Merge branch 'x86-entry-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 entry updates from Ingo Molnar: "This contains x32 and compat syscall improvements, the biggest one of which splits x32 syscalls into their own table, which allows new syscalls to share the x32 and x86-64 number - which turns the 512-547 special syscall numbers range into a legacy wart that won't be extended going forward" * 'x86-entry-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/syscalls: Split the x32 syscalls into their own table x86/syscalls: Disallow compat entries for all types of 64-bit syscalls x86/syscalls: Use the compat versions of rt_sigsuspend() and rt_sigprocmask() x86/syscalls: Make __X32_SYSCALL_BIT be unsigned long
This commit is contained in:
Linus Torvalds
commit
e0d60a1e68
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@ -285,15 +285,16 @@ __visible void do_syscall_64(unsigned long nr, struct pt_regs *regs)
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if (READ_ONCE(ti->flags) & _TIF_WORK_SYSCALL_ENTRY)
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nr = syscall_trace_enter(regs);
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/*
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* NB: Native and x32 syscalls are dispatched from the same
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* table. The only functional difference is the x32 bit in
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* regs->orig_ax, which changes the behavior of some syscalls.
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*/
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nr &= __SYSCALL_MASK;
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if (likely(nr < NR_syscalls)) {
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nr = array_index_nospec(nr, NR_syscalls);
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regs->ax = sys_call_table[nr](regs);
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#ifdef CONFIG_X86_X32_ABI
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} else if (likely((nr & __X32_SYSCALL_BIT) &&
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(nr & ~__X32_SYSCALL_BIT) < X32_NR_syscalls)) {
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nr = array_index_nospec(nr & ~__X32_SYSCALL_BIT,
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X32_NR_syscalls);
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regs->ax = x32_sys_call_table[nr](regs);
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#endif
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}
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syscall_return_slowpath(regs);
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@ -10,10 +10,13 @@
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/* this is a lie, but it does not hurt as sys_ni_syscall just returns -EINVAL */
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extern asmlinkage long sys_ni_syscall(const struct pt_regs *);
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#define __SYSCALL_64(nr, sym, qual) extern asmlinkage long sym(const struct pt_regs *);
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#define __SYSCALL_X32(nr, sym, qual) __SYSCALL_64(nr, sym, qual)
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#include <asm/syscalls_64.h>
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#undef __SYSCALL_64
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#undef __SYSCALL_X32
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#define __SYSCALL_64(nr, sym, qual) [nr] = sym,
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#define __SYSCALL_X32(nr, sym, qual)
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asmlinkage const sys_call_ptr_t sys_call_table[__NR_syscall_max+1] = {
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/*
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@ -23,3 +26,25 @@ asmlinkage const sys_call_ptr_t sys_call_table[__NR_syscall_max+1] = {
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[0 ... __NR_syscall_max] = &sys_ni_syscall,
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#include <asm/syscalls_64.h>
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};
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#undef __SYSCALL_64
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#undef __SYSCALL_X32
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#ifdef CONFIG_X86_X32_ABI
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#define __SYSCALL_64(nr, sym, qual)
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#define __SYSCALL_X32(nr, sym, qual) [nr] = sym,
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asmlinkage const sys_call_ptr_t x32_sys_call_table[__NR_syscall_x32_max+1] = {
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/*
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* Smells like a compiler bug -- it doesn't work
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* when the & below is removed.
