Commit 4e21fc13 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal

Pull third pile of kernel_execve() patches from Al Viro:
 "The last bits of infrastructure for kernel_thread() et.al., with
  alpha/arm/x86 use of those.  Plus sanitizing the asm glue and
  do_notify_resume() on alpha, fixing the "disabled irq while running
  task_work stuff" breakage there.

  At that point the rest of kernel_thread/kernel_execve/sys_execve work
  can be done independently for different architectures.  The only
  pending bits that do depend on having all architectures converted are
  restrictred to fs/* and kernel/* - that'll obviously have to wait for
  the next cycle.

  I thought we'd have to wait for all of them done before we start
  eliminating the longjump-style insanity in kernel_execve(), but it
  turned out there's a very simple way to do that without flagday-style
  changes."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal:
  alpha: switch to saner kernel_execve() semantics
  arm: switch to saner kernel_execve() semantics
  x86, um: convert to saner kernel_execve() semantics
  infrastructure for saner ret_from_kernel_thread semantics
  make sure that kernel_thread() callbacks call do_exit() themselves
  make sure that we always have a return path from kernel_execve()
  ppc: eeh_event should just use kthread_run()
  don't bother with kernel_thread/kernel_execve for launching linuxrc
  alpha: get rid of switch_stack argument of do_work_pending()
  alpha: don't bother passing switch_stack separately from regs
  alpha: take SIGPENDING/NOTIFY_RESUME loop into signal.c
  alpha: simplify TIF_NEED_RESCHED handling
parents 8418263e 5522be6a
......@@ -274,6 +274,9 @@ config ARCH_WANT_OLD_COMPAT_IPC
config GENERIC_KERNEL_THREAD
bool
config GENERIC_KERNEL_EXECVE
bool
config HAVE_ARCH_SECCOMP_FILTER
bool
help
......
......@@ -21,6 +21,7 @@ config ALPHA
select GENERIC_STRNCPY_FROM_USER
select GENERIC_STRNLEN_USER
select GENERIC_KERNEL_THREAD
select GENERIC_KERNEL_EXECVE
help
The Alpha is a 64-bit general-purpose processor designed and
marketed by the Digital Equipment Corporation of blessed memory,
......
......@@ -482,7 +482,6 @@
#define __ARCH_WANT_SYS_SIGPENDING
#define __ARCH_WANT_SYS_RT_SIGSUSPEND
#define __ARCH_WANT_SYS_EXECVE
#define __ARCH_WANT_KERNEL_EXECVE
/* "Conditional" syscalls. What we want is
......
......@@ -311,7 +311,7 @@ entSys:
.align 4
ret_from_sys_call:
cmovne $26, 0, $19 /* $19 = 0 => non-restartable */
cmovne $26, 0, $18 /* $18 = 0 => non-restartable */
ldq $0, SP_OFF($sp)
and $0, 8, $0
beq $0, ret_to_kernel
......@@ -320,8 +320,8 @@ ret_to_user:
sampling and the rti. */
lda $16, 7
call_pal PAL_swpipl
ldl $5, TI_FLAGS($8)
and $5, _TIF_WORK_MASK, $2
ldl $17, TI_FLAGS($8)
and $17, _TIF_WORK_MASK, $2
bne $2, work_pending
restore_all:
RESTORE_ALL
......@@ -341,10 +341,10 @@ $syscall_error:
* frame to indicate that a negative return value wasn't an
* error number..
*/
ldq $19, 0($sp) /* old syscall nr (zero if success) */
beq $19, $ret_success
ldq $18, 0($sp) /* old syscall nr (zero if success) */
beq $18, $ret_success
ldq $20, 72($sp) /* .. and this a3 */
ldq $19, 72($sp) /* .. and this a3 */
subq $31, $0, $0 /* with error in v0 */
addq $31, 1, $1 /* set a3 for errno return */
stq $0, 0($sp)
......@@ -362,51 +362,35 @@ $ret_success:
* Do all cleanup when returning from all interrupts and system calls.
*
* Arguments:
* $5: TI_FLAGS.
* $8: current.
* $19: The old syscall number, or zero if this is not a return
* $17: TI_FLAGS.
* $18: The old syscall number, or zero if this is not a return
* from a syscall that errored and is possibly restartable.
