1 files changed, 166 insertions, 78 deletions

diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
index d028e9acdf1c..86169a24b0d8 100644
--- a/arch/x86/include/asm/efi.h
+++ b/arch/x86/include/asm/efi.h
@@ -8,6 +8,7 @@
 #include <asm/tlb.h>
 #include <asm/nospec-branch.h>
 #include <asm/mmu_context.h>
+#include <linux/build_bug.h>
 
 /*
  * We map the EFI regions needed for runtime services non-contiguously,
@@ -19,13 +20,16 @@
  * This is the main reason why we're doing stable VA mappings for RT
  * services.
  *
- * This flag is used in conjunction with a chicken bit called
- * "efi=old_map" which can be used as a fallback to the old runtime
- * services mapping method in case there's some b0rkage with a
- * particular EFI implementation (haha, it is hard to hold up the
- * sarcasm here...).
+ * SGI UV1 machines are known to be incompatible with this scheme, so we
+ * provide an opt-out for these machines via a DMI quirk that sets the
+ * attribute below.
  */
-#define EFI_OLD_MEMMAP		EFI_ARCH_1
+#define EFI_UV1_MEMMAP         EFI_ARCH_1
+
+static inline bool efi_have_uv1_memmap(void)
+{
+	return IS_ENABLED(CONFIG_X86_UV) && efi_enabled(EFI_UV1_MEMMAP);
+}
 
 #define EFI32_LOADER_SIGNATURE	"EL32"
 #define EFI64_LOADER_SIGNATURE	"EL64"
@@ -34,10 +38,46 @@
 
 #define ARCH_EFI_IRQ_FLAGS_MASK	X86_EFLAGS_IF
 
-#ifdef CONFIG_X86_32
+/*
+ * The EFI services are called through variadic functions in many cases. These
+ * functions are implemented in assembler and support only a fixed number of
+ * arguments. The macros below allows us to check at build time that we don't
+ * try to call them with too many arguments.
+ *
+ * __efi_nargs() will return the number of arguments if it is 7 or less, and
+ * cause a BUILD_BUG otherwise. The limitations of the C preprocessor make it
+ * impossible to calculate the exact number of arguments beyond some
+ * pre-defined limit. The maximum number of arguments currently supported by
+ * any of the thunks is 7, so this is good enough for now and can be extended
+ * in the obvious way if we ever need more.
+ */
 
-extern asmlinkage unsigned long efi_call_phys(void *, ...);
+#define __efi_nargs(...) __efi_nargs_(__VA_ARGS__)
+#define __efi_nargs_(...) __efi_nargs__(0, ##__VA_ARGS__,	\
+	__efi_arg_sentinel(7), __efi_arg_sentinel(6),		\
+	__efi_arg_sentinel(5), __efi_arg_sentinel(4),		\
+	__efi_arg_sentinel(3), __efi_arg_sentinel(2),		\
+	__efi_arg_sentinel(1), __efi_arg_sentinel(0))
+#define __efi_nargs__(_0, _1, _2, _3, _4, _5, _6, _7, n, ...)	\
+	__take_second_arg(n,					\
+		({ BUILD_BUG_ON_MSG(1, "__efi_nargs limit exceeded"); 8; }))
+#define __efi_arg_sentinel(n) , n
 
+/*
+ * __efi_nargs_check(f, n, ...) will cause a BUILD_BUG if the ellipsis
+ * represents more than n arguments.
+ */
+
+#define __efi_nargs_check(f, n, ...)					\
+	__efi_nargs_check_(f, __efi_nargs(__VA_ARGS__), n)
+#define __efi_nargs_check_(f, p, n) __efi_nargs_check__(f, p, n)
+#define __efi_nargs_check__(f, p, n) ({					\
+	BUILD_BUG_ON_MSG(						\
+		(p) > (n),						\
+		#f " called with too many arguments (" #p ">" #n ")");	\
+})
+
+#ifdef CONFIG_X86_32
 #define arch_efi_call_virt_setup()					\
 ({									\
 	kernel_fpu_begin();						\
@@ -51,13 +91,7 @@ extern asmlinkage unsigned long efi_call_phys(void *, ...);
 })
 
