[GIT PULL 0/5] more EFI changes for v4.17

[GIT PULL 0/5] more EFI changes for v4.17

[Ard Biesheuvel]

The following changes since commit f779ca740f25c8a6a72d951334f9efc3158a318b:

  efi: Make const array 'apple' static (2018-03-09 09:30:35 +0100)

are available in the Git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi.git tags/efi-next

for you to fetch changes up to a6072c0ecf3a39e9eadfaea1477533fd24261b05:

  efi: use string literals for efi_char16_t variable initializers (2018-03-10 11:05:19 +0000)

----------------------------------------------------------------
Second batch of EFI changes for v4.17:
- take 2 of 'use efi_switch_mm() on x86 instead of manipulating %cr3 directly'
- fix early memremap leak in ESRT code
- switch to L"xxx" notation for wide string literals

----------------------------------------------------------------
Ard Biesheuvel (2):
      efi/esrt: fix handling of early ESRT table mapping
      efi: use string literals for efi_char16_t variable initializers

Sai Praneeth (3):
      efi: Use efi_mm in x86 as well as ARM
      x86/efi: Replace efi_pgd with efi_mm.pgd
      x86/efi: Use efi_switch_mm() rather than manually twiddling with %cr3

 arch/x86/boot/compressed/eboot.c          |  3 +-
 arch/x86/include/asm/efi.h                | 26 ++++++--------
 arch/x86/platform/efi/efi_64.c            | 59 +++++++++++++++++--------------
 arch/x86/platform/efi/efi_thunk_64.S      |  2 +-
 arch/x86/platform/efi/quirks.c            |  8 +++--
 drivers/firmware/efi/arm-runtime.c        |  9 -----
 drivers/firmware/efi/efi.c                |  9 +++++
 drivers/firmware/efi/esrt.c               | 17 +++------
 drivers/firmware/efi/libstub/Makefile     |  2 +-
 drivers/firmware/efi/libstub/secureboot.c | 12 ++-----
 drivers/firmware/efi/libstub/tpm.c        |  7 ++--
 include/linux/efi.h                       |  2 ++
 12 files changed, 72 insertions(+), 84 deletions(-)

[PATCH 1/5] efi: Use efi_mm in x86 as well as ARM

[Ard Biesheuvel]

From: Sai Praneeth <sai.praneeth.prakhya@intel.com>

Presently, only ARM uses mm_struct to manage efi page tables and efi
runtime region mappings. As this is the preferred approach, let's make
this data structure common across architectures. Specially, for x86,
using this data structure improves code maintainability and readability.

Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Cc: "Lee, Chun-Yi" <jlee@suse.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Ricardo Neri <ricardo.neri@intel.com>
Cc: Ravi Shankar <ravi.v.shankar@intel.com>
Tested-by: Bhupesh Sharma <bhsharma@redhat.com>
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
[ardb: don't #include the world to get a declaration of struct mm_struct]
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/x86/include/asm/efi.h         | 1 +
 arch/x86/platform/efi/efi_64.c     | 3 +++
 drivers/firmware/efi/arm-runtime.c | 9 ---------
 drivers/firmware/efi/efi.c         | 9 +++++++++
 include/linux/efi.h                | 2 ++
 5 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
index a399c1ebf6f0..c62443fa7d0a 100644
--- a/arch/x86/include/asm/efi.h
+++ b/arch/x86/include/asm/efi.h
@@ -7,6 +7,7 @@
 #include <asm/processor-flags.h>
 #include <asm/tlb.h>
 #include <asm/nospec-branch.h>
+#include <asm/mmu_context.h>
 
 /*
  * We map the EFI regions needed for runtime services non-contiguously,
diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
index c310a8284358..0045efe9947b 100644
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -231,6 +231,9 @@ int __init efi_alloc_page_tables(void)
 		return -ENOMEM;
 	}
 
+	mm_init_cpumask(&efi_mm);
+	init_new_context(NULL, &efi_mm);
+
 	return 0;
 }
 
diff --git a/drivers/firmware/efi/arm-runtime.c b/drivers/firmware/efi/arm-runtime.c
index 13561aeb7396..5889cbea60b8 100644
--- a/drivers/firmware/efi/arm-runtime.c
+++ b/drivers/firmware/efi/arm-runtime.c
@@ -31,15 +31,6 @@
 
 extern u64 efi_system_table;
 
-static struct mm_struct efi_mm = {
-	.mm_rb			= RB_ROOT,
-	.mm_users		= ATOMIC_INIT(2),
-	.mm_count		= ATOMIC_INIT(1),
-	.mmap_sem		= __RWSEM_INITIALIZER(efi_mm.mmap_sem),
-	.page_table_lock	= __SPIN_LOCK_UNLOCKED(efi_mm.page_table_lock),
-	.mmlist			= LIST_HEAD_INIT(efi_mm.mmlist),
-};
-
 #ifdef CONFIG_ARM64_PTDUMP_DEBUGFS
 #include <asm/ptdump.h>
 
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 92b9e79e5da9..232f4915223b 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -75,6 +75,15 @@ static unsigned long *efi_tables[] = {
 	&efi.mem_attr_table,
 };
 
+struct mm_struct efi_mm = {
+	.mm_rb			= RB_ROOT,
+	.mm_users		= ATOMIC_INIT(2),
+	.mm_count		= ATOMIC_INIT(1),
+	.mmap_sem		= __RWSEM_INITIALIZER(efi_mm.mmap_sem),
+	.page_table_lock	= __SPIN_LOCK_UNLOCKED(efi_mm.page_table_lock),
+	.mmlist			= LIST_HEAD_INIT(efi_mm.mmlist),
+};
+
 static bool disable_runtime;
 static int __init setup_noefi(char *arg)
 {
diff --git a/include/linux/efi.h b/include/linux/efi.h
index f5083aa72eae..f1b7d68ac460 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -966,6 +966,8 @@ extern struct efi {
 	unsigned long flags;
 } efi;
 