* $20: The old a3 value
* $19: The old a3 value
*/
.align 4
.ent work_pending
work_pending:
and $5, _TIF_NEED_RESCHED, $2
beq $2, $work_notifysig
and $17, _TIF_NOTIFY_RESUME | _TIF_SIGPENDING, $2
bne $2, $work_notifysig
$work_resched:
subq $sp, 16, $sp
stq $19, 0($sp) /* save syscall nr */
stq $20, 8($sp) /* and error indication (a3) */
/*
* We can get here only if we returned from syscall without SIGPENDING
* or got through work_notifysig already. Either case means no syscall
* restarts for us, so let $18 and $19 burn.
*/
jsr $26, schedule
ldq $19, 0($sp)
ldq $20, 8($sp)
addq $sp, 16, $sp
/* Make sure need_resched and sigpending don't change between
sampling and the rti. */
lda $16, 7
call_pal PAL_swpipl
ldl $5, TI_FLAGS($8)
and $5, _TIF_WORK_MASK, $2
beq $2, restore_all
and $5, _TIF_NEED_RESCHED, $2
bne $2, $work_resched
mov 0, $18
br ret_to_user
$work_notifysig:
mov $sp, $16
bsr $1, do_switch_stack
mov $sp, $17
mov $5, $18
mov $19, $9 /* save old syscall number */
mov $20, $10 /* save old a3 */
and $5, _TIF_SIGPENDING, $2
cmovne $2, 0, $9 /* we don't want double syscall restarts */
jsr $26, do_notify_resume
mov $9, $19
mov $10, $20
jsr $26, do_work_pending
bsr $1, undo_switch_stack
br ret_to_user
br restore_all
.end work_pending
/*
......@@ -454,9 +438,9 @@ $strace_success:
.align 3
$strace_error:
ldq $19, 0($sp) /* old syscall nr (zero if success) */
beq $19, $strace_success
ldq $20, 72($sp) /* .. and this a3 */
ldq $18, 0($sp) /* old syscall nr (zero if success) */
beq $18, $strace_success
ldq $19, 72($sp) /* .. and this a3 */
subq $31, $0, $0 /* with error in v0 */
addq $31, 1, $1 /* set a3 for errno return */
......@@ -464,11 +448,11 @@ $strace_error:
stq $1, 72($sp) /* a3 for return */
bsr $1, do_switch_stack
mov $19, $9 /* save old syscall number */
mov $20, $10 /* save old a3 */
mov $18, $9 /* save old syscall number */
mov $19, $10 /* save old a3 */
jsr $26, syscall_trace_leave
mov $9, $19
mov $10, $20
mov $9, $18
mov $10, $19
bsr $1, undo_switch_stack
mov $31, $26 /* tell "ret_from_sys_call" we can restart */
......@@ -619,24 +603,9 @@ ret_from_kernel_thread:
mov $9, $27
mov $10, $16
jsr $26, ($9)
ldgp $gp, 0($26)
mov $0, $16
mov $31, $26
jmp $31, sys_exit
.end ret_from_kernel_thread
.globl ret_from_kernel_execve
.align 4
.ent ret_from_kernel_execve
ret_from_kernel_execve:
mov $16, $sp
/* Avoid the HAE being gratuitously wrong, to avoid restoring it. */
ldq $2, alpha_mv+HAE_CACHE
stq $2, 152($sp) /* HAE */
mov $31, $19 /* to disable syscall restarts */
br $31, ret_to_user
.end ret_from_kernel_execve
.end ret_from_kernel_thread
/*
......
