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Commit 0156411b authored by Catalin Marinas's avatar Catalin Marinas
Browse files

arm64: Implement the compat_sys_call_table in C 



Unlike the sys_call_table[], the compat one was implemented in sys32.S
making it impossible to notice discrepancies between the number of
compat syscalls and the __NR_compat_syscalls macro, the latter having to
be defined in asm/unistd.h as including asm/unistd32.h would cause
conflicts on __NR_* definitions. With this patch, incorrect
__NR_compat_syscalls values will result in a build-time error.

Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Suggested-by: default avatarMark Rutland <mark.rutland@arm.com>
Acked-by: default avatarMark Rutland <mark.rutland@arm.com>
parent 54e45c16

arch/arm64/include/asm/unistd.h

+3 −0
Original line number Diff line number Diff line
@@ -48,6 +48,9 @@ 
#endif



#define __ARCH_WANT_SYS_CLONE



#ifndef __COMPAT_SYSCALL_NR

#include <uapi/asm/unistd.h>

#endif



#define NR_syscalls (__NR_syscalls)

arch/arm64/kernel/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -19,7 +19,7 @@ arm64-obj-y := cputable.o debug-monitors.o entry.o irq.o fpsimd.o \ 
			   cpuinfo.o cpu_errata.o alternative.o cacheinfo.o



arm64-obj-$(CONFIG_COMPAT)		+= sys32.o kuser32.o signal32.o 	\

					   sys_compat.o 			\

					   sys_compat.o entry32.o		\

					   ../../arm/kernel/opcodes.o

arm64-obj-$(CONFIG_FUNCTION_TRACER)	+= ftrace.o entry-ftrace.o

arm64-obj-$(CONFIG_MODULES)		+= arm64ksyms.o module.o

arch/arm64/kernel/entry.S

+1 −1
Original line number Diff line number Diff line
@@ -433,7 +433,7 @@ el0_svc_compat: 
	/*

	 * AArch32 syscall handling

	 */

	adr	stbl, compat_sys_call_table	// load compat syscall table pointer

	adrp	stbl, compat_sys_call_table	// load compat syscall table pointer

	uxtw	scno, w7			// syscall number in w7 (r7)

	mov     sc_nr, #__NR_compat_syscalls

	b	el0_svc_naked

arch/arm64/kernel/sys32.S→arch/arm64/kernel/entry32.S

+12 −22
Original line number Diff line number Diff line
@@ -27,26 +27,26 @@ 
 * System call wrappers for the AArch32 compatibility layer.

 */



compat_sys_sigreturn_wrapper:

ENTRY(compat_sys_sigreturn_wrapper)

	mov	x0, sp

	mov	x27, #0		// prevent syscall restart handling (why)

	b	compat_sys_sigreturn

ENDPROC(compat_sys_sigreturn_wrapper)



compat_sys_rt_sigreturn_wrapper:

ENTRY(compat_sys_rt_sigreturn_wrapper)

	mov	x0, sp

	mov	x27, #0		// prevent syscall restart handling (why)

	b	compat_sys_rt_sigreturn

ENDPROC(compat_sys_rt_sigreturn_wrapper)



compat_sys_statfs64_wrapper:

ENTRY(compat_sys_statfs64_wrapper)

	mov	w3, #84

	cmp	w1, #88

	csel	w1, w3, w1, eq

	b	compat_sys_statfs64

ENDPROC(compat_sys_statfs64_wrapper)



compat_sys_fstatfs64_wrapper:

ENTRY(compat_sys_fstatfs64_wrapper)

	mov	w3, #84

	cmp	w1, #88

	csel	w1, w3, w1, eq
@@ -58,33 +58,33 @@ ENDPROC(compat_sys_fstatfs64_wrapper) 
 * in registers or that take 32-bit parameters which require sign

 * extension.