+extern struct mm_struct efi_mm;
+
 static inline int
 efi_guidcmp (efi_guid_t left, efi_guid_t right)
 {
-- 
2.15.1

[tip:efi/core] efi: Use efi_mm in x86 as well as ARM

[tip-bot for Sai Praneeth]

Commit-ID:  7e904a91bf6049071ef9d605a52f863ae774081d
Gitweb:     https://git.kernel.org/tip/7e904a91bf6049071ef9d605a52f863ae774081d
Author:     Sai Praneeth <sai.praneeth.prakhya@intel.com>
AuthorDate: Mon, 12 Mar 2018 08:44:56 +0000
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Mon, 12 Mar 2018 10:05:01 +0100

efi: Use efi_mm in x86 as well as ARM

Presently, only ARM uses mm_struct to manage EFI page tables and EFI
runtime region mappings. As this is the preferred approach, let's make
this data structure common across architectures. Specially, for x86,
using this data structure improves code maintainability and readability.

Tested-by: Bhupesh Sharma <bhsharma@redhat.com>
[ardb: don't #include the world to get a declaration of struct mm_struct]
Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Lee, Chun-Yi <jlee@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Shankar <ravi.v.shankar@intel.com>
Cc: Ricardo Neri <ricardo.neri@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20180312084500.10764-2-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/include/asm/efi.h         | 1 +
 arch/x86/platform/efi/efi_64.c     | 3 +++
 drivers/firmware/efi/arm-runtime.c | 9 ---------
 drivers/firmware/efi/efi.c         | 9 +++++++++
 include/linux/efi.h                | 2 ++
 5 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
index a399c1ebf6f0..c62443fa7d0a 100644
--- a/arch/x86/include/asm/efi.h
+++ b/arch/x86/include/asm/efi.h
@@ -7,6 +7,7 @@
 #include <asm/processor-flags.h>
 #include <asm/tlb.h>
 #include <asm/nospec-branch.h>
+#include <asm/mmu_context.h>
 
 /*
  * We map the EFI regions needed for runtime services non-contiguously,
diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
index 780460aa5ea5..29425b6c98a7 100644
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -233,6 +233,9 @@ int __init efi_alloc_page_tables(void)
 		return -ENOMEM;
 	}
 
+	mm_init_cpumask(&efi_mm);
+	init_new_context(NULL, &efi_mm);
+
 	return 0;
 }
 
diff --git a/drivers/firmware/efi/arm-runtime.c b/drivers/firmware/efi/arm-runtime.c
index 13561aeb7396..5889cbea60b8 100644
--- a/drivers/firmware/efi/arm-runtime.c
+++ b/drivers/firmware/efi/arm-runtime.c
@@ -31,15 +31,6 @@
 
 extern u64 efi_system_table;
 
-static struct mm_struct efi_mm = {
-	.mm_rb			= RB_ROOT,
-	.mm_users		= ATOMIC_INIT(2),
-	.mm_count		= ATOMIC_INIT(1),
-	.mmap_sem		= __RWSEM_INITIALIZER(efi_mm.mmap_sem),
-	.page_table_lock	= __SPIN_LOCK_UNLOCKED(efi_mm.page_table_lock),
-	.mmlist			= LIST_HEAD_INIT(efi_mm.mmlist),
-};
-
 #ifdef CONFIG_ARM64_PTDUMP_DEBUGFS
 #include <asm/ptdump.h>
 
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 92b9e79e5da9..232f4915223b 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -75,6 +75,15 @@ static unsigned long *efi_tables[] = {
 	&efi.mem_attr_table,
 };
 
+struct mm_struct efi_mm = {
+	.mm_rb			= RB_ROOT,
+	.mm_users		= ATOMIC_INIT(2),
+	.mm_count		= ATOMIC_INIT(1),
+	.mmap_sem		= __RWSEM_INITIALIZER(efi_mm.mmap_sem),
+	.page_table_lock	= __SPIN_LOCK_UNLOCKED(efi_mm.page_table_lock),
+	.mmlist			= LIST_HEAD_INIT(efi_mm.mmlist),
+};
+
 static bool disable_runtime;
 static int __init setup_noefi(char *arg)
 {
diff --git a/include/linux/efi.h b/include/linux/efi.h
index f5083aa72eae..f1b7d68ac460 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -966,6 +966,8 @@ extern struct efi {
 	unsigned long flags;
 } efi;
 
+extern struct mm_struct efi_mm;
+
 static inline int
 efi_guidcmp (efi_guid_t left, efi_guid_t right)
 {

[PATCH 2/5] x86/efi: Replace efi_pgd with efi_mm.pgd

[Ard Biesheuvel]

From: Sai Praneeth <sai.praneeth.prakhya@intel.com>

Since the previous patch added support for efi_mm, let's handle efi_pgd
through efi_mm and remove global variable efi_pgd.

Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Cc: "Lee, Chun-Yi" <jlee@suse.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Bhupesh Sharma <bhsharma@redhat.com>
Cc: Ricardo Neri <ricardo.neri@intel.com>
Cc: Ravi Shankar <ravi.v.shankar@intel.com>
Tested-by: Bhupesh Sharma <bhsharma@redhat.com>
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/x86/platform/efi/efi_64.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
index 0045efe9947b..8881e601c32d 100644
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -190,8 +190,6 @@ void __init efi_call_phys_epilog(pgd_t *save_pgd)
 	early_code_mapping_set_exec(0);
 }
 
-static pgd_t *efi_pgd;
-
 /*
  * We need our own copy of the higher levels of the page tables
  * because we want to avoid inserting EFI region mappings (EFI_VA_END
@@ -203,7 +201,7 @@ static pgd_t *efi_pgd;
  */
 int __init efi_alloc_page_tables(void)
 {
-	pgd_t *pgd;
+	pgd_t *pgd, *efi_pgd;
 	p4d_t *p4d;
 	pud_t *pud;
 	gfp_t gfp_mask;
@@ -231,6 +229,7 @@ int __init efi_alloc_page_tables(void)
 		return -ENOMEM;
 	}
 
