Merge branch 'efi-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull EFI updates from Ingo Molnar:
 "The main EFI changes in this cycle were:

   - Fix the apple-properties code (Andy Shevchenko)

   - Add WARN() on arm64 if UEFI Runtime Services corrupt the reserved
     x18 register (Ard Biesheuvel)

   - Use efi_switch_mm() on x86 instead of manipulating %cr3 directly
     (Sai Praneeth)

   - Fix early memremap leak in ESRT code (Ard Biesheuvel)

   - Switch to L"xxx" notation for wide string literals (Ard Biesheuvel)

   - ... plus misc other cleanups and bugfixes"

* 'efi-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/efi: Use efi_switch_mm() rather than manually twiddling with %cr3
  x86/efi: Replace efi_pgd with efi_mm.pgd
  efi: Use string literals for efi_char16_t variable initializers
  efi/esrt: Fix handling of early ESRT table mapping
  efi: Use efi_mm in x86 as well as ARM
  efi: Make const array 'apple' static
  efi/apple-properties: Use memremap() instead of ioremap()
  efi: Reorder pr_notice() with add_device_randomness() call
  x86/efi: Replace GFP_ATOMIC with GFP_KERNEL in efi_query_variable_store()
  efi/arm64: Check whether x18 is preserved by runtime services calls
  efi/arm*: Stop printing addresses of virtual mappings
  efi/apple-properties: Remove redundant attribute initialization from unmarshal_key_value_pairs()
  efi/arm*: Only register page tables when they exist

18 files changed, 141 insertions, 108 deletions

diff --git a/arch/arm64/include/asm/efi.h b/arch/arm64/include/asm/efi.h
index 8389050328bb..192d791f1103 100644
--- a/arch/arm64/include/asm/efi.h
+++ b/arch/arm64/include/asm/efi.h
@@ -31,7 +31,7 @@ int efi_set_mapping_permissions(struct mm_struct *mm, efi_memory_desc_t *md);
 ({                                                                      \
         efi_##f##_t *__f;                                               \
         __f = p->f;                                                     \
-        __f(args);                                                      \
+        __efi_rt_asm_wrapper(__f, #f, args);                            \
 })
 
 #define arch_efi_call_virt_teardown()                                   \
@@ -40,6 +40,8 @@ int efi_set_mapping_permissions(struct mm_struct *mm, efi_memory_desc_t *md);
         efi_virtmap_unload();                                           \
 })
 
+efi_status_t __efi_rt_asm_wrapper(void *, const char *, ...);
+
 #define ARCH_EFI_IRQ_FLAGS_MASK (PSR_D_BIT | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT)
 
 /* arch specific definitions used by the stub code */
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index b87541360f43..6a4bd80c75bd 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -38,7 +38,8 @@ arm64-obj-$(CONFIG_CPU_PM)		+= sleep.o suspend.o
 arm64-obj-$(CONFIG_CPU_IDLE)            += cpuidle.o
 arm64-obj-$(CONFIG_JUMP_LABEL)          += jump_label.o
 arm64-obj-$(CONFIG_KGDB)                += kgdb.o
-arm64-obj-$(CONFIG_EFI)                 += efi.o efi-entry.stub.o
+arm64-obj-$(CONFIG_EFI)                 += efi.o efi-entry.stub.o               \
+                                           efi-rt-wrapper.o
 arm64-obj-$(CONFIG_PCI)                 += pci.o
 arm64-obj-$(CONFIG_ARMV8_DEPRECATED)    += armv8_deprecated.o
 arm64-obj-$(CONFIG_ACPI)                += acpi.o
diff --git a/arch/arm64/kernel/efi-rt-wrapper.S b/arch/arm64/kernel/efi-rt-wrapper.S
new file mode 100644
index 000000000000..05235ebb336d
--- /dev/null
+++ b/arch/arm64/kernel/efi-rt-wrapper.S
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2018 Linaro Ltd <ard.biesheuvel@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/linkage.h>
+
+ENTRY(__efi_rt_asm_wrapper)
+        stp     x29, x30, [sp, #-32]!
+        mov     x29, sp
+
+        /*
+         * Register x18 is designated as the 'platform' register by the AAPCS,
+         * which means firmware running at the same exception level as the OS
+         * (such as UEFI) should never touch it.
+         */
+        stp     x1, x18, [sp, #16]
+
+        /*
+         * We are lucky enough that no EFI runtime services take more than
+         * 5 arguments, so all are passed in registers rather than via the
+         * stack.
+         */
+        mov     x8, x0
+        mov     x0, x2
+        mov     x1, x3
+        mov     x2, x4
+        mov     x3, x5
+        mov     x4, x6
+        blr     x8
+
+        ldp     x1, x2, [sp, #16]
+        cmp     x2, x18
+        ldp     x29, x30, [sp], #32
+        b.ne    0f
+        ret
+0:      b       efi_handle_corrupted_x18        // tail call
+ENDPROC(__efi_rt_asm_wrapper)
diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
index a8bf1c892b90..4f9acb5fbe97 100644
--- a/arch/arm64/kernel/efi.c
+++ b/arch/arm64/kernel/efi.c
@@ -126,3 +126,9 @@ bool efi_poweroff_required(void)
 {
         return efi_enabled(EFI_RUNTIME_SERVICES);
 }
+
+asmlinkage efi_status_t efi_handle_corrupted_x18(efi_status_t s, const char *f)
+{
+        pr_err_ratelimited(FW_BUG "register x18 corrupted by EFI %s\n", f);
+        return s;
+}
diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index 886a9115af62..47d3efff6805 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -421,9 +421,10 @@ static void retrieve_apple_device_properties(struct boot_params *boot_params)
         }
 }
 
