diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2014-10-23 14:45:09 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-10-23 14:45:09 -0700 |
commit | 8c81f48e16fbe103e682d7ee7b2f16d065c42954 (patch) | |
tree | 1eac3abf36ed9330b3d5f9e550d1ccbc0c174f9b /drivers/firmware/efi/runtime-wrappers.c | |
parent | 5de551e0eeddf470928e9fee59825a3645641bc7 (diff) | |
parent | 75b128573b275d5a5a7210b98c4b8cb3b39c12e7 (diff) |
Merge branch 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 EFI updates from Peter Anvin:
"This patchset falls under the "maintainers that grovel" clause in the
v3.18-rc1 announcement. We had intended to push it late in the merge
window since we got it into the -tip tree relatively late.
Many of these are relatively simple things, but there are a couple of
key bits, especially Ard's and Matt's patches"
* 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
rtc: Disable EFI rtc for x86
efi: rtc-efi: Export platform:rtc-efi as module alias
efi: Delete the in_nmi() conditional runtime locking
efi: Provide a non-blocking SetVariable() operation
x86/efi: Adding efi_printks on memory allocationa and pci.reads
x86/efi: Mark initialization code as such
x86/efi: Update comment regarding required phys mapped EFI services
x86/efi: Unexport add_efi_memmap variable
x86/efi: Remove unused efi_call* macros
efi: Resolve some shadow warnings
arm64: efi: Format EFI memory type & attrs with efi_md_typeattr_format()
ia64: efi: Format EFI memory type & attrs with efi_md_typeattr_format()
x86: efi: Format EFI memory type & attrs with efi_md_typeattr_format()
efi: Introduce efi_md_typeattr_format()
efi: Add macro for EFI_MEMORY_UCE memory attribute
x86/efi: Clear EFI_RUNTIME_SERVICES if failing to enter virtual mode
arm64/efi: Do not enter virtual mode if booting with efi=noruntime or noefi
arm64/efi: uefi_init error handling fix
efi: Add kernel param efi=noruntime
lib: Add a generic cmdline parse function parse_option_str
...
Diffstat (limited to 'drivers/firmware/efi/runtime-wrappers.c')
-rw-r--r-- | drivers/firmware/efi/runtime-wrappers.c | 164 |
1 files changed, 154 insertions, 10 deletions
diff --git a/drivers/firmware/efi/runtime-wrappers.c b/drivers/firmware/efi/runtime-wrappers.c index 10daa4bbb258..228bbf910461 100644 --- a/drivers/firmware/efi/runtime-wrappers.c +++ b/drivers/firmware/efi/runtime-wrappers.c @@ -14,11 +14,80 @@ * This file is released under the GPLv2. */ +#include <linux/bug.h> #include <linux/efi.h> -#include <linux/spinlock.h> /* spinlock_t */ +#include <linux/mutex.h> +#include <linux/spinlock.h> #include <asm/efi.h> /* + * 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. (source: UEFI Specification v2.4A) + * + * Table 31. Rules for Reentry Into Runtime Services + * +------------------------------------+-------------------------------+ + * | If previous call is busy in | Forbidden to call | + * +------------------------------------+-------------------------------+ + * | Any | SetVirtualAddressMap() | + * +------------------------------------+-------------------------------+ + * | ConvertPointer() | ConvertPointer() | + * +------------------------------------+-------------------------------+ + * | SetVariable() | ResetSystem() | + * | UpdateCapsule() | | + * | SetTime() | | + * | SetWakeupTime() | | + * | GetNextHighMonotonicCount() | | + * +------------------------------------+-------------------------------+ + * | GetVariable() | GetVariable() | + * | GetNextVariableName() | GetNextVariableName() | + * | SetVariable() | SetVariable() | + * | QueryVariableInfo() | QueryVariableInfo() | + * | UpdateCapsule() | UpdateCapsule() | + * | QueryCapsuleCapabilities() | QueryCapsuleCapabilities() | + * | GetNextHighMonotonicCount() | GetNextHighMonotonicCount() | + * +------------------------------------+-------------------------------+ + * | GetTime() | GetTime() | + * | SetTime() | SetTime() | + * | GetWakeupTime() | GetWakeupTime() | + * | SetWakeupTime() | SetWakeupTime() | + * +------------------------------------+-------------------------------+ + * + * Due to the fact that the EFI pstore may write to the variable store in + * interrupt context, we need to use a spinlock for at least the groups that + * contain SetVariable() and QueryVariableInfo(). That leaves little else, as + * none of the remaining functions are actually ever called at runtime. + * So let's just use a single spinlock to serialize all Runtime Services calls. + */ +static DEFINE_SPINLOCK(efi_runtime_lock); + +/* + * Some runtime services calls can be reentrant under NMI, even if the table + * above says they are not. (source: UEFI Specification v2.4A) + * + * Table 32. Functions that may be called after Machine Check, INIT and NMI + * +----------------------------+------------------------------------------+ + * | Function | Called after Machine Check, INIT and NMI | + * +----------------------------+------------------------------------------+ + * | GetTime() | Yes, even if previously busy. | + * | GetVariable() | Yes, even if previously busy | + * | GetNextVariableName() | Yes, even if previously busy | + * | QueryVariableInfo() | Yes, even if previously busy | + * | SetVariable() | Yes, even if previously busy | + * | UpdateCapsule() | Yes, even if previously busy | + * | QueryCapsuleCapabilities() | Yes, even if previously busy | + * | ResetSystem() | Yes, even if previously busy | + * +----------------------------+------------------------------------------+ + * + * In order to prevent deadlocks under NMI, the wrappers for these functions + * may only grab the efi_runtime_lock or rtc_lock spinlocks if !efi_in_nmi(). + * However, not all of the services listed are reachable through NMI code paths, + * so the the special handling as suggested by the UEFI spec is only implemented + * for QueryVariableInfo() and SetVariable(), as these can be reached in NMI + * context through efi_pstore_write(). + */ + +/* * As per commit ef68c8f87ed1 ("x86: Serialize EFI time accesses on rtc_lock"), * the EFI specification requires that callers of the time related runtime * functions serialize with other CMOS accesses in the kernel, as the EFI time @@ -32,7 +101,9 @@ static efi_status_t virt_efi_get_time(efi_time_t *tm, efi_time_cap_t *tc) efi_status_t status; spin_lock_irqsave(&rtc_lock, flags); + spin_lock(&efi_runtime_lock); status = efi_call_virt(get_time, tm, tc); + spin_unlock(&efi_runtime_lock); spin_unlock_irqrestore(&rtc_lock, flags); return status; } @@ -43,7 +114,9 @@ static efi_status_t virt_efi_set_time(efi_time_t *tm) efi_status_t status; spin_lock_irqsave(&rtc_lock, flags); + spin_lock(&efi_runtime_lock); status = efi_call_virt(set_time, tm); + spin_unlock(&efi_runtime_lock); spin_unlock_irqrestore(&rtc_lock, flags); return status; } @@ -56,7 +129,9 @@ static efi_status_t virt_efi_get_wakeup_time(efi_bool_t *enabled, efi_status_t status; spin_lock_irqsave(&rtc_lock, flags); + spin_lock(&efi_runtime_lock); status = efi_call_virt(get_wakeup_time, enabled, pending, tm); + spin_unlock(&efi_runtime_lock); spin_unlock_irqrestore(&rtc_lock, flags); return status; } @@ -67,7 +142,9 @@ static efi_status_t virt_efi_set_wakeup_time(efi_bool_t enabled, efi_time_t *tm) efi_status_t status; spin_lock_irqsave(&rtc_lock, flags); + spin_lock(&efi_runtime_lock); status = efi_call_virt(set_wakeup_time, enabled, tm); + spin_unlock(&efi_runtime_lock); spin_unlock_irqrestore(&rtc_lock, flags); return status; } @@ -78,14 +155,27 @@ static efi_status_t virt_efi_get_variable(efi_char16_t *name, unsigned long *data_size, void *data) { - return efi_call_virt(get_variable, name, vendor, attr, data_size, data); + unsigned long flags; + efi_status_t status; + + spin_lock_irqsave(&efi_runtime_lock, flags); + status = efi_call_virt(get_variable, name, vendor, attr, data_size, + data); + spin_unlock_irqrestore(&efi_runtime_lock, flags); + return status; } static efi_status_t virt_efi_get_next_variable(unsigned long *name_size, efi_char16_t *name, efi_guid_t *vendor) { - return efi_call_virt(get_next_variable, name_size, name, vendor); + unsigned long flags; + efi_status_t