 
-/*
- * Wrap all the virtual calls in a way that forces the parameters on the stack.
- */
-#define arch_efi_call_virt(p, f, args...)				\
-({									\
-	((efi_##f##_t __attribute__((regparm(0)))*) p->f)(args);	\
-})
+#define arch_efi_call_virt(p, f, args...)	p->f(args)
 
 #define efi_ioremap(addr, size, type, attr)	ioremap_cache(addr, size)
 
@@ -65,9 +99,12 @@ extern asmlinkage unsigned long efi_call_phys(void *, ...);
 
 #define EFI_LOADER_SIGNATURE	"EL64"
 
-extern asmlinkage u64 efi_call(void *fp, ...);
+extern asmlinkage u64 __efi_call(void *fp, ...);
 
-#define efi_call_phys(f, args...)		efi_call((f), args)
+#define efi_call(...) ({						\
+	__efi_nargs_check(efi_call, 7, __VA_ARGS__);			\
+	__efi_call(__VA_ARGS__);					\
+})
 
 /*
  * struct efi_scratch - Scratch space used while switching to/from efi_mm
@@ -85,7 +122,7 @@ struct efi_scratch {
 	kernel_fpu_begin();						\
 	firmware_restrict_branch_speculation_start();			\
 									\
-	if (!efi_enabled(EFI_OLD_MEMMAP))				\
+	if (!efi_have_uv1_memmap())					\
 		efi_switch_mm(&efi_mm);					\
 })
 
@@ -94,7 +131,7 @@ struct efi_scratch {
 
 #define arch_efi_call_virt_teardown()					\
 ({									\
-	if (!efi_enabled(EFI_OLD_MEMMAP))				\
+	if (!efi_have_uv1_memmap())					\
 		efi_switch_mm(efi_scratch.prev_mm);			\
 									\
 	firmware_restrict_branch_speculation_end();			\
@@ -121,8 +158,6 @@ extern void __iomem *__init efi_ioremap(unsigned long addr, unsigned long size,
 extern struct efi_scratch efi_scratch;
 extern void __init efi_set_executable(efi_memory_desc_t *md, bool executable);
 extern int __init efi_memblock_x86_reserve_range(void);
-extern pgd_t * __init efi_call_phys_prolog(void);
-extern void __init efi_call_phys_epilog(pgd_t *save_pgd);
 extern void __init efi_print_memmap(void);
 extern void __init efi_memory_uc(u64 addr, unsigned long size);
 extern void __init efi_map_region(efi_memory_desc_t *md);
@@ -140,6 +175,8 @@ extern void efi_delete_dummy_variable(void);
 extern void efi_switch_mm(struct mm_struct *mm);
 extern void efi_recover_from_page_fault(unsigned long phys_addr);
 extern void efi_free_boot_services(void);
+extern pgd_t * __init efi_uv1_memmap_phys_prolog(void);
+extern void __init efi_uv1_memmap_phys_epilog(pgd_t *save_pgd);
 
 struct efi_setup_data {
 	u64 fw_vendor;
@@ -152,93 +189,144 @@ struct efi_setup_data {
 extern u64 efi_setup;
 
 #ifdef CONFIG_EFI
+extern efi_status_t __efi64_thunk(u32, ...);
 
-static inline bool efi_is_native(void)
+#define efi64_thunk(...) ({						\
+	__efi_nargs_check(efi64_thunk, 6, __VA_ARGS__);			\
+	__efi64_thunk(__VA_ARGS__);					\
+})
+
+static inline bool efi_is_mixed(void)
 {
-	return IS_ENABLED(CONFIG_X86_64) == efi_enabled(EFI_64BIT);
+	if (!IS_ENABLED(CONFIG_EFI_MIXED))
+		return false;
+	return IS_ENABLED(CONFIG_X86_64) && !efi_enabled(EFI_64BIT);
 }
 
 static inline bool efi_runtime_supported(void)
 {
-	if (efi_is_native())
-		return true;
-
-	if (IS_ENABLED(CONFIG_EFI_MIXED) && !efi_enabled(EFI_OLD_MEMMAP))
+	if (IS_ENABLED(CONFIG_X86_64) == efi_enabled(EFI_64BIT))
 		return true;
 
