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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: Liam R. Howlett <Liam.Howlett@Oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Liam R. Howlett 2017-01-17 10:59:03 -05:00 committed by David S. Miller
parent 7a7dc961a2
commit 047487241f
1 changed files with 73 additions and 0 deletions
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73
arch/sparc/kernel/traps_64.c
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@ -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) {