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Subject[PATCH v4 19/24] 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.

This revision of the patch now addresses Catalin's comment regarding the
duplicate reading of the task-flags in the el0_svc-handler and simply
relies on the flags having been read by the kernel_entry macro.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Signed-off-by: Christoph Muellner <christoph.muellner@theobroma-systems.com>
---
arch/arm64/include/asm/unistd.h | 4 +
arch/arm64/kernel/Makefile | 1 +
arch/arm64/kernel/entry.S | 12 ++-
arch/arm64/kernel/sys_ilp32.c | 173 ++++++++++++++++++++++++++++++++++++++++
4 files changed, 189 insertions(+), 1 deletion(-)
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 bed97c3..10397e8 100644
--- a/arch/arm64/include/asm/unistd.h
+++ b/arch/arm64/include/asm/unistd.h
@@ -13,6 +13,10 @@
* 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_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
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 3cf8120..131996d 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -23,6 +23,7 @@ arm64-obj-$(CONFIG_AARCH32_EL0) += sys32.o kuser32.o signal32.o \
sys_compat.o entry32.o \
../../arm/kernel/opcodes.o
arm64-obj-$(CONFIG_FUNCTION_TRACER) += ftrace.o entry-ftrace.o
+arm64-obj-$(CONFIG_ARM64_ILP32) += sys_ilp32.o
arm64-obj-$(CONFIG_MODULES) += arm64ksyms.o module.o
arm64-obj-$(CONFIG_SMP) += smp.o smp_spin_table.o topology.o
arm64-obj-$(CONFIG_PERF_EVENTS) += perf_regs.o
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 0dce3d0..39fdf67 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -642,9 +642,13 @@ 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
@@ -664,6 +668,12 @@ 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..06c05ce
--- /dev/null
+++ b/arch/arm64/kernel/sys_ilp32.c
@@ -0,0 +1,173 @@
+/*
+ * AArch64- ILP32 specific system calls implementation
+ *
+ * Copyright (C) 2013 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/>.
+ */
+
+#include <linux/compiler.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/export.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/syscalls.h>
+#include <linux/compat.h>
+
+/*
+ * Wrappers to pass the pt_regs argument.
+ */
+#define sys_rt_sigreturn sys_rt_sigreturn_wrapper
+
+/* Using Compat syscalls where necessary */
+#define sys_ioctl compat_sys_ioctl
+/* iovec */
+#define sys_readv compat_sys_readv
+#define sys_writev compat_sys_writev
+#define sys_preadv compat_sys_preadv64
+#define sys_pwritev compat_sys_pwritev64
+#define sys_vmsplice compat_sys_vmsplice
+/* robust_list_head */
+#define sys_set_robust_list compat_sys_set_robust_list
+#define sys_get_robust_list compat_sys_get_robust_list
+
+/* kexec_segment */
+#define sys_kexec_load compat_sys_kexec_load
+
+/* Ptrace has some structures which are different between ILP32 and LP64 */
+#define sys_ptrace compat_sys_ptrace
+
+/* struct msghdr */
+#define sys_recvfrom compat_sys_recvfrom
+#define sys_recvmmsg compat_sys_recvmmsg
+#define sys_sendmmsg compat_sys_sendmmsg
+#define sys_sendmsg compat_sys_sendmsg
+#define sys_recvmsg compat_sys_recvmsg
+
+#define sys_setsockopt compat_sys_setsockopt
+#define sys_getsockopt compat_sys_getsockopt
+
