From 161485e8273001e56b2f20755ad9b6217b601fb3 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Mon, 4 Aug 2014 18:16:00 +0200 Subject: efi: Implement mandatory locking for UEFI Runtime Services According to section 7.1 of the UEFI spec, Runtime Services are not fully reentrant, and there are particular combinations of calls that need to be serialized. Use a spinlock to serialize all Runtime Services with respect to all others, even if this is more than strictly needed. We've managed to get away without requiring a runtime services lock until now because most of the interactions with EFI involve EFI variables, and those operations are already serialised with __efivars->lock. Some of the assumptions underlying the decision whether locks are needed or not (e.g., SetVariable() against ResetSystem()) may not apply universally to all [new] architectures that implement UEFI. Rather than try to reason our way out of this, let's just implement at least what the spec requires in terms of locking. Signed-off-by: Ard Biesheuvel Signed-off-by: Matt Fleming --- arch/x86/include/asm/efi.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'arch/x86/include') diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h index 044a2fd3c5fe..b39ee5f2c02d 100644 --- a/arch/x86/include/asm/efi.h +++ b/arch/x86/include/asm/efi.h @@ -86,6 +86,8 @@ extern void __iomem *efi_ioremap(unsigned long addr, unsigned long size, #endif /* CONFIG_X86_32 */ +#define efi_in_nmi() in_nmi() + extern int add_efi_memmap; extern struct efi_scratch efi_scratch; extern void efi_set_executable(efi_memory_desc_t *md, bool executable); -- cgit v1.2.3 From 24ffd84b606dafa93a5f8f6e6dbaa06fbde11632 Mon Sep 17 00:00:00 2001 From: Mathias Krause Date: Sun, 7 Sep 2014 19:42:14 +0200 Subject: x86/efi: Remove unused efi_call* macros Complement commit 62fa6e69a436 ("x86/efi: Delete most of the efi_call* macros") and delete the stub macros for the !CONFIG_EFI case, too. In fact, there are no EFI calls in this case so we don't need a dummy for efi_call() even. Signed-off-by: Mathias Krause Signed-off-by: Matt Fleming --- arch/x86/include/asm/efi.h | 10 ---------- 1 file changed, 10 deletions(-) (limited to 'arch/x86/include') diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h index b39ee5f2c02d..5375df643818 100644 --- a/arch/x86/include/asm/efi.h +++ b/arch/x86/include/asm/efi.h @@ -188,16 +188,6 @@ extern struct efi_config *efi_early; extern bool efi_reboot_required(void); #else -/* - * IF EFI is not configured, have the EFI calls return -ENOSYS. - */ -#define efi_call0(_f) (-ENOSYS) -#define efi_call1(_f, _a1) (-ENOSYS) -#define efi_call2(_f, _a1, _a2) (-ENOSYS) -#define efi_call3(_f, _a1, _a2, _a3) (-ENOSYS) -#define efi_call4(_f, _a1, _a2, _a3, _a4) (-ENOSYS) -#define efi_call5(_f, _a1, _a2, _a3, _a4, _a5) (-ENOSYS) -#define efi_call6(_f, _a1, _a2, _a3, _a4, _a5, _a6) (-ENOSYS) static inline void parse_efi_setup(u64 phys_addr, u32 data_len) {} static inline bool efi_reboot_required(void) { -- cgit v1.2.3 From 609206854767559ecbb1c308bbd6ef7af13d8c6e Mon Sep 17 00:00:00 2001 From: Mathias Krause Date: Sun, 7 Sep 2014 19:42:15 +0200 Subject: x86/efi: Unexport add_efi_memmap variable This variable was accidentally exported, even though it's only used in this compilation unit and only during initialization. Remove the bogus export, make the variable static instead and mark it as __initdata. Fixes: 200001eb140e ("x86 boot: only pick up additional EFI memmap...") Cc: Paul Jackson Signed-off-by: Mathias Krause Signed-off-by: Matt Fleming --- arch/x86/include/asm/efi.h | 1 - arch/x86/platform/efi/efi.c | 4 +--- 2 files changed, 1 insertion(+), 4 deletions(-) (limited to 'arch/x86/include') diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h index 5375df643818..ce7b1c5ff78d 100644 --- a/arch/x86/include/asm/efi.h +++ b/arch/x86/include/asm/efi.h @@ -88,7 +88,6 @@ extern void __iomem *efi_ioremap(unsigned long addr, unsigned long size, #define efi_in_nmi() in_nmi() -extern int add_efi_memmap; extern struct efi_scratch efi_scratch; extern void efi_set_executable(efi_memory_desc_t *md, bool executable); extern int efi_memblock_x86_reserve_range(void); diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index f0be3d1da3de..03938d17ad6d 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -70,9 +70,7 @@ static efi_config_table_type_t arch_tables[] __initdata = { u64 efi_setup; /* efi setup_data physical address */ -int add_efi_memmap; -EXPORT_SYMBOL(add_efi_memmap); - +static int add_efi_memmap __initdata; static int __init setup_add_efi_memmap(char *arg) { add_efi_memmap = 1; -- cgit v1.2.3 From 4e78eb056136b002ecdfbbf61436fedfb8a3c76b Mon Sep 17 00:00:00 2001 From: Mathias Krause Date: Sun, 7 Sep 2014 19:42:17 +0200 Subject: x86/efi: Mark initialization code as such The 32 bit and 64 bit implementations differ in their __init annotations for some functions referenced from the common EFI code. Namely, the 32 bit variant is missing some of the __init annotations the 64 bit variant has. To solve the colliding annotations, mark the corresponding functions in efi_32.c as initialization code, too -- as it is such. Actually, quite a few more functions are only used during initialization and therefore can be marked __init. They are therefore annotated, too. Also add the __init annotation to the prototypes in the efi.h header so users of those functions will see it's meant as initialization code only. This patch also fixes the "prelog" typo. ("prologue" / "epilogue" might be more appropriate but this is C code after all, not an opera! :D) Signed-off-by: Mathias Krause Signed-off-by: Matt Fleming --- arch/x86/include/asm/efi.h | 20 ++++++++++---------- arch/x86/platform/efi/efi.c | 4 ++-- arch/x86/platform/efi/efi_32.c | 12 +++++++----- arch/x86/platform/efi/efi_64.c | 6 +++--- arch/x86/platform/efi/efi_stub_32.S | 4 ++-- 5 files changed, 24 insertions(+), 22 deletions(-) (limited to 'arch/x86/include') diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h index ce7b1c5ff78d..abba1fe1db5e 100644 --- a/arch/x86/include/asm/efi.h +++ b/arch/x86/include/asm/efi.h @@ -81,25 +81,25 @@ extern u64 asmlinkage efi_call(void *fp, ...); */ #define __efi_call_virt(f, args...) efi_call_virt(f, args) -extern void __iomem *efi_ioremap(unsigned long addr, unsigned long size, - u32 type, u64 attribute); +extern void __iomem *__init efi_ioremap(unsigned long addr, unsigned long size, + u32 type, u64 attribute); #endif /* CONFIG_X86_32 */ #define efi_in_nmi() in_nmi() extern struct efi_scratch efi_scratch; -extern void efi_set_executable(efi_memory_desc_t *md, bool executable); -extern int efi_memblock_x86_reserve_range(void); -extern void efi_call_phys_prelog(void); -extern void efi_call_phys_epilog(void); -extern void efi_unmap_memmap(void); -extern void efi_memory_uc(u64 addr, unsigned long size); +extern void __init efi_set_executable(efi_memory_desc_t *md, bool executable); +extern int __init efi_memblock_x86_reserve_range(void); +extern void __init efi_call_phys_prolog(void); +extern void __init efi_call_phys_epilog(void); +extern void __init efi_unmap_memmap(void); +extern void __init efi_memory_uc(u64 addr, unsigned long size); extern void __init efi_map_region(efi_memory_desc_t *md); extern void __init efi_map_region_fixed(efi_memory_desc_t *md); extern void efi_sync_low_kernel_mappings(void); -extern int efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages); -extern void efi_cleanup_page_tables(unsigned long pa_memmap, unsigned num_pages); +extern int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages); +extern void __init efi_cleanup_page_tables(unsigned long pa_memmap, unsigned num_pages); extern void __init