Revert "x86-64/efi: Use EFI to deal with platform wall clock (again)"

This reverts commit bd52276fa1d4 ("x86-64/efi: Use EFI to deal with
platform wall clock (again)"), and the two supporting commits:

  da5a108d05b4: "x86/kernel: remove tboot 1:1 page table creation code"

  185034e72d59: "x86, efi: 1:1 pagetable mapping for virtual EFI calls")

as they all depend semantically on commit 53b87cf088e2 ("x86, mm:
Include the entire kernel memory map in trampoline_pgd") that got
reverted earlier due to the problems it caused.

This was pointed out by Yinghai Lu, and verified by me on my Macbook Air
that uses EFI.

Pointed-out-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

7 files changed, 116 insertions, 55 deletions

diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
index fd13815fe85..6e8fdf5ad11 100644
--- a/arch/x86/include/asm/efi.h
+++ b/arch/x86/include/asm/efi.h
@@ -69,37 +69,23 @@ extern u64 efi_call6(void *fp, u64 arg1, u64 arg2, u64 arg3,
         efi_call6((void *)(f), (u64)(a1), (u64)(a2), (u64)(a3),         \
                   (u64)(a4), (u64)(a5), (u64)(a6))
 
-extern unsigned long efi_call_virt_prelog(void);
-extern void efi_call_virt_epilog(unsigned long);
-
-#define efi_callx(x, func, ...)                                 \
-        ({                                                      \
-                efi_status_t __status;                          \
-                unsigned long __pgd;                            \
-                                                                \
-                __pgd = efi_call_virt_prelog();                 \
-                __status = efi_call##x(func, __VA_ARGS__);      \
-                efi_call_virt_epilog(__pgd);                    \
-                __status;                                       \
-        })
-
 #define efi_call_virt0(f)                               \
-        efi_callx(0, (void *)(efi.systab->runtime->f))
+        efi_call0((void *)(efi.systab->runtime->f))
 #define efi_call_virt1(f, a1)                                   \
-        efi_callx(1, (void *)(efi.systab->runtime->f), (u64)(a1))
+        efi_call1((void *)(efi.systab->runtime->f), (u64)(a1))
 #define efi_call_virt2(f, a1, a2)                                       \
-        efi_callx(2, (void *)(efi.systab->runtime->f), (u64)(a1), (u64)(a2))
+        efi_call2((void *)(efi.systab->runtime->f), (u64)(a1), (u64)(a2))
 #define efi_call_virt3(f, a1, a2, a3)                                   \
-        efi_callx(3, (void *)(efi.systab->runtime->f), (u64)(a1), (u64)(a2), \
+        efi_call3((void *)(efi.systab->runtime->f), (u64)(a1), (u64)(a2), \
                   (u64)(a3))
 #define efi_call_virt4(f, a1, a2, a3, a4)                               \
-        efi_callx(4, (void *)(efi.systab->runtime->f), (u64)(a1), (u64)(a2), \
+        efi_call4((void *)(efi.systab->runtime->f), (u64)(a1), (u64)(a2), \
                   (u64)(a3), (u64)(a4))
 #define efi_call_virt5(f, a1, a2, a3, a4, a5)                           \
-        efi_callx(5, (void *)(efi.systab->runtime->f), (u64)(a1), (u64)(a2), \
+        efi_call5((void *)(efi.systab->runtime->f), (u64)(a1), (u64)(a2), \
                   (u64)(a3), (u64)(a4), (u64)(a5))
 #define efi_call_virt6(f, a1, a2, a3, a4, a5, a6)                       \
-        efi_callx(6, (void *)(efi.systab->runtime->f), (u64)(a1), (u64)(a2), \
+        efi_call6((void *)(efi.systab->runtime->f), (u64)(a1), (u64)(a2), \
                   (u64)(a3), (u64)(a4), (u64)(a5), (u64)(a6))
 
 extern void __iomem *efi_ioremap(unsigned long addr, unsigned long size,
diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c
index d4f460f962e..f84fe00fad4 100644
--- a/arch/x86/kernel/tboot.c
+++ b/arch/x86/kernel/tboot.c
@@ -103,13 +103,71 @@ void __init tboot_probe(void)
         pr_debug("tboot_size: 0x%x\n", tboot->tboot_size);
 }
 
