[PATCH V2] csky: Reconstruct signal.c and entry.S

From: guoren
Date: Fri Apr 05 2019 - 00:23:07 EST

From: Guo Ren <ren_guo@xxxxxxxxx>

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

Changelog:
- Fixup compile error with verify_area in signal.c

Signed-off-by: Guo Ren <ren_guo@xxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
---
arch/csky/abiv1/inc/abi/entry.h | 7 -
arch/csky/abiv1/inc/abi/regdef.h | 2 +
arch/csky/abiv2/inc/abi/entry.h | 7 -
arch/csky/abiv2/inc/abi/regdef.h | 2 +
arch/csky/kernel/atomic.S | 26 +--
arch/csky/kernel/entry.S | 152 ++++++++---------
arch/csky/kernel/signal.c | 343 +++++++++++++++------------------------
7 files changed, 207 insertions(+), 332 deletions(-)

diff --git a/arch/csky/abiv1/inc/abi/entry.h b/arch/csky/abiv1/inc/abi/entry.h
index f041299..fa26461 100644
--- a/arch/csky/abiv1/inc/abi/entry.h
+++ b/arch/csky/abiv1/inc/abi/entry.h
@@ -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
diff --git a/arch/csky/abiv1/inc/abi/regdef.h b/arch/csky/abiv1/inc/abi/regdef.h
index 9e7e692..729b1c3 100644
--- a/arch/csky/abiv1/inc/abi/regdef.h
+++ b/arch/csky/abiv1/inc/abi/regdef.h
@@ -21,4 +21,6 @@

#define SYSTRACE_SAVENUM 2

+#define TRAP0_SIZE 2
+
#endif /* __ASM_CSKY_REGDEF_H */
diff --git a/arch/csky/abiv2/inc/abi/entry.h b/arch/csky/abiv2/inc/abi/entry.h
index b4232c3..31d0aa9 100644
--- a/arch/csky/abiv2/inc/abi/entry.h
+++ b/arch/csky/abiv2/inc/abi/entry.h
@@ -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)
diff --git a/arch/csky/abiv2/inc/abi/regdef.h b/arch/csky/abiv2/inc/abi/regdef.h
index 652f5ce..77cb178 100644
--- a/arch/csky/abiv2/inc/abi/regdef.h
+++ b/arch/csky/abiv2/inc/abi/regdef.h
@@ -21,4 +21,6 @@

#define SYSTRACE_SAVENUM 5

+#define TRAP0_SIZE 4
+
#endif /* __ASM_CSKY_REGDEF_H */
diff --git a/arch/csky/kernel/atomic.S b/arch/csky/kernel/atomic.S
index d2357c8..5b84f11 100644
--- a/arch/csky/kernel/atomic.S
+++ b/arch/csky/kernel/atomic.S
@@ -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
*/
diff --git a/arch/csky/kernel/entry.S b/arch/csky/kernel/entry.S
index d40fbd5..efcd7a1 100644
--- a/arch/csky/kernel/entry.S
+++ b/arch/csky/kernel/entry.S
@@ -2,19 +2,19 @@
// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.

#include <linux/linkage.h>
-#include <abi/entry.h>
-#include <abi/pgtable-bits.h>
-#include <asm/errno.h>
-#include <asm/setup.h>
-#include <asm/unistd.h>
-#include <asm/asm-offsets.h>
#include <linux/threads.h>
-#include <asm/setup.h>
+
+#include <asm/asm-offsets.h>
+#include <asm/errno.h>
#include <asm/page.h>
+#include <asm/setup.h>
#include <asm/thread_info.h>
+#include <asm/unistd.h>

-.macro tlbop_begin
- SAVE_ALL EPC_KEEP
+#include <abi/entry.h>
+
+.macro TLBOP_PREPARE
+ SAVE_ALL 0
#ifdef CONFIG_CPU_HAS_TLBI
RD_MEH a1
tlbi.vaas a1
@@ -27,67 +27,66 @@
#endif
.endm

