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csky: Reconstruct signal processing 

Linux kernel has provided some apis for arch signal's implementation.
For example:
	restore_saved_sigmask()
	set_current_blocked()
	restore_altstack()

But in last version of csky signal.c didn't use them and some codes are
confusing, so reconstruct signal.c with reference to riscv's code.

Now csky signal.c implementation are very close to riscv and we can
get the following benefits:
 - Clear code structure
 - The signal code of riscv and csky can be reviewed together
 - Promoting the unification of arch's signal implementation

Also modified the related code in entry.S

Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Cc: Arnd Bergmann <arnd@arndb.de>
This commit is contained in:
Guo Ren 2019-04-01 19:06:09 +08:00
parent f4625ee0e4
commit bf24168293
7 changed files with 161 additions and 285 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
arch/csky/abiv1/inc/abi/entry.h
View File

@ -16,9 +16,6 @@
#define LSAVE_A4 40
#define LSAVE_A5 44
#define EPC_INCREASE 2
#define EPC_KEEP 0
.macro USPTOKSP
mtcr sp, ss1
mfcr sp, ss0
@ -29,10 +26,6 @@
mfcr sp, ss1
.endm
.macro INCTRAP rx
addi \rx, EPC_INCREASE
.endm
.macro SAVE_ALL epc_inc
mtcr r13, ss2
mfcr r13, epsr

2
arch/csky/abiv1/inc/abi/regdef.h
View File

@ -21,4 +21,6 @@
#define SYSTRACE_SAVENUM 2
#define TRAP0_SIZE 2
#endif /* __ASM_CSKY_REGDEF_H */

7
arch/csky/abiv2/inc/abi/entry.h
View File

@ -14,18 +14,11 @@
#define LSAVE_A2 32
#define LSAVE_A3 36
#define EPC_INCREASE 4
#define EPC_KEEP 0
#define KSPTOUSP
#define USPTOKSP
#define usp cr<14, 1>
.macro INCTRAP rx
addi \rx, EPC_INCREASE
.endm
.macro SAVE_ALL epc_inc
subi sp, 152
stw tls, (sp, 0)

2
arch/csky/abiv2/inc/abi/regdef.h
View File

@ -21,4 +21,6 @@
#define SYSTRACE_SAVENUM 5
#define TRAP0_SIZE 4
#endif /* __ASM_CSKY_REGDEF_H */

26
arch/csky/kernel/atomic.S
View File

@ -12,11 +12,10 @@
* If *ptr != oldval && return 1,
* else *ptr = newval return 0.
*/
#ifdef CONFIG_CPU_HAS_LDSTEX
ENTRY(csky_cmpxchg)
USPTOKSP
mfcr a3, epc
INCTRAP a3
addi a3, TRAP0_SIZE
subi sp, 8
stw a3, (sp, 0)
@ -24,6 +23,7 @@ ENTRY(csky_cmpxchg)
stw a3, (sp, 4)
psrset ee
#ifdef CONFIG_CPU_HAS_LDSTEX
1:
ldex a3, (a2)
cmpne a0, a3
@ -33,27 +33,7 @@ ENTRY(csky_cmpxchg)
bez a3, 1b
2:
sync.is
mvc a0
ldw a3, (sp, 0)
mtcr a3, epc
ldw a3, (sp, 4)
mtcr a3, epsr
addi sp, 8
KSPTOUSP
rte
END(csky_cmpxchg)
#else
ENTRY(csky_cmpxchg)
USPTOKSP
mfcr a3, epc
INCTRAP a3
subi sp, 8
stw a3, (sp, 0)
mfcr a3, epsr
stw a3, (sp, 4)
psrset ee
1:
ldw a3, (a2)
cmpne a0, a3
@ -61,6 +41,7 @@ ENTRY(csky_cmpxchg)
2:
stw a1, (a2)
3:
#endif
mvc a0
ldw a3, (sp, 0)
mtcr a3, epc
@ -71,6 +52,7 @@ ENTRY(csky_cmpxchg)
rte
END(csky_cmpxchg)
#ifndef CONFIG_CPU_HAS_LDSTEX
/*
* Called from tlbmodified exception
*/

