Patchwork [v9,11/26] efi: Let architectures decide the flags that should be saved/restored

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Submitter Julien Thierry
Date Jan. 21, 2019, 3:33 p.m.
Message ID <1548084825-8803-12-git-send-email-julien.thierry@arm.com>
Download mbox | patch
Permalink /patch/705755/
State New
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Comments

Julien Thierry - Jan. 21, 2019, 3:33 p.m.
Currently, irqflags are saved before calling runtime services and
checked for mismatch on return.

Provide a pair of overridable macros to save and restore (if needed) the
state that need to be preserved on return from a runtime service.
This allows to check for flags that are not necesarly related to
irqflags.

Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: linux-efi@vger.kernel.org
---
 drivers/firmware/efi/runtime-wrappers.c | 17 +++++++++++++++--
 include/linux/efi.h                     |  5 +++--
 2 files changed, 18 insertions(+), 4 deletions(-)
Ard Biesheuvel - Jan. 21, 2019, 3:42 p.m.
On Mon, 21 Jan 2019 at 16:34, Julien Thierry <julien.thierry@arm.com> wrote:
>
> Currently, irqflags are saved before calling runtime services and
> checked for mismatch on return.
>
> Provide a pair of overridable macros to save and restore (if needed) the
> state that need to be preserved on return from a runtime service.
> This allows to check for flags that are not necesarly related to
> irqflags.
>
> Signed-off-by: Julien Thierry <julien.thierry@arm.com>
> Acked-by: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Cc: linux-efi@vger.kernel.org
> ---
>  drivers/firmware/efi/runtime-wrappers.c | 17 +++++++++++++++--
>  include/linux/efi.h                     |  5 +++--
>  2 files changed, 18 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/firmware/efi/runtime-wrappers.c b/drivers/firmware/efi/runtime-wrappers.c
> index 8903b9c..2f4b68b 100644
> --- a/drivers/firmware/efi/runtime-wrappers.c
> +++ b/drivers/firmware/efi/runtime-wrappers.c
> @@ -89,11 +89,24 @@
>         efi_rts_work.status;                                            \
>  })
>
> +#ifndef arch_efi_save_flags
> +#define arch_efi_save_flags(state_flags)       local_save_flags(state_flags)
> +#define arch_efi_restore_flags(state_flags)    local_irq_restore(state_flags)
> +#endif
> +
> +inline unsigned long efi_call_virt_save_flags(void)