+/* Array of pointers */
+#define sys_execve compat_sys_execve
+#define sys_move_pages compat_sys_move_pages
+
+/* iovec */
+#define sys_process_vm_readv compat_sys_process_vm_readv
+#define sys_process_vm_writev compat_sys_process_vm_writev
+
+/* Pointer in struct */
+#define sys_mount compat_sys_mount
+
+/* NUMA */
+/* unsigned long bitmaps */
+#define sys_get_mempolicy compat_sys_get_mempolicy
+#define sys_set_mempolicy compat_sys_set_mempolicy
+#define sys_mbind compat_sys_mbind
+/* array of pointers */
+/* unsigned long bitmaps */
+#define sys_migrate_pages compat_sys_migrate_pages
+
+/* Scheduler */
+/* unsigned long bitmaps */
+#define sys_sched_setaffinity compat_sys_sched_setaffinity
+#define sys_sched_getaffinity compat_sys_sched_getaffinity
+
+/* iov usage */
+#define sys_keyctl compat_sys_keyctl
+
+/* aio */
+/* Pointer to Pointer */
+#define sys_io_setup compat_sys_io_setup
+/* Array of pointers */
+#define sys_io_submit compat_sys_io_submit
+
+/* We need to make sure the pointer gets copied correctly. */
+asmlinkage long ilp32_sys_mq_notify(mqd_t mqdes, const struct sigevent __user *u_notification)
+{
+ struct sigevent __user *p = NULL;
+ if (u_notification) {
+ struct sigevent n;
+ p = compat_alloc_user_space(sizeof(*p));
+ if (copy_from_user(&n, u_notification, sizeof(*p)))
+ return -EFAULT;
+ if (n.sigev_notify == SIGEV_THREAD)
+ n.sigev_value.sival_ptr = compat_ptr((uintptr_t)n.sigev_value.sival_ptr);
+ if (copy_to_user(p, &n, sizeof(*p)))
+ return -EFAULT;
+ }
+ return sys_mq_notify(mqdes, p);
+}
+
+/* sigevent contains sigval_t which is now 64bit always
+ but need special handling due to padding for SIGEV_THREAD. */
+#define sys_mq_notify ilp32_sys_mq_notify
+
+
+/* sigaltstack needs some special handling as the
+ padding for stack_t might not be non-zero. */
+long ilp32_sys_sigaltstack(const stack_t __user *uss_ptr,
+ stack_t __user *uoss_ptr)
+{
+ stack_t uss, uoss;
+ int ret;
+ mm_segment_t seg;
+
+ if (uss_ptr) {
+ if (!access_ok(VERIFY_READ, uss_ptr, sizeof(*uss_ptr)))
+ return -EFAULT;
+ if (__get_user(uss.ss_sp, &uss_ptr->ss_sp) |
+ __get_user(uss.ss_flags, &uss_ptr->ss_flags) |
+ __get_user(uss.ss_size, &uss_ptr->ss_size))
+ return -EFAULT;
+ /* Zero extend the sp address and the size. */
+ uss.ss_sp = (void *)(uintptr_t)(unsigned int)(uintptr_t)uss.ss_sp;
+ uss.ss_size = (size_t)(unsigned int)uss.ss_size;
+ }
+ seg = get_fs();
+ set_fs(KERNEL_DS);
+ /* Note we need to use uoss as we have changed the segment to the
+ kernel one so passing an user one around is wrong. */
+ ret = sys_sigaltstack((stack_t __force __user *) (uss_ptr ? &uss : NULL),
+ (stack_t __force __user *) &uoss);
+ set_fs(seg);
+ if (ret >= 0 && uoss_ptr) {
+ if (!access_ok(VERIFY_WRITE, uoss_ptr, sizeof(stack_t)) ||
+ __put_user(uoss.ss_sp, &uoss_ptr->ss_sp) ||
+ __put_user(uoss.ss_flags, &uoss_ptr->ss_flags) ||
+ __put_user(uoss.ss_size, &uoss_ptr->ss_size))
+ ret = -EFAULT;
+ }
+ return ret;
+}
+
+/* sigaltstack needs some special handling as the padding
+ for stack_t might not be non-zero. */
+#define sys_sigaltstack ilp32_sys_sigaltstack
+
+
+#include <asm/syscalls.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>
+};
--
1.9.1


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