......@@ -298,8 +298,9 @@ get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
static long
setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
struct switch_stack *sw, unsigned long mask, unsigned long sp)
unsigned long mask, unsigned long sp)
{
struct switch_stack *sw = (struct switch_stack *)regs - 1;
long i, err = 0;
err |= __put_user(on_sig_stack((unsigned long)sc), &sc->sc_onstack);
......@@ -354,7 +355,7 @@ setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
static int
setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
struct pt_regs *regs, struct switch_stack * sw)
struct pt_regs *regs)
{
unsigned long oldsp, r26, err = 0;
struct sigframe __user *frame;
......@@ -364,7 +365,7 @@ setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
return -EFAULT;
err |= setup_sigcontext(&frame->sc, regs, sw, set->sig[0], oldsp);
err |= setup_sigcontext(&frame->sc, regs, set->sig[0], oldsp);
if (err)
return -EFAULT;
......@@ -401,7 +402,7 @@ setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
static int
setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
sigset_t *set, struct pt_regs *regs, struct switch_stack * sw)
sigset_t *set, struct pt_regs *regs)
{
unsigned long oldsp, r26, err = 0;
struct rt_sigframe __user *frame;
......@@ -420,7 +421,7 @@ setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
err |= __put_user(sas_ss_flags(oldsp), &frame->uc.uc_stack.ss_flags);
err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, sw,
err |= setup_sigcontext(&frame->uc.uc_mcontext, regs,
set->sig[0], oldsp);
err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
if (err)
......@@ -464,15 +465,15 @@ setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
*/
static inline void
handle_signal(int sig, struct k_sigaction *ka, siginfo_t *info,
struct pt_regs * regs, struct switch_stack *sw)
struct pt_regs * regs)
{
sigset_t *oldset = sigmask_to_save();
int ret;
if (ka->sa.sa_flags & SA_SIGINFO)
ret = setup_rt_frame(sig, ka, info, oldset, regs, sw);
ret = setup_rt_frame(sig, ka, info, oldset, regs);
else
ret = setup_frame(sig, ka, oldset, regs, sw);
ret = setup_frame(sig, ka, oldset, regs);
if (ret) {
force_sigsegv(sig, current);
......@@ -519,8 +520,7 @@ syscall_restart(unsigned long r0, unsigned long r19,
* all (if we get here from anything but a syscall return, it will be 0)
*/
static void
do_signal(struct pt_regs * regs, struct switch_stack * sw,
unsigned long r0, unsigned long r19)
do_signal(struct pt_regs *regs, unsigned long r0, unsigned long r19)
{
siginfo_t info;
int signr;
......@@ -537,7 +537,7 @@ do_signal(struct pt_regs * regs, struct switch_stack * sw,
/* Whee! Actually deliver the signal. */
if (r0)
syscall_restart(r0, r19, regs, &ka);
handle_signal(signr, &ka, &info, regs, sw);
handle_signal(signr, &ka, &info, regs);
if (single_stepping)
ptrace_set_bpt(current); /* re-set bpt */
return;
......@@ -568,15 +568,23 @@ do_signal(struct pt_regs * regs, struct switch_stack * sw,
}
void
do_notify_resume(struct pt_regs *regs, struct switch_stack *sw,
unsigned long thread_info_flags,
do_work_pending(struct pt_regs *regs, unsigned long thread_flags,
unsigned long r0, unsigned long r19)
{
if (thread_info_flags & _TIF_SIGPENDING)
do_signal(regs, sw, r0, r19);
if (thread_info_flags & _TIF_NOTIFY_RESUME) {
clear_thread_flag(TIF_NOTIFY_RESUME);
tracehook_notify_resume(regs);
}
do {
if (thread_flags & _TIF_NEED_RESCHED) {
schedule();
} else {
local_irq_enable();
if (thread_flags & _TIF_SIGPENDING) {
do_signal(regs, r0, r19);
r0 = 0;
} else {
clear_thread_flag(TIF_NOTIFY_RESUME);
tracehook_notify_resume(regs);
}
}
local_irq_disable();
thread_flags = current_thread_info()->flags;
} while (thread_flags & _TIF_WORK_MASK);
}
......@@ -53,6 +53,7 @@ config ARM
select GENERIC_STRNLEN_USER
select DCACHE_WORD_ACCESS if (CPU_V6 || CPU_V6K || CPU_V7) && !CPU_BIG_ENDIAN
select GENERIC_KERNEL_THREAD
select GENERIC_KERNEL_EXECVE
help
The ARM series is a line of low-power-consumption RISC chip designs
licensed by ARM Ltd and targeted at embedded applications and
......
......@@ -479,7 +479,6 @@
#define __ARCH_WANT_SYS_SOCKETCALL
#endif
#define __ARCH_WANT_SYS_EXECVE
#define __ARCH_WANT_KERNEL_EXECVE
/*
* "Conditional" syscalls
......
