[PATCH v6 13/21] arm64:ilp32: add sys_ilp32.c and a separate table (in entry.S) to use it

[Yury Norov]

From: Andrew Pinski <apinski@xxxxxxxxxx>

Add a separate syscall-table for ILP32, which dispatches either to native
LP64 system call implementation or to compat-syscalls, as appropriate.

Signed-off-by: Andrew Pinski <Andrew.Pinski@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Yury Norov <ynorov@xxxxxxxxxxxxxxxxxx>
---
 arch/arm64/include/asm/unistd.h | 11 ++++++-
 arch/arm64/kernel/Makefile      |  2 +-
 arch/arm64/kernel/entry.S       | 12 +++++++-
 arch/arm64/kernel/sys_ilp32.c   | 63 +++++++++++++++++++++++++++++++++++++++++
 4 files changed, 85 insertions(+), 3 deletions(-)
 create mode 100644 arch/arm64/kernel/sys_ilp32.c

diff --git a/arch/arm64/include/asm/unistd.h b/arch/arm64/include/asm/unistd.h
index 2971dea..5ea18ef 100644
--- a/arch/arm64/include/asm/unistd.h
+++ b/arch/arm64/include/asm/unistd.h
@@ -13,9 +13,18 @@
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
+
+#ifdef CONFIG_COMPAT
+#define __ARCH_WANT_COMPAT_STAT64
+#endif
+
+#ifdef CONFIG_ARM64_ILP32
+#define __ARCH_WANT_COMPAT_SYS_PREADV64
+#define __ARCH_WANT_COMPAT_SYS_PWRITEV64
+#endif
+
 #ifdef CONFIG_AARCH32_EL0
 #define __ARCH_WANT_COMPAT_SYS_GETDENTS64
-#define __ARCH_WANT_COMPAT_STAT64
 #define __ARCH_WANT_SYS_GETHOSTNAME
 #define __ARCH_WANT_SYS_PAUSE
 #define __ARCH_WANT_SYS_GETPGRP
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index ad7158c..a35f2f8 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -28,7 +28,7 @@ $(obj)/%.stub.o: $(obj)/%.o FORCE
 arm64-obj-$(CONFIG_AARCH32_EL0)		+= sys32.o kuser32.o signal32.o 	\
 					   sys_compat.o entry32.o		\
 					   ../../arm/kernel/opcodes.o binfmt_elf32.o
-arm64-obj-$(CONFIG_ARM64_ILP32)		+= binfmt_ilp32.o
+arm64-obj-$(CONFIG_ARM64_ILP32)		+= binfmt_ilp32.o sys_ilp32.o
 arm64-obj-$(CONFIG_FUNCTION_TRACER)	+= ftrace.o entry-ftrace.o
 arm64-obj-$(CONFIG_MODULES)		+= arm64ksyms.o module.o
 arm64-obj-$(CONFIG_PERF_EVENTS)		+= perf_regs.o perf_callchain.o
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 5eb1bb7..f348f58 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -666,9 +666,13 @@ ENDPROC(ret_from_fork)
  */
 	.align	6
 el0_svc:
-	adrp	stbl, sys_call_table		// load syscall table pointer
 	uxtw	scno, w8			// syscall number in w8
 	mov	sc_nr, #__NR_syscalls
+#ifdef CONFIG_ARM64_ILP32
+	ldr	x16, [tsk, #TI_FLAGS]
+	tbnz	x16, #TIF_32BIT_AARCH64, el0_ilp32_svc // We are using ILP32
+#endif
+	adrp	stbl, sys_call_table		// load syscall table pointer
 el0_svc_naked:					// compat entry point
 	stp	x0, scno, [sp, #S_ORIG_X0]	// save the original x0 and syscall number
 	enable_dbg_and_irq
@@ -688,6 +692,12 @@ ni_sys:
 	b	ret_fast_syscall
 ENDPROC(el0_svc)
 
+#ifdef CONFIG_ARM64_ILP32
+el0_ilp32_svc:
+	adrp	stbl, sys_call_ilp32_table // load syscall table pointer
+	b el0_svc_naked
+#endif
+
 	/*
 	 * This is the really slow path.  We're going to be doing context
 	 * switches, and waiting for our parent to respond.
diff --git a/arch/arm64/kernel/sys_ilp32.c b/arch/arm64/kernel/sys_ilp32.c
new file mode 100644
index 0000000..0659b89
--- /dev/null
+++ b/arch/arm64/kernel/sys_ilp32.c
@@ -0,0 +1,63 @@
+/*
+ * AArch64- ILP32 specific system calls implementation
+ *
+ * Copyright (C) 2016 Cavium Inc.
+ * Author: Andrew Pinski <apinski@xxxxxxxxxx>
+ *
+ * This program is free software; 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://www.gnu.org/licenses/>.
+ */
+
+#include <linux/compiler.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/msg.h>
+#include <linux/export.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/syscalls.h>
+#include <linux/compat.h>
+#include <asm-generic/syscalls.h>
+
+/* Using non-compat syscalls where necessary */
+#define compat_sys_fadvise64_64        sys_fadvise64_64
+#define compat_sys_fallocate           sys_fallocate
+#define compat_sys_ftruncate64         sys_ftruncate
+#define compat_sys_lookup_dcookie      sys_lookup_dcookie
+#define compat_sys_pread64             sys_pread64
+#define compat_sys_pwrite64            sys_pwrite64
+#define compat_sys_readahead           sys_readahead
+#define compat_sys_shmat               sys_shmat
+#define compat_sys_sync_file_range     sys_sync_file_range
+#define compat_sys_truncate64          sys_truncate
+#define sys_llseek                     sys_lseek
+#define sys_mmap2		       sys_mmap
+
+#include <asm/syscall.h>
+
+#undef __SYSCALL
+#undef __SC_COMP
+#undef __SC_3264
+#undef __SC_COMP_3264
+
+#define __SYSCALL_COMPAT
+#define __SYSCALL(nr, sym)	[nr] = sym,
+
+/*
+ * The sys_call_ilp32_table array must be 4K aligned to be accessible from
+ * kernel/entry.S.
+ */
+void *sys_call_ilp32_table[__NR_syscalls] __aligned(4096) = {
+	[0 ... __NR_syscalls - 1] = sys_ni_syscall,
+#include <asm/unistd.h>
+};
-- 
2.5.0