+static pgd_t *tboot_pg_dir;
+static struct mm_struct tboot_mm = {
+        .mm_rb          = RB_ROOT,
+        .pgd            = swapper_pg_dir,
+        .mm_users       = ATOMIC_INIT(2),
+        .mm_count       = ATOMIC_INIT(1),
+        .mmap_sem       = __RWSEM_INITIALIZER(init_mm.mmap_sem),
+        .page_table_lock =  __SPIN_LOCK_UNLOCKED(init_mm.page_table_lock),
+        .mmlist         = LIST_HEAD_INIT(init_mm.mmlist),
+};
+
 static inline void switch_to_tboot_pt(void)
 {
-#ifdef CONFIG_X86_32
-        load_cr3(initial_page_table);
-#else
-        write_cr3(real_mode_header->trampoline_pgd);
-#endif
+        write_cr3(virt_to_phys(tboot_pg_dir));
+}
+
+static int map_tboot_page(unsigned long vaddr, unsigned long pfn,
+                          pgprot_t prot)
+{
+        pgd_t *pgd;
+        pud_t *pud;
+        pmd_t *pmd;
+        pte_t *pte;
+
+        pgd = pgd_offset(&tboot_mm, vaddr);
+        pud = pud_alloc(&tboot_mm, pgd, vaddr);
+        if (!pud)
+                return -1;
+        pmd = pmd_alloc(&tboot_mm, pud, vaddr);
+        if (!pmd)
+                return -1;
+        pte = pte_alloc_map(&tboot_mm, NULL, pmd, vaddr);
+        if (!pte)
+                return -1;
+        set_pte_at(&tboot_mm, vaddr, pte, pfn_pte(pfn, prot));
+        pte_unmap(pte);
+        return 0;
+}
+
+static int map_tboot_pages(unsigned long vaddr, unsigned long start_pfn,
+                           unsigned long nr)
+{
+        /* Reuse the original kernel mapping */
+        tboot_pg_dir = pgd_alloc(&tboot_mm);
+        if (!tboot_pg_dir)
+                return -1;
+
+        for (; nr > 0; nr--, vaddr += PAGE_SIZE, start_pfn++) {
+                if (map_tboot_page(vaddr, start_pfn, PAGE_KERNEL_EXEC))
+                        return -1;
+        }
+
+        return 0;
+}
+
+static void tboot_create_trampoline(void)
+{
+        u32 map_base, map_size;
+
+        /* Create identity map for tboot shutdown code. */
+        map_base = PFN_DOWN(tboot->tboot_base);
+        map_size = PFN_UP(tboot->tboot_size);
+        if (map_tboot_pages(map_base << PAGE_SHIFT, map_base, map_size))
+                panic("tboot: Error mapping tboot pages (mfns) @ 0x%x, 0x%x\n",
+                      map_base, map_size);
 }
 
 #ifdef CONFIG_ACPI_SLEEP
@@ -167,6 +225,14 @@ void tboot_shutdown(u32 shutdown_type)
         if (!tboot_enabled())
                 return;
 
+        /*
+         * if we're being called before the 1:1 mapping is set up then just
+         * return and let the normal shutdown happen; this should only be
+         * due to very early panic()
+         */
+        if (!tboot_pg_dir)
+                return;
+
         /* if this is S3 then set regions to MAC */
         if (shutdown_type == TB_SHUTDOWN_S3)
                 if (tboot_setup_sleep())
@@ -277,6 +343,8 @@ static __init int tboot_late_init(void)
         if (!tboot_enabled())
                 return 0;
 
+        tboot_create_trampoline();
+
         atomic_set(&ap_wfs_count, 0);
         register_hotcpu_notifier(&tboot_cpu_notifier);
 
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 931930a9616..a718e0d2350 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -919,13 +919,11 @@ static int change_page_attr_set_clr(unsigned long *addr, int numpages,
 
         /*
          * On success we use clflush, when the CPU supports it to
-         * avoid the wbindv. If the CPU does not support it, in the
-         * error case, and during early boot (for EFI) we fall back
-         * to cpa_flush_all (which uses wbinvd):
+         * avoid the wbindv. If the CPU does not support it and in the
+         * error case we fall back to cpa_flush_all (which uses
+         * wbindv):
          */
-        if (early_boot_irqs_disabled)
-                __cpa_flush_all((void *)(long)cache);
-        else if (!ret && cpu_has_clflush) {
+        if (!ret && cpu_has_clflush) {
                 if (cpa.flags & (CPA_PAGES_ARRAY | CPA_ARRAY)) {
                         cpa_flush_array(addr, numpages, cache,
                                         cpa.flags, pages);
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 0a34d9e9c26..ad4439145f8 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -239,7 +239,22 @@ static efi_status_t __init phys_efi_set_virtual_address_map(
         return status;
 }
 