+	efi_mm.pgd = efi_pgd;
 	mm_init_cpumask(&efi_mm);
 	init_new_context(NULL, &efi_mm);
 
@@ -246,6 +245,7 @@ void efi_sync_low_kernel_mappings(void)
 	pgd_t *pgd_k, *pgd_efi;
 	p4d_t *p4d_k, *p4d_efi;
 	pud_t *pud_k, *pud_efi;
+	pgd_t *efi_pgd = efi_mm.pgd;
 
 	if (efi_enabled(EFI_OLD_MEMMAP))
 		return;
@@ -339,7 +339,7 @@ int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
 	unsigned long pfn, text, pf;
 	struct page *page;
 	unsigned npages;
-	pgd_t *pgd;
+	pgd_t *pgd = efi_mm.pgd;
 
 	if (efi_enabled(EFI_OLD_MEMMAP))
 		return 0;
@@ -349,8 +349,7 @@ int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
 	 * this value is loaded into cr3 the PGD will be decrypted during
 	 * the pagetable walk.
 	 */
-	efi_scratch.efi_pgt = (pgd_t *)__sme_pa(efi_pgd);
-	pgd = efi_pgd;
+	efi_scratch.efi_pgt = (pgd_t *)__sme_pa(pgd);
 
 	/*
 	 * It can happen that the physical address of new_memmap lands in memory
@@ -420,7 +419,7 @@ static void __init __map_region(efi_memory_desc_t *md, u64 va)
 {
 	unsigned long flags = _PAGE_RW;
 	unsigned long pfn;
-	pgd_t *pgd = efi_pgd;
+	pgd_t *pgd = efi_mm.pgd;
 
 	if (!(md->attribute & EFI_MEMORY_WB))
 		flags |= _PAGE_PCD;
@@ -524,7 +523,7 @@ void __init parse_efi_setup(u64 phys_addr, u32 data_len)
 static int __init efi_update_mappings(efi_memory_desc_t *md, unsigned long pf)
 {
 	unsigned long pfn;
-	pgd_t *pgd = efi_pgd;
+	pgd_t *pgd = efi_mm.pgd;
 	int err1, err2;
 
 	/* Update the 1:1 mapping */
@@ -621,7 +620,7 @@ void __init efi_dump_pagetable(void)
 	if (efi_enabled(EFI_OLD_MEMMAP))
 		ptdump_walk_pgd_level(NULL, swapper_pg_dir);
 	else
-		ptdump_walk_pgd_level(NULL, efi_pgd);
+		ptdump_walk_pgd_level(NULL, efi_mm.pgd);
 #endif
 }
 
-- 
2.15.1

Re: [PATCH 2/5] x86/efi: Replace efi_pgd with efi_mm.pgd

[Ingo Molnar]

* Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:

> From: Sai Praneeth <sai.praneeth.prakhya@intel.com>
> 
> Since the previous patch added support for efi_mm, let's handle efi_pgd
> through efi_mm and remove global variable efi_pgd.
> 
> Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
> Cc: "Lee, Chun-Yi" <jlee@suse.com>
> Cc: Borislav Petkov <bp@alien8.de>
> Cc: Tony Luck <tony.luck@intel.com>
> Cc: Andy Lutomirski <luto@kernel.org>
> Cc: Michael S. Tsirkin <mst@redhat.com>
> Cc: Bhupesh Sharma <bhsharma@redhat.com>
> Cc: Ricardo Neri <ricardo.neri@intel.com>
> Cc: Ravi Shankar <ravi.v.shankar@intel.com>
> Tested-by: Bhupesh Sharma <bhsharma@redhat.com>
> Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
>  arch/x86/platform/efi/efi_64.c | 17 ++++++++---------
>  1 file changed, 8 insertions(+), 9 deletions(-)
> 
> diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
> index 0045efe9947b..8881e601c32d 100644
> --- a/arch/x86/platform/efi/efi_64.c
> +++ b/arch/x86/platform/efi/efi_64.c
> @@ -190,8 +190,6 @@ void __init efi_call_phys_epilog(pgd_t *save_pgd)
>  	early_code_mapping_set_exec(0);
>  }
>  
> -static pgd_t *efi_pgd;
> -

Hm, so there's some interaction here with:

  116fef640859: x86/mm/dump_pagetables: Add the EFI pagetable to the debugfs 'page_tables' directory

which is in tip:x86/mm.

Could you please resolve that conflict? I'll sort out the topic branches 
afterwards.

Thanks,

	Ingo

Re: [PATCH 2/5] x86/efi: Replace efi_pgd with efi_mm.pgd

[Ingo Molnar]

* Ingo Molnar <mingo@kernel.org> wrote:

> > -static pgd_t *efi_pgd;
> > -
> 
> Hm, so there's some interaction here with:
> 
>   116fef640859: x86/mm/dump_pagetables: Add the EFI pagetable to the debugfs 'page_tables' directory
> 
> which is in tip:x86/mm.
> 
> Could you please resolve that conflict? I'll sort out the topic branches 
> afterwards.

So I've resolved it the following way, I merged the conflicting commit into 
tip:efi/core and applied the 3 unrelated patches from your series:

 36b649760e94: efi: Use string literals for efi_char16_t variable initializers
 136d5d57e35c: efi/esrt: Fix handling of early ESRT table mapping
 7e904a91bf60: efi: Use efi_mm in x86 as well as ARM
 b0599e2801df: Merge branch 'x86/mm' into efi/core

and pushed it out.

So if you could resolve the two conflicting patches on top of 36b649760e94 then we 
should be good going forward.

