mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-11-26 01:40:53 +07:00
2cf0966683
... and switch i386 to HAVE_SYSCALL_WRAPPERS, killing open-coded uses of asmlinkage_protect() in a bunch of syscalls. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
398 lines
8.9 KiB
C
398 lines
8.9 KiB
C
/*
|
|
* Copyright (C) 2005 Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
|
|
* Licensed under the GPL
|
|
*/
|
|
|
|
#include <linux/percpu.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/syscalls.h>
|
|
#include <asm/uaccess.h>
|
|
#include <os.h>
|
|
#include <skas.h>
|
|
#include <sysdep/tls.h>
|
|
|
|
/*
|
|
* If needed we can detect when it's uninitialized.
|
|
*
|
|
* These are initialized in an initcall and unchanged thereafter.
|
|
*/
|
|
static int host_supports_tls = -1;
|
|
int host_gdt_entry_tls_min;
|
|
|
|
int do_set_thread_area(struct user_desc *info)
|
|
{
|
|
int ret;
|
|
u32 cpu;
|
|
|
|
cpu = get_cpu();
|
|
ret = os_set_thread_area(info, userspace_pid[cpu]);
|
|
put_cpu();
|
|
|
|
if (ret)
|
|
printk(KERN_ERR "PTRACE_SET_THREAD_AREA failed, err = %d, "
|
|
"index = %d\n", ret, info->entry_number);
|
|
|
|
return ret;
|
|
}
|
|
|
|
int do_get_thread_area(struct user_desc *info)
|
|
{
|
|
int ret;
|
|
u32 cpu;
|
|
|
|
cpu = get_cpu();
|
|
ret = os_get_thread_area(info, userspace_pid[cpu]);
|
|
put_cpu();
|
|
|
|
if (ret)
|
|
printk(KERN_ERR "PTRACE_GET_THREAD_AREA failed, err = %d, "
|
|
"index = %d\n", ret, info->entry_number);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* sys_get_thread_area: get a yet unused TLS descriptor index.
|
|
* XXX: Consider leaving one free slot for glibc usage at first place. This must
|
|
* be done here (and by changing GDT_ENTRY_TLS_* macros) and nowhere else.
|
|
*
|
|
* Also, this must be tested when compiling in SKAS mode with dynamic linking
|
|
* and running against NPTL.
|
|
*/
|
|
static int get_free_idx(struct task_struct* task)
|
|
{
|
|
struct thread_struct *t = &task->thread;
|
|
int idx;
|
|
|
|
if (!t->arch.tls_array)
|
|
return GDT_ENTRY_TLS_MIN;
|
|
|
|
for (idx = 0; idx < GDT_ENTRY_TLS_ENTRIES; idx++)
|
|
if (!t->arch.tls_array[idx].present)
|
|
return idx + GDT_ENTRY_TLS_MIN;
|
|
return -ESRCH;
|
|
}
|
|
|
|
static inline void clear_user_desc(struct user_desc* info)
|
|
{
|
|
/* Postcondition: LDT_empty(info) returns true. */
|
|
memset(info, 0, sizeof(*info));
|
|
|
|
/*
|
|
* Check the LDT_empty or the i386 sys_get_thread_area code - we obtain
|
|
* indeed an empty user_desc.
|
|
*/
|
|
info->read_exec_only = 1;
|
|
info->seg_not_present = 1;
|
|
}
|
|
|
|
#define O_FORCE 1
|
|
|
|
static int load_TLS(int flags, struct task_struct *to)
|
|
{
|
|
int ret = 0;
|
|
int idx;
|
|
|
|
for (idx = GDT_ENTRY_TLS_MIN; idx < GDT_ENTRY_TLS_MAX; idx++) {
|
|
struct uml_tls_struct* curr =
|
|
&to->thread.arch.tls_array[idx - GDT_ENTRY_TLS_MIN];
|
|
|
|
/*
|
|
* Actually, now if it wasn't flushed it gets cleared and
|
|
* flushed to the host, which will clear it.
|
|
*/
|
|
if (!curr->present) {
|
|
if (!curr->flushed) {
|
|
clear_user_desc(&curr->tls);
|
|
curr->tls.entry_number = idx;
|
|
} else {
|
|
WARN_ON(!LDT_empty(&curr->tls));
|
|
continue;
|
|
}
|
|
}
|
|
|
|
if (!(flags & O_FORCE) && curr->flushed)
|
|
continue;
|
|
|
|
ret = do_set_thread_area(&curr->tls);
|
|
if (ret)
|
|
goto out;
|
|
|
|
curr->flushed = 1;
|
|
}
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Verify if we need to do a flush for the new process, i.e. if there are any
|
|
* present desc's, only if they haven't been flushed.