-	return false;
+	return IS_ENABLED(CONFIG_EFI_MIXED);
 }
 
 extern void parse_efi_setup(u64 phys_addr, u32 data_len);
 
 extern void efifb_setup_from_dmi(struct screen_info *si, const char *opt);
 
-#ifdef CONFIG_EFI_MIXED
 extern void efi_thunk_runtime_setup(void);
-extern efi_status_t efi_thunk_set_virtual_address_map(
-	void *phys_set_virtual_address_map,
-	unsigned long memory_map_size,
-	unsigned long descriptor_size,
-	u32 descriptor_version,
-	efi_memory_desc_t *virtual_map);
-#else
-static inline void efi_thunk_runtime_setup(void) {}
-static inline efi_status_t efi_thunk_set_virtual_address_map(
-	void *phys_set_virtual_address_map,
-	unsigned long memory_map_size,
-	unsigned long descriptor_size,
-	u32 descriptor_version,
-	efi_memory_desc_t *virtual_map)
-{
-	return EFI_SUCCESS;
-}
-#endif /* CONFIG_EFI_MIXED */
-
+efi_status_t efi_set_virtual_address_map(unsigned long memory_map_size,
+					 unsigned long descriptor_size,
+					 u32 descriptor_version,
+					 efi_memory_desc_t *virtual_map);
 
 /* arch specific definitions used by the stub code */
 
-struct efi_config {
-	u64 image_handle;
-	u64 table;
-	u64 runtime_services;
-	u64 boot_services;
-	u64 text_output;
-	efi_status_t (*call)(unsigned long, ...);
-	bool is64;
-} __packed;
-
-__pure const struct efi_config *__efi_early(void);
+__attribute_const__ bool efi_is_64bit(void);
 
-static inline bool efi_is_64bit(void)
+static inline bool efi_is_native(void)
 {
 	if (!IS_ENABLED(CONFIG_X86_64))
-		return false;
-
+		return true;
 	if (!IS_ENABLED(CONFIG_EFI_MIXED))
 		return true;
+	return efi_is_64bit();
+}
+
+#define efi_mixed_mode_cast(attr)					\
+	__builtin_choose_expr(						\
+		__builtin_types_compatible_p(u32, __typeof__(attr)),	\
+			(unsigned long)(attr), (attr))
 
-	return __efi_early()->is64;
+#define efi_table_attr(inst, attr)					\
+	(efi_is_native()						\
+		? inst->attr						\
+		: (__typeof__(inst->attr))				\
+			efi_mixed_mode_cast(inst->mixed_mode.attr))
+
+/*
+ * The following macros allow translating arguments if necessary from native to
+ * mixed mode. The use case for this is to initialize the upper 32 bits of
+ * output parameters, and where the 32-bit method requires a 64-bit argument,
+ * which must be split up into two arguments to be thunked properly.
+ *
+ * As examples, the AllocatePool boot service returns the address of the
+ * allocation, but it will not set the high 32 bits of the address. To ensure
+ * that the full 64-bit address is initialized, we zero-init the address before
+ * calling the thunk.
+ *
+ * The FreePages boot service takes a 64-bit physical address even in 32-bit
+ * mode. For the thunk to work correctly, a native 64-bit call of
+ * 	free_pages(addr, size)
+ * must be translated to
+ * 	efi64_thunk(free_pages, addr & U32_MAX, addr >> 32, size)
+ * so that the two 32-bit halves of addr get pushed onto the stack separately.
+ */
+
+static inline void *efi64_zero_upper(void *p)
+{
+	((u32 *)p)[1] = 0;
+	return p;
 }
 