37
arch/csky/kernel/entry.S
View File

@ -91,7 +91,7 @@ ENTRY(csky_\name)
mfcr a3, ss2
mfcr r6, ss3
mfcr a2, ss4
SAVE_ALL EPC_KEEP
SAVE_ALL 0
.endm
.macro tlbop_end is_write
RD_MEH a2
@ -117,7 +117,7 @@ jbsr csky_cmpxchg_fixup
tlbop_end 1
ENTRY(csky_systemcall)
SAVE_ALL EPC_INCREASE
SAVE_ALL TRAP0_SIZE
psrset ee, ie
@ -190,11 +190,9 @@ ENTRY(ret_from_fork)
ldw r8, (r9, TINFO_FLAGS)
ANDI_R3 r8, (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_TRACEPOINT | _TIF_SYSCALL_AUDIT)
cmpnei r8, 0
bf 3f
bf ret_from_exception
mov a0, sp /* sp = pt_regs pointer */
jbsr syscall_trace_exit
3:
jbsr ret_from_exception
ret_from_exception:
ld syscallid, (sp, LSAVE_PSR)
@ -209,34 +207,29 @@ ret_from_exception:
bmaski r10, THREAD_SHIFT
andn r9, r10
resume_userspace:
ldw r8, (r9, TINFO_FLAGS)
andi r8, (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED)
cmpnei r8, 0
bt exit_work
1: RESTORE_ALL
1:
RESTORE_ALL
exit_work:
lrw syscallid, ret_from_exception
mov lr, syscallid
btsti r8, TIF_NEED_RESCHED
bt work_resched
/* If thread_info->flag is empty, RESTORE_ALL */
cmpnei r8, 0
bf 1b
mov a0, r8
mov a1, sp
jbsr do_notify_resume /* do signals */
br resume_userspace
mov a0, sp
mov a1, r8
jmpi do_notify_resume
work_resched:
lrw syscallid, ret_from_exception
mov r15, syscallid /* Return address in link */
jmpi schedule
ENTRY(sys_rt_sigreturn)
jmpi do_rt_sigreturn
ENTRY(csky_trap)
SAVE_ALL EPC_KEEP
SAVE_ALL 0
psrset ee
mov a0, sp /* Push Stack pointer arg */
jbsr trap_c /* Call C-level trap handler */
@ -252,7 +245,7 @@ ENTRY(csky_get_tls)
/* increase epc for continue */
mfcr a0, epc
INCTRAP a0
addi a0, TRAP0_SIZE
mtcr a0, epc
/* get current task thread_info with kernel 8K stack */
@ -269,7 +262,7 @@ ENTRY(csky_get_tls)
rte
ENTRY(csky_irq)
SAVE_ALL EPC_KEEP
SAVE_ALL 0
psrset ee
#ifdef CONFIG_PREEMPT