+static const efi_char16_t apple[] = L"Apple";
+
 static void setup_quirks(struct boot_params *boot_params)
 {
-        efi_char16_t const apple[] = { 'A', 'p', 'p', 'l', 'e', 0 };
         efi_char16_t *fw_vendor = (efi_char16_t *)(unsigned long)
                 efi_table_attr(efi_system_table, fw_vendor, sys_table);
 
diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
index a399c1ebf6f0..cec5fae23eb3 100644
--- a/arch/x86/include/asm/efi.h
+++ b/arch/x86/include/asm/efi.h
@@ -7,6 +7,7 @@
 #include <asm/processor-flags.h>
 #include <asm/tlb.h>
 #include <asm/nospec-branch.h>
+#include <asm/mmu_context.h>
 
 /*
  * We map the EFI regions needed for runtime services non-contiguously,
@@ -69,14 +70,13 @@ extern asmlinkage u64 efi_call(void *fp, ...);
 #define efi_call_phys(f, args...)               efi_call((f), args)
 
 /*
- * Scratch space used for switching the pagetable in the EFI stub
+ * struct efi_scratch - Scratch space used while switching to/from efi_mm
+ * @phys_stack: stack used during EFI Mixed Mode
+ * @prev_mm:    store/restore stolen mm_struct while switching to/from efi_mm
  */
 struct efi_scratch {
-        u64     r15;
-        u64     prev_cr3;
-        pgd_t   *efi_pgt;
-        bool    use_pgd;
-        u64     phys_stack;
+        u64                     phys_stack;
+        struct mm_struct        *prev_mm;
 } __packed;
 
 #define arch_efi_call_virt_setup()                                      \
@@ -86,11 +86,8 @@ struct efi_scratch {
         __kernel_fpu_begin();                                           \
         firmware_restrict_branch_speculation_start();                   \
                                                                         \
-        if (efi_scratch.use_pgd) {                                      \
-                efi_scratch.prev_cr3 = __read_cr3();                    \
-                write_cr3((unsigned long)efi_scratch.efi_pgt);          \
-                __flush_tlb_all();                                      \
-        }                                                               \
+        if (!efi_enabled(EFI_OLD_MEMMAP))                               \
+                efi_switch_mm(&efi_mm);                                 \
 })
 
 #define arch_efi_call_virt(p, f, args...)                               \
@@ -98,10 +95,8 @@ struct efi_scratch {
 
 #define arch_efi_call_virt_teardown()                                   \
 ({                                                                      \
-        if (efi_scratch.use_pgd) {                                      \
-                write_cr3(efi_scratch.prev_cr3);                        \
+        if (!efi_enabled(EFI_OLD_MEMMAP))                               \
+                efi_switch_mm(efi_scratch.pre