2012-03-05 19:49:31 +08:00
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/*
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* AArch64-specific system calls implementation
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*
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* Copyright (C) 2012 ARM Ltd.
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* Author: Catalin Marinas <catalin.marinas@arm.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/compiler.h>
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#include <linux/errno.h>
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#include <linux/fs.h>
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#include <linux/mm.h>
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#include <linux/export.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/syscalls.h>
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2018-07-11 21:56:42 +08:00
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2016-04-18 17:28:37 +08:00
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#include <asm/cpufeature.h>
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2018-07-11 21:56:42 +08:00
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#include <asm/syscall.h>
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2012-03-05 19:49:31 +08:00
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2018-07-11 21:56:54 +08:00
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SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
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unsigned long, prot, unsigned long, flags,
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unsigned long, fd, off_t, off)
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2012-03-05 19:49:31 +08:00
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{
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if (offset_in_page(off) != 0)
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return -EINVAL;
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2018-03-11 18:34:46 +08:00
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return ksys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
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2012-03-05 19:49:31 +08:00
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}
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2016-04-18 17:28:37 +08:00
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SYSCALL_DEFINE1(arm64_personality, unsigned int, personality)
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{
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if (personality(personality) == PER_LINUX32 &&
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!system_supports_32bit_el0())
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return -EINVAL;
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2018-07-11 21:56:52 +08:00
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return ksys_personality(personality);
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2016-04-18 17:28:37 +08:00
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}
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2012-03-05 19:49:31 +08:00
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/*
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* Wrappers to pass the pt_regs argument.
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*/
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2016-04-18 17:28:37 +08:00
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#define sys_personality sys_arm64_personality
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2012-03-05 19:49:31 +08:00
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arm64: implement syscall wrappers
To minimize the risk of userspace-controlled values being used under
speculation, this patch adds pt_regs based syscall wrappers for arm64,
which pass the minimum set of required userspace values to syscall
implementations. For each syscall, a wrapper which takes a pt_regs
argument is automatically generated, and this extracts the arguments
before calling the "real" syscall implementation.
Each syscall has three functions generated:
* __do_<compat_>sys_<name> is the "real" syscall implementation, with
the expected prototype.
* __se_<compat_>sys_<name> is the sign-extension/narrowing wrapper,
inherited from common code. This takes a series of long parameters,
casting each to the requisite types required by the "real" syscall
implementation in __do_<compat_>sys_<name>.
This wrapper *may* not be necessary on arm64 given the AAPCS rules on
unused register bits, but it seemed safer to keep the wrapper for now.
* __arm64_<compat_>_sys_<name> takes a struct pt_regs pointer, and
extracts *only* the relevant register values, passing these on to the
__se_<compat_>sys_<name> wrapper.
The syscall invocation code is updated to handle the calling convention
required by __arm64_<compat_>_sys_<name>, and passes a single struct
pt_regs pointer.
The compiler can fold the syscall implementation and its wrappers, such
that the overhead of this approach is minimized.
Note that we play games with sys_ni_syscall(). It can't be defined with
SYSCALL_DEFINE0() because we must avoid the possibility of error
injection. Additionally, there are a couple of locations where we need
to call it from C code, and we don't (currently) have a
ksys_ni_syscall(). While it has no wrapper, passing in a redundant
pt_regs pointer is benign per the AAPCS.
When ARCH_HAS_SYSCALL_WRAPPER is selected, no prototype is defines for
sys_ni_syscall(). Since we need to treat it differently for in-kernel
calls and the syscall tables, the prototype is defined as-required.
The wrappers are largely the same as their x86 counterparts, but
simplified as we don't have a variety of compat calling conventions that
require separate stubs. Unlike x86, we have some zero-argument compat
syscalls, and must define COMPAT_SYSCALL_DEFINE0() to ensure that these
are also given an __arm64_compat_sys_ prefix.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2018-07-11 21:56:56 +08:00
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asmlinkage long sys_ni_syscall(const struct pt_regs *);
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#define __arm64_sys_ni_syscall sys_ni_syscall
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#undef __SYSCALL
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#define __SYSCALL(nr, sym) asmlinkage long __arm64_##sym(const struct pt_regs *);
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#include <asm/unistd.h>
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2012-03-05 19:49:31 +08:00
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#undef __SYSCALL
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arm64: implement syscall wrappers
To minimize the risk of userspace-controlled values being used under
speculation, this patch adds pt_regs based syscall wrappers for arm64,
which pass the minimum set of required userspace values to syscall
implementations. For each syscall, a wrapper which takes a pt_regs
argument is automatically generated, and this extracts the arguments
before calling the "real" syscall implementation.
Each syscall has three functions generated:
* __do_<compat_>sys_<name> is the "real" syscall implementation, with
the expected prototype.
* __se_<compat_>sys_<name> is the sign-extension/narrowing wrapper,
inherited from common code. This takes a series of long parameters,
casting each to the requisite types required by the "real" syscall
implementation in __do_<compat_>sys_<name>.
This wrapper *may* not be necessary on arm64 given the AAPCS rules on
unused register bits, but it seemed safer to keep the wrapper for now.
* __arm64_<compat_>_sys_<name> takes a struct pt_regs pointer, and
extracts *only* the relevant register values, passing these on to the
__se_<compat_>sys_<name> wrapper.
The syscall invocation code is updated to handle the calling convention
required by __arm64_<compat_>_sys_<name>, and passes a single struct
pt_regs pointer.
The compiler can fold the syscall implementation and its wrappers, such
that the overhead of this approach is minimized.
Note that we play games with sys_ni_syscall(). It can't be defined with
SYSCALL_DEFINE0() because we must avoid the possibility of error
injection. Additionally, there are a couple of locations where we need
to call it from C code, and we don't (currently) have a
ksys_ni_syscall(). While it has no wrapper, passing in a redundant
pt_regs pointer is benign per the AAPCS.
When ARCH_HAS_SYSCALL_WRAPPER is selected, no prototype is defines for
sys_ni_syscall(). Since we need to treat it differently for in-kernel
calls and the syscall tables, the prototype is defined as-required.
The wrappers are largely the same as their x86 counterparts, but
simplified as we don't have a variety of compat calling conventions that
require separate stubs. Unlike x86, we have some zero-argument compat
syscalls, and must define COMPAT_SYSCALL_DEFINE0() to ensure that these
are also given an __arm64_compat_sys_ prefix.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2018-07-11 21:56:56 +08:00
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#define __SYSCALL(nr, sym) [nr] = (syscall_fn_t)__arm64_##sym,
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2012-03-05 19:49:31 +08:00
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2018-07-11 21:56:49 +08:00
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const syscall_fn_t sys_call_table[__NR_syscalls] = {
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2018-07-11 21:56:42 +08:00
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[0 ... __NR_syscalls - 1] = (syscall_fn_t)sys_ni_syscall,
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2012-03-05 19:49:31 +08:00
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#include <asm/unistd.h>
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};
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