365
arch/csky/kernel/signal.c
View File

@ -1,26 +1,10 @@
// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/syscalls.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/ptrace.h>
#include <linux/unistd.h>
#include <linux/stddef.h>
#include <linux/highuid.h>
#include <linux/personality.h>
#include <linux/tty.h>
#include <linux/binfmts.h>
#include <linux/tracehook.h>
#include <linux/freezer.h>
#include <linux/uaccess.h>
#include <linux/syscalls.h>
#include <linux/tracehook.h>
#include <asm/setup.h>
#include <asm/pgtable.h>
#include <asm/traps.h>
#include <asm/ucontext.h>
#include <asm/vdso.h>
@ -29,110 +13,117 @@
#ifdef CONFIG_CPU_HAS_FPU
#include <abi/fpu.h>
static int restore_fpu_state(struct sigcontext *sc)
static int restore_fpu_state(struct sigcontext __user *sc)
{
int err = 0;
struct user_fp user_fp;
err = copy_from_user(&user_fp, &sc->sc_user_fp, sizeof(user_fp));
err = __copy_from_user(&user_fp, &sc->sc_user_fp, sizeof(user_fp));
restore_from_user_fp(&user_fp);
return err;
}
static int save_fpu_state(struct sigcontext *sc)
static int save_fpu_state(struct sigcontext __user *sc)
{
struct user_fp user_fp;
save_to_user_fp(&user_fp);
return copy_to_user(&sc->sc_user_fp, &user_fp, sizeof(user_fp));
return __copy_to_user(&sc->sc_user_fp, &user_fp, sizeof(user_fp));
}
#else
static inline int restore_fpu_state(struct sigcontext *sc) { return 0; }
static inline int save_fpu_state(struct sigcontext *sc) { return 0; }
#define restore_fpu_state(sigcontext) (0)
#define save_fpu_state(sigcontext) (0)
#endif
struct rt_sigframe {
int sig;
struct siginfo *pinfo;
void *puc;
struct siginfo info;
struct ucontext uc;
};
static int
restore_sigframe(struct pt_regs *regs,
struct sigcontext *sc, int *pr2)
static long restore_sigcontext(struct pt_regs *regs,
struct sigcontext __user *sc)
{
int err = 0;
/* Always make any pending restarted system calls return -EINTR */
current_thread_info()->task->restart_block.fn = do_no_restart_syscall;
err |= copy_from_user(regs, &sc->sc_pt_regs, sizeof(struct pt_regs));
/* sc_pt_regs is structured the same as the start of pt_regs */
err |= __copy_from_user(regs, &sc->sc_pt_regs, sizeof(struct pt_regs));
/* Restore the floating-point state. */
err |= restore_fpu_state(sc);
*pr2 = regs->a0;
return err;
}
asmlinkage int
do_rt_sigreturn(void)
SYSCALL_DEFINE0(rt_sigreturn)
{
sigset_t set;
int a0;
struct pt_regs *regs = current_pt_regs();
struct rt_sigframe *frame = (struct rt_sigframe *)(regs->usp);
struct rt_sigframe __user *frame;
struct task_struct *task;
sigset_t set;
/* Always make any pending restarted system calls return -EINTR */
current->restart_block.fn = do_no_restart_syscall;
frame = (struct rt_sigframe __user *)regs->usp;
if (!access_ok(frame, sizeof(*frame)))
goto badframe;
if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
goto badframe;
sigdelsetmask(&set, (sigmask(SIGKILL) | sigmask(SIGSTOP)));
spin_lock_irq(&current->sighand->siglock);
current->blocked = set;
recalc_sigpending();
spin_unlock_irq(&current->sighand->siglock);
set_current_blocked(&set);
if (restore_sigframe(regs, &frame->uc.uc_mcontext, &a0))
if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
goto badframe;
return a0;
if (restore_altstack(&frame->uc.uc_stack))
goto badframe;
return regs->a0;
badframe:
force_sig(SIGSEGV, current);
task = current;
force_sig(SIGSEGV, task);
return 0;
}
static int setup_sigframe(struct sigcontext *sc, struct pt_regs *regs)
static int setup_sigcontext(struct rt_sigframe __user *frame,
struct pt_regs *regs)
{
struct sigcontext __user *sc = &frame->uc.uc_mcontext;
int err = 0;
err |= copy_to_user(&sc->sc_pt_regs, regs, sizeof(struct pt_regs));
err |= __copy_to_user(&sc->sc_pt_regs, regs, sizeof(struct pt_regs));
err |= save_fpu_state(sc);
return err;
}
static inline void *
get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size)
static inline void __user *get_sigframe(struct ksignal *ksig,
struct pt_regs *regs, size_t framesize)
{
unsigned long usp;
unsigned long sp;
/* Default to using normal stack */
sp = regs->usp;
/* Default to using normal stack. */
usp = regs->usp;
/*
* If we are on the alternate signal stack and would overflow it, don't.