 */

compat_sys_pread64_wrapper:

ENTRY(compat_sys_pread64_wrapper)

	regs_to_64	x3, x4, x5

	b	sys_pread64

ENDPROC(compat_sys_pread64_wrapper)



compat_sys_pwrite64_wrapper:

ENTRY(compat_sys_pwrite64_wrapper)

	regs_to_64	x3, x4, x5

	b	sys_pwrite64

ENDPROC(compat_sys_pwrite64_wrapper)



compat_sys_truncate64_wrapper:

ENTRY(compat_sys_truncate64_wrapper)

	regs_to_64	x1, x2, x3

	b	sys_truncate

ENDPROC(compat_sys_truncate64_wrapper)



compat_sys_ftruncate64_wrapper:

ENTRY(compat_sys_ftruncate64_wrapper)

	regs_to_64	x1, x2, x3

	b	sys_ftruncate

ENDPROC(compat_sys_ftruncate64_wrapper)



compat_sys_readahead_wrapper:

ENTRY(compat_sys_readahead_wrapper)

	regs_to_64	x1, x2, x3

	mov	w2, w4

	b	sys_readahead

ENDPROC(compat_sys_readahead_wrapper)



compat_sys_fadvise64_64_wrapper:

ENTRY(compat_sys_fadvise64_64_wrapper)

	mov	w6, w1

	regs_to_64	x1, x2, x3

	regs_to_64	x2, x4, x5
@@ -92,24 +92,14 @@ compat_sys_fadvise64_64_wrapper: 
	b	sys_fadvise64_64

ENDPROC(compat_sys_fadvise64_64_wrapper)



compat_sys_sync_file_range2_wrapper:

ENTRY(compat_sys_sync_file_range2_wrapper)

	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:

ENTRY(compat_sys_fallocate_wrapper)

	regs_to_64	x2, x2, x3

	regs_to_64	x3, x4, x5

	b	sys_fallocate

ENDPROC(compat_sys_fallocate_wrapper)
 


#undef __SYSCALL

#define __SYSCALL(x, y)		.quad	y	// x



/*

 * The system calls table must be 4KB aligned.

 */

	.align	12

ENTRY(compat_sys_call_table)

#include <asm/unistd32.h>

arch/arm64/kernel/sys32.c

0 → 100644
+51 −0
Original line number Diff line number Diff line 
/*

 * arch/arm64/kernel/sys32.c

 *

 * Copyright (C) 2015 ARM Ltd.

 *

 * This program is free software(void); you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program.  If not, see <http(void);//www.gnu.org/licenses/>.

 */



/*

 * Needed to avoid conflicting __NR_* macros between uapi/asm/unistd.h and

 * asm/unistd32.h.

 */

#define __COMPAT_SYSCALL_NR



#include <linux/compiler.h>

#include <linux/syscalls.h>



asmlinkage long compat_sys_sigreturn_wrapper(void);

asmlinkage long compat_sys_rt_sigreturn_wrapper(void);

asmlinkage long compat_sys_statfs64_wrapper(void);

asmlinkage long compat_sys_fstatfs64_wrapper(void);

asmlinkage long compat_sys_pread64_wrapper(void);

asmlinkage long compat_sys_pwrite64_wrapper(void);

asmlinkage long compat_sys_truncate64_wrapper(void);

asmlinkage long compat_sys_ftruncate64_wrapper(void);

asmlinkage long compat_sys_readahead_wrapper(void);

asmlinkage long compat_sys_fadvise64_64_wrapper(void);

asmlinkage long compat_sys_sync_file_range2_wrapper(void);

asmlinkage long compat_sys_fallocate_wrapper(void);



#undef __SYSCALL

#define __SYSCALL(nr, sym)	[nr] = sym,



/*

 * The sys_call_table array must be 4K aligned to be accessible from

 * kernel/entry.S.

 */

void * const compat_sys_call_table[__NR_compat_syscalls] __aligned(4096) = {

	[0 ... __NR_compat_syscalls - 1] = sys_ni_syscall,

#include <asm/unistd32.h>

};