......@@ -86,35 +86,14 @@ ENDPROC(ret_to_user)
*/
ENTRY(ret_from_fork)
bl schedule_tail
cmp r5, #0
movne r0, r4
movne lr, pc
movne pc, r5
get_thread_info tsk
mov why, #1
b ret_slow_syscall
ENDPROC(ret_from_fork)
ENTRY(ret_from_kernel_thread)
UNWIND(.fnstart)
UNWIND(.cantunwind)
bl schedule_tail
mov r0, r4
adr lr, BSYM(1f) @ kernel threads should not exit
mov pc, r5
1: bl do_exit
nop
UNWIND(.fnend)
ENDPROC(ret_from_kernel_thread)
/*
* turn a kernel thread into userland process
* use: ret_from_kernel_execve(struct pt_regs *normal)
*/
ENTRY(ret_from_kernel_execve)
mov why, #0 @ not a syscall
str why, [r0, #S_R0] @ ... and we want 0 in ->ARM_r0 as well
get_thread_info tsk @ thread structure
mov sp, r0 @ stack pointer just under pt_regs
b ret_slow_syscall
ENDPROC(ret_from_kernel_execve)
.equ NR_syscalls,0
#define CALL(x) .equ NR_syscalls,NR_syscalls+1
#include "calls.S"
......
......@@ -373,7 +373,6 @@ void release_thread(struct task_struct *dead_task)
}
asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
asmlinkage void ret_from_kernel_thread(void) __asm__("ret_from_kernel_thread");
int
copy_thread(unsigned long clone_flags, unsigned long stack_start,
......@@ -388,13 +387,13 @@ copy_thread(unsigned long clone_flags, unsigned long stack_start,
*childregs = *regs;
childregs->ARM_r0 = 0;
childregs->ARM_sp = stack_start;
thread->cpu_context.pc = (unsigned long)ret_from_fork;
} else {
memset(childregs, 0, sizeof(struct pt_regs));
thread->cpu_context.r4 = stk_sz;
thread->cpu_context.r5 = stack_start;
thread->cpu_context.pc = (unsigned long)ret_from_kernel_thread;
childregs->ARM_cpsr = SVC_MODE;
}
thread->cpu_context.pc = (unsigned long)ret_from_fork;
thread->cpu_context.sp = (unsigned long)childregs;
clear_ptrace_hw_breakpoint(p);
......
......@@ -23,6 +23,7 @@
#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
#include <linux/kthread.h>
#include <asm/eeh_event.h>
#include <asm/ppc-pci.h>
......@@ -59,8 +60,6 @@ static int eeh_event_handler(void * dummy)
struct eeh_event *event;
struct eeh_pe *pe;
set_task_comm(current, "eehd");
spin_lock_irqsave(&eeh_eventlist_lock, flags);
event = NULL;
......@@ -108,7 +107,7 @@ static int eeh_event_handler(void * dummy)
*/
static void eeh_thread_launcher(struct work_struct *dummy)
{
if (kernel_thread(eeh_event_handler, NULL, CLONE_KERNEL) < 0)
if (IS_ERR(kthread_run(eeh_event_handler, NULL, "eehd")))
printk(KERN_ERR "Failed to start EEH daemon\n");
}
......
......@@ -26,7 +26,6 @@ struct thread_struct {
jmp_buf *fault_catcher;
struct task_struct *prev_sched;
unsigned long temp_stack;
jmp_buf *exec_buf;
struct arch_thread arch;
jmp_buf switch_buf;
int mm_count;
......@@ -54,7 +53,6 @@ struct thread_struct {
.fault_addr = NULL, \
.prev_sched = NULL, \
.temp_stack = 0, \
.exec_buf = NULL, \
.arch = INIT_ARCH_THREAD, \
.request = { 0 } \
}
......
......@@ -191,7 +191,6 @@ extern int os_getpid(void);
extern int os_getpgrp(void);
extern void init_new_thread_signals(void);
extern int run_kernel_thread(int (*fn)(void *), void *arg, jmp_buf **jmp_ptr);
extern int os_map_memory(void *virt, int fd, unsigned long long off,
unsigned long len, int r, int w, int x);
......
......@@ -47,8 +47,3 @@ void start_thread(struct pt_regs *regs, unsigned long eip, unsigned long esp)
#endif
}
EXPORT_SYMBOL(start_thread);
void __noreturn ret_from_kernel_execve(struct pt_regs *unused)
{
UML_LONGJMP(current->thread.exec_buf, 1);
}
......@@ -135,14 +135,10 @@ void new_thread_handler(void)
arg = current->thread.request.u.thread.arg;
/*
* The return value is 1 if the kernel thread execs a process,
* 0 if it just exits
* callback returns only if the kernel thread execs a process
*/
n = run_kernel_thread(fn, arg, &current->thread.exec_buf);
if (n == 1)
userspace(&current->thread.regs.regs);
else
do_exit(0);
n = fn(arg);
userspace(&current->thread.regs.regs);
}
/* Called magically, see new_thread_handler above */
......