If you drop the 'inline' here,

Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

> +{
> +       unsigned long flags;
> +
> +       arch_efi_save_flags(flags);
> +       return flags;
> +}
> +
>  void efi_call_virt_check_flags(unsigned long flags, const char *call)
>  {
>         unsigned long cur_flags, mismatch;
>
> -       local_save_flags(cur_flags);
> +       cur_flags = efi_call_virt_save_flags();
>
>         mismatch = flags ^ cur_flags;
>         if (!WARN_ON_ONCE(mismatch & ARCH_EFI_IRQ_FLAGS_MASK))
> @@ -102,7 +115,7 @@ void efi_call_virt_check_flags(unsigned long flags, const char *call)
>         add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_NOW_UNRELIABLE);
>         pr_err_ratelimited(FW_BUG "IRQ flags corrupted (0x%08lx=>0x%08lx) by EFI %s\n",
>                            flags, cur_flags, call);
> -       local_irq_restore(flags);
> +       arch_efi_restore_flags(flags);
>  }
>
>  /*
> diff --git a/include/linux/efi.h b/include/linux/efi.h
> index 45ff763..bd80b7e 100644
> --- a/include/linux/efi.h
> +++ b/include/linux/efi.h
> @@ -1607,6 +1607,7 @@ efi_status_t efi_setup_gop(efi_system_table_t *sys_table_arg,
>
>  bool efi_runtime_disabled(void);
>  extern void efi_call_virt_check_flags(unsigned long flags, const char *call);
> +extern unsigned long efi_call_virt_save_flags(void);
>
>  enum efi_secureboot_mode {
>         efi_secureboot_mode_unset,
> @@ -1652,7 +1653,7 @@ enum efi_secureboot_mode {
>                                                                         \
>         arch_efi_call_virt_setup();                                     \
>                                                                         \
> -       local_save_flags(__flags);                                      \
> +       __flags = efi_call_virt_save_flags();                           \
>         __s = arch_efi_call_virt(p, f, args);                           \
>         efi_call_virt_check_flags(__flags, __stringify(f));             \
>                                                                         \
> @@ -1667,7 +1668,7 @@ enum efi_secureboot_mode {
>                                                                         \
>         arch_efi_call_virt_setup();                                     \
>                                                                         \
> -       local_save_flags(__flags);                                      \
> +       __flags = efi_call_virt_save_flags();                           \
>         arch_efi_call_virt(p, f, args);                                 \
>         efi_call_virt_check_flags(__flags, __stringify(f));             \
>                                                                         \
> --
> 1.9.1
>
Julien Thierry - Jan. 23, 2019, 9:04 a.m.
On 21/01/2019 15:42, Ard Biesheuvel wrote:
> On Mon, 21 Jan 2019 at 16:34, Julien Thierry <julien.thierry@arm.com> wrote:
>>
>> Currently, irqflags are saved before calling runtime services and
>> checked for mismatch on return.
>>
>> Provide a pair of overridable macros to save and restore (if needed) the
>> state that need to be preserved on return from a runtime service.
>> This allows to check for flags that are not necesarly related to
>> irqflags.
>>
>> Signed-off-by: Julien Thierry <julien.thierry@arm.com>
>> Acked-by: Catalin Marinas <catalin.marinas@arm.com>
>> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>> Cc: linux-efi@vger.kernel.org
>> ---
>>  drivers/firmware/efi/runtime-wrappers.c | 17 +++++++++++++++--
>>  include/linux/efi.h                     |  5 +++--
>>  2 files changed, 18 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/firmware/efi/runtime-wrappers.c b/drivers/firmware/efi/runtime-wrappers.c
>> index 8903b9c..2f4b68b 100644
>> --- a/drivers/firmware/efi/runtime-wrappers.c
>> +++ b/drivers/firmware/efi/runtime-wrappers.c
>> @@ -89,11 +89,24 @@
>>         efi_rts_work.status;                                            \
>>  })
>>
>> +#ifndef arch_efi_save_flags
>> +#define arch_efi_save_flags(state_flags)       local_save_flags(state_flags)
>> +#define arch_efi_restore_flags(state_flags)    local_irq_restore(state_flags)
>> +#endif
>> +
>> +inline unsigned long efi_call_virt_save_flags(void)
> 
> If you drop the 'inline' here,
> 

Sure, I'll drop it in the next version.

> Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> 

Thanks,

Julien

>> +{
>> +       unsigned long flags;
>> +
>> +       arch_efi_save_flags(flags);
>> +       return flags;
>> +}
>> +
>>  void efi_call_virt_check_flags(unsigned long flags, const char *call)
>>  {
>>         unsigned long cur_flags, mismatch;
>>
>> -       local_save_flags(cur_flags);
>> +       cur_flags = efi_call_virt_save_flags();
>>
>>         mismatch = flags ^ cur_flags;
>>         if (!WARN_ON_ONCE(mismatch & ARCH_EFI_IRQ_FLAGS_MASK))
>> @@ -102,7 +115,7 @@ void efi_call_virt_check_flags(unsigned long flags, const char *call)
>>         add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_NOW_UNRELIABLE);
>>         pr_err_ratelimited(FW_BUG "IRQ flags corrupted (0x%08lx=>0x%08lx) by EFI %s\n",
>>                            flags, cur_flags, call);
>> -       local_irq_restore(flags);
>> +       arch_efi_restore_flags(flags);
>>  }
>>
>>  /*
>> diff --git a/include/linux/efi.h b/include/linux/efi.h
>> index 45ff763..bd80b7e 100644
>> --- a/include/linux/efi.h
>> +++ b/include/linux/efi.h
>> @@ -1607,6 +1607,7 @@ efi_status_t efi_setup_gop(efi_system_table_t *sys_table_arg,
>>
>>  bool efi_runtime_disabled(void);
>>  extern void efi_call_virt_check_flags(unsigned long flags, const char *call);
>> +extern unsigned long efi_call_virt_save_flags(void);
>>
>>  enum efi_secureboot_mode {
>>         efi_secureboot_mode_unset,
>> @@ -1652,7 +1653,7 @@ enum efi_secureboot_mode {
>>                                                                         \
>>         arch_efi_call_virt_setup();                                     \
>>                                                                         \
>> -       local_save_flags(__flags);                                      \
>> +       __flags = efi_call_virt_save_flags();                           \
>>         __s = arch_efi_call_virt(p, f, args);                           \
>>         efi_call_virt_check_flags(__flags, __stringify(f));             \
>>                                                                         \
>> @@ -1667,7 +1668,7 @@ enum efi_secureboot_mode {
>>                                                                         \
>>         arch_efi_call_virt_setup();                                     \
>>                                                                         \
>> -       local_save_flags(__flags);                                      \
>> +       __flags = efi_call_virt_save_flags();                           \
>>         arch_efi_call_virt(p, f, args);                                 \
>>         efi_call_virt_check_flags(__flags, __stringify(f));             \
>>                                                                         \
>> --
>> 1.9.1
>>
Marc Zyngier - Jan. 28, 2019, 10 a.m.
On Mon, 21 Jan 2019 15:33:30 +0000,
Julien Thierry <julien.thierry@arm.com> wrote:
> 
> Currently, irqflags are saved before calling runtime services and
> checked for mismatch on return.
> 
> Provide a pair of overridable macros to save and restore (if needed) the
> state that need to be preserved on return from a runtime service.
> This allows to check for flags that are not necesarly related to
> irqflags.
> 
> Signed-off-by: Julien Thierry <julien.thierry@arm.com>
> Acked-by: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Cc: linux-efi@vger.kernel.org

