sparc64: Add support for ADI register fields, ASIs and traps

SPARC M7 processor adds new control register fields, ASIs and a new
trap to support the ADI (Application Data Integrity) feature. This
patch adds definitions for these register fields, ASIs and a handler
for the new precise memory corruption detected trap.

Signed-off-by: Khalid Aziz <khalid.aziz@oracle.com>
Cc: Khalid Aziz <khalid@gonehiking.org>
Reviewed-by: Anthony Yznaga <anthony.yznaga@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 54 insertions, 0 deletions

diff --git a/arch/sparc/kernel/traps_64.c b/arch/sparc/kernel/traps_64.c
index 0a56dc257cb9..fc73baa588f6 100644
--- a/arch/sparc/kernel/traps_64.c
+++ b/arch/sparc/kernel/traps_64.c
@@ -2656,6 +2656,60 @@ void sun4v_do_mna(struct pt_regs *regs, unsigned long addr, unsigned long type_c
 	force_sig_info(SIGBUS, &info, current);
 }
 
+/* sun4v_mem_corrupt_detect_precise() - Handle precise exception on an ADI
+ * tag mismatch.
+ *
+ * ADI version tag mismatch on a load from memory always results in a
+ * precise exception. Tag mismatch on a store to memory will result in
+ * precise exception if MCDPER or PMCDPER is set to 1.
+ */
+void sun4v_mem_corrupt_detect_precise(struct pt_regs *regs, unsigned long addr,
+				      unsigned long context)
+{
+	siginfo_t info;
+
+	if (notify_die(DIE_TRAP, "memory corruption precise exception", regs,
+		       0, 0x8, SIGSEGV) == NOTIFY_STOP)
+		return;
+
+	if (regs->tstate & TSTATE_PRIV) {
+		/* MCD exception could happen because the task was running
+		 * a system call with MCD enabled and passed a non-versioned
+		 * pointer or pointer with bad version tag to  the system
+		 * call.
+		 */
+		const struct exception_table_entry *entry;
+
+		entry = search_exception_tables(regs->tpc);
+		if (entry) {
+			/* Looks like a bad syscall parameter */
+#ifdef DEBUG_EXCEPTIONS
+			pr_emerg("Exception: PC<%016lx> faddr<UNKNOWN>\n",
+				 regs->tpc);
+			pr_emerg("EX_TABLE: insn<%016lx> fixup<%016lx>\n",
+				 regs->tpc, entry->fixup);
+#endif
+			regs->tpc = entry->fixup;
+			regs->tnpc = regs->tpc + 4;
+			return;
+		}
+		pr_emerg("%s: ADDR[%016lx] CTX[%lx], going.\n",
+			 __func__, addr, context);
+		die_if_kernel("MCD precise", regs);
+	}
+
+	if (test_thread_flag(TIF_32BIT)) {
+		regs->tpc &= 0xffffffff;
+		regs->tnpc &= 0xffffffff;
+	}
+	info.si_signo = SIGSEGV;
+	info.si_code = SEGV_ADIPERR;
+	info.si_errno = 0;
+	info.si_addr = (void __user *) addr;
+	info.si_trapno = 0;
+	force_sig_info(SIGSEGV, &info, current);
+}
+
 void do_privop(struct pt_regs *regs)
 {
 	enum ctx_state prev_state = exception_enter();