* Return an always-bogus address instead so we will die with SIGSEGV.
*/
if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize)))
return (void __user __force *)(-1UL);
/* This is the X/Open sanctioned signal stack switching. */
if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(usp)) {
if (!on_sig_stack(usp))
usp = current->sas_ss_sp + current->sas_ss_size;
}
return (void *)((usp - frame_size) & -8UL);
/* This is the X/Open sanctioned signal stack switching. */
sp = sigsp(sp, ksig) - framesize;
/* Align the stack frame. */
sp &= -8UL;
return (void __user *)sp;
}
static int
@ -140,208 +131,128 @@ setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
{
struct rt_sigframe *frame;
int err = 0;
struct csky_vdso *vdso = current->mm->context.vdso;
frame = get_sigframe(&ksig->ka, regs, sizeof(*frame));
if (!frame)
return 1;
frame = get_sigframe(ksig, regs, sizeof(*frame));
if (!access_ok(frame, sizeof(*frame)))
return -EFAULT;
err |= __put_user(ksig->sig, &frame->sig);
err |= __put_user(&frame->info, &frame->pinfo);
err |= __put_user(&frame->uc, &frame->puc);
err |= copy_siginfo_to_user(&frame->info, &ksig->info);
/* Create the ucontext. */
/* Create the ucontext. */
err |= __put_user(0, &frame->uc.uc_flags);
err |= __put_user(0, &frame->uc.uc_link);
err |= __put_user((void *)current->sas_ss_sp,
&frame->uc.uc_stack.ss_sp);
err |= __put_user(sas_ss_flags(regs->usp),
&frame->uc.uc_stack.ss_flags);
err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
err |= setup_sigframe(&frame->uc.uc_mcontext, regs);
err |= copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
err |= __put_user(NULL, &frame->uc.uc_link);
err |= __save_altstack(&frame->uc.uc_stack, regs->usp);
err |= setup_sigcontext(frame, regs);
err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
if (err)
goto give_sigsegv;
return -EFAULT;
/* Set up registers for signal handler */
regs->usp = (unsigned long)frame;
regs->pc = (unsigned long)ksig->ka.sa.sa_handler;
regs->lr = (unsigned long)vdso->rt_signal_retcode;
adjust_stack:
regs->a0 = ksig->sig; /* first arg is signo */
regs->a1 = (unsigned long)(&(frame->info));
regs->a2 = (unsigned long)(&(frame->uc));
return err;
give_sigsegv:
if (ksig->sig == SIGSEGV)
ksig->ka.sa.sa_handler = SIG_DFL;
force_sig(SIGSEGV, current);
goto adjust_stack;
}
/*
* OK, we're invoking a handler
*/
static int
handle_signal(struct ksignal *ksig, struct pt_regs *regs)
{
int ret;
sigset_t *oldset = sigmask_to_save();
/* Set up to return from userspace. */
regs->lr = (unsigned long)(vdso->rt_signal_retcode);
/*
* set up the stack frame, regardless of SA_SIGINFO,
* and pass info anyway.
* Set up registers for signal handler.
* Registers that we don't modify keep the value they had from
* user-space at the time we took the signal.
* We always pass siginfo and mcontext, regardless of SA_SIGINFO,
* since some things rely on this (e.g. glibc's debug/segfault.c).
*/
ret = setup_rt_frame(ksig, oldset, regs);
if (ret != 0) {
force_sigsegv(ksig->sig, current);
return ret;
}
/* Block the signal if we were successful. */
spin_lock_irq(&current->sighand->siglock);
sigorsets(&current->blocked, &current->blocked, &ksig->ka.sa.sa_mask);
if (!(ksig->ka.sa.sa_flags & SA_NODEFER))
sigaddset(&current->blocked, ksig->sig);
recalc_sigpending();
spin_unlock_irq(&current->sighand->siglock);
regs->pc = (unsigned long)ksig->ka.sa.sa_handler;
regs->usp = (unsigned long)frame;
regs->a0 = ksig->sig; /* a0: signal number */
regs->a1 = (unsigned long)(&(frame->info)); /* a1: siginfo pointer */
regs->a2 = (unsigned long)(&(frame->uc)); /* a2: ucontext pointer */
return 0;
}
/*
* Note that 'init' is a special process: it doesn't get signals it doesn't
* want to handle. Thus you cannot kill init even with a SIGKILL even by
* mistake.
*
* Note that we go through the signals twice: once to check the signals
* that the kernel can handle, and then we build all the user-level signal
* handling stack-frames in one go after that.
*/
static void do_signal(struct pt_regs *regs)
static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
{
unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
