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

Pull EFI fixes from Ingo Molnar:
 "A boot crash fix and a build warning fix"

* 'efi-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/efi: Prevent mixed mode boot corruption with CONFIG_VMAP_STACK=y
  x86/efi: Fix EFI memmap pointer size warning

2 files changed, 58 insertions, 24 deletions

diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index bf99aa7005eb..936a488d6cf6 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -861,7 +861,7 @@ static void __init __efi_enter_virtual_mode(void)
 	int count = 0, pg_shift = 0;
 	void *new_memmap = NULL;
 	efi_status_t status;
-	phys_addr_t pa;
+	unsigned long pa;
 
 	efi.systab = NULL;
 
diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
index 58b0f801f66f..319148bd4b05 100644
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -31,6 +31,7 @@
 #include <linux/io.h>
 #include <linux/reboot.h>
 #include <linux/slab.h>
+#include <linux/ucs2_string.h>
 
 #include <asm/setup.h>
 #include <asm/page.h>
@@ -211,6 +212,35 @@ void efi_sync_low_kernel_mappings(void)
 	memcpy(pud_efi, pud_k, sizeof(pud_t) * num_entries);
 }
 
+/*
+ * Wrapper for slow_virt_to_phys() that handles NULL addresses.
+ */
+static inline phys_addr_t
+virt_to_phys_or_null_size(void *va, unsigned long size)
+{
+	bool bad_size;
+
+	if (!va)
+		return 0;
+
+	if (virt_addr_valid(va))
+		return virt_to_phys(va);
+
+	/*
+	 * A fully aligned variable on the stack is guaranteed not to
+	 * cross a page bounary. Try to catch strings on the stack by
+	 * checking that 'size' is a power of two.
+	 */
+	bad_size = size > PAGE_SIZE || !is_power_of_2(size);
+
+	WARN_ON(!IS_ALIGNED((unsigned long)va, size) || bad_size);
+
+	return slow_virt_to_phys(va);
+}
+
+#define virt_to_phys_or_null(addr)				\
+	virt_to_phys_or_null_size((addr), sizeof(*(addr)))
+
 int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
 {
 	unsigned long pfn, text;
@@ -494,8 +524,8 @@ static efi_status_t efi_thunk_get_time(efi_time_t *tm, efi_time_cap_t *tc)
 
 	spin_lock(&rtc_lock);
 
-	phys_tm = virt_to_phys(tm);
-	phys_tc = virt_to_phys(tc);
+	phys_tm = virt_to_phys_or_null(tm);
+	phys_tc = virt_to_phys_or_null(tc);
 
 	status = efi_thunk(get_time, phys_tm, phys_tc);
 
@@ -511,7 +541,7 @@ static efi_status_t efi_thunk_set_time(efi_time_t *tm)
 
 	spin_lock(&rtc_lock);
 
-	phys_tm = virt_to_phys(tm);
+	phys_tm = virt_to_phys_or_null(tm);
 
 	status = efi_thunk(set_time, phys_tm);
 
@@ -529,9 +559,9 @@ efi_thunk_get_wakeup_time(efi_bool_t *enabled, efi_bool_t *pending,
 
 	spin_lock(&rtc_lock);
 
-	phys_enabled = virt_to_phys(enabled);
-	phys_pending = virt_to_phys(pending);
-	phys_tm = virt_to_phys(tm);
+	phys_enabled = virt_to_phys_or_null(enabled);
+	phys_pending = virt_to_phys_or_null(pending);
+	phys_tm = virt_to_phys_or_null(tm);
 
 	status = efi_thunk(get_wakeup_time, phys_enabled,
 			     phys_pending, phys_tm);
@@ -549,7 +579,7 @@ efi_thunk_set_wakeup_time(efi_bool_t enabled, efi_time_t *tm)
 
 	spin_lock(&rtc_lock);
 
-	phys_tm = virt_to_phys(tm);
+	phys_tm = virt_to_phys_or_null(tm);
 
 	status = efi_thunk(set_wakeup_time, enabled, phys_tm);
 