-.macro tlbop_end
- mov a0, sp
+.macro TLBOP_FINISH
+ mov a0, sp
RD_MEH a1
- psrset ee, ie
- jbsr do_page_fault
- jmpi ret_from_exception
+ psrset ee, ie
+ jbsr do_page_fault
+ br ret_from_exception
.endm

.text
-
ENTRY(csky_tlbinvalidl)
- tlbop_begin
- tlbop_end
+ TLBOP_PREPARE
+ TLBOP_FINISH

ENTRY(csky_tlbinvalids)
- tlbop_begin
- tlbop_end
+ TLBOP_PREPARE
+ TLBOP_FINISH

ENTRY(csky_tlbmodified)
- tlbop_begin
+ TLBOP_PREPARE
#ifndef CONFIG_CPU_HAS_LDSTEX
- jbsr csky_cmpxchg_fixup
+ jbsr csky_cmpxchg_fixup
#endif
- tlbop_end
+ TLBOP_FINISH

ENTRY(csky_systemcall)
- SAVE_ALL EPC_INCREASE
+ SAVE_ALL TRAP0_SIZE

- psrset ee, ie
+ psrset ee, ie

- lrw r11, __NR_syscalls
- cmphs syscallid, r11 /* Check nr of syscall */
- bt ret_from_exception
+ lrw r11, __NR_syscalls
+ cmphs syscallid, r11 /* Check nr of syscall */
+ bt ret_from_exception

- lrw r13, sys_call_table
- ixw r13, syscallid
- ldw r11, (r13)
- cmpnei r11, 0
- bf ret_from_exception
+ lrw r13, sys_call_table
+ ixw r13, syscallid
+ ldw r11, (r13)
+ cmpnei r11, 0
+ bf ret_from_exception

- mov r9, sp
- bmaski r10, THREAD_SHIFT
- andn r9, r10
- ldw r8, (r9, TINFO_FLAGS)
+ mov r9, sp
+ bmaski r10, THREAD_SHIFT
+ andn r9, r10
+ ldw r8, (r9, TINFO_FLAGS)
ANDI_R3 r8, (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_TRACEPOINT | _TIF_SYSCALL_AUDIT)
cmpnei r8, 0
- bt csky_syscall_trace
+ bt csky_syscall_trace
#if defined(__CSKYABIV2__)
- subi sp, 8
- stw r5, (sp, 0x4)
- stw r4, (sp, 0x0)
- jsr r11 /* Do system call */
- addi sp, 8
+ subi sp, 8
+ stw r5, (sp, 0x4)
+ stw r4, (sp, 0x0)
+ jsr r11
+ addi sp, 8
#else
- jsr r11
+ jsr r11
#endif
- stw a0, (sp, LSAVE_A0) /* Save return value */
- jmpi ret_from_exception
+ stw a0, (sp, LSAVE_A0) /* Save return value */
+ br ret_from_exception

csky_syscall_trace:
- mov a0, sp /* sp = pt_regs pointer */
+ mov a0, sp /* a0 = pt_regs pointer */
jbsr syscall_trace_enter
/* Prepare args before do system call */
ldw a0, (sp, LSAVE_A0)
@@ -102,21 +101,21 @@ csky_syscall_trace:
ldw r6, (sp, LSAVE_A4)
ldw r7, (sp, LSAVE_A5)
#endif
- jsr r11 /* Do system call */
+ jsr r11
#if defined(__CSKYABIV2__)
addi sp, 8
#endif
stw a0, (sp, LSAVE_A0) /* Save return value */

- mov a0, sp /* right now, sp --> pt_regs */
- jbsr syscall_trace_exit
+ mov a0, sp /* a0 = pt_regs pointer */
+ jbsr syscall_trace_exit
br ret_from_exception

ENTRY(ret_from_kernel_thread)
jbsr schedule_tail
mov a0, r8
jsr r9
- jbsr ret_from_exception
+ br ret_from_exception

ENTRY(ret_from_fork)
jbsr schedule_tail
@@ -126,16 +125,14 @@ 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
- mov a0, sp /* sp = pt_regs pointer */
+ bf ret_from_exception
+ mov a0, sp /* a0 = pt_regs pointer */
jbsr syscall_trace_exit
-3:
- jbsr ret_from_exception

ret_from_exception:
ld syscallid, (sp, LSAVE_PSR)
btsti syscallid, 31
- bt 1f
+ bt 1f /* return to kernel */