Thanks,

	Ingo

Re: [PATCH 2/5] x86/efi: Replace efi_pgd with efi_mm.pgd

[Ard Biesheuvel]

On 12 March 2018 at 09:26, Ingo Molnar <mingo@kernel.org> wrote:
>
> * Ingo Molnar <mingo@kernel.org> wrote:
>
>> > -static pgd_t *efi_pgd;
>> > -
>>
>> Hm, so there's some interaction here with:
>>
>>   116fef640859: x86/mm/dump_pagetables: Add the EFI pagetable to the debugfs 'page_tables' directory
>>
>> which is in tip:x86/mm.
>>
>> Could you please resolve that conflict? I'll sort out the topic branches
>> afterwards.
>
> So I've resolved it the following way, I merged the conflicting commit into
> tip:efi/core and applied the 3 unrelated patches from your series:
>
>  36b649760e94: efi: Use string literals for efi_char16_t variable initializers
>  136d5d57e35c: efi/esrt: Fix handling of early ESRT table mapping
>  7e904a91bf60: efi: Use efi_mm in x86 as well as ARM
>  b0599e2801df: Merge branch 'x86/mm' into efi/core
>
> and pushed it out.
>
> So if you could resolve the two conflicting patches on top of 36b649760e94 then we
> should be good going forward.
>

By 'resolve' you mean rebase and resend, right?

Re: [PATCH 2/5] x86/efi: Replace efi_pgd with efi_mm.pgd

[Ingo Molnar]

* Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:

> On 12 March 2018 at 09:26, Ingo Molnar <mingo@kernel.org> wrote:
> >
> > * Ingo Molnar <mingo@kernel.org> wrote:
> >
> >> > -static pgd_t *efi_pgd;
> >> > -
> >>
> >> Hm, so there's some interaction here with:
> >>
> >>   116fef640859: x86/mm/dump_pagetables: Add the EFI pagetable to the debugfs 'page_tables' directory
> >>
> >> which is in tip:x86/mm.
> >>
> >> Could you please resolve that conflict? I'll sort out the topic branches
> >> afterwards.
> >
> > So I've resolved it the following way, I merged the conflicting commit into
> > tip:efi/core and applied the 3 unrelated patches from your series:
> >
> >  36b649760e94: efi: Use string literals for efi_char16_t variable initializers
> >  136d5d57e35c: efi/esrt: Fix handling of early ESRT table mapping
> >  7e904a91bf60: efi: Use efi_mm in x86 as well as ARM
> >  b0599e2801df: Merge branch 'x86/mm' into efi/core
> >
> > and pushed it out.
> >
> > So if you could resolve the two conflicting patches on top of 36b649760e94 then we
> > should be good going forward.
> >
> 
> By 'resolve' you mean rebase and resend, right?

Yeah.

I expected it to probably be a bit more work than a regular rebase, because we 
grew a new efi_pgd user and I didn't want to trivialize the conflict resolution 
effort - hence the 'resolve the conflict' formulation! :-)

Thanks,

	Ingo

[PATCH 3/5] x86/efi: Use efi_switch_mm() rather than manually twiddling with %cr3

[Ard Biesheuvel]

From: Sai Praneeth <sai.praneeth.prakhya@intel.com>

Use helper function efi_switch_mm() to switch to/from efi_mm when
invoking any UEFI runtime services.

Likewise, we need to switch back to previous mm (mm context stolen
by efi_mm) after the above calls return successfully. We can use
efi_switch_mm() helper function only with x86_64 kernel and
"efi=old_map" disabled because, x86_32 and efi=old_map do not use
efi_pgd, rather they use swapper_pg_dir.

Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Cc: "Lee, Chun-Yi" <jlee@suse.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Bhupesh Sharma <bhsharma@redhat.com>
Cc: Ricardo Neri <ricardo.neri@intel.com>
Cc: Ravi Shankar <ravi.v.shankar@intel.com>
Tested-by: Bhupesh Sharma <bhsharma@redhat.com>
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
[ardb: add #include of sched/task.h for task_lock/_unlock]
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/x86/include/asm/efi.h           | 25 +++++++++-------------
 arch/x86/platform/efi/efi_64.c       | 41 +++++++++++++++++++-----------------
 arch/x86/platform/efi/efi_thunk_64.S |  2 +-
 3 files changed, 33 insertions(+), 35 deletions(-)

diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
index c62443fa7d0a..cec5fae23eb3 100644
--- a/arch/x86/include/asm/efi.h
+++ b/arch/x86/include/asm/efi.h
@@ -70,14 +70,13 @@ extern asmlinkage u64 efi_call(void *fp, ...);
 #define efi_call_phys(f, args...)		efi_call((f), args)
 
 /*
- * Scratch space used for switching the pagetable in the EFI stub
+ * struct efi_scratch - Scratch space used while switching to/from efi_mm
+ * @phys_stack: stack used during EFI Mixed Mode
+ * @prev_mm:    store/restore stolen mm_struct while switching to/from efi_mm
  */
 struct efi_scratch {
-	u64	r15;
-	u64	prev_cr3;
-	pgd_t	*efi_pgt;
-	bool	use_pgd;
-	u64	phys_stack;
+	u64			phys_stack;
+	struct mm_struct	*prev_mm;
 } __packed;
 
 #define arch_efi_call_virt_setup()					\
@@ -87,11 +86,8 @@ struct efi_scratch {
 	__kernel_fpu_begin();						\
 	firmware_restrict_branch_speculation_start();			\
 									\
-	if (efi_scratch.use_pgd) {					\
-		efi_scratch.prev_cr3 = __read_cr3();			\
-		write_cr3((unsigned long)efi_scratch.efi_pgt);		\
-		__flush_tlb_all();					\
-	}								\
+	if (!efi_enabled(EFI_OLD_MEMMAP))				\
+		efi_switch_mm(&efi_mm);					\
 })
 
 #define arch_efi_call_virt(p, f, args...)				\
@@ -99,10 +95,8 @@ struct efi_scratch {
 
