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authorLinus Torvalds <torvalds@linux-foundation.org>2019-09-16 19:06:29 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-09-16 19:06:29 -0700
commite0d60a1e68a3fbf42cdf3546004e00230d9048ba (patch)
treee283f864ee0d53fa8df68701b463365e6b73683b
parent22331f895298bd23ca9f99f6a237aae883c9e1c7 (diff)
parent6365b842aae4490ebfafadfc6bb27a6d3cc54757 (diff)
downloadlinux-e0d60a1e68a3fbf42cdf3546004e00230d9048ba.tar.bz2
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
-rw-r--r--arch/x86/entry/common.c13
-rw-r--r--arch/x86/entry/syscall_64.c25
-rw-r--r--arch/x86/entry/syscalls/syscall_32.tbl4
-rw-r--r--arch/x86/entry/syscalls/syscalltbl.sh35
-rw-r--r--arch/x86/include/asm/syscall.h4
-rw-r--r--arch/x86/include/asm/unistd.h6
-rw-r--r--arch/x86/include/uapi/asm/unistd.h2
-rw-r--r--arch/x86/kernel/asm-offsets_64.c20
-rw-r--r--tools/testing/selftests/x86/Makefile2
-rw-r--r--tools/testing/selftests/x86/syscall_numbering.c89
10 files changed, 168 insertions, 32 deletions
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index 536b574b6161..3f8e22615812 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -285,15 +285,16 @@ __visible void do_syscall_64(unsigned long nr, struct pt_regs *regs)
if (READ_ONCE(ti->flags) & _TIF_WORK_SYSCALL_ENTRY)
nr = syscall_trace_enter(regs);
- /*
- * NB: Native and x32 syscalls are dispatched from the same
- * table. The only functional difference is the x32 bit in
- * regs->orig_ax, which changes the behavior of some syscalls.
- */
- nr &= __SYSCALL_MASK;
if (likely(nr < NR_syscalls)) {
nr = array_index_nospec(nr, NR_syscalls);
regs->ax = sys_call_table[nr](regs);
+#ifdef CONFIG_X86_X32_ABI
+ } else if (likely((nr & __X32_SYSCALL_BIT) &&
+ (nr & ~__X32_SYSCALL_BIT) < X32_NR_syscalls)) {
+ nr = array_index_nospec(nr & ~__X32_SYSCALL_BIT,
+ X32_NR_syscalls);
+ regs->ax = x32_sys_call_table[nr](regs);
+#endif
}
syscall_return_slowpath(regs);
diff --git a/arch/x86/entry/syscall_64.c b/arch/x86/entry/syscall_64.c
index d5252bc1e380..b1bf31713374 100644
--- a/arch/x86/entry/syscall_64.c
+++ b/arch/x86/entry/syscall_64.c
@@ -10,10 +10,13 @@
/* this is a lie, but it does not hurt as sys_ni_syscall just returns -EINVAL */
extern asmlinkage long sys_ni_syscall(const struct pt_regs *);
#define __SYSCALL_64(nr, sym, qual) extern asmlinkage long sym(const struct pt_regs *);
+#define __SYSCALL_X32(nr, sym, qual) __SYSCALL_64(nr, sym, qual)
#include <asm/syscalls_64.h>
#undef __SYSCALL_64
+#undef __SYSCALL_X32
#define __SYSCALL_64(nr, sym, qual) [nr] = sym,
+#define __SYSCALL_X32(nr, sym, qual)
asmlinkage const sys_call_ptr_t sys_call_table[__NR_syscall_max+1] = {
/*
@@ -23,3 +26,25 @@ asmlinkage const sys_call_ptr_t sys_call_table[__NR_syscall_max+1] = {
[0 ... __NR_syscall_max] = &sys_ni_syscall,
#include <asm/syscalls_64.h>
};
+
+#undef __SYSCALL_64
+#undef __SYSCALL_X32
+
+#ifdef CONFIG_X86_X32_ABI
+
+#define __SYSCALL_64(nr, sym, qual)
+#define __SYSCALL_X32(nr, sym, qual) [nr] = sym,
+
+asmlinkage const sys_call_ptr_t x32_sys_call_table[__NR_syscall_x32_max+1] = {
+ /*
+ * Smells like a compiler bug -- it doesn't work
+ * when the & below is removed.
