Commit 55b89540 authored by Matthew Leach's avatar Matthew Leach Committed by Catalin Marinas
Browse files

arm64: compat: correct register concatenation for syscall wrappers 



The arm64 port contains wrappers for arm32 syscalls that pass 64-bit
values. These wrappers concatenate the two registers to hold a 64-bit
value in a single X register. On BE, however, the lower and higher
words are swapped.

Create a new assembler macro, regs_to_64, that when on BE systems
swaps the registers in the orr instruction.

Acked-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarMatthew Leach <matthew.leach@arm.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent a795a38e

arch/arm64/include/asm/assembler.h

+12 −0
Original line number Diff line number Diff line
@@ -115,3 +115,15 @@ lr .req x30 // link register 
	.align	7

	b	\label

	.endm

/*

 * Define a macro that constructs a 64-bit value by concatenating two

 * 32-bit registers. Note that on big endian systems the order of the

 * registers is swapped.

 */

#ifndef CONFIG_CPU_BIG_ENDIAN

	.macro	regs_to_64, rd, lbits, hbits

#else

	.macro	regs_to_64, rd, hbits, lbits

#endif

	orr	\rd, \lbits, \hbits, lsl #32

	.endm

arch/arm64/kernel/sys32.S

+11 −11
Original line number Diff line number Diff line
@@ -59,48 +59,48 @@ ENDPROC(compat_sys_fstatfs64_wrapper) 
 * extension.

 */

compat_sys_pread64_wrapper:

	orr	x3, x4, x5, lsl #32

	regs_to_64	x3, x4, x5

	b	sys_pread64

ENDPROC(compat_sys_pread64_wrapper)



compat_sys_pwrite64_wrapper:

	orr	x3, x4, x5, lsl #32

	regs_to_64	x3, x4, x5

	b	sys_pwrite64

ENDPROC(compat_sys_pwrite64_wrapper)



compat_sys_truncate64_wrapper:

	orr	x1, x2, x3, lsl #32

	regs_to_64	x1, x2, x3

	b	sys_truncate

ENDPROC(compat_sys_truncate64_wrapper)



compat_sys_ftruncate64_wrapper:

	orr	x1, x2, x3, lsl #32

	regs_to_64	x1, x2, x3

	b	sys_ftruncate

ENDPROC(compat_sys_ftruncate64_wrapper)



compat_sys_readahead_wrapper:

	orr	x1, x2, x3, lsl #32

	regs_to_64	x1, x2, x3

	mov	w2, w4

	b	sys_readahead

ENDPROC(compat_sys_readahead_wrapper)



compat_sys_fadvise64_64_wrapper:

	mov	w6, w1

	orr	x1, x2, x3, lsl #32

	orr	x2, x4, x5, lsl #32

	regs_to_64	x1, x2, x3

	regs_to_64	x2, x4, x5

	mov	w3, w6

	b	sys_fadvise64_64

ENDPROC(compat_sys_fadvise64_64_wrapper)



compat_sys_sync_file_range2_wrapper:

	orr	x2, x2, x3, lsl #32

	orr	x3, x4, x5, lsl #32

	regs_to_64	x2, x2, x3

	regs_to_64	x3, x4, x5

	b	sys_sync_file_range2

ENDPROC(compat_sys_sync_file_range2_wrapper)



compat_sys_fallocate_wrapper:

	orr	x2, x2, x3, lsl #32

	orr	x3, x4, x5, lsl #32

	regs_to_64	x2, x2, x3

	regs_to_64	x3, x4, x5

	b	sys_fallocate

ENDPROC(compat_sys_fallocate_wrapper)

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