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Commit 6b5c8045 authored by Al Viro's avatar Al Viro
Browse files

arm: new way of handling ERESTART_RESTARTBLOCK 



new "syscall start" flag; handled in syscall_trace() by switching
syscall number to that of syscall_restart(2).  Restarts of that
kind (ERESTART_RESTARTBLOCK) are handled by setting that bit;
syscall number is not modified until the actual call.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 21c1176a

arch/arm/include/asm/thread_info.h

+4 −1
Original line number Diff line number Diff line
@@ -148,6 +148,7 @@ extern int vfp_restore_user_hwstate(struct user_vfp __user *, 
#define TIF_NOTIFY_RESUME	2	/* callback before returning to user */

#define TIF_SYSCALL_TRACE	8

#define TIF_SYSCALL_AUDIT	9

#define TIF_SYSCALL_RESTARTSYS	10

#define TIF_POLLING_NRFLAG	16

#define TIF_USING_IWMMXT	17

#define TIF_MEMDIE		18	/* is terminating due to OOM killer */
@@ -163,9 +164,11 @@ extern int vfp_restore_user_hwstate(struct user_vfp __user *, 
#define _TIF_USING_IWMMXT	(1 << TIF_USING_IWMMXT)

#define _TIF_RESTORE_SIGMASK	(1 << TIF_RESTORE_SIGMASK)

#define _TIF_SECCOMP		(1 << TIF_SECCOMP)

#define _TIF_SYSCALL_RESTARTSYS	(1 << TIF_SYSCALL_RESTARTSYS)



/* Checks for any syscall work in entry-common.S */

#define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT)

#define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \

			   _TIF_SYSCALL_RESTARTSYS)



/*

 * Change these and you break ASM code in entry-common.S

arch/arm/kernel/ptrace.c

+3 −0
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ 
#include <linux/hw_breakpoint.h>

#include <linux/regset.h>

#include <linux/audit.h>

#include <linux/unistd.h>



#include <asm/pgtable.h>

#include <asm/traps.h>
@@ -916,6 +917,8 @@ asmlinkage int syscall_trace(int why, struct pt_regs *regs, int scno) 
		audit_syscall_entry(AUDIT_ARCH_ARM, scno, regs->ARM_r0,

				    regs->ARM_r1, regs->ARM_r2, regs->ARM_r3);



	if (why == 0 && test_and_clear_thread_flag(TIF_SYSCALL_RESTARTSYS))

		scno = __NR_restart_syscall - __NR_SYSCALL_BASE;

	if (!test_thread_flag(TIF_SYSCALL_TRACE))

		return scno;

	if (!(current->ptrace & PT_PTRACED))

arch/arm/kernel/signal.c

+6 −27
Original line number Diff line number Diff line
@@ -624,12 +624,10 @@ static void do_signal(struct pt_regs *regs, int syscall) 
		case -ERESTARTNOHAND:

		case -ERESTARTSYS:

		case -ERESTARTNOINTR:

		case -ERESTART_RESTARTBLOCK:

			regs->ARM_r0 = regs->ARM_ORIG_r0;

			regs->ARM_pc = restart_addr;

			break;

		case -ERESTART_RESTARTBLOCK:

			regs->ARM_r0 = -EINTR;

			break;

		}

	}
@@ -647,12 +645,14 @@ static void do_signal(struct pt_regs *regs, int syscall) 
		 * debugger has chosen to restart at a different PC.

		 */

		if (regs->ARM_pc == restart_addr) {

			if (retval == -ERESTARTNOHAND

			if (retval == -ERESTARTNOHAND ||

			    retval == -ERESTART_RESTARTBLOCK

			    || (retval == -ERESTARTSYS

				&& !(ka.sa.sa_flags & SA_RESTART))) {

				regs->ARM_r0 = -EINTR;

				regs->ARM_pc = continue_addr;

			}

			clear_thread_flag(TIF_SYSCALL_RESTARTSYS);

		}



		if (test_thread_flag(TIF_RESTORE_SIGMASK))
@@ -679,29 +679,8 @@ static void do_signal(struct pt_regs *regs, int syscall) 
		 * ignore the restart.

		 */

		if (retval == -ERESTART_RESTARTBLOCK

		    && regs->ARM_pc == continue_addr) {

			if (thumb_mode(regs)) {

				regs->ARM_r7 = __NR_restart_syscall - __NR_SYSCALL_BASE;

				regs->ARM_pc -= 2;

			} else {

#if defined(CONFIG_AEABI) && !defined(CONFIG_OABI_COMPAT)

				regs->ARM_r7 = __NR_restart_syscall;

				regs->ARM_pc -= 4;

#else

				u32 __user *usp;



				regs->ARM_sp -= 4;

				usp = (u32 __user *)regs->ARM_sp;



				if (put_user(regs->ARM_pc, usp) == 0) {

					regs->ARM_pc = KERN_RESTART_CODE;

				} else {

					regs->ARM_sp += 4;

					force_sigsegv(0, current);

				}

#endif

			}

		}

		    && regs->ARM_pc == restart_addr)

			set_thread_flag(TIF_SYSCALL_RESTARTSYS);

	}



	/* If there's no signal to deliver, we just put the saved sigmask