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*/
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[0 ... __NR_syscall_x32_max] = &sys_ni_syscall,
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#include <asm/syscalls_64.h>
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};
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#undef __SYSCALL_64
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#undef __SYSCALL_X32
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#endif
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@ -186,11 +186,11 @@
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172 i386 prctl sys_prctl __ia32_sys_prctl
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173 i386 rt_sigreturn sys_rt_sigreturn sys32_rt_sigreturn
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174 i386 rt_sigaction sys_rt_sigaction __ia32_compat_sys_rt_sigaction
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175 i386 rt_sigprocmask sys_rt_sigprocmask __ia32_sys_rt_sigprocmask
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175 i386 rt_sigprocmask sys_rt_sigprocmask __ia32_compat_sys_rt_sigprocmask
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176 i386 rt_sigpending sys_rt_sigpending __ia32_compat_sys_rt_sigpending
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177 i386 rt_sigtimedwait sys_rt_sigtimedwait_time32 __ia32_compat_sys_rt_sigtimedwait_time32
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178 i386 rt_sigqueueinfo sys_rt_sigqueueinfo __ia32_compat_sys_rt_sigqueueinfo
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179 i386 rt_sigsuspend sys_rt_sigsuspend __ia32_sys_rt_sigsuspend
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179 i386 rt_sigsuspend sys_rt_sigsuspend __ia32_compat_sys_rt_sigsuspend
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180 i386 pread64 sys_pread64 __ia32_compat_sys_x86_pread
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181 i386 pwrite64 sys_pwrite64 __ia32_compat_sys_x86_pwrite
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182 i386 chown sys_chown16 __ia32_sys_chown16
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@ -1,13 +1,13 @@
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#!/bin/sh
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#!/bin/bash
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# SPDX-License-Identifier: GPL-2.0
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in="$1"
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out="$2"
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syscall_macro() {
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abi="$1"
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nr="$2"
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entry="$3"
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local abi="$1"
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local nr="$2"
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local entry="$3"
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# Entry can be either just a function name or "function/qualifier"
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real_entry="${entry%%/*}"
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@ -21,14 +21,14 @@ syscall_macro() {
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}
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emit() {
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abi="$1"
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nr="$2"
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entry="$3"
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compat="$4"
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umlentry=""
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local abi="$1"
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local nr="$2"
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local entry="$3"
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local compat="$4"
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local umlentry=""
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if [ "$abi" = "64" -a -n "$compat" ]; then
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echo "a compat entry for a 64-bit syscall makes no sense" >&2
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if [ "$abi" != "I386" -a -n "$compat" ]; then
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echo "a compat entry ($abi: $compat) for a 64-bit syscall makes no sense" >&2
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exit 1
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fi
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@ -62,14 +62,17 @@ grep '^[0-9]' "$in" | sort -n | (
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while read nr abi name entry compat; do
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abi=`echo "$abi" | tr '[a-z]' '[A-Z]'`
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if [ "$abi" = "COMMON" -o "$abi" = "64" ]; then
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# COMMON is the same as 64, except that we don't expect X32
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# programs to use it. Our expectation has nothing to do with
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# any generated code, so treat them the same.
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emit 64 "$nr" "$entry" "$compat"
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elif [ "$abi" = "X32" ]; then
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# X32 is equivalent to 64 on an X32-compatible kernel.
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if [ "$abi" = "COMMON" ]; then
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# COMMON means that this syscall exists in the same form for
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# 64-bit and X32.
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echo "#ifdef CONFIG_X86_X32_ABI"
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emit 64 "$nr" "$entry" "$compat"
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emit X32 "$nr" "$entry" "$compat"
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echo "#endif"
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fi
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elif [ "$abi" = "X32" ]; then
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echo "#ifdef CONFIG_X86_X32_ABI"
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emit X32 "$nr" "$entry" "$compat"
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echo "#endif"
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elif [ "$abi" = "I386" ]; then
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emit "$abi" "$nr" "$entry" "$compat"
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@ -36,6 +36,10 @@ extern const sys_call_ptr_t sys_call_table[];
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extern const sys_call_ptr_t ia32_sys_call_table[];
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#endif
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#ifdef CONFIG_X86_X32_ABI
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extern const sys_call_ptr_t x32_sys_call_table[];
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#endif
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/*
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* Only the low 32 bits of orig_ax are meaningful, so we return int.
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* This importantly ignores the high bits on 64-bit, so comparisons
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@ -5,12 +5,6 @@
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#include <uapi/asm/unistd.h>
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# ifdef CONFIG_X86_X32_ABI
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# define __SYSCALL_MASK (~(__X32_SYSCALL_BIT))
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# else
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# define __SYSCALL_MASK (~0)
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# endif
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# ifdef CONFIG_X86_32
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# include <asm/unistd_32.h>
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@ -3,7 +3,7 @@
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#define _UAPI_ASM_X86_UNISTD_H
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/* x32 syscall flag bit */
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#define __X32_SYSCALL_BIT 0x40000000
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#define __X32_SYSCALL_BIT 0x40000000UL
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#ifndef __KERNEL__
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# ifdef __i386__
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@ -6,13 +6,28 @@
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#include <asm/ia32.h>
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#define __SYSCALL_64(nr, sym, qual) [nr] = 1,
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#define __SYSCALL_X32(nr, sym, qual)
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static char syscalls_64[] = {