 #define arch_efi_call_virt_teardown()					\
 ({									\
-	if (efi_scratch.use_pgd) {					\
-		write_cr3(efi_scratch.prev_cr3);			\
-		__flush_tlb_all();					\
-	}								\
+	if (!efi_enabled(EFI_OLD_MEMMAP))				\
+		efi_switch_mm(efi_scratch.prev_mm);			\
 									\
 	firmware_restrict_branch_speculation_end();			\
 	__kernel_fpu_end();						\
@@ -145,6 +139,7 @@ extern void __init efi_dump_pagetable(void);
 extern void __init efi_apply_memmap_quirks(void);
 extern int __init efi_reuse_config(u64 tables, int nr_tables);
 extern void efi_delete_dummy_variable(void);
+extern void efi_switch_mm(struct mm_struct *mm);
 
 struct efi_setup_data {
 	u64 fw_vendor;
diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
index 8881e601c32d..229af5bbecb8 100644
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -33,6 +33,7 @@
 #include <linux/slab.h>
 #include <linux/ucs2_string.h>
 #include <linux/mem_encrypt.h>
+#include <linux/sched/task.h>
 
 #include <asm/setup.h>
 #include <asm/page.h>
@@ -81,9 +82,8 @@ pgd_t * __init efi_call_phys_prolog(void)
 	int n_pgds, i, j;
 
 	if (!efi_enabled(EFI_OLD_MEMMAP)) {
-		save_pgd = (pgd_t *)__read_cr3();
-		write_cr3((unsigned long)efi_scratch.efi_pgt);
-		goto out;
+		efi_switch_mm(&efi_mm);
+		return NULL;
 	}
 
 	early_code_mapping_set_exec(1);
@@ -155,8 +155,7 @@ void __init efi_call_phys_epilog(pgd_t *save_pgd)
 	pud_t *pud;
 
 	if (!efi_enabled(EFI_OLD_MEMMAP)) {
-		write_cr3((unsigned long)save_pgd);
-		__flush_tlb_all();
+		efi_switch_mm(efi_scratch.prev_mm);
 		return;
 	}
 
@@ -344,13 +343,6 @@ int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
 	if (efi_enabled(EFI_OLD_MEMMAP))
 		return 0;
 
-	/*
-	 * Since the PGD is encrypted, set the encryption mask so that when
-	 * this value is loaded into cr3 the PGD will be decrypted during
-	 * the pagetable walk.
-	 */
-	efi_scratch.efi_pgt = (pgd_t *)__sme_pa(pgd);
-
 	/*
 	 * It can happen that the physical address of new_memmap lands in memory
 	 * which is not mapped in the EFI page table. Therefore we need to go
@@ -364,8 +356,6 @@ int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
 		return 1;
 	}
 
-	efi_scratch.use_pgd = true;
-
 	/*
 	 * Certain firmware versions are way too sentimential and still believe
 	 * they are exclusive and unquestionable owners of the first physical page,
@@ -624,6 +614,22 @@ void __init efi_dump_pagetable(void)
 #endif
 }
 
+/*
+ * Makes the calling thread switch to/from efi_mm context. Can be used
+ * for SetVirtualAddressMap() i.e. current->active_mm == init_mm as well
+ * as during efi runtime calls i.e current->active_mm == current_mm.
+ * We are not mm_dropping()/mm_grabbing() any mm, because we are not
+ * losing/creating any references.
+ */
+void efi_switch_mm(struct mm_struct *mm)
+{
+	task_lock(current);
+	efi_scratch.prev_mm = current->active_mm;
+	current->active_mm = mm;
+	switch_mm(efi_scratch.prev_mm, mm, NULL);
+	task_unlock(current);
+}
+
 #ifdef CONFIG_EFI_MIXED
 extern efi_status_t efi64_thunk(u32, ...);
 
@@ -677,16 +683,13 @@ efi_status_t efi_thunk_set_virtual_address_map(
 	efi_sync_low_kernel_mappings();
 	local_irq_save(flags);
 
-	efi_scratch.prev_cr3 = __read_cr3();
-	write_cr3((unsigned long)efi_scratch.efi_pgt);
-	__flush_tlb_all();
+	efi_switch_mm(&efi_mm);
 
 	func = (u32)(unsigned long)phys_set_virtual_address_map;
 	status = efi64_thunk(func, memory_map_size, descriptor_size,
 			     descriptor_version, virtual_map);
 
-	write_cr3(efi_scratch.prev_cr3);
-	__flush_tlb_all();
+	efi_switch_mm(efi_scratch.prev_mm);
 	local_irq_restore(flags);
 
 	return status;
diff --git a/arch/x86/platform/efi/efi_thunk_64.S b/arch/x86/platform/efi/efi_thunk_64.S
index 189b218da87c..46c58b08739c 100644
--- a/arch/x86/platform/efi/efi_thunk_64.S
+++ b/arch/x86/platform/efi/efi_thunk_64.S
@@ -33,7 +33,7 @@ ENTRY(efi64_thunk)
 	 * Switch to 1:1 mapped 32-bit stack pointer.
 	 */
 	movq	%rsp, efi_saved_sp(%rip)
-	movq	efi_scratch+25(%rip), %rsp
+	movq	efi_scratch(%rip), %rsp
 
 	/*
 	 * Calculate the physical address of the kernel text.
-- 
2.15.1

[PATCH 4/5] efi/esrt: fix handling of early ESRT table mapping

[Ard Biesheuvel]

As reported by Tyler, efi_esrt_init() will return without releasing the
ESRT table header mapping if it encounters a table with an unexpected
version. Replacing the 'return' with 'goto err_memunmap' would fix this
particular occurrence, but, as it turns out, the code is rather peculiar
to begin with:
- it never uses the header mapping after memcpy()'ing out its contents,
- it maps and unmaps the entire table without ever looking at the
  contents.