......@@ -244,16 +244,3 @@ void init_new_thread_signals(void)
signal(SIGWINCH, SIG_IGN);
signal(SIGTERM, SIG_DFL);
}
int run_kernel_thread(int (*fn)(void *), void *arg, jmp_buf **jmp_ptr)
{
jmp_buf buf;
int n;
*jmp_ptr = &buf;
n = UML_SETJMP(&buf);
if (n != 0)
return n;
(*fn)(arg);
return 0;
}
......@@ -109,6 +109,7 @@ config X86
select HAVE_RCU_USER_QS if X86_64
select HAVE_IRQ_TIME_ACCOUNTING
select GENERIC_KERNEL_THREAD
select GENERIC_KERNEL_EXECVE
config INSTRUCTION_DECODER
def_bool y
......
......@@ -51,7 +51,6 @@
# define __ARCH_WANT_SYS_UTIME
# define __ARCH_WANT_SYS_WAITPID
# define __ARCH_WANT_SYS_EXECVE
# define __ARCH_WANT_KERNEL_EXECVE
/*
* "Conditional" syscalls
......
......@@ -299,12 +299,20 @@ ENTRY(ret_from_fork)
CFI_ENDPROC
END(ret_from_fork)
ENTRY(ret_from_kernel_execve)
movl %eax, %esp
movl $0,PT_EAX(%esp)
ENTRY(ret_from_kernel_thread)
CFI_STARTPROC
pushl_cfi %eax
call schedule_tail
GET_THREAD_INFO(%ebp)
popl_cfi %eax
pushl_cfi $0x0202 # Reset kernel eflags
popfl_cfi
movl PT_EBP(%esp),%eax
call *PT_EBX(%esp)
movl $0,PT_EAX(%esp)
jmp syscall_exit
END(ret_from_kernel_execve)
CFI_ENDPROC
ENDPROC(ret_from_kernel_thread)
/*
* Interrupt exit functions should be protected against kprobes
......@@ -1015,21 +1023,6 @@ END(spurious_interrupt_bug)
*/
.popsection
ENTRY(ret_from_kernel_thread)
CFI_STARTPROC
pushl_cfi %eax
call schedule_tail
GET_THREAD_INFO(%ebp)
popl_cfi %eax
pushl_cfi $0x0202 # Reset kernel eflags
popfl_cfi
movl PT_EBP(%esp),%eax
call *PT_EBX(%esp)
call do_exit
ud2 # padding for call trace
CFI_ENDPROC
ENDPROC(ret_from_kernel_thread)
#ifdef CONFIG_XEN
/* Xen doesn't set %esp to be precisely what the normal sysenter
entrypoint expects, so fix it up before using the normal path. */
......
......@@ -563,15 +563,13 @@ ENTRY(ret_from_fork)
jmp ret_from_sys_call # go to the SYSRET fastpath
1:
subq $REST_SKIP, %rsp # move the stack pointer back
subq $REST_SKIP, %rsp # leave space for volatiles
CFI_ADJUST_CFA_OFFSET REST_SKIP
movq %rbp, %rdi
call *%rbx
# exit
mov %eax, %edi
call do_exit
ud2 # padding for call trace
movl $0, RAX(%rsp)
RESTORE_REST
jmp int_ret_from_sys_call
CFI_ENDPROC
END(ret_from_fork)
......@@ -1326,20 +1324,6 @@ bad_gs:
jmp 2b
.previous
ENTRY(ret_from_kernel_execve)
movq %rdi, %rsp
movl $0, RAX(%rsp)
// RESTORE_REST
movq 0*8(%rsp), %r15
movq 1*8(%rsp), %r14
movq 2*8(%rsp), %r13
movq 3*8(%rsp), %r12
movq 4*8(%rsp), %rbp
movq 5*8(%rsp), %rbx
addq $(6*8), %rsp
jmp int_ret_from_sys_call
END(ret_from_kernel_execve)
/* Call softirq on interrupt stack. Interrupts are off. */
ENTRY(call_softirq)
CFI_STARTPROC
......
......@@ -14,6 +14,7 @@ config UML_X86
def_bool y
select GENERIC_FIND_FIRST_BIT
select GENERIC_KERNEL_THREAD
select GENERIC_KERNEL_EXECVE
config 64BIT
bool "64-bit kernel" if SUBARCH = "x86"
......
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