With the changes requested by Ard,

Acked-by: Marc Zyngier <marc.zyngier@arm.com>

	M.

Patch

diff --git a/drivers/firmware/efi/runtime-wrappers.c b/drivers/firmware/efi/runtime-wrappers.c
index 8903b9c..2f4b68b 100644
--- a/drivers/firmware/efi/runtime-wrappers.c
+++ b/drivers/firmware/efi/runtime-wrappers.c
@@ -89,11 +89,24 @@ 
 	efi_rts_work.status;						\
 })
 
+#ifndef arch_efi_save_flags
+#define arch_efi_save_flags(state_flags)	local_save_flags(state_flags)
+#define arch_efi_restore_flags(state_flags)	local_irq_restore(state_flags)
+#endif
+
+inline unsigned long efi_call_virt_save_flags(void)
+{
+	unsigned long flags;
+
+	arch_efi_save_flags(flags);
+	return flags;
+}
+
 void efi_call_virt_check_flags(unsigned long flags, const char *call)
 {
 	unsigned long cur_flags, mismatch;
 
-	local_save_flags(cur_flags);
+	cur_flags = efi_call_virt_save_flags();
 
 	mismatch = flags ^ cur_flags;
 	if (!WARN_ON_ONCE(mismatch & ARCH_EFI_IRQ_FLAGS_MASK))
@@ -102,7 +115,7 @@  void efi_call_virt_check_flags(unsigned long flags, const char *call)
 	add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_NOW_UNRELIABLE);
 	pr_err_ratelimited(FW_BUG "IRQ flags corrupted (0x%08lx=>0x%08lx) by EFI %s\n",
 			   flags, cur_flags, call);
-	local_irq_restore(flags);
+	arch_efi_restore_flags(flags);
 }
 
 /*
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 45ff763..bd80b7e 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -1607,6 +1607,7 @@  efi_status_t efi_setup_gop(efi_system_table_t *sys_table_arg,
 
 bool efi_runtime_disabled(void);
 extern void efi_call_virt_check_flags(unsigned long flags, const char *call);
+extern unsigned long efi_call_virt_save_flags(void);
 
 enum efi_secureboot_mode {
 	efi_secureboot_mode_unset,
@@ -1652,7 +1653,7 @@  enum efi_secureboot_mode {
 									\
 	arch_efi_call_virt_setup();					\
 									\
-	local_save_flags(__flags);					\
+	__flags = efi_call_virt_save_flags();				\
 	__s = arch_efi_call_virt(p, f, args);				\
 	efi_call_virt_check_flags(__flags, __stringify(f));		\
 									\
@@ -1667,7 +1668,7 @@  enum efi_secureboot_mode {
 									\
 	arch_efi_call_virt_setup();					\
 									\
-	local_save_flags(__flags);					\
+	__flags = efi_call_virt_save_flags();				\
 	arch_efi_call_virt(p, f, args);					\
 	efi_call_virt_check_flags(__flags, __stringify(f));		\
 									\