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[v6,09/25] asm-generic: compat: Support BE for long long args in 32-bit ABIs

Message ID 20220921065605.1051927-10-rmclure@linux.ibm.com (mailing list archive)
State Accepted
Headers show
Series powerpc: Syscall wrapper and register clearing | expand

Commit Message

Rohan McLure Sept. 21, 2022, 6:55 a.m. UTC 
32-bit ABIs support passing 64-bit integers by registers via argument
translation. Commit 59c10c52f573 ("riscv: compat: syscall: Add
compat_sys_call_table implementation") implements the compat_arg_u64
macro for efficiently defining little endian compatibility syscalls.

Architectures supporting big endianness may benefit from reciprocal
argument translation, but are welcome also to implement their own.

Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Arnd Bergmann <arnd@anrdb.de>
---
V5: New patch.
---
 include/asm-generic/compat.h | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)
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Patch

diff --git a/include/asm-generic/compat.h b/include/asm-generic/compat.h
index d06308a2a7a8..aeb257ad3d1a 100644
--- a/include/asm-generic/compat.h
+++ b/include/asm-generic/compat.h
@@ -14,12 +14,17 @@ 
 #define COMPAT_OFF_T_MAX	0x7fffffff
 #endif
 
-#if !defined(compat_arg_u64) && !defined(CONFIG_CPU_BIG_ENDIAN)
+#ifndef compat_arg_u64
+#ifdef CONFIG_CPU_BIG_ENDIAN
 #define compat_arg_u64(name)		u32  name##_lo, u32  name##_hi
 #define compat_arg_u64_dual(name)	u32, name##_lo, u32, name##_hi
+#else
+#define compat_arg_u64(name)		u32  name##_hi, u32  name##_lo
+#define compat_arg_u64_dual(name)	u32, name##_hi, u32, name##_lo
+#endif
 #define compat_arg_u64_glue(name)	(((u64)name##_lo & 0xffffffffUL) | \
 					 ((u64)name##_hi << 32))
-#endif
+#endif /* compat_arg_u64 */
 
 /* These types are common across all compat ABIs */
 typedef u32 compat_size_t;