable.h>
 #include <asm/homecache.h>
 #include <asm/cachectl.h>
+#include <asm/byteorder.h>
 #include <arch/chip.h>
 
 SYSCALL_DEFINE3(cacheflush, unsigned long, addr, unsigned long, len,
@@ -59,13 +60,19 @@ SYSCALL_DEFINE3(cacheflush, unsigned long, addr, unsigned long, len,
 
 #if !defined(__tilegx__) || defined(CONFIG_COMPAT)
 
-ssize_t sys32_readahead(int fd, u32 offset_lo, u32 offset_hi, u32 count)
+#ifdef __BIG_ENDIAN
+#define SYSCALL_PAIR(name) u32 name ## _hi, u32 name ## _lo
+#else
+#define SYSCALL_PAIR(name) u32 name ## _lo, u32 name ## _hi
+#endif
+
+ssize_t sys32_readahead(int fd, SYSCALL_PAIR(offset), u32 count)
 {
 	return sys_readahead(fd, ((loff_t)offset_hi << 32) | offset_lo, count);
 }
 
-int sys32_fadvise64_64(int fd, u32 offset_lo, u32 offset_hi,
-		       u32 len_lo, u32 len_hi, int advice)
+int sys32_fadvise64_64(int fd, SYSCALL_PAIR(offset),
+		       SYSCALL_PAIR(len), int advice)
 {
 	return sys_fadvise64_64(fd, ((loff_t)offset_hi << 32) | offset_lo,
 				((loff_t)len_hi << 32) | len_lo, advice);
-- 
2.7.2