|
|
*/
|
|
static inline int needs_TLS_update(struct task_struct *task)
|
|
{
|
|
int i;
|
|
int ret = 0;
|
|
|
|
for (i = GDT_ENTRY_TLS_MIN; i < GDT_ENTRY_TLS_MAX; i++) {
|
|
struct uml_tls_struct* curr =
|
|
&task->thread.arch.tls_array[i - GDT_ENTRY_TLS_MIN];
|
|
|
|
/*
|
|
* Can't test curr->present, we may need to clear a descriptor
|
|
* which had a value.
|
|
*/
|
|
if (curr->flushed)
|
|
continue;
|
|
ret = 1;
|
|
break;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* On a newly forked process, the TLS descriptors haven't yet been flushed. So
|
|
* we mark them as such and the first switch_to will do the job.
|
|
*/
|
|
void clear_flushed_tls(struct task_struct *task)
|
|
{
|
|
int i;
|
|
|
|
for (i = GDT_ENTRY_TLS_MIN; i < GDT_ENTRY_TLS_MAX; i++) {
|
|
struct uml_tls_struct* curr =
|
|
&task->thread.arch.tls_array[i - GDT_ENTRY_TLS_MIN];
|
|
|
|
/*
|
|
* Still correct to do this, if it wasn't present on the host it
|
|
* will remain as flushed as it was.
|
|
*/
|
|
if (!curr->present)
|
|
continue;
|
|
|
|
curr->flushed = 0;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* In SKAS0 mode, currently, multiple guest threads sharing the same ->mm have a
|
|
* common host process. So this is needed in SKAS0 too.
|
|
*
|
|
* However, if each thread had a different host process (and this was discussed
|
|
* for SMP support) this won't be needed.
|
|
*
|
|
* And this will not need be used when (and if) we'll add support to the host
|
|
* SKAS patch.
|
|
*/
|
|
|
|
int arch_switch_tls(struct task_struct *to)
|
|
{
|
|
if (!host_supports_tls)
|
|
return 0;
|
|
|
|
/*
|
|
* We have no need whatsoever to switch TLS for kernel threads; beyond
|
|
* that, that would also result in us calling os_set_thread_area with
|
|
* userspace_pid[cpu] == 0, which gives an error.
|
|
*/
|
|
if (likely(to->mm))
|
|
return load_TLS(O_FORCE, to);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int set_tls_entry(struct task_struct* task, struct user_desc *info,
|
|
int idx, int flushed)
|
|
{
|
|
struct thread_struct *t = &task->thread;
|
|
|
|
if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
|
|
return -EINVAL;
|
|
|
|
t->arch.tls_array[idx - GDT_ENTRY_TLS_MIN].tls = *info;
|
|
t->arch.tls_array[idx - GDT_ENTRY_TLS_MIN].present = 1;
|
|
t->arch.tls_array[idx - GDT_ENTRY_TLS_MIN].flushed = flushed;
|
|
|
|
return 0;
|
|
}
|
|
|
|
int arch_copy_tls(struct task_struct *new)
|
|
{
|
|
struct user_desc info;
|
|
int idx, ret = -EFAULT;
|
|
|
|
if (copy_from_user(&info,
|
|
(void __user *) UPT_SI(&new->thread.regs.regs),
|
|
sizeof(info)))
|
|
goto out;
|
|
|
|
ret = -EINVAL;
|
|
if (LDT_empty(&info))
|
|
goto out;
|
|
|
|
idx = info.entry_number;
|
|
|
|
ret = set_tls_entry(new, &info, idx, 0);
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
/* XXX: use do_get_thread_area to read the host value? I'm not at all sure! */
|
|
static int get_tls_entry(struct task_struct *task, struct user_desc *info,
|
|
int idx)
|
|
{
|
|
struct thread_struct *t = &task->thread;
|
|
|
|
if (!t->arch.tls_array)
|
|
goto clear;
|
|
|
|
if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
|
|
return -EINVAL;
|
|
|
|
if (!t->arch.tls_array[idx - GDT_ENTRY_TLS_MIN].present)
|
|
goto clear;
|
|
|
|
*info = t->arch.tls_array[idx - GDT_ENTRY_TLS_MIN].tls;
|
|
|
|
out:
|
|
/*
|
|
* Temporary debugging check, to make sure that things have been
|
|
* flushed. This could be triggered if load_TLS() failed.