@@ -558,6 +588,10 @@ efi_thunk_set_wakeup_time(efi_bool_t enabled, efi_time_t *tm)
 	return status;
 }
 
+static unsigned long efi_name_size(efi_char16_t *name)
+{
+	return ucs2_strsize(name, EFI_VAR_NAME_LEN) + 1;
+}
 
 static efi_status_t
 efi_thunk_get_variable(efi_char16_t *name, efi_guid_t *vendor,
@@ -567,11 +601,11 @@ efi_thunk_get_variable(efi_char16_t *name, efi_guid_t *vendor,
 	u32 phys_name, phys_vendor, phys_attr;
 	u32 phys_data_size, phys_data;
 
-	phys_data_size = virt_to_phys(data_size);
-	phys_vendor = virt_to_phys(vendor);
-	phys_name = virt_to_phys(name);
-	phys_attr = virt_to_phys(attr);
-	phys_data = virt_to_phys(data);
+	phys_data_size = virt_to_phys_or_null(data_size);
+	phys_vendor = virt_to_phys_or_null(vendor);
+	phys_name = virt_to_phys_or_null_size(name, efi_name_size(name));
+	phys_attr = virt_to_phys_or_null(attr);
+	phys_data = virt_to_phys_or_null_size(data, *data_size);
 
 	status = efi_thunk(get_variable, phys_name, phys_vendor,
 			   phys_attr, phys_data_size, phys_data);
@@ -586,9 +620,9 @@ efi_thunk_set_variable(efi_char16_t *name, efi_guid_t *vendor,
 	u32 phys_name, phys_vendor, phys_data;
 	efi_status_t status;
 
-	phys_name = virt_to_phys(name);
-	phys_vendor = virt_to_phys(vendor);
-	phys_data = virt_to_phys(data);
+	phys_name = virt_to_phys_or_null_size(name, efi_name_size(name));
+	phys_vendor = virt_to_phys_or_null(vendor);
+	phys_data = virt_to_phys_or_null_size(data, data_size);
 
 	/* If data_size is > sizeof(u32) we've got problems */
 	status = efi_thunk(set_variable, phys_name, phys_vendor,
@@ -605,9 +639,9 @@ efi_thunk_get_next_variable(unsigned long *name_size,
 	efi_status_t status;
 	u32 phys_name_size, phys_name, phys_vendor;
 
-	phys_name_size = virt_to_phys(name_size);
-	phys_vendor = virt_to_phys(vendor);
-	phys_name = virt_to_phys(name);
+	phys_name_size = virt_to_phys_or_null(name_size);
+	phys_vendor = virt_to_phys_or_null(vendor);
+	phys_name = virt_to_phys_or_null_size(name, *name_size);
 
 	status = efi_thunk(get_next_variable, phys_name_size,
 			   phys_name, phys_vendor);
@@ -621,7 +655,7 @@ efi_thunk_get_next_high_mono_count(u32 *count)
 	efi_status_t status;
 	u32 phys_count;
 
-	phys_count = virt_to_phys(count);
+	phys_count = virt_to_phys_or_null(count);
 	status = efi_thunk(get_next_high_mono_count, phys_count);
 
 	return status;
@@ -633,7 +667,7 @@ efi_thunk_reset_system(int reset_type, efi_status_t status,
 {
 	u32 phys_data;
 
-	phys_data = virt_to_phys(data);
+	phys_data = virt_to_phys_or_null_size(data, data_size);
 
 	efi_thunk(reset_system, reset_type, status, data_size, phys_data);
 }
@@ -661,9 +695,9 @@ efi_thunk_query_variable_info(u32 attr, u64 *storage_space,
 	if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
 		return EFI_UNSUPPORTED;
 
-	phys_storage = virt_to_phys(storage_space);
-	phys_remaining = virt_to_phys(remaining_space);
-	phys_max = virt_to_phys(max_variable_size);
+	phys_storage = virt_to_phys_or_null(storage_space);
+	phys_remaining = virt_to_phys_or_null(remaining_space);
+	phys_max = virt_to_phys_or_null(max_variable_size);
 
 	status = efi_thunk(query_variable_info, attr, phys_storage,
 			   phys_remaining, phys_max);