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linux/arch/x86/um/sys_call_table_32.c
Josh Poimboeuf 9142be9e64 x86/syscall: Mark exit[_group] syscall handlers __noreturn
The direct-call syscall dispatch function doesn't know that the exit()
and exit_group() syscall handlers don't return, so the call sites aren't
optimized accordingly.

Fix that by marking the exit syscall declarations __noreturn.

Fixes the following warnings:

  vmlinux.o: warning: objtool: x64_sys_call+0x2804: __x64_sys_exit() is missing a __noreturn annotation
  vmlinux.o: warning: objtool: ia32_sys_call+0x29b6: __ia32_sys_exit_group() is missing a __noreturn annotation

Fixes: 1e3ad78334 ("x86/syscall: Don't force use of indirect calls for system calls")
Closes: https://lkml.kernel.org/lkml/6dba9b32-db2c-4e6d-9500-7a08852f17a3@paulmck-laptop
Reported-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/r/5d8882bc077d8eadcc7fd1740b56dfb781f12288.1719381528.git.jpoimboe@kernel.org
2024-06-28 15:23:38 +02:00

41 lines
1.2 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* System call table for UML/i386, copied from arch/x86/kernel/syscall_*.c
* with some changes for UML.
*/
#include <linux/linkage.h>
#include <linux/sys.h>
#include <linux/cache.h>
#include <asm/syscall.h>
extern asmlinkage long sys_ni_syscall(unsigned long, unsigned long,
unsigned long, unsigned long,
unsigned long, unsigned long);
/*
* Below you can see, in terms of #define's, the differences between the x86-64
* and the UML syscall table.
*/
/* Not going to be implemented by UML, since we have no hardware. */
#define sys_iopl sys_ni_syscall
#define sys_ioperm sys_ni_syscall
#define sys_vm86old sys_ni_syscall
#define sys_vm86 sys_ni_syscall
#define __SYSCALL_WITH_COMPAT(nr, native, compat) __SYSCALL(nr, native)
#define __SYSCALL_NORETURN __SYSCALL
#define __SYSCALL(nr, sym) extern asmlinkage long sym(unsigned long, unsigned long, unsigned long, unsigned long, unsigned long, unsigned long);
#include <asm/syscalls_32.h>
#undef __SYSCALL
#define __SYSCALL(nr, sym) sym,
const sys_call_ptr_t sys_call_table[] ____cacheline_aligned = {
#include <asm/syscalls_32.h>
};
int syscall_table_size = sizeof(sys_call_table);