/*
* Load address of current->thread_info, Then get address of task_struct
@@ -145,38 +142,33 @@ 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 /* Return address in link */
+
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 */
- jmpi ret_from_exception
+ mov a0, sp
+ jbsr trap_c
+ br ret_from_exception

/*
Â*ÂPrototype from libc for abiv1:
@@ -188,7 +180,7 @@ 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 */
@@ -205,7 +197,7 @@ ENTRY(csky_get_tls)
rte

ENTRY(csky_irq)
- SAVE_ALL EPC_KEEP
+ SAVE_ALL 0
psrset ee

#ifdef CONFIG_PREEMPT
@@ -240,12 +232,12 @@ ENTRY(csky_irq)
bt 1b /* go again */
#endif
2:
- jmpi ret_from_exception
+ br ret_from_exception

/*
- * a0 = prev task_struct *
- * a1 = next task_struct *
- * a0 = return next
+ * a0 = prev task_struct *
+ * a1 = next task_struct *
+ * a0 = return next
*/
ENTRY(__switch_to)
lrw a3, TASK_THREAD
@@ -269,7 +261,7 @@ ENTRY(__switch_to)
ldw a2, (a3, THREAD_SR) /* Set next PSR */
mtcr a2, psr

-#if defined(__CSKYABIV2__)
+#if defined(__CSKYABIV2__)
addi r7, a1, TASK_THREAD_INFO
ldw tls, (r7, TINFO_TP_VALUE)
#endif
diff --git a/arch/csky/kernel/signal.c b/arch/csky/kernel/signal.c
index 5a18940..04a43cf 100644
--- a/arch/csky/kernel/signal.c
+++ b/arch/csky/kernel/signal.c
@@ -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/uaccess.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 <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_sigcontext(regs, &frame->uc.uc_mcontext))
+ goto badframe;

- if (restore_sigframe(regs, &frame->uc.uc_mcontext, &a0))
+ if (restore_altstack(&frame->uc.uc_stack))
goto badframe;

- return a0;
+ 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;
+ /* Set up to return from userspace. */
+ 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;
+ /*
+ * 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).
+ */
+ 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 */

-give_sigsegv:
- if (ksig->sig == SIGSEGV)
- ksig->ka.sa.sa_handler = SIG_DFL;
- force_sig(SIGSEGV, current);
- goto adjust_stack;
+ return 0;
}

-/*
- * OK, we're invoking a handler
- */
-static int
-handle_signal(struct ksignal *ksig, struct pt_regs *regs)
+static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
{
- int ret;
sigset_t *oldset = sigmask_to_save();
+ int ret;

- /*
- * set up the stack frame, regardless of SA_SIGINFO,
- * and pass info anyway.
- */
- ret = setup_rt_frame(ksig, oldset, regs);
+ /* Are we from a system call? */
+ if (in_syscall(regs)) {
+ /* Avoid additional syscall restarting via ret_from_exception */
+ forget_syscall(regs);
+
+ /* If so, check system call restarting.. */
+ switch (regs->a0) {
+ case -ERESTART_RESTARTBLOCK:
+ case -ERESTARTNOHAND:
+ regs->a0 = -EINTR;
+ break;

- if (ret != 0) {
- force_sigsegv(ksig->sig, current);
- return ret;
+ 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;
+ }
}

- /* 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);
+ /* Set up the stack frame */
+ ret = setup_rt_frame(ksig, oldset, regs);

- return 0;
+ signal_setup_done(ret, ksig, 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)
{
- unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
struct ksignal ksig;

- /*
- * 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))
+ if (get_signal(&ksig)) {
+ /* Actually deliver the signal */
+ handle_signal(&ksig, regs);
return;
+ }

- /*
- * If we were from a system call, check for system call restarting...
- */
+ /* Did we come 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) {
+ /* 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);
}
--
2.7.4