Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull more arm64 fixes from Will Deacon:

 - Fix incorrect LDADD instruction encoding in our disassembly macros

 - Disable the broken ARM64_PSEUDO_NMI support for now

 - Add workaround for Cortex-A76 CPU erratum #1463225

 - Handle Cortex-A76/Neoverse-N1 erratum #1418040 w/ existing workaround

 - Fix IORT build failure if IOMMU_SUPPORT=n

 - Fix place-relative module relocation range checking and its
   interaction with KASLR

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: insn: Add BUILD_BUG_ON() for invalid masks
  arm64: insn: Fix ldadd instruction encoding
  arm64: Kconfig: Make ARM64_PSEUDO_NMI depend on BROKEN for now
  arm64: Handle erratum 1418040 as a superset of erratum 1188873
  arm64/module: deal with ambiguity in PRELxx relocation ranges
  ACPI/IORT: Fix build error when IOMMU_SUPPORT is disabled
  arm64/kernel: kaslr: reduce module randomization range to 2 GB
  arm64: errata: Add workaround for Cortex-A76 erratum #1463225
  arm64: Remove useless message during oops

1 files changed, 33 insertions, 0 deletions

diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index dda234bcc020..a30818ed9c60 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -811,6 +811,36 @@ void __init hook_debug_fault_code(int nr,
 	debug_fault_info[nr].name	= name;
 }
 
+#ifdef CONFIG_ARM64_ERRATUM_1463225
+DECLARE_PER_CPU(int, __in_cortex_a76_erratum_1463225_wa);
+
+static int __exception
+cortex_a76_erratum_1463225_debug_handler(struct pt_regs *regs)
+{
+	if (user_mode(regs))
+		return 0;
+
+	if (!__this_cpu_read(__in_cortex_a76_erratum_1463225_wa))
+		return 0;
+
+	/*
+	 * We've taken a dummy step exception from the kernel to ensure
+	 * that interrupts are re-enabled on the syscall path. Return back
+	 * to cortex_a76_erratum_1463225_svc_handler() with debug exceptions
+	 * masked so that we can safely restore the mdscr and get on with
+	 * handling the syscall.
+	 */
+	regs->pstate |= PSR_D_BIT;
+	return 1;
+}
+#else
+static int __exception
+cortex_a76_erratum_1463225_debug_handler(struct pt_regs *regs)
+{
+	return 0;
+}
+#endif /* CONFIG_ARM64_ERRATUM_1463225 */
+
 asmlinkage void __exception do_debug_exception(unsigned long addr_if_watchpoint,
 					       unsigned int esr,
 					       struct pt_regs *regs)
@@ -818,6 +848,9 @@ asmlinkage void __exception do_debug_exception(unsigned long addr_if_watchpoint,
 	const struct fault_info *inf = esr_to_debug_fault_info(esr);
 	unsigned long pc = instruction_pointer(regs);
 
+	if (cortex_a76_erratum_1463225_debug_handler(regs))
+		return;
+
 	/*
 	 * Tell lockdep we disabled irqs in entry.S. Do nothing if they were
 	 * already disabled to preserve the last enabled/disabled addresses.