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Subject[PATCH 14/20] arm64: ilp32: add sys_ilp32.c and a separate table (in entry.S) to use it
Date
From: Andrew Pinski <apinski@cavium.com>

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@caviumnetworks.com>
Signed-off-by: Yury Norov <ynorov@caviumnetworks.com>
---
arch/arm64/include/asm/unistd.h | 8 ++-
arch/arm64/include/uapi/asm/unistd.h | 12 +++++
arch/arm64/kernel/Makefile | 2 +-
arch/arm64/kernel/entry.S | 28 +++++++++-
arch/arm64/kernel/sys_ilp32.c | 100 +++++++++++++++++++++++++++++++++++
5 files changed, 145 insertions(+), 5 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 fe9d6c1..851cc8a 100644
--- a/arch/arm64/include/asm/unistd.h
+++ b/arch/arm64/include/asm/unistd.h
@@ -13,13 +13,17 @@
* 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
+#define __ARCH_WANT_SYS_LLSEEK
+#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
-#define __ARCH_WANT_SYS_LLSEEK
#define __ARCH_WANT_SYS_NICE
#define __ARCH_WANT_SYS_SIGPENDING
#define __ARCH_WANT_SYS_SIGPROCMASK
diff --git a/arch/arm64/include/uapi/asm/unistd.h b/arch/arm64/include/uapi/asm/unistd.h
index 48355a6..e7106bb 100644
--- a/arch/arm64/include/uapi/asm/unistd.h
+++ b/arch/arm64/include/uapi/asm/unistd.h
@@ -14,7 +14,19 @@
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/

+/*
+ * Use AARCH32 interface for sys_sync_file_range() as it passes 64-bit arguments.
+ */
+#if defined(__ILP32__) || defined(__SYSCALL_COMPAT)
+#define __ARCH_WANT_SYNC_FILE_RANGE2
+#endif
+
+/*
+ * AARCH64/ILP32 is introduced after next syscalls were deprecated.
+ */
+#if !(defined(__ILP32__) || defined(__SYSCALL_COMPAT))
#define __ARCH_WANT_RENAMEAT
#define __ARCH_WANT_SET_GET_RLIMIT
+#endif

#include <asm-generic/unistd.h>
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 9123bb8..06070f5 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -29,7 +29,7 @@ $(obj)/%.stub.o: $(obj)/%.o FORCE

arm64-obj-$(CONFIG_AARCH32_EL0) += sys32.o kuser32.o signal32.o \
sys_compat.o entry32.o binfmt_elf32.o
-arm64-obj-$(CONFIG_ARM64_ILP32) += binfmt_ilp32.o
+arm64-obj-$(CONFIG_ARM64_ILP32) += binfmt_ilp32.o sys_ilp32.o
arm64-obj-$(CONFIG_COMPAT) += entry32_common.o
arm64-obj-$(CONFIG_FUNCTION_TRACER) += ftrace.o entry-ftrace.o
arm64-obj-$(CONFIG_MODULES) += arm64ksyms.o module.o
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 45e74df..9b1ac4c 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -308,6 +308,23 @@ tsk .req x28 // current thread_info

.text

+#ifdef CONFIG_ARM64_ILP32
+/*
+ * AARCH64/ILP32. Zero top halves of x0-x7
+ * registers as userspace may put garbage there.
+ */
+ .macro delouse_input_regs
+ mov w0, w0
+ mov w1, w1
+ mov w2, w2
+ mov w3, w3
+ mov w4, w4
+ mov w5, w5
+ mov w6, w6
+ mov w7, w7
+ .endm
+#endif
+
/*
* Exception vectors.
*/
@@ -576,6 +593,7 @@ el0_svc_compat:
* AArch32 syscall handling
*/
adrp stbl, compat_sys_call_table // load compat syscall table pointer
+ ldr x16, [tsk, #TSK_TI_FLAGS]
uxtw scno, w7 // syscall number in w7 (r7)
mov sc_nr, #__NR_compat_syscalls
b el0_svc_naked
@@ -797,15 +815,21 @@ ENDPROC(ret_from_fork)
.align 6
el0_svc:
adrp stbl, sys_call_table // load syscall table pointer
+ ldr x16, [tsk, #TSK_TI_FLAGS]
uxtw scno, w8 // syscall number in w8
mov sc_nr, #__NR_syscalls
+#ifdef CONFIG_ARM64_ILP32
+ tst x16, #_TIF_32BIT_AARCH64
+ b.eq el0_svc_naked // We are using LP64 syscall table
+ adrp stbl, sys_call_ilp32_table // load ilp32 syscall table pointer
+ delouse_input_regs
+#endif
el0_svc_naked: // compat entry point
stp x0, scno, [sp, #S_ORIG_X0] // save the original x0 and syscall number
enable_dbg_and_irq
ct_user_exit 1