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#include <asm/syscalls_64.h>
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};
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#undef __SYSCALL_64
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#undef __SYSCALL_X32
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#ifdef CONFIG_X86_X32_ABI
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#define __SYSCALL_64(nr, sym, qual)
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#define __SYSCALL_X32(nr, sym, qual) [nr] = 1,
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static char syscalls_x32[] = {
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#include <asm/syscalls_64.h>
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};
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#undef __SYSCALL_64
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#undef __SYSCALL_X32
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#endif
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#define __SYSCALL_I386(nr, sym, qual) [nr] = 1,
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static char syscalls_ia32[] = {
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#include <asm/syscalls_32.h>
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};
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#undef __SYSCALL_I386
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#if defined(CONFIG_KVM_GUEST) && defined(CONFIG_PARAVIRT_SPINLOCKS)
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#include <asm/kvm_para.h>
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@ -80,6 +95,11 @@ int main(void)
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DEFINE(__NR_syscall_max, sizeof(syscalls_64) - 1);
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DEFINE(NR_syscalls, sizeof(syscalls_64));
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#ifdef CONFIG_X86_X32_ABI
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DEFINE(__NR_syscall_x32_max, sizeof(syscalls_x32) - 1);
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DEFINE(X32_NR_syscalls, sizeof(syscalls_x32));
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#endif
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DEFINE(__NR_syscall_compat_max, sizeof(syscalls_ia32) - 1);
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DEFINE(IA32_NR_syscalls, sizeof(syscalls_ia32));
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@ -17,7 +17,7 @@ TARGETS_C_BOTHBITS := single_step_syscall sysret_ss_attrs syscall_nt test_mremap
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TARGETS_C_32BIT_ONLY := entry_from_vm86 test_syscall_vdso unwind_vdso \
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test_FCMOV test_FCOMI test_FISTTP \
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vdso_restorer
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TARGETS_C_64BIT_ONLY := fsgsbase sysret_rip
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TARGETS_C_64BIT_ONLY := fsgsbase sysret_rip syscall_numbering
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# Some selftests require 32bit support enabled also on 64bit systems
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TARGETS_C_32BIT_NEEDED := ldt_gdt ptrace_syscall
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@ -0,0 +1,89 @@
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/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* syscall_arg_fault.c - tests faults 32-bit fast syscall stack args
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* Copyright (c) 2018 Andrew Lutomirski
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*/
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#define _GNU_SOURCE
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#include <stdlib.h>
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#include <stdio.h>
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#include <stdbool.h>
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#include <errno.h>
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#include <unistd.h>
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#include <syscall.h>
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static int nerrs;
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#define X32_BIT 0x40000000UL
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static void check_enosys(unsigned long nr, bool *ok)
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{
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/* If this fails, a segfault is reasonably likely. */
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fflush(stdout);
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long ret = syscall(nr, 0, 0, 0, 0, 0, 0);
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if (ret == 0) {
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printf("[FAIL]\tsyscall %lu succeeded, but it should have failed\n", nr);
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*ok = false;
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} else if (errno != ENOSYS) {
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printf("[FAIL]\tsyscall %lu had error code %d, but it should have reported ENOSYS\n", nr, errno);
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*ok = false;
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}
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}
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static void test_x32_without_x32_bit(void)
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{
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bool ok = true;
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/*
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* Syscalls 512-547 are "x32" syscalls. They are intended to be
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* called with the x32 (0x40000000) bit set. Calling them without
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* the x32 bit set is nonsense and should not work.
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*/
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printf("[RUN]\tChecking syscalls 512-547\n");
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for (int i = 512; i <= 547; i++)
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check_enosys(i, &ok);
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/*
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* Check that a handful of 64-bit-only syscalls are rejected if the x32
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* bit is set.
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*/
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printf("[RUN]\tChecking some 64-bit syscalls in x32 range\n");
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check_enosys(16 | X32_BIT, &ok); /* ioctl */
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check_enosys(19 | X32_BIT, &ok); /* readv */
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check_enosys(20 | X32_BIT, &ok); /* writev */
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/*
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* Check some syscalls with high bits set.
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*/
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printf("[RUN]\tChecking numbers above 2^32-1\n");
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check_enosys((1UL << 32), &ok);
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check_enosys(X32_BIT | (1UL << 32), &ok);
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if (!ok)
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nerrs++;
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else
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printf("[OK]\tThey all returned -ENOSYS\n");
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}
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int main()
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{
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/*
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* Anyone diagnosing a failure will want to know whether the kernel
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* supports x32. Tell them.
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*/
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printf("\tChecking for x32...");
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fflush(stdout);
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if (syscall(39 | X32_BIT, 0, 0, 0, 0, 0, 0) >= 0) {
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printf(" supported\n");
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} else if (errno == ENOSYS) {
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printf(" not supported\n");
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} else {
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printf(" confused\n");
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}
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test_x32_without_x32_bit();
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return nerrs ? 1 : 0;
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}
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