+ */
+ [0 ... __NR_syscall_x32_max] = &sys_ni_syscall,
+#include <asm/syscalls_64.h>
+};
+
+#undef __SYSCALL_64
+#undef __SYSCALL_X32
+
+#endif
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index c00019abd076..3fe02546aed3 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -186,11 +186,11 @@
172 i386 prctl sys_prctl __ia32_sys_prctl
173 i386 rt_sigreturn sys_rt_sigreturn sys32_rt_sigreturn
174 i386 rt_sigaction sys_rt_sigaction __ia32_compat_sys_rt_sigaction
-175 i386 rt_sigprocmask sys_rt_sigprocmask __ia32_sys_rt_sigprocmask
+175 i386 rt_sigprocmask sys_rt_sigprocmask __ia32_compat_sys_rt_sigprocmask
176 i386 rt_sigpending sys_rt_sigpending __ia32_compat_sys_rt_sigpending
177 i386 rt_sigtimedwait sys_rt_sigtimedwait_time32 __ia32_compat_sys_rt_sigtimedwait_time32
178 i386 rt_sigqueueinfo sys_rt_sigqueueinfo __ia32_compat_sys_rt_sigqueueinfo
-179 i386 rt_sigsuspend sys_rt_sigsuspend __ia32_sys_rt_sigsuspend
+179 i386 rt_sigsuspend sys_rt_sigsuspend __ia32_compat_sys_rt_sigsuspend
180 i386 pread64 sys_pread64 __ia32_compat_sys_x86_pread
181 i386 pwrite64 sys_pwrite64 __ia32_compat_sys_x86_pwrite
182 i386 chown sys_chown16 __ia32_sys_chown16
diff --git a/arch/x86/entry/syscalls/syscalltbl.sh b/arch/x86/entry/syscalls/syscalltbl.sh
index 94fcd1951aca..1af2be39e7d9 100644
--- a/arch/x86/entry/syscalls/syscalltbl.sh
+++ b/arch/x86/entry/syscalls/syscalltbl.sh
@@ -1,13 +1,13 @@
-#!/bin/sh
+#!/bin/bash
# SPDX-License-Identifier: GPL-2.0
in="$1"
out="$2"
syscall_macro() {
- abi="$1"
- nr="$2"
- entry="$3"
+ local abi="$1"
+ local nr="$2"
+ local entry="$3"
# Entry can be either just a function name or "function/qualifier"
real_entry="${entry%%/*}"
@@ -21,14 +21,14 @@ syscall_macro() {
}
emit() {
- abi="$1"
- nr="$2"
- entry="$3"
- compat="$4"
- umlentry=""
+ local abi="$1"
+ local nr="$2"
+ local entry="$3"
+ local compat="$4"
+ local umlentry=""
- if [ "$abi" = "64" -a -n "$compat" ]; then
- echo "a compat entry for a 64-bit syscall makes no sense" >&2
+ if [ "$abi" != "I386" -a -n "$compat" ]; then
+ echo "a compat entry ($abi: $compat) for a 64-bit syscall makes no sense" >&2
exit 1
fi
@@ -62,14 +62,17 @@ grep '^[0-9]' "$in" | sort -n | (
while read nr abi name entry compat; do
abi=`echo "$abi" | tr '[a-z]' '[A-Z]'`
if [ "$abi" = "COMMON" -o "$abi" = "64" ]; then
- # COMMON is the same as 64, except that we don't expect X32
- # programs to use it. Our expectation has nothing to do with
- # any generated code, so treat them the same.
emit 64 "$nr" "$entry" "$compat"
+ if [ "$abi" = "COMMON" ]; then
+ # COMMON means that this syscall exists in the same form for
+ # 64-bit and X32.
