From: Liam R. Howlett <Liam.Howlett@Oracle.com>
Date: Thu, 22 Dec 2016 02:57:42 +0000 (-0500)
Subject: sparc64: Don't panic on user mode non-resumable errors
X-Git-Tag: v4.1.12-92~1^2~23
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=f6100a00a484ee012b501e7bf65f89bb546365f8;p=users%2Fjedix%2Flinux-maple.git

sparc64: Don't panic on user mode non-resumable errors

Send a SIGBUS to the offending process on all userspace non-resumable
traps.  This prevents userspace applications from creating a kernel
panic.  The siginfo will return the code BUS_ADRERR and a valid address
if possible.

orabug: 23054018

Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Signed-off-by: Allen Pais <allen.pais@oracle.com>
---

diff --git a/arch/sparc/kernel/traps_64.c b/arch/sparc/kernel/traps_64.c
index 012726850be06..813dedc848dde 100644
--- a/arch/sparc/kernel/traps_64.c
+++ b/arch/sparc/kernel/traps_64.c
@@ -2076,6 +2076,27 @@ void sun4v_nonresum_error(struct pt_regs *regs, unsigned long offset)
 
 	put_cpu();
 
+	if (!(regs->tstate & TSTATE_PRIV)) {
+		/* DON'T PANIC.  This error was from userspace. */
+		siginfo_t info;
+		unsigned int insn;
+
+		info.si_signo = SIGBUS;
+		info.si_code = BUS_ADRERR;
+		info.si_errno = 0;
+		info.si_trapno = 0;
+		info.si_addr = 0;
+
+		if (!copy_from_user(&insn, (void __user *)regs->tpc, 4)) {
+			info.si_addr = (void __user *)
+				compute_effective_address(regs, insn,
+						(insn >> 25) & 0x1f);
+		}
+
+		force_sig_info(SIGBUS, &info, current);
+		return;
+	}
+
 #ifdef CONFIG_PCI
 	/* Check for the special PCI poke sequence. */
 	if (pci_poke_in_progress && pci_poke_cpu == cpu) {