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

Pull arm64 updates from Will Deacon:

 - Support for new architectural features introduced in ARMv8.1:
   * Privileged Access Never (PAN) to catch user pointer dereferences in
     the kernel
   * Large System Extension (LSE) for building scalable atomics and locks
     (depends on locking/arch-atomic from tip, which is included here)
   * Hardware Dirty Bit Management (DBM) for updating clean PTEs
     automatically

 - Move our PSCI implementation out into drivers/firmware/, where it can
   be shared with arch/arm/. RMK has also pulled this component branch
   and has additional patches moving arch/arm/ over. MAINTAINERS is
   updated accordingly.

 - Better BUG implementation based on the BRK instruction for trapping

 - Leaf TLB invalidation for unmapping user pages

 - Support for PROBE_ONLY PCI configurations

 - Various cleanups and non-critical fixes, including:
   * Always flush FP/SIMD state over exec()
   * Restrict memblock additions based on range of linear mapping
   * Ensure *(LIST_POISON) generates a fatal fault
   * Context-tracking syscall return no longer corrupts return value when
     not forced on.
   * Alternatives patching synchronisation/stability improvements
   * Signed sub-word cmpxchg compare fix (tickled by HAVE_CMPXCHG_LOCAL)
   * Force SMP=y
   * Hide direct DCC access from userspace
   * Fix EFI stub memory allocation when DRAM starts at 0x0

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (92 commits)
  arm64: flush FP/SIMD state correctly after execve()
  arm64: makefile: fix perf_callchain.o kconfig dependency
  arm64: set MAX_MEMBLOCK_ADDR according to linear region size
  of/fdt: make memblock maximum physical address arch configurable
  arm64: Fix source code file path in comments
  arm64: entry: always restore x0 from the stack on syscall return
  arm64: mdscr_el1: avoid exposing DCC to userspace
  arm64: kconfig: Move LIST_POISON to a safe value
  arm64: Add __exception_irq_entry definition for function graph
  arm64: mm: ensure patched kernel text is fetched from PoU
  arm64: alternatives: ensure secondary CPUs execute ISB after patching
  arm64: make ll/sc __cmpxchg_case_##name asm consistent
  arm64: dma-mapping: Simplify pgprot handling
  arm64: restore cpu suspend/resume functionality
  ARM64: PCI: do not enable resources on PROBE_ONLY systems
  arm64: cmpxchg: truncate sub-word signed types before comparison
  arm64: alternative: put secondary CPUs into polling loop during patch
  arm64/Documentation: clarify wording regarding memory below the Image
  arm64: lse: fix lse cmpxchg code indentation
  arm64: remove redundant object file list
  ...

1 files changed, 26 insertions, 2 deletions

diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 94d98cd1aad8..aba9ead1384c 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -30,9 +30,11 @@
 #include <linux/highmem.h>
 #include <linux/perf_event.h>
 
+#include <asm/cpufeature.h>
 #include <asm/exception.h>
 #include <asm/debug-monitors.h>
 #include <asm/esr.h>
+#include <asm/sysreg.h>
 #include <asm/system_misc.h>
 #include <asm/pgtable.h>
 #include <asm/tlbflush.h>
@@ -224,6 +226,13 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
 	}
 
 	/*
+	 * PAN bit set implies the fault happened in kernel space, but not
+	 * in the arch's user access functions.
+	 */
+	if (IS_ENABLED(CONFIG_ARM64_PAN) && (regs->pstate & PSR_PAN_BIT))
+		goto no_context;
+
+	/*
 	 * As per x86, we may deadlock here. However, since the kernel only
 	 * validly references user space from well defined areas of the code,
 	 * we can bug out early if this is from code which shouldn't.
@@ -492,14 +501,22 @@ asmlinkage void __exception do_sp_pc_abort(unsigned long addr,
 	arm64_notify_die("Oops - SP/PC alignment exception", regs, &info, esr);
 }
 
-static struct fault_info debug_fault_info[] = {
+int __init early_brk64(unsigned long addr, unsigned int esr,
+		       struct pt_regs *regs);
+
+/*
+ * __refdata because early_brk64 is __init, but the reference to it is
+ * clobbered at arch_initcall time.
+ * See traps.c and debug-monitors.c:debug_traps_init().
+ */
+static struct fault_info __refdata debug_fault_info[] = {
 	{ do_bad,	SIGTRAP,	TRAP_HWBKPT,	"hardware breakpoint"	},
 	{ do_bad,	SIGTRAP,	TRAP_HWBKPT,	"hardware single-step"	},
 	{ do_bad,	SIGTRAP,	TRAP_HWBKPT,	"hardware watchpoint"	},
 	{ do_bad,	SIGBUS,		0,		"unknown 3"		},
 	{ do_bad,	SIGTRAP,	TRAP_BRKPT,	"aarch32 BKPT"		},
 	{ do_bad,	SIGTRAP,	0,		"aarch32 vector catch"	},
-	{ do_bad,	SIGTRAP,	TRAP_BRKPT,	"aarch64 BRK"		},
+	{ early_brk64,	SIGTRAP,	TRAP_BRKPT,	"aarch64 BRK"		},
 	{ do_bad,	SIGBUS,		0,		"unknown 7"		},
 };
 
@@ -536,3 +553,10 @@ asmlinkage int __exception do_debug_exception(unsigned long addr,
 
 	return 0;
 }
+
+#ifdef CONFIG_ARM64_PAN
+void cpu_enable_pan(void)
+{
+	config_sctlr_el1(SCTLR_EL1_SPAN, 0);
+}
+#endif /* CONFIG_ARM64_PAN */