Merge branch 'audit' of git://git.linaro.org/people/rmk/linux-arm
Pull ARM audit/signal updates from Russell King: "ARM audit/signal handling updates from Al and Will. This improves on the work Viro did last merge window, and sorts out some of the issues found with that work." * 'audit' of git://git.linaro.org/people/rmk/linux-arm: ARM: 7475/1: sys_trace: allow all syscall arguments to be updated via ptrace ARM: 7474/1: get rid of TIF_SYSCALL_RESTARTSYS ARM: 7473/1: deal with handlerless restarts without leaving the kernel ARM: 7472/1: pull all work_pending logics into C function ARM: 7471/1: Revert "7442/1: Revert "remove unused restart trampoline"" ARM: 7470/1: Revert "7443/1: Revert "new way of handling ERESTART_RESTARTBLOCK""
This commit is contained in:
commit
02a6ec6a24
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@ -51,23 +51,15 @@ ret_fast_syscall:
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fast_work_pending:
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str r0, [sp, #S_R0+S_OFF]! @ returned r0
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work_pending:
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tst r1, #_TIF_NEED_RESCHED
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bne work_resched
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/*
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* TIF_SIGPENDING or TIF_NOTIFY_RESUME must've been set if we got here
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*/
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ldr r2, [sp, #S_PSR]
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mov r0, sp @ 'regs'
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tst r2, #15 @ are we returning to user mode?
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bne no_work_pending @ no? just leave, then...
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mov r2, why @ 'syscall'
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tst r1, #_TIF_SIGPENDING @ delivering a signal?
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movne why, #0 @ prevent further restarts
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bl do_notify_resume
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b ret_slow_syscall @ Check work again
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bl do_work_pending
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cmp r0, #0
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beq no_work_pending
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movlt scno, #(__NR_restart_syscall - __NR_SYSCALL_BASE)
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ldmia sp, {r0 - r6} @ have to reload r0 - r6
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b local_restart @ ... and off we go
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work_resched:
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bl schedule
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/*
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* "slow" syscall return path. "why" tells us if this was a real syscall.
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*/
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@ -409,6 +401,7 @@ ENTRY(vector_swi)
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eor scno, scno, #__NR_SYSCALL_BASE @ check OS number
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#endif
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local_restart:
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ldr r10, [tsk, #TI_FLAGS] @ check for syscall tracing
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stmdb sp!, {r4, r5} @ push fifth and sixth args
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@ -450,7 +443,8 @@ __sys_trace:
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mov scno, r0 @ syscall number (possibly new)
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add r1, sp, #S_R0 + S_OFF @ pointer to regs
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cmp scno, #NR_syscalls @ check upper syscall limit
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ldmccia r1, {r0 - r3} @ have to reload r0 - r3
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ldmccia r1, {r0 - r6} @ have to reload r0 - r6
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stmccia sp, {r4, r5} @ and update the stack args
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ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
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b 2b
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@ -25,6 +25,7 @@
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#include <linux/regset.h>
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#include <linux/audit.h>
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#include <linux/tracehook.h>
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#include <linux/unistd.h>
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#include <asm/pgtable.h>
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#include <asm/traps.h>
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@ -27,7 +27,6 @@
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*/
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#define SWI_SYS_SIGRETURN (0xef000000|(__NR_sigreturn)|(__NR_OABI_SYSCALL_BASE))
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#define SWI_SYS_RT_SIGRETURN (0xef000000|(__NR_rt_sigreturn)|(__NR_OABI_SYSCALL_BASE))
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#define SWI_SYS_RESTART (0xef000000|__NR_restart_syscall|__NR_OABI_SYSCALL_BASE)
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/*
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* With EABI, the syscall number has to be loaded into r7.
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@ -47,18 +46,6 @@ const unsigned long sigreturn_codes[7] = {
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MOV_R7_NR_RT_SIGRETURN, SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN,
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};
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/*
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* Either we support OABI only, or we have EABI with the OABI
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* compat layer enabled. In the later case we don't know if
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* user space is EABI or not, and if not we must not clobber r7.
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* Always using the OABI syscall solves that issue and works for
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* all those cases.
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*/
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const unsigned long syscall_restart_code[2] = {
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SWI_SYS_RESTART, /* swi __NR_restart_syscall */
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0xe49df004, /* ldr pc, [sp], #4 */
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};
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/*
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* atomically swap in the new signal mask, and wait for a signal.
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*/
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@ -582,12 +569,13 @@ handle_signal(unsigned long sig, struct k_sigaction *ka,
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* the kernel can handle, and then we build all the user-level signal handling
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* stack-frames in one go after that.
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*/
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static void do_signal(struct pt_regs *regs, int syscall)
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static int do_signal(struct pt_regs *regs, int syscall)
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{
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unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
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struct k_sigaction ka;
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siginfo_t info;
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int signr;
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int restart = 0;
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/*
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* If we were from a system call, check for system call restarting...