-#define efi_table_attr(table, attr, instance)				\
-	(efi_is_64bit() ?						\
-		((table##_64_t *)(unsigned long)instance)->attr :	\
-		((table##_32_t *)(unsigned long)instance)->attr)
+#define __efi64_argmap_free_pages(addr, size)				\
+	((addr), 0, (size))
+
+#define __efi64_argmap_get_memory_map(mm_size, mm, key, size, ver)	\
+	((mm_size), (mm), efi64_zero_upper(key), efi64_zero_upper(size), (ver))
+
+#define __efi64_argmap_allocate_pool(type, size, buffer)		\
+	((type), (size), efi64_zero_upper(buffer))
 
-#define efi_call_proto(protocol, f, instance, ...)			\
-	__efi_early()->call(efi_table_attr(protocol, f, instance),	\
-		instance, ##__VA_ARGS__)
+#define __efi64_argmap_handle_protocol(handle, protocol, interface)	\
+	((handle), (protocol), efi64_zero_upper(interface))
 
-#define efi_call_early(f, ...)						\
-	__efi_early()->call(efi_table_attr(efi_boot_services, f,	\
-		__efi_early()->boot_services), __VA_ARGS__)
+#define __efi64_argmap_locate_protocol(protocol, reg, interface)	\
+	((protocol), (reg), efi64_zero_upper(interface))
 
-#define __efi_call_early(f, ...)					\
-	__efi_early()->call((unsigned long)f, __VA_ARGS__);
+/* PCI I/O */
+#define __efi64_argmap_get_location(protocol, seg, bus, dev, func)	\
+	((protocol), efi64_zero_upper(seg), efi64_zero_upper(bus),	\
+	 efi64_zero_upper(dev), efi64_zero_upper(func))
+
+/*
+ * The macros below handle the plumbing for the argument mapping. To add a
+ * mapping for a specific EFI method, simply define a macro
+ * __efi64_argmap_<method name>, following the examples above.
+ */
 
-#define efi_call_runtime(f, ...)					\
-	__efi_early()->call(efi_table_attr(efi_runtime_services, f,	\
-		__efi_early()->runtime_services), __VA_ARGS__)
+#define __efi64_thunk_map(inst, func, ...)				\
+	efi64_thunk(inst->mixed_mode.func,				\
+		__efi64_argmap(__efi64_argmap_ ## func(__VA_ARGS__),	\
+			       (__VA_ARGS__)))
+
+#define __efi64_argmap(mapped, args)					\
+	__PASTE(__efi64_argmap__, __efi_nargs(__efi_eat mapped))(mapped, args)
+#define __efi64_argmap__0(mapped, args) __efi_eval mapped
+#define __efi64_argmap__1(mapped, args) __efi_eval args
+
+#define __efi_eat(...)
+#define __efi_eval(...) __VA_ARGS__
+
+/* The three macros below handle dispatching via the thunk if needed */
+
+#define efi_call_proto(inst, func, ...)					\
+	(efi_is_native()						\
+		? inst->func(inst, ##__VA_ARGS__)			\
+		: __efi64_thunk_map(inst, func, inst, ##__VA_ARGS__))
+
+#define efi_bs_call(func, ...)						\
+	(efi_is_native()						\
+		? efi_system_table()->boottime->func(__VA_ARGS__)	\
+		: __efi64_thunk_map(efi_table_attr(efi_system_table(),	\
+				boottime), func, __VA_ARGS__))
+
+#define efi_rt_call(func, ...)						\
+	(efi_is_native()						\
+		? efi_system_table()->runtime->func(__VA_ARGS__)	\
+		: __efi64_thunk_map(efi_table_attr(efi_system_table(),	\
+				runtime), func, __VA_ARGS__))
 
 extern bool efi_reboot_required(void);
 extern bool efi_is_table_address(unsigned long phys_addr);