So let's refactor this code to unmap the table header right after the
memcpy() so we can get rid of the error handling path altogether, and
drop the second mapping entirely.

Cc: Peter Jones <pjones@redhat.com>
Reported-by: Tyler Baicar <tbaicar@codeaurora.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 drivers/firmware/efi/esrt.c | 17 ++++-------------
 1 file changed, 4 insertions(+), 13 deletions(-)

diff --git a/drivers/firmware/efi/esrt.c b/drivers/firmware/efi/esrt.c
index c47e0c6ec00f..1ab80e06e7c5 100644
--- a/drivers/firmware/efi/esrt.c
+++ b/drivers/firmware/efi/esrt.c
@@ -279,6 +279,7 @@ void __init efi_esrt_init(void)
 	}
 
 	memcpy(&tmpesrt, va, sizeof(tmpesrt));
+	early_memunmap(va, size);
 
 	if (tmpesrt.fw_resource_version == 1) {
 		entry_size = sizeof (*v1_entries);
@@ -291,7 +292,7 @@ void __init efi_esrt_init(void)
 	if (tmpesrt.fw_resource_count > 0 && max - size < entry_size) {
 		pr_err("ESRT memory map entry can only hold the header. (max: %zu size: %zu)\n",
 		       max - size, entry_size);
-		goto err_memunmap;
+		return;
 	}
 
 	/*
@@ -304,7 +305,7 @@ void __init efi_esrt_init(void)
 	if (tmpesrt.fw_resource_count > 128) {
 		pr_err("ESRT says fw_resource_count has very large value %d.\n",
 		       tmpesrt.fw_resource_count);
-		goto err_memunmap;
+		return;
 	}
 
 	/*
@@ -315,18 +316,10 @@ void __init efi_esrt_init(void)
 	if (max < size + entries_size) {
 		pr_err("ESRT does not fit on single memory map entry (size: %zu max: %zu)\n",
 		       size, max);
-		goto err_memunmap;
+		return;
 	}
 
-	/* remap it with our (plausible) new pages */
-	early_memunmap(va, size);
 	size += entries_size;
-	va = early_memremap(efi.esrt, size);
-	if (!va) {
-		pr_err("early_memremap(%p, %zu) failed.\n", (void *)efi.esrt,
-		       size);
-		return;
-	}
 
 	esrt_data = (phys_addr_t)efi.esrt;
 	esrt_data_size = size;
@@ -336,8 +329,6 @@ void __init efi_esrt_init(void)
 	efi_mem_reserve(esrt_data, esrt_data_size);
 
 	pr_debug("esrt-init: loaded.\n");
-err_memunmap:
-	early_memunmap(va, size);
 }
 
 static int __init register_entries(void)
-- 
2.15.1

[tip:efi/core] efi/esrt: Fix handling of early ESRT table mapping

[tip-bot for Ard Biesheuvel]

Commit-ID:  136d5d57e35cc6985c57d23d0c823133e3508bed
Gitweb:     https://git.kernel.org/tip/136d5d57e35cc6985c57d23d0c823133e3508bed
Author:     Ard Biesheuvel <ard.biesheuvel@linaro.org>
AuthorDate: Mon, 12 Mar 2018 08:44:59 +0000
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Mon, 12 Mar 2018 10:05:01 +0100

efi/esrt: Fix handling of early ESRT table mapping

As reported by Tyler, efi_esrt_init() will return without releasing the
ESRT table header mapping if it encounters a table with an unexpected
version. Replacing the 'return' with 'goto err_memunmap' would fix this
particular occurrence, but, as it turns out, the code is rather peculiar
to begin with:

 - it never uses the header mapping after memcpy()'ing out its contents,
 - it maps and unmaps the entire table without ever looking at the
   contents.

So let's refactor this code to unmap the table header right after the
memcpy() so we can get rid of the error handling path altogether, and
drop the second mapping entirely.

Reported-by: Tyler Baicar <tbaicar@codeaurora.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Jones <pjones@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20180312084500.10764-5-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 drivers/firmware/efi/esrt.c | 17 ++++-------------
 1 file changed, 4 insertions(+), 13 deletions(-)

diff --git a/drivers/firmware/efi/esrt.c b/drivers/firmware/efi/esrt.c
index c47e0c6ec00f..1ab80e06e7c5 100644
--- a/drivers/firmware/efi/esrt.c
+++ b/drivers/firmware/efi/esrt.c
@@ -279,6 +279,7 @@ void __init efi_esrt_init(void)
 	}
 
 	memcpy(&tmpesrt, va, sizeof(tmpesrt));
+	early_memunmap(va, size);
 
 	if (tmpesrt.fw_resource_version == 1) {
 		entry_size = sizeof (*v1_entries);
@@ -291,7 +292,7 @@ void __init efi_esrt_init(void)
 	if (tmpesrt.fw_resource_count > 0 && max - size < entry_size) {
 		pr_err("ESRT memory map entry can only hold the header. (max: %zu size: %zu)\n",
 		       max - size, entry_size);
-		goto err_memunmap;
+		return;
 	}
 
 	/*
@@ -304,7 +305,7 @@ void __init efi_esrt_init(void)
 	if (tmpesrt.fw_resource_count > 128) {
 		pr_err("ESRT says fw_resource_count has very large value %d.\n",
 		       tmpesrt.fw_resource_count);
-		goto err_memunmap;
+		return;
 	}
 
 	/*
@@ -315,18 +316,10 @@ void __init efi_esrt_init(void)
 	if (max < size + entries_size) {
 		pr_err("ESRT does not fit on single memory map entry (size: %zu max: %zu)\n",
 		       size, max);
-		goto err_memunmap;
+		return;
 	}
 
-	/* remap it with our (plausible) new pages */
-	early_memunmap(va, size);
 	size += entries_size;
-	va = early_memremap(efi.esrt, size);
-	if (!va) {
-		pr_err("early_memremap(%p, %zu) failed.\n", (void *)efi.esrt,
-		       size);
-		return;
-	}
 
 	esrt_data = (phys_addr_t)efi.esrt;
 	esrt_data_size = size;
@@ -336,8 +329,6 @@ void __init efi_esrt_init(void)
 	efi_mem_reserve(esrt_data, esrt_data_size);
 
 	pr_debug("esrt-init: loaded.\n");
-err_memunmap:
-	early_memunmap(va, size);
 }
 
 static int __init register_entries(void)

[PATCH 5/5] efi: use string literals for efi_char16_t variable initializers

[Ard Biesheuvel]

Now that we unambiguously build the entire kernel with -fshort-wchar,
it is no longer necessary to open code efi_char16_t[] initializers as
arrays of characters, and we can move to the L"xxx" notation instead.