+ echo "#ifdef CONFIG_X86_X32_ABI"
+ emit X32 "$nr" "$entry" "$compat"
+ echo "#endif"
+ fi
elif [ "$abi" = "X32" ]; then
- # X32 is equivalent to 64 on an X32-compatible kernel.
echo "#ifdef CONFIG_X86_X32_ABI"
- emit 64 "$nr" "$entry" "$compat"
+ emit X32 "$nr" "$entry" "$compat"
echo "#endif"
elif [ "$abi" = "I386" ]; then
emit "$abi" "$nr" "$entry" "$compat"
diff --git a/arch/x86/include/asm/syscall.h b/arch/x86/include/asm/syscall.h
index 2dc4a021beea..8db3fdb6102e 100644
--- a/arch/x86/include/asm/syscall.h
+++ b/arch/x86/include/asm/syscall.h
@@ -36,6 +36,10 @@ extern const sys_call_ptr_t sys_call_table[];
extern const sys_call_ptr_t ia32_sys_call_table[];
#endif
+#ifdef CONFIG_X86_X32_ABI
+extern const sys_call_ptr_t x32_sys_call_table[];
+#endif
+
/*
* Only the low 32 bits of orig_ax are meaningful, so we return int.
* This importantly ignores the high bits on 64-bit, so comparisons
diff --git a/arch/x86/include/asm/unistd.h b/arch/x86/include/asm/unistd.h
index 097589753fec..a7dd080749ce 100644
--- a/arch/x86/include/asm/unistd.h
+++ b/arch/x86/include/asm/unistd.h
@@ -5,12 +5,6 @@
#include <uapi/asm/unistd.h>
-# ifdef CONFIG_X86_X32_ABI
-# define __SYSCALL_MASK (~(__X32_SYSCALL_BIT))
-# else
-# define __SYSCALL_MASK (~0)
-# endif
-
# ifdef CONFIG_X86_32
# include <asm/unistd_32.h>
diff --git a/arch/x86/include/uapi/asm/unistd.h b/arch/x86/include/uapi/asm/unistd.h
index 30d7d04d72d6..196fdd02b8b1 100644
--- a/arch/x86/include/uapi/asm/unistd.h
+++ b/arch/x86/include/uapi/asm/unistd.h
@@ -3,7 +3,7 @@
#define _UAPI_ASM_X86_UNISTD_H
/* x32 syscall flag bit */
-#define __X32_SYSCALL_BIT 0x40000000
+#define __X32_SYSCALL_BIT 0x40000000UL
#ifndef __KERNEL__
# ifdef __i386__
diff --git a/arch/x86/kernel/asm-offsets_64.c b/arch/x86/kernel/asm-offsets_64.c
index d3d075226c0a..70e97727a26a 100644
--- a/arch/x86/kernel/asm-offsets_64.c
+++ b/arch/x86/kernel/asm-offsets_64.c
@@ -6,13 +6,28 @@
#include <asm/ia32.h>
#define __SYSCALL_64(nr, sym, qual) [nr] = 1,
+#define __SYSCALL_X32(nr, sym, qual)
static char syscalls_64[] = {
#include <asm/syscalls_64.h>
};
+#undef __SYSCALL_64
+#undef __SYSCALL_X32
+
+#ifdef CONFIG_X86_X32_ABI
+#define __SYSCALL_64(nr, sym, qual)
+#define __SYSCALL_X32(nr, sym, qual) [nr] = 1,
+static char syscalls_x32[] = {
+#include <asm/syscalls_64.h>
+};
+#undef __SYSCALL_64
+#undef __SYSCALL_X32
+#endif
+
#define __SYSCALL_I386(nr, sym, qual) [nr] = 1,
static char syscalls_ia32[] = {
#include <asm/syscalls_32.h>
};
+#undef __SYSCALL_I386
#if defined(CONFIG_KVM_GUEST) && defined(CONFIG_PARAVIRT_SPINLOCKS)
#include <asm/kvm_para.h>
@@ -80,6 +95,11 @@ int main(void)
DEFINE(__NR_syscall_max, sizeof(syscalls_64) - 1);
DEFINE(NR_syscalls, sizeof(syscalls_64));
+#ifdef CONFIG_X86_X32_ABI
+ DEFINE(__NR_syscall_x32_max, sizeof(syscalls_x32) - 1);
+ DEFINE(X32_NR_syscalls, sizeof(syscalls_x32));
+#endif
+
DEFINE(__NR_syscall_compat_max, sizeof(syscalls_ia32) - 1);
DEFINE(IA32_NR_syscalls, sizeof(syscalls_ia32));
diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile
index 3bc5b744e644..5d49bfec1e9a 100644
--- a/tools/testing/selftests/x86/Makefile
+++ b/tools/testing/selftests/x86/Makefile
@@ -17,7 +17,7 @@ TARGETS_C_BOTHBITS := single_step_syscall sysret_ss_attrs syscall_nt test_mremap
TARGETS_C_32BIT_ONLY := entry_from_vm86 test_syscall_vdso unwind_vdso \
test_FCMOV test_FCOMI test_FISTTP \
vdso_restorer
-TARGETS_C_64BIT_ONLY := fsgsbase sysret_rip
+TARGETS_C_64BIT_ONLY := fsgsbase sysret_rip syscall_numbering
# Some selftests require 32bit support enabled also on 64bit systems
TARGETS_C_32BIT_NEEDED := ldt_gdt ptrace_syscall
diff --git a/tools/testing/selftests/x86/syscall_numbering.c b/tools/testing/selftests/x86/syscall_numbering.c
new file mode 100644
index 000000000000..d6b09cb1aa2c
--- /dev/null
+++ b/tools/testing/selftests/x86/syscall_numbering.c
@@ -0,0 +1,89 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * syscall_arg_fault.c - tests faults 32-bit fast syscall stack args
+ * Copyright (c) 2018 Andrew Lutomirski
+ */
+
+#define _GNU_SOURCE
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <errno.h>
+#include <unistd.h>
+#include <syscall.h>
+
+static int nerrs;
+
+#define X32_BIT 0x40000000UL
+
+static void check_enosys(unsigned long nr, bool *ok)
+{
+ /* If this fails, a segfault is reasonably likely. */
+ fflush(stdout);
+
+ long ret = syscall(nr, 0, 0, 0, 0, 0, 0);
+ if (ret == 0) {
+ printf("[FAIL]\tsyscall %lu succeeded, but it should have failed\n", nr);
+ *ok = false;
+ } else if (errno != ENOSYS) {
+ printf("[FAIL]\tsyscall %lu had error code %d, but it should have reported ENOSYS\n", nr, errno);
+ *ok = false;
+ }
+}
+
+static void test_x32_without_x32_bit(void)
+{
+ bool ok = true;
+
+ /*
+ * Syscalls 512-547 are "x32" syscalls. They are intended to be
+ * called with the x32 (0x40000000) bit set. Calling them without
+ * the x32 bit set is nonsense and should not work.
+ */
+ printf("[RUN]\tChecking syscalls 512-547\n");
+ for (int i = 512; i <= 547; i++)
+ check_enosys(i, &ok);
+
+ /*
+ * Check that a handful of 64-bit-only syscalls are rejected if the x32
+ * bit is set.
+ */
+ printf("[RUN]\tChecking some 64-bit syscalls in x32 range\n");
+ check_enosys(16 | X32_BIT, &ok); /* ioctl */
+ check_enosys(19 | X32_BIT, &ok); /* readv */
+ check_enosys(20 | X32_BIT, &ok); /* writev */
+
+ /*
+ * Check some syscalls with high bits set.
+ */
+ printf("[RUN]\tChecking numbers above 2^32-1\n");
+ check_enosys((1UL << 32), &ok);
+ check_enosys(X32_BIT | (1UL << 32), &ok);
+
+ if (!ok)
+ nerrs++;
+ else
+ printf("[OK]\tThey all returned -ENOSYS\n");
+}
+
+int main()
+{
+ /*
+ * Anyone diagnosing a failure will want to know whether the kernel
+ * supports x32. Tell them.
+ */
+ printf("\tChecking for x32...");
+ fflush(stdout);
+ if (syscall(39 | X32_BIT, 0, 0, 0, 0, 0, 0) >= 0) {
+ printf(" supported\n");
+ } else if (errno == ENOSYS) {
+ printf(" not supported\n");
+ } else {
+ printf(" confused\n");
+ }
+
+ test_x32_without_x32_bit();
+
+ return nerrs ? 1 : 0;
+}