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SubjectRe: [PATCH 14/19] arm64: ilp32: add sys_ilp32.c and a separate table (in entry.S) to use it
On Sat, Jun 18, 2016 at 02:54:23AM +0300, Yury Norov wrote:
> 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 | 6 ++-
> arch/arm64/kernel/Makefile | 2 +-
> arch/arm64/kernel/entry.S | 29 +++++++++++++-
> arch/arm64/kernel/sys_ilp32.c | 84 +++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 117 insertions(+), 4 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..250654c 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_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/kernel/Makefile b/arch/arm64/kernel/Makefile
> index d11572d..205bc03 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-$(CONFIG_COMPAT) += entry32_common.o
> arm64-obj-$(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 21a0624..b2b9725 100644
> --- a/arch/arm64/kernel/entry.S
> +++ b/arch/arm64/kernel/entry.S
> @@ -239,6 +239,23 @@ 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.
> */
> @@ -501,6 +518,7 @@ el0_svc_compat:
> * AArch32 syscall handling
> */
> adrp stbl, compat_sys_call_table // load compat syscall table pointer
> + ldr x16, [tsk, #TI_FLAGS]
> uxtw scno, w7 // syscall number in w7 (r7)
> mov sc_nr, #__NR_compat_syscalls
> b el0_svc_naked
> @@ -717,15 +735,22 @@ ENDPROC(ret_from_fork)
> .align 6
> el0_svc:
> adrp stbl, sys_call_table // load syscall table pointer
> + ldr x16, [tsk, #TI_FLAGS]
> uxtw scno, w8 // syscall number in w8
> mov sc_nr, #__NR_syscalls
> +#ifdef CONFIG_ARM64_ILP32
> + adrp x17, sys_call_ilp32_table // load ilp32 syscall table pointer
> + tst x16, #_TIF_32BIT_AARCH64
> + b.eq el0_svc_naked // We are using LP64 syscall table
> + mov stbl, x17 // We are using ILP32 syscall table
> + delouse_input_regs
> +#endif

It should be like this:
#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, #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..00c4d4b
> --- /dev/null
> +++ b/arch/arm64/kernel/sys_ilp32.c
> @@ -0,0 +1,84 @@
> +/*
> + * AArch64- ILP32 specific system calls implementation
> + *
> + * Copyright (C) 2016 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>
> +
> +/*
> + * Using aarch32 syscall handlerss where off_t is passed.
> + */
> +#define compat_sys_fadvise64_64 compat_sys_fadvise64_64_wrapper
> +#define compat_sys_fallocate compat_sys_fallocate_wrapper
> +#define compat_sys_fcntl64 sys_fcntl
> +#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_shmat sys_shmat
> +#define compat_sys_sync_file_range compat_sys_sync_file_range2_wrapper
> +#define compat_sys_truncate64 compat_sys_truncate64_wrapper
> +#define sys_mmap2 compat_sys_mmap2_wrapper
> +#define sys_ptrace compat_sys_ptrace
> +
> +/*
> + * Use non-compat syscall handlerss where stat and statfs structure
> + * pointers are passed, as their layout is identical to LP64.
> + */
> +#define compat_sys_fstatfs64 sys_fstatfs
> +#define compat_sys_statfs64 sys_statfs
> +#define sys_fstat64 sys_newfstat
> +#define sys_fstatat64 sys_newfstatat
> +
> +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);
> +#define compat_sys_rt_sigreturn ilp32_sys_rt_sigreturn_wrapper
> +
> +#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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