old_map_region(efi_memory_desc_t *md); extern void __init runtime_code_page_mkexec(void); extern void __init efi_runtime_mkexec(void); diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index 1bc2c878e42e..dbc8627a5cdf 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -86,7 +86,7 @@ static efi_status_t __init phys_efi_set_virtual_address_map( { efi_status_t status; - efi_call_phys_prelog(); + efi_call_phys_prolog(); status = efi_call_phys(efi_phys.set_virtual_address_map, memory_map_size, descriptor_size, descriptor_version, virtual_map); @@ -530,7 +530,7 @@ void __init runtime_code_page_mkexec(void) } } -void efi_memory_uc(u64 addr, unsigned long size) +void __init efi_memory_uc(u64 addr, unsigned long size) { unsigned long page_shift = 1UL << EFI_PAGE_SHIFT; u64 npages; diff --git a/arch/x86/platform/efi/efi_32.c b/arch/x86/platform/efi/efi_32.c index 9ee3491e31fb..40e7cda52936 100644 --- a/arch/x86/platform/efi/efi_32.c +++ b/arch/x86/platform/efi/efi_32.c @@ -33,7 +33,7 @@ /* * To make EFI call EFI runtime service in physical addressing mode we need - * prelog/epilog before/after the invocation to disable interrupt, to + * prolog/epilog before/after the invocation to disable interrupt, to * claim EFI runtime service handler exclusively and to duplicate a memory in * low memory space say 0 - 3G. */ @@ -41,11 +41,13 @@ static unsigned long efi_rt_eflags; void efi_sync_low_kernel_mappings(void) {} void __init efi_dump_pagetable(void) {} -int efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages) +int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages) { return 0; } -void efi_cleanup_page_tables(unsigned long pa_memmap, unsigned num_pages) {} +void __init efi_cleanup_page_tables(unsigned long pa_memmap, unsigned num_pages) +{ +} void __init efi_map_region(efi_memory_desc_t *md) { @@ -55,7 +57,7 @@ void __init efi_map_region(efi_memory_desc_t *md) void __init efi_map_region_fixed(efi_memory_desc_t *md) {} void __init parse_efi_setup(u64 phys_addr, u32 data_len) {} -void efi_call_phys_prelog(void) +void __init efi_call_phys_prolog(void) { struct desc_ptr gdt_descr; @@ -69,7 +71,7 @@ void efi_call_phys_prelog(void) load_gdt(&gdt_descr); } -void efi_call_phys_epilog(void) +void __init efi_call_phys_epilog(void) { struct desc_ptr gdt_descr; diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c index 290d397e1dd9..35aecb6042fb 100644 --- a/arch/x86/platform/efi/efi_64.c +++ b/arch/x86/platform/efi/efi_64.c @@ -79,7 +79,7 @@ static void __init early_code_mapping_set_exec(int executable) } } -void __init efi_call_phys_prelog(void) +void __init efi_call_phys_prolog(void) { unsigned long vaddress; int pgd; @@ -139,7 +139,7 @@ void efi_sync_low_kernel_mappings(void) sizeof(pgd_t) * num_pgds); } -int efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages) +int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages) { unsigned long text; struct page *page; @@ -192,7 +192,7 @@ int efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages) return 0; } -void efi_cleanup_page_tables(unsigned long pa_memmap, unsigned num_pages) +void __init efi_cleanup_page_tables(unsigned long pa_memmap, unsigned num_pages) { pgd_t *pgd = (pgd_t *)__va(real_mode_header->trampoline_pgd); diff --git a/arch/x86/platform/efi/efi_stub_32.S b/arch/x86/platform/efi/efi_stub_32.S index fbe66e626c09..040192b50d02 100644 --- a/arch/x86/platform/efi/efi_stub_32.S +++ b/arch/x86/platform/efi/efi_stub_32.S @@ -27,13 +27,13 @@ ENTRY(efi_call_phys) * set to 0x0010, DS and SS have been set to 0x0018. In EFI, I found * the values of these registers are the same. And, the corresponding * GDT entries are identical. So I will do nothing about segment reg - * and GDT, but change GDT base register in prelog and epilog. + * and GDT, but change GDT base register in prolog and epilog. */ /* * 1. Now I am running with EIP = + PAGE_OFFSET. * But to make it smoothly switch from virtual mode to flat mode. - * The mapping of lower virtual memory has been created in prelog and + * The mapping of lower virtual memory has been created in prolog and * epilog. */ movl $1f, %edx -- cgit v1.2.3 From 60b4dc7720a5251f5dbda69ad404e0bcb3cb6bfb Mon Sep 17 00:00:00 2001 From: Matt Fleming Date: Tue, 30 Sep 2014 15:03:38 +0100 Subject: efi: Delete the in_nmi() conditional runtime locking commit 5dc3826d9f08 ("efi: Implement mandatory locking for UEFI Runtime Services") implemented some conditional locking when accessing variable runtime services that Ingo described as "pretty disgusting". The intention with the !efi_in_nmi() checks was to avoid live-locks when trying to write pstore crash data into an EFI variable. Such lockless accesses are allowed according to the UEFI specification when we're in a "non-recoverable" state, but whether or not things are implemented correctly in actual firmware implementations remains an unanswered question, and so it would seem sensible to avoid doing any kind of unsynchronized variable accesses. Furthermore, the efi_in_nmi() tests are inadequate because they don't account for the case where we call EFI variable services from panic or oops callbacks and aren't executing in NMI context. In other words, live-locking is still possible. Let's just remove the conditional locking altogether. Now we've got the ->set_variable_nonblocking() EFI variable operation we can abort if the runtime lock is already held. Aborting is by far the safest option. Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Ard Biesheuvel Cc: Matthew Garrett Signed-off-by: Matt Fleming --- arch/x86/include/asm/efi.h | 2 -- drivers/firmware/efi/runtime-wrappers.c | 17 ++++------------- 2 files changed, 4 insertions(+), 15 deletions(-) (limited to 'arch/x86/include') diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h index abba1fe1db5e..408ad6d3222e 100644 --- a/arch/x86/include/asm/efi.h +++ b/arch/x86/include/asm/efi.h @@ -86,8 +86,6 @@ extern void __iomem *__init efi_ioremap(unsigned long addr, unsigned long size, #endif /* CONFIG_X86_32 */ -#define efi_in_nmi() in_nmi() - 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); diff --git a/drivers/firmware/efi/runtime-wrappers.c b/drivers/firmware/efi/runtime-wrappers.c index 4349206198b2..228bbf910461 100644 --- a/drivers/firmware/efi/runtime-wrappers.c +++ b/drivers/firmware/efi/runtime-wrappers.c @@ -86,9 +86,6 @@ static DEFINE_SPINLOCK(efi_runtime_lock); * for QueryVariableInfo() and SetVariable(), as these can be reached in NMI * context through efi_pstore_write(). */ -#ifndef efi_in_nmi -#define efi_in_nmi() (0) -#endif /* * As per commit ef68c8f87ed1 ("x86: Serialize EFI time accesses on rtc_lock"), @@ -189,14 +186,11 @@ static efi_status_t virt_efi_set_variable(efi_char16_t *name, { unsigned long flags; efi_status_t status; - bool __in_nmi = efi_in_nmi(); - if (!__in_nmi) - spin_lock_irqsave(&efi_runtime_lock, flags); + spin_lock_irqsave(&efi_runtime_lock, flags); status = efi_call_virt(set_variable, name, vendor, attr, data_size, data); - if (!__in_nmi) - spin_unlock_irqrestore(&efi_runtime_lock, flags); + spin_unlock_irqrestore(&efi_runtime_lock, flags); return status; } @@ -225,17 +219,14 @@ static efi_status_t virt_efi_query_variable_info(u32 attr, { unsigned long flags; efi_status_t status; - bool __in_nmi = efi_in_nmi(); if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) return EFI_UNSUPPORTED; - if (!__in_nmi) - spin_lock_irqsave(&efi_runtime_lock, flags); + spin_lock_irqsave(&efi_runtime_lock, flags); status = efi_call_virt(query_variable_info, attr, storage_space, remaining_space, max_variable_size); - if (!__in_nmi) - spin_unlock_irqrestore(&efi_runtime_lock, flags); + spin_unlock_irqrestore(&efi_runtime_lock, flags); return status; } -- cgit v1.2.3