linux_dsm_epyc7002/arch/powerpc/kernel/systbl_chk.c
Michael Ellerman 529d235a0e powerpc: Add a proper syscall for switching endianness
We currently have a "special" syscall for switching endianness. This is
syscall number 0x1ebe, which is handled explicitly in the 64-bit syscall
exception entry.

That has a few problems, firstly the syscall number is outside of the
usual range, which confuses various tools. For example strace doesn't
recognise the syscall at all.

Secondly it's handled explicitly as a special case in the syscall
exception entry, which is complicated enough without it.

As a first step toward removing the special syscall, we need to add a
regular syscall that implements the same functionality.

The logic is simple, it simply toggles the MSR_LE bit in the userspace
MSR. This is the same as the special syscall, with the caveat that the
special syscall clobbers fewer registers.

This version clobbers r9-r12, XER, CTR, and CR0-1,5-7.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-03-28 22:03:40 +11:00

61 lines
1.7 KiB
C

/*
* This file, when run through CPP produces a list of syscall numbers
* in the order of systbl.h. That way we can check for gaps and syscalls
* that are out of order.
*
* Unfortunately, we cannot check for the correct ordering of entries
* using SYSX().
*
* Copyright © IBM Corporation
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <asm/unistd.h>
#define SYSCALL(func) __NR_##func
#define COMPAT_SYS(func) __NR_##func
#define PPC_SYS(func) __NR_##func
#ifdef CONFIG_PPC64
#define OLDSYS(func) -1
#define SYS32ONLY(func) -1
#define PPC64ONLY(func) __NR_##func
#else
#define OLDSYS(func) __NR_old##func
#define SYS32ONLY(func) __NR_##func
#define PPC64ONLY(func) -1
#endif
#define SYSX(f, f3264, f32) -1
#define SYSCALL_SPU(func) SYSCALL(func)
#define COMPAT_SYS_SPU(func) COMPAT_SYS(func)
#define PPC_SYS_SPU(func) PPC_SYS(func)
#define SYSX_SPU(f, f3264, f32) SYSX(f, f3264, f32)
/* Just insert a marker for ni_syscalls */
#define __NR_ni_syscall -1
/*
* These are the known exceptions.
* Hopefully, there will be no more.
*/
#define __NR_llseek __NR__llseek
#undef __NR_umount
#define __NR_umount __NR_umount2
#define __NR_old_getrlimit __NR_getrlimit
#define __NR_newstat __NR_stat
#define __NR_newlstat __NR_lstat
#define __NR_newfstat __NR_fstat
#define __NR_newuname __NR_uname
#define __NR_sysctl __NR__sysctl
#define __NR_olddebug_setcontext __NR_sys_debug_setcontext
/* We call sys_ugetrlimit for syscall number __NR_getrlimit */
#define getrlimit ugetrlimit
START_TABLE
#include <asm/systbl.h>
END_TABLE __NR_syscalls