status; + + spin_lock_irqsave(&efi_runtime_lock, flags); + status = efi_call_virt(get_next_variable, name_size, name, vendor); + spin_unlock_irqrestore(&efi_runtime_lock, flags); + return status; } static efi_status_t virt_efi_set_variable(efi_char16_t *name, @@ -94,24 +184,61 @@ static efi_status_t virt_efi_set_variable(efi_char16_t *name, unsigned long data_size, void *data) { - return efi_call_virt(set_variable, name, vendor, attr, data_size, data); + unsigned long flags; + efi_status_t status; + + spin_lock_irqsave(&efi_runtime_lock, flags); + status = efi_call_virt(set_variable, name, vendor, attr, data_size, + data); + spin_unlock_irqrestore(&efi_runtime_lock, flags); + return status; } +static efi_status_t +virt_efi_set_variable_nonblocking(efi_char16_t *name, efi_guid_t *vendor, + u32 attr, unsigned long data_size, + void *data) +{ + unsigned long flags; + efi_status_t status; + + if (!spin_trylock_irqsave(&efi_runtime_lock, flags)) + return EFI_NOT_READY; + + status = efi_call_virt(set_variable, name, vendor, attr, data_size, + data); + spin_unlock_irqrestore(&efi_runtime_lock, flags); + return status; +} + + static efi_status_t virt_efi_query_variable_info(u32 attr, u64 *storage_space, u64 *remaining_space, u64 *max_variable_size) { + unsigned long flags; + efi_status_t status; + if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) return EFI_UNSUPPORTED; - return efi_call_virt(query_variable_info, attr, storage_space, - remaining_space, max_variable_size); + spin_lock_irqsave(&efi_runtime_lock, flags); + status = efi_call_virt(query_variable_info, attr, storage_space, + remaining_space, max_variable_size); + spin_unlock_irqrestore(&efi_runtime_lock, flags); + return status; } static efi_status_t virt_efi_get_next_high_mono_count(u32 *count) { - return efi_call_virt(get_next_high_mono_count, count); + unsigned long flags; + efi_status_t status; + + spin_lock_irqsave(&efi_runtime_lock, flags); + status = efi_call_virt(get_next_high_mono_count, count); + spin_unlock_irqrestore(&efi_runtime_lock, flags); + return status; } static void virt_efi_reset_system(int reset_type, @@ -119,17 +246,27 @@ static void virt_efi_reset_system(int reset_type, unsigned long data_size, efi_char16_t *data) { + unsigned long flags; + + spin_lock_irqsave(&efi_runtime_lock, flags); __efi_call_virt(reset_system, reset_type, status, data_size, data); + spin_unlock_irqrestore(&efi_runtime_lock, flags); } static efi_status_t virt_efi_update_capsule(efi_capsule_header_t **capsules, unsigned long count, unsigned long sg_list) { + unsigned long flags; + efi_status_t status; + if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) return EFI_UNSUPPORTED; - return efi_call_virt(update_capsule, capsules, count, sg_list); + spin_lock_irqsave(&efi_runtime_lock, flags); + status = efi_call_virt(update_capsule, capsules, count, sg_list); + spin_unlock_irqrestore(&efi_runtime_lock, flags); + return status; } static efi_status_t virt_efi_query_capsule_caps(efi_capsule_header_t **capsules, @@ -137,11 +274,17 @@ static efi_status_t virt_efi_query_capsule_caps(efi_capsule_header_t **capsules, u64 *max_size, int *reset_type) { + unsigned long flags; + efi_status_t status; + if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) return EFI_UNSUPPORTED; - return efi_call_virt(query_capsule_caps, capsules, count, max_size, - reset_type); + spin_lock_irqsave(&efi_runtime_lock, flags); + status = efi_call_virt(query_capsule_caps, capsules, count, max_size, + reset_type); + spin_unlock_irqrestore(&efi_runtime_lock, flags); + return status; } void efi_native_runtime_setup(void) @@ -153,6 +296,7 @@ void efi_native_runtime_setup(void) efi.get_variable = virt_efi_get_variable; efi.get_next_variable = virt_efi_get_next_variable; efi.set_variable = virt_efi_set_variable; + efi.set_variable_nonblocking = virt_efi_set_variable_nonblocking; efi.get_next_high_mono_count = virt_efi_get_next_high_mono_count; efi.reset_system = virt_efi_reset_system; efi.query_variable_info = virt_efi_query_variable_info; |