529d235a0e
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>
75 lines
2.1 KiB
C
75 lines
2.1 KiB
C
/*
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* System call callback functions for SPUs
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*/
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#undef DEBUG
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#include <linux/kallsyms.h>
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#include <linux/export.h>
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#include <linux/syscalls.h>
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#include <asm/spu.h>
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#include <asm/syscalls.h>
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#include <asm/unistd.h>
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/*
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* This table defines the system calls that an SPU can call.
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* It is currently a subset of the 64 bit powerpc system calls,
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* with the exact semantics.
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*
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* The reasons for disabling some of the system calls are:
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* 1. They interact with the way SPU syscalls are handled
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* and we can't let them execute ever:
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* restart_syscall, exit, for, execve, ptrace, ...
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* 2. They are deprecated and replaced by other means:
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* uselib, pciconfig_*, sysfs, ...
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* 3. They are somewhat interacting with the system in a way
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* we don't want an SPU to:
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* reboot, init_module, mount, kexec_load
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* 4. They are optional and we can't rely on them being
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* linked into the kernel. Unfortunately, the cond_syscall
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* helper does not work here as it does not add the necessary
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* opd symbols:
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* mbind, mq_open, ipc, ...
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*/
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static void *spu_syscall_table[] = {
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#define SYSCALL(func) sys_ni_syscall,
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#define COMPAT_SYS(func) sys_ni_syscall,
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#define PPC_SYS(func) sys_ni_syscall,
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#define OLDSYS(func) sys_ni_syscall,
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#define SYS32ONLY(func) sys_ni_syscall,
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#define PPC64ONLY(func) sys_ni_syscall,
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#define SYSX(f, f3264, f32) sys_ni_syscall,
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#define SYSCALL_SPU(func) sys_##func,
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#define COMPAT_SYS_SPU(func) sys_##func,
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#define PPC_SYS_SPU(func) ppc_##func,
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#define SYSX_SPU(f, f3264, f32) f,
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#include <asm/systbl.h>
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};
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long spu_sys_callback(struct spu_syscall_block *s)
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{
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long (*syscall)(u64 a1, u64 a2, u64 a3, u64 a4, u64 a5, u64 a6);
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if (s->nr_ret >= ARRAY_SIZE(spu_syscall_table)) {
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pr_debug("%s: invalid syscall #%lld", __func__, s->nr_ret);
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return -ENOSYS;
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}
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syscall = spu_syscall_table[s->nr_ret];
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pr_debug("SPU-syscall "
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"%pSR:syscall%lld(%llx, %llx, %llx, %llx, %llx, %llx)\n",
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syscall,
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s->nr_ret,
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s->parm[0], s->parm[1], s->parm[2],
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s->parm[3], s->parm[4], s->parm[5]);
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return syscall(s->parm[0], s->parm[1], s->parm[2],
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s->parm[3], s->parm[4], s->parm[5]);
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}
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EXPORT_SYMBOL_GPL(spu_sys_callback);
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