-static int efi_set_rtc_mmss(unsigned long nowtime)
+static efi_status_t __init phys_efi_get_time(efi_time_t *tm,
+                                             efi_time_cap_t *tc)
+{
+        unsigned long flags;
+        efi_status_t status;
+
+        spin_lock_irqsave(&rtc_lock, flags);
+        efi_call_phys_prelog();
+        status = efi_call_phys2(efi_phys.get_time, virt_to_phys(tm),
+                                virt_to_phys(tc));
+        efi_call_phys_epilog();
+        spin_unlock_irqrestore(&rtc_lock, flags);
+        return status;
+}
+
+int efi_set_rtc_mmss(unsigned long nowtime)
 {
         int real_seconds, real_minutes;
         efi_status_t    status;
@@ -268,7 +283,7 @@ static int efi_set_rtc_mmss(unsigned long nowtime)
         return 0;
 }
 
-static unsigned long efi_get_time(void)
+unsigned long efi_get_time(void)
 {
         efi_status_t status;
         efi_time_t eft;
@@ -624,13 +639,18 @@ static int __init efi_runtime_init(void)
         }
         /*
          * We will only need *early* access to the following
-         * EFI runtime service before set_virtual_address_map
+         * two EFI runtime services before set_virtual_address_map
          * is invoked.
          */
+        efi_phys.get_time = (efi_get_time_t *)runtime->get_time;
         efi_phys.set_virtual_address_map =
                 (efi_set_virtual_address_map_t *)
                 runtime->set_virtual_address_map;
-
+        /*
+         * Make efi_get_time can be called before entering
+         * virtual mode.
+         */
+        efi.get_time = phys_efi_get_time;
         early_iounmap(runtime, sizeof(efi_runtime_services_t));
 
         return 0;
@@ -716,10 +736,12 @@ void __init efi_init(void)
                 efi_enabled = 0;
                 return;
         }
+#ifdef CONFIG_X86_32
         if (efi_is_native()) {
                 x86_platform.get_wallclock = efi_get_time;
                 x86_platform.set_wallclock = efi_set_rtc_mmss;
         }
+#endif
 
 #if EFI_DEBUG
         print_efi_memmap();
diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
index 06c8b2e662a..95fd505dfeb 100644
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -58,21 +58,6 @@ static void __init early_code_mapping_set_exec(int executable)
         }
 }
 
-unsigned long efi_call_virt_prelog(void)
-{
-        unsigned long saved;
-
-        saved = read_cr3();
-        write_cr3(real_mode_header->trampoline_pgd);
-
-        return saved;
-}
-
-void efi_call_virt_epilog(unsigned long saved)
-{
-        write_cr3(saved);
-}
-
 void __init efi_call_phys_prelog(void)
 {
         unsigned long vaddress;
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 02a69418be1..8b84916dc67 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -587,6 +587,8 @@ extern u64 efi_mem_attribute (unsigned long phys_addr, unsigned long size);
 extern int __init efi_uart_console_only (void);
 extern void efi_initialize_iomem_resources(struct resource *code_resource,
                 struct resource *data_resource, struct resource *bss_resource);
+extern unsigned long efi_get_time(void);
+extern int efi_set_rtc_mmss(unsigned long nowtime);
 extern void efi_reserve_boot_services(void);
 extern struct efi_memory_map memmap;
 
diff --git a/init/main.c b/init/main.c
index 6af5470b806..63ae904a99a 100644
--- a/init/main.c
+++ b/init/main.c
@@ -463,10 +463,6 @@ static void __init mm_init(void)
         percpu_init_late();
         pgtable_cache_init();
         vmalloc_init();
-#ifdef CONFIG_X86
-        if (efi_enabled)
-                efi_enter_virtual_mode();
-#endif
 }
 
 asmlinkage void __init start_kernel(void)
@@ -607,6 +603,10 @@ asmlinkage void __init start_kernel(void)
         calibrate_delay();
         pidmap_init();
         anon_vma_init();
+#ifdef CONFIG_X86
+        if (efi_enabled)
+                efi_enter_virtual_mode();
+#endif
         thread_info_cache_init();
         cred_init();
         fork_init(totalram_pages);