Commit 43d5de2b authored by Rohan McLure's avatar Rohan McLure Committed by Michael Ellerman
Browse files

asm-generic: compat: Support BE for long long args in 32-bit ABIs 



32-bit ABIs support passing 64-bit integers by registers via argument
translation. Commit 59c10c52 ("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: default avatarRohan McLure <rmclure@linux.ibm.com>
Reviewed-by: default avatarNicholas Piggin <npiggin@gmail.com>
Reviewed-by: default avatarArnd Bergmann <arnd@anrdb.de>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220921065605.1051927-10-rmclure@linux.ibm.com
parent 016ff72b

include/asm-generic/compat.h

+7 −2
Original line number Original line Diff line number Diff line
@@ -14,12 +14,17 @@ 
#define COMPAT_OFF_T_MAX	0x7fffffff

#define COMPAT_OFF_T_MAX	0x7fffffff

#endif

#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(name)		u32  name##_lo, u32  name##_hi

#define compat_arg_u64_dual(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) | \

#define compat_arg_u64_glue(name)	(((u64)name##_lo & 0xffffffffUL) | \

					 ((u64)name##_hi << 32))

					 ((u64)name##_hi << 32))

#endif

#endif /* compat_arg_u64 */





/* These types are common across all compat ABIs */

/* These types are common across all compat ABIs */

typedef u32 compat_size_t;

typedef u32 compat_size_t;