struct ksignal ksig;
sigset_t *oldset = sigmask_to_save();
int ret;
/*
* We want the common case to go fast, which
* is why we may in certain cases get here from
* kernel mode. Just return without doing anything
* if so.
*/
if (!user_mode(regs))
return;
/*
* If we were from a system call, check for system call restarting...
*/
/* Are we from a system call? */
if (in_syscall(regs)) {
/* Avoid additional syscall restarting via ret_from_exception */
forget_syscall(regs);
continue_addr = regs->pc;
#if defined(__CSKYABIV2__)
restart_addr = continue_addr - 4;
#else
restart_addr = continue_addr - 2;
#endif
retval = regs->a0;
/*
* Prepare for system call restart. We do this here so that a
* debugger will see the already changed.
*/
switch (retval) {
/* If so, check system call restarting.. */
switch (regs->a0) {
case -ERESTART_RESTARTBLOCK:
case -ERESTARTNOHAND:
regs->a0 = -EINTR;
break;
case -ERESTARTSYS:
if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
regs->a0 = -EINTR;
break;
}
/* fallthrough */
case -ERESTARTNOINTR:
regs->a0 = regs->orig_a0;
regs->pc -= TRAP0_SIZE;
break;
}
}
/* Set up the stack frame */
ret = setup_rt_frame(ksig, oldset, regs);
signal_setup_done(ret, ksig, 0);
}
static void do_signal(struct pt_regs *regs)
{
struct ksignal ksig;
if (get_signal(&ksig)) {
/* Actually deliver the signal */
handle_signal(&ksig, regs);
return;
}
/* Did we come from a system call? */
if (in_syscall(regs)) {
/* Avoid additional syscall restarting via ret_from_exception */
forget_syscall(regs);
/* Restart the system call - no handlers present */
switch (regs->a0) {
case -ERESTARTNOHAND:
case -ERESTARTSYS:
case -ERESTARTNOINTR:
regs->a0 = regs->orig_a0;
regs->pc = restart_addr;
regs->pc -= TRAP0_SIZE;
break;
case -ERESTART_RESTARTBLOCK:
regs->a0 = -EINTR;
regs->a0 = regs->orig_a0;
regs_syscallid(regs) = __NR_restart_syscall;
regs->pc -= TRAP0_SIZE;
break;
}
}
if (try_to_freeze())
goto no_signal;
/*
* Get the signal to deliver. When running under ptrace, at this
* point the debugger may change all our registers ...
* If there is no signal to deliver, we just put the saved
* sigmask back.
*/
if (get_signal(&ksig)) {
/*
* Depending on the signal settings we may need to revert the
* decision to restart the system call. But skip this if a
* debugger has chosen to restart at a different PC.
*/
if (regs->pc == restart_addr) {
if (retval == -ERESTARTNOHAND ||
(retval == -ERESTARTSYS &&
!(ksig.ka.sa.sa_flags & SA_RESTART))) {
regs->a0 = -EINTR;
regs->pc = continue_addr;
}
}
/* Whee! Actually deliver the signal. */
if (handle_signal(&ksig, regs) == 0) {
/*
* A signal was successfully delivered; the saved
* sigmask will have been stored in the signal frame,
* and will be restored by sigreturn, so we can simply
* clear the TIF_RESTORE_SIGMASK flag.
*/
if (test_thread_flag(TIF_RESTORE_SIGMASK))
clear_thread_flag(TIF_RESTORE_SIGMASK);
}
return;
}
no_signal:
if (in_syscall(regs)) {
forget_syscall(regs);
/*
* Handle restarting a different system call. As above,
* if a debugger has chosen to restart at a different PC,
* ignore the restart.
*/
if (retval == -ERESTART_RESTARTBLOCK
&& regs->pc == continue_addr) {
#if defined(__CSKYABIV2__)
regs->regs[3] = __NR_restart_syscall;
regs->pc -= 4;
#else
regs->regs[9] = __NR_restart_syscall;
regs->pc -= 2;
#endif
}
/*
* If there's no signal to deliver, we just put the saved
* sigmask back.
*/
if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
clear_thread_flag(TIF_RESTORE_SIGMASK);
sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
}
}
restore_saved_sigmask();
}
asmlinkage void
do_notify_resume(unsigned int thread_flags, struct pt_regs *regs)
/*
* notification of userspace execution resumption
* - triggered by the _TIF_WORK_MASK flags
*/
asmlinkage void do_notify_resume(struct pt_regs *regs,
unsigned long thread_info_flags)
{
if (thread_flags & _TIF_SIGPENDING)
/* Handle pending signal delivery */
if (thread_info_flags & _TIF_SIGPENDING)
do_signal(regs);
if (thread_flags & _TIF_NOTIFY_RESUME) {
if (thread_info_flags & _TIF_NOTIFY_RESUME) {
clear_thread_flag(TIF_NOTIFY_RESUME);
tracehook_notify_resume(regs);
}