[S390] remove reset of system call restart on psw changes (cfc9066b) · Commits · 戴 / test

git commit "signal race with restarting system calls" added code to the poke_user/poke_user_compat to reset the system call restart information in the thread-info if the PSW address is changed. The purpose of that change has been to workaround old gdbs that do not know about the REGSET_SYSTEM_CALL. It turned out that this is not a good idea, it makes the behaviour of the debuggee dependent on the order of specific ptrace call, e.g. the REGSET_SYSTEM_CALL register set needs to be written last. And the workaround does not really fix old gdbs, inferior calls on interrupted restarting system calls do not work either way. Signed-off-by:

Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/kernel/ptrace.c

+0 −12

Original line number	Diff line number	Diff line
		@@ -296,13 +296,6 @@ static int __poke_user(struct task_struct *child, addr_t addr, addr_t data)
		((data & PSW_MASK_EA) && !(data & PSW_MASK_BA))))
		/* Invalid psw mask. */
		return -EINVAL;
		if (addr == (addr_t) &dummy->regs.psw.addr)
		/*
		* The debugger changed the instruction address,
		* reset system call restart, see signal.c:do_signal
		*/
		task_thread_info(child)->system_call = 0;

		(addr_t )((addr_t) &task_pt_regs(child)->psw + addr) = data;

		} else if (addr < (addr_t) (&dummy->regs.orig_gpr2)) {
		@@ -614,11 +607,6 @@ static int __poke_user_compat(struct task_struct *child,
		/* Transfer 31 bit amode bit to psw mask. */
		regs->psw.mask = (regs->psw.mask & ~PSW_MASK_BA) \|
		(__u64)(tmp & PSW32_ADDR_AMODE);
		/*
		* The debugger changed the instruction address,
		* reset system call restart, see signal.c:do_signal
		*/
		task_thread_info(child)->system_call = 0;
		} else {
		/* gpr 0-15 */
		(__u32)((addr_t) &regs->psw + addr*2 + 4) = tmp;

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