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/x86/boot/compressed/eboot.c          |  3 ++-
 arch/x86/platform/efi/quirks.c            |  8 +++++---
 drivers/firmware/efi/libstub/Makefile     |  2 +-
 drivers/firmware/efi/libstub/secureboot.c | 12 +++---------
 drivers/firmware/efi/libstub/tpm.c        |  7 ++-----
 5 files changed, 13 insertions(+), 19 deletions(-)

diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index f2251c1c9853..47d3efff6805 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -421,9 +421,10 @@ static void retrieve_apple_device_properties(struct boot_params *boot_params)
 	}
 }
 
+static const efi_char16_t apple[] = L"Apple";
+
 static void setup_quirks(struct boot_params *boot_params)
 {
-	static efi_char16_t const apple[] = { 'A', 'p', 'p', 'l', 'e', 0 };
 	efi_char16_t *fw_vendor = (efi_char16_t *)(unsigned long)
 		efi_table_attr(efi_system_table, fw_vendor, sys_table);
 
diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
index 1ef11c26f79b..36c1f8b9f7e0 100644
--- a/arch/x86/platform/efi/quirks.c
+++ b/arch/x86/platform/efi/quirks.c
@@ -75,7 +75,7 @@ struct quark_security_header {
 	u32 rsvd[2];
 };
 
-static efi_char16_t efi_dummy_name[6] = { 'D', 'U', 'M', 'M', 'Y', 0 };
+static const efi_char16_t efi_dummy_name[] = L"DUMMY";
 
 static bool efi_no_storage_paranoia;
 
@@ -105,7 +105,8 @@ early_param("efi_no_storage_paranoia", setup_storage_paranoia);
 */
 void efi_delete_dummy_variable(void)
 {
-	efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID,
+	efi.set_variable((efi_char16_t *)efi_dummy_name,
+			 &EFI_DUMMY_GUID,
 			 EFI_VARIABLE_NON_VOLATILE |
 			 EFI_VARIABLE_BOOTSERVICE_ACCESS |
 			 EFI_VARIABLE_RUNTIME_ACCESS,
@@ -182,7 +183,8 @@ efi_status_t efi_query_variable_store(u32 attributes, unsigned long size,
 		if (!dummy)
 			return EFI_OUT_OF_RESOURCES;
 
-		status = efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID,
+		status = efi.set_variable((efi_char16_t *)efi_dummy_name,
+					  &EFI_DUMMY_GUID,
 					  EFI_VARIABLE_NON_VOLATILE |
 					  EFI_VARIABLE_BOOTSERVICE_ACCESS |
 					  EFI_VARIABLE_RUNTIME_ACCESS,
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index 7b3ba40f0745..a34e9290a699 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -9,7 +9,7 @@ cflags-$(CONFIG_X86_32)		:= -march=i386
 cflags-$(CONFIG_X86_64)		:= -mcmodel=small
 cflags-$(CONFIG_X86)		+= -m$(BITS) -D__KERNEL__ -O2 \
 				   -fPIC -fno-strict-aliasing -mno-red-zone \
-				   -mno-mmx -mno-sse
+				   -mno-mmx -mno-sse -fshort-wchar
 
 cflags-$(CONFIG_ARM64)		:= $(subst -pg,,$(KBUILD_CFLAGS)) -fpie
 cflags-$(CONFIG_ARM)		:= $(subst -pg,,$(KBUILD_CFLAGS)) \
diff --git a/drivers/firmware/efi/libstub/secureboot.c b/drivers/firmware/efi/libstub/secureboot.c
index 959777ec8a77..8f07eb414c00 100644
--- a/drivers/firmware/efi/libstub/secureboot.c
+++ b/drivers/firmware/efi/libstub/secureboot.c
@@ -16,18 +16,12 @@
 
 /* BIOS variables */
 static const efi_guid_t efi_variable_guid = EFI_GLOBAL_VARIABLE_GUID;
-static const efi_char16_t efi_SecureBoot_name[] = {
-	'S', 'e', 'c', 'u', 'r', 'e', 'B', 'o', 'o', 't', 0
-};
-static const efi_char16_t efi_SetupMode_name[] = {
-	'S', 'e', 't', 'u', 'p', 'M', 'o', 'd', 'e', 0
-};
+static const efi_char16_t efi_SecureBoot_name[] = L"SecureBoot";
+static const efi_char16_t efi_SetupMode_name[] = L"SetupMode";
 
 /* SHIM variables */
 static const efi_guid_t shim_guid = EFI_SHIM_LOCK_GUID;
-static efi_char16_t const shim_MokSBState_name[] = {
-	'M', 'o', 'k', 'S', 'B', 'S', 't', 'a', 't', 'e', 0
-};
+static const efi_char16_t shim_MokSBState_name[] = L"MokSBState";
 