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@ -602,15 +590,15 @@ static void do_signal(struct pt_regs *regs, int syscall)
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* debugger will see the already changed PSW.
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*/
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switch (retval) {
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case -ERESTART_RESTARTBLOCK:
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restart -= 2;
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case -ERESTARTNOHAND:
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case -ERESTARTSYS:
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case -ERESTARTNOINTR:
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restart++;
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regs->ARM_r0 = regs->ARM_ORIG_r0;
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regs->ARM_pc = restart_addr;
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break;
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case -ERESTART_RESTARTBLOCK:
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regs->ARM_r0 = -EINTR;
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break;
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}
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}
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@ -619,14 +607,17 @@ static void do_signal(struct pt_regs *regs, int syscall)
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* point the debugger may change all our registers ...
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*/
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signr = get_signal_to_deliver(&info, &ka, regs, NULL);
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if (signr > 0) {
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/*
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* Depending on the signal settings we may need to revert the
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* decision to restart the system call. But skip this if a
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* debugger has chosen to restart at a different PC.
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*/
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if (regs->ARM_pc == restart_addr) {
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if (retval == -ERESTARTNOHAND
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if (regs->ARM_pc != restart_addr)
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restart = 0;
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if (signr > 0) {
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if (unlikely(restart)) {
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if (retval == -ERESTARTNOHAND ||
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retval == -ERESTART_RESTARTBLOCK
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|| (retval == -ERESTARTSYS
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&& !(ka.sa.sa_flags & SA_RESTART))) {
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regs->ARM_r0 = -EINTR;
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@ -635,52 +626,43 @@ static void do_signal(struct pt_regs *regs, int syscall)
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}
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handle_signal(signr, &ka, &info, regs);
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return;
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}
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if (syscall) {
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/*
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* Handle restarting a different system call. As above,
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* if a debugger has chosen to restart at a different PC,
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* ignore the restart.
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*/
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if (retval == -ERESTART_RESTARTBLOCK
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&& regs->ARM_pc == continue_addr) {
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if (thumb_mode(regs)) {
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regs->ARM_r7 = __NR_restart_syscall - __NR_SYSCALL_BASE;
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regs->ARM_pc -= 2;
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} else {
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#if defined(CONFIG_AEABI) && !defined(CONFIG_OABI_COMPAT)
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regs->ARM_r7 = __NR_restart_syscall;
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regs->ARM_pc -= 4;
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#else
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u32 __user *usp;
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regs->ARM_sp -= 4;
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usp = (u32 __user *)regs->ARM_sp;
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if (put_user(regs->ARM_pc, usp) == 0) {
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regs->ARM_pc = KERN_RESTART_CODE;
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} else {
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regs->ARM_sp += 4;
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force_sigsegv(0, current);
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}
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#endif
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}
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}
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return 0;
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}
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restore_saved_sigmask();
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if (unlikely(restart))
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regs->ARM_pc = continue_addr;
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return restart;
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}
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asmlinkage void
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do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall)
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asmlinkage int
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do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
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{
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if (thread_flags & _TIF_SIGPENDING)
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do_signal(regs, syscall);
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if (thread_flags & _TIF_NOTIFY_RESUME) {
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do {
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if (likely(thread_flags & _TIF_NEED_RESCHED)) {
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schedule();
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} else {
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if (unlikely(!user_mode(regs)))
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return 0;
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local_irq_enable();
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if (thread_flags & _TIF_SIGPENDING) {
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int restart = do_signal(regs, syscall);
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if (unlikely(restart)) {
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/*
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* Restart without handlers.
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* Deal with it without leaving
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* the kernel space.
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*/
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return restart;
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}
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syscall = 0;
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} else {
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clear_thread_flag(TIF_NOTIFY_RESUME);
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tracehook_notify_resume(regs);
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}
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}
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local_irq_disable();
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thread_flags = current_thread_info()->flags;
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} while (thread_flags & _TIF_WORK_MASK);
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return 0;
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}
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@ -8,7 +8,5 @@
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* published by the Free Software Foundation.
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*/
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#define KERN_SIGRETURN_CODE (CONFIG_VECTORS_BASE + 0x00000500)
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#define KERN_RESTART_CODE (KERN_SIGRETURN_CODE + sizeof(sigreturn_codes))
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extern const unsigned long sigreturn_codes[7];
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extern const unsigned long syscall_restart_code[2];
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@ -844,8 +844,6 @@ void __init early_trap_init(void *vectors_base)
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*/
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memcpy((void *)(vectors + KERN_SIGRETURN_CODE - CONFIG_VECTORS_BASE),
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sigreturn_codes, sizeof(sigreturn_codes));
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memcpy((void *)(vectors + KERN_RESTART_CODE - CONFIG_VECTORS_BASE),
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syscall_restart_code, sizeof(syscall_restart_code));
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flush_icache_range(vectors, vectors + PAGE_SIZE);
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modify_domain(DOMAIN_USER, DOMAIN_CLIENT);
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