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Commit 04748724 authored by Liam R. Howlett's avatar Liam R. Howlett Committed by David S. Miller
Browse files

sparc64: Handle PIO & MEM non-resumable errors. 



User processes trying to access an invalid memory address via PIO will
receive a SIGBUS signal instead of causing a panic.  Memory errors will
receive a SIGKILL since a SIGBUS may result in a coredump which may
attempt to repeat the faulting access.

Signed-off-by: default avatarLiam R. Howlett <Liam.Howlett@Oracle.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7a7dc961

arch/sparc/kernel/traps_64.c

+73 −0
Original line number Diff line number Diff line
@@ -2051,6 +2051,73 @@ void sun4v_resum_overflow(struct pt_regs *regs) 
	atomic_inc(&sun4v_resum_oflow_cnt);

}



/* Given a set of registers, get the virtual addressi that was being accessed

 * by the faulting instructions at tpc.

 */

static unsigned long sun4v_get_vaddr(struct pt_regs *regs)

{

	unsigned int insn;



	if (!copy_from_user(&insn, (void __user *)regs->tpc, 4)) {

		return compute_effective_address(regs, insn,

						 (insn >> 25) & 0x1f);

	}

	return 0;

}



/* Attempt to handle non-resumable errors generated from userspace.

 * Returns true if the signal was handled, false otherwise.

 */

bool sun4v_nonresum_error_user_handled(struct pt_regs *regs,

				  struct sun4v_error_entry *ent) {



	unsigned int attrs = ent->err_attrs;



	if (attrs & SUN4V_ERR_ATTRS_MEMORY) {

		unsigned long addr = ent->err_raddr;

		siginfo_t info;



		if (addr == ~(u64)0) {

			/* This seems highly unlikely to ever occur */

			pr_emerg("SUN4V NON-RECOVERABLE ERROR: Memory error detected in unknown location!\n");

		} else {

			unsigned long page_cnt = DIV_ROUND_UP(ent->err_size,

							      PAGE_SIZE);



			/* Break the unfortunate news. */

			pr_emerg("SUN4V NON-RECOVERABLE ERROR: Memory failed at %016lX\n",

				 addr);

			pr_emerg("SUN4V NON-RECOVERABLE ERROR:   Claiming %lu ages.\n",

				 page_cnt);



			while (page_cnt-- > 0) {

				if (pfn_valid(addr >> PAGE_SHIFT))

					get_page(pfn_to_page(addr >> PAGE_SHIFT));

				addr += PAGE_SIZE;

			}

		}

		info.si_signo = SIGKILL;

		info.si_errno = 0;

		info.si_trapno = 0;

		force_sig_info(info.si_signo, &info, current);



		return true;

	}

	if (attrs & SUN4V_ERR_ATTRS_PIO) {

		siginfo_t info;



		info.si_signo = SIGBUS;

		info.si_code = BUS_ADRERR;

		info.si_addr = (void __user *)sun4v_get_vaddr(regs);

		force_sig_info(info.si_signo, &info, current);



		return true;

	}



	/* Default to doing nothing */

	return false;

}



/* We run with %pil set to PIL_NORMAL_MAX and PSTATE_IE enabled in %pstate.

 * Log the event, clear the first word of the entry, and die.

 */
@@ -2075,6 +2142,12 @@ void sun4v_nonresum_error(struct pt_regs *regs, unsigned long offset) 


	put_cpu();



	if (!(regs->tstate & TSTATE_PRIV) &&

	    sun4v_nonresum_error_user_handled(regs, &local_copy)) {

		/* DON'T PANIC: This userspace error was handled. */

		return;

	}



#ifdef CONFIG_PCI

	/* Check for the special PCI poke sequence. */

	if (pci_poke_in_progress && pci_poke_cpu == cpu) {