- ldr x16, [tsk, #TSK_TI_FLAGS] // check for syscall hooks
- tst x16, #_TIF_SYSCALL_WORK
+ tst x16, #_TIF_SYSCALL_WORK // check for syscall hooks
b.ne __sys_trace
cmp scno, sc_nr // check upper syscall limit
b.hs ni_sys
diff --git a/arch/arm64/kernel/sys_ilp32.c b/arch/arm64/kernel/sys_ilp32.c
new file mode 100644
index 0000000..d203dec
--- /dev/null
+++ b/arch/arm64/kernel/sys_ilp32.c
@@ -0,0 +1,100 @@
+/*
+ * AArch64- ILP32 specific system calls implementation
+ *
+ * Copyright (C) 2017 Cavium Inc.
+ * Author: Andrew Pinski <apinski@cavium.com>
+ *
+ * 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/>.
+ */
+
+#define __SYSCALL_COMPAT
+
+#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>
+
+/*
+ * AARCH32 requires 4-page alignement for shared memory,
+ * but AARCH64 - only 1 page. This is the only difference
+ * between compat and native sys_shmat(). So ILP32 just pick
+ * AARCH64 version.
+ */
+#define compat_sys_shmat sys_shmat
+
+/*
+ * ILP32 needs special handling for some ptrace requests.
+ */
+#define sys_ptrace compat_sys_ptrace
+
+/*
+ * Using AARCH32 interface for syscalls that take 64-bit
+ * parameters in registers.
+ */
+#define compat_sys_fadvise64_64 compat_sys_fadvise64_64_wrapper
+#define compat_sys_fallocate compat_sys_fallocate_wrapper
+#define compat_sys_ftruncate64 compat_sys_ftruncate64_wrapper
+#define compat_sys_pread64 compat_sys_pread64_wrapper
+#define compat_sys_pwrite64 compat_sys_pwrite64_wrapper
+#define compat_sys_readahead compat_sys_readahead_wrapper
+#define compat_sys_sync_file_range2 compat_sys_sync_file_range2_wrapper
+#define compat_sys_truncate64 compat_sys_truncate64_wrapper
+#define sys_mmap2 compat_sys_mmap2_wrapper
+
+/*
+ * Using AARCH32 interface for syscalls that take the size of
+ * sfruct statfs as an argument, as it's calculated differently
+ * in kernel and user spaces.
+ */
+#define compat_sys_fstatfs64 compat_sys_fstatfs64_wrapper
+#define compat_sys_statfs64 compat_sys_statfs64_wrapper
+
+/*
+ * Using custom wrapper for rt_sigreturn() to handle custom
+ * struct rt_sigframe.
+ */
+#define compat_sys_rt_sigreturn ilp32_sys_rt_sigreturn_wrapper
+
+asmlinkage long compat_sys_fstatfs64_wrapper(void);
+asmlinkage long compat_sys_statfs64_wrapper(void);
+asmlinkage long compat_sys_fadvise64_64_wrapper(void);
+asmlinkage long compat_sys_fallocate_wrapper(void);
+asmlinkage long compat_sys_ftruncate64_wrapper(void);
+asmlinkage long compat_sys_mmap2_wrapper(void);
+asmlinkage long compat_sys_pread64_wrapper(void);
+asmlinkage long compat_sys_pwrite64_wrapper(void);
+asmlinkage long compat_sys_readahead_wrapper(void);
+asmlinkage long compat_sys_sync_file_range2_wrapper(void);
+asmlinkage long compat_sys_truncate64_wrapper(void);
+asmlinkage long ilp32_sys_rt_sigreturn_wrapper(void);
+
+#include <asm/syscall.h>
+
+#undef __SYSCALL
+#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>
+};
--
2.7.4
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