|
|
*/
|
|
if (unlikely(task == current &&
|
|
!t->arch.tls_array[idx - GDT_ENTRY_TLS_MIN].flushed)) {
|
|
printk(KERN_ERR "get_tls_entry: task with pid %d got here "
|
|
"without flushed TLS.", current->pid);
|
|
}
|
|
|
|
return 0;
|
|
clear:
|
|
/*
|
|
* When the TLS entry has not been set, the values read to user in the
|
|
* tls_array are 0 (because it's cleared at boot, see
|
|
* arch/i386/kernel/head.S:cpu_gdt_table). Emulate that.
|
|
*/
|
|
clear_user_desc(info);
|
|
info->entry_number = idx;
|
|
goto out;
|
|
}
|
|
|
|
SYSCALL_DEFINE1(set_thread_area, struct user_desc __user *, user_desc)
|
|
{
|
|
struct user_desc info;
|
|
int idx, ret;
|
|
|
|
if (!host_supports_tls)
|
|
return -ENOSYS;
|
|
|
|
if (copy_from_user(&info, user_desc, sizeof(info)))
|
|
return -EFAULT;
|
|
|
|
idx = info.entry_number;
|
|
|
|
if (idx == -1) {
|
|
idx = get_free_idx(current);
|
|
if (idx < 0)
|
|
return idx;
|
|
info.entry_number = idx;
|
|
/* Tell the user which slot we chose for him.*/
|
|
if (put_user(idx, &user_desc->entry_number))
|
|
return -EFAULT;
|
|
}
|
|
|
|
ret = do_set_thread_area(&info);
|
|
if (ret)
|
|
return ret;
|
|
return set_tls_entry(current, &info, idx, 1);
|
|
}
|
|
|
|
/*
|
|
* Perform set_thread_area on behalf of the traced child.
|
|
* Note: error handling is not done on the deferred load, and this differ from
|
|
* i386. However the only possible error are caused by bugs.
|
|
*/
|
|
int ptrace_set_thread_area(struct task_struct *child, int idx,
|
|
struct user_desc __user *user_desc)
|
|
{
|
|
struct user_desc info;
|
|
|
|
if (!host_supports_tls)
|
|
return -EIO;
|
|
|
|
if (copy_from_user(&info, user_desc, sizeof(info)))
|
|
return -EFAULT;
|
|
|
|
return set_tls_entry(child, &info, idx, 0);
|
|
}
|
|
|
|
SYSCALL_DEFINE1(get_thread_area, struct user_desc __user *, user_desc)
|
|
{
|
|
struct user_desc info;
|
|
int idx, ret;
|
|
|
|
if (!host_supports_tls)
|
|
return -ENOSYS;
|
|
|
|
if (get_user(idx, &user_desc->entry_number))
|
|
return -EFAULT;
|
|
|
|
ret = get_tls_entry(current, &info, idx);
|
|
if (ret < 0)
|
|
goto out;
|
|
|
|
if (copy_to_user(user_desc, &info, sizeof(info)))
|
|
ret = -EFAULT;
|
|
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Perform get_thread_area on behalf of the traced child.
|
|
*/
|
|
int ptrace_get_thread_area(struct task_struct *child, int idx,
|
|
struct user_desc __user *user_desc)
|
|
{
|
|
struct user_desc info;
|
|
int ret;
|
|
|
|
if (!host_supports_tls)
|
|
return -EIO;
|
|
|
|
ret = get_tls_entry(child, &info, idx);
|
|
if (ret < 0)
|
|
goto out;
|
|
|
|
if (copy_to_user(user_desc, &info, sizeof(info)))
|
|
ret = -EFAULT;
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* This code is really i386-only, but it detects and logs x86_64 GDT indexes
|
|
* if a 32-bit UML is running on a 64-bit host.
|
|
*/
|
|
static int __init __setup_host_supports_tls(void)
|
|
{
|
|
check_host_supports_tls(&host_supports_tls, &host_gdt_entry_tls_min);
|
|
if (host_supports_tls) {
|
|
printk(KERN_INFO "Host TLS support detected\n");
|
|
printk(KERN_INFO "Detected host type: ");
|
|
switch (host_gdt_entry_tls_min) {
|
|
case GDT_ENTRY_TLS_MIN_I386:
|
|
printk(KERN_CONT "i386");
|
|
break;
|
|
case GDT_ENTRY_TLS_MIN_X86_64:
|
|
printk(KERN_CONT "x86_64");
|
|
break;
|
|
}
|
|
printk(KERN_CONT " (GDT indexes %d to %d)\n",
|
|
host_gdt_entry_tls_min,
|
|
host_gdt_entry_tls_min + GDT_ENTRY_TLS_ENTRIES);
|
|
} else
|
|
printk(KERN_ERR " Host TLS support NOT detected! "
|
|
"TLS support inside UML will not work\n");
|
|
return 0;
|
|
}
|
|
|
|
__initcall(__setup_host_supports_tls);
|