 #define get_efi_var(name, vendor, ...) \
 	efi_call_runtime(get_variable, \
diff --git a/drivers/firmware/efi/libstub/tpm.c b/drivers/firmware/efi/libstub/tpm.c
index da661bf8cb96..2298560cea72 100644
--- a/drivers/firmware/efi/libstub/tpm.c
+++ b/drivers/firmware/efi/libstub/tpm.c
@@ -16,11 +16,8 @@
 #include "efistub.h"
 
 #ifdef CONFIG_RESET_ATTACK_MITIGATION
-static const efi_char16_t efi_MemoryOverWriteRequest_name[] = {
-	'M', 'e', 'm', 'o', 'r', 'y', 'O', 'v', 'e', 'r', 'w', 'r', 'i', 't',
-	'e', 'R', 'e', 'q', 'u', 'e', 's', 't', 'C', 'o', 'n', 't', 'r', 'o',
-	'l', 0
-};
+static const efi_char16_t efi_MemoryOverWriteRequest_name[] =
+	L"MemoryOverwriteRequestControl";
 
 #define MEMORY_ONLY_RESET_CONTROL_GUID \
 	EFI_GUID(0xe20939be, 0x32d4, 0x41be, 0xa1, 0x50, 0x89, 0x7f, 0x85, 0xd4, 0x98, 0x29)
-- 
2.15.1

[tip:efi/core] efi: Use string literals for efi_char16_t variable initializers

[tip-bot for Ard Biesheuvel]

Commit-ID:  36b649760e94968e0495b73284aaf07eed0a328f
Gitweb:     https://git.kernel.org/tip/36b649760e94968e0495b73284aaf07eed0a328f
Author:     Ard Biesheuvel <ard.biesheuvel@linaro.org>
AuthorDate: Mon, 12 Mar 2018 08:45:00 +0000
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Mon, 12 Mar 2018 10:05:02 +0100

efi: Use string literals for efi_char16_t variable initializers

Now that we unambiguously build the entire kernel with -fshort-wchar,
it is no longer necessary to open code efi_char16_t[] initializers as
arrays of characters, and we can move to the L"xxx" notation instead.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Lukas Wunner <lukas@wunner.de>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20180312084500.10764-6-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/boot/compressed/eboot.c          |  3 ++-
 arch/x86/platform/efi/quirks.c            |  8 +++++---
 drivers/firmware/efi/libstub/Makefile     |  2 +-
 drivers/firmware/efi/libstub/secureboot.c | 12 +++---------
 drivers/firmware/efi/libstub/tpm.c        |  7 ++-----
 5 files changed, 13 insertions(+), 19 deletions(-)

diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index f2251c1c9853..47d3efff6805 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -421,9 +421,10 @@ static void retrieve_apple_device_properties(struct boot_params *boot_params)
 	}
 }
 
+static const efi_char16_t apple[] = L"Apple";
+
 static void setup_quirks(struct boot_params *boot_params)
 {
-	static efi_char16_t const apple[] = { 'A', 'p', 'p', 'l', 'e', 0 };
 	efi_char16_t *fw_vendor = (efi_char16_t *)(unsigned long)
 		efi_table_attr(efi_system_table, fw_vendor, sys_table);
 
diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
index 1ef11c26f79b..36c1f8b9f7e0 100644
--- a/arch/x86/platform/efi/quirks.c
+++ b/arch/x86/platform/efi/quirks.c
@@ -75,7 +75,7 @@ struct quark_security_header {
 	u32 rsvd[2];
 };
 
-static efi_char16_t efi_dummy_name[6] = { 'D', 'U', 'M', 'M', 'Y', 0 };
+static const efi_char16_t efi_dummy_name[] = L"DUMMY";
 
 static bool efi_no_storage_paranoia;
 
@@ -105,7 +105,8 @@ early_param("efi_no_storage_paranoia", setup_storage_paranoia);
 */
 void efi_delete_dummy_variable(void)
 {
-	efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID,
+	efi.set_variable((efi_char16_t *)efi_dummy_name,
+			 &EFI_DUMMY_GUID,
 			 EFI_VARIABLE_NON_VOLATILE |
 			 EFI_VARIABLE_BOOTSERVICE_ACCESS |
 			 EFI_VARIABLE_RUNTIME_ACCESS,
@@ -182,7 +183,8 @@ efi_status_t efi_query_variable_store(u32 attributes, unsigned long size,
 		if (!dummy)
 			return EFI_OUT_OF_RESOURCES;
 
-		status = efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID,
+		status = efi.set_variable((efi_char16_t *)efi_dummy_name,
+					  &EFI_DUMMY_GUID,
 					  EFI_VARIABLE_NON_VOLATILE |
 					  EFI_VARIABLE_BOOTSERVICE_ACCESS |
 					  EFI_VARIABLE_RUNTIME_ACCESS,
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index 7b3ba40f0745..a34e9290a699 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -9,7 +9,7 @@ cflags-$(CONFIG_X86_32)		:= -march=i386
 cflags-$(CONFIG_X86_64)		:= -mcmodel=small
 cflags-$(CONFIG_X86)		+= -m$(BITS) -D__KERNEL__ -O2 \
 				   -fPIC -fno-strict-aliasing -mno-red-zone \
-				   -mno-mmx -mno-sse
+				   -mno-mmx -mno-sse -fshort-wchar
 
 cflags-$(CONFIG_ARM64)		:= $(subst -pg,,$(KBUILD_CFLAGS)) -fpie
 cflags-$(CONFIG_ARM)		:= $(subst -pg,,$(KBUILD_CFLAGS)) \
diff --git a/drivers/firmware/efi/libstub/secureboot.c b/drivers/firmware/efi/libstub/secureboot.c
index 959777ec8a77..8f07eb414c00 100644
--- a/drivers/firmware/efi/libstub/secureboot.c
+++ b/drivers/firmware/efi/libstub/secureboot.c
@@ -16,18 +16,12 @@
 
 /* BIOS variables */
 static const efi_guid_t efi_variable_guid = EFI_GLOBAL_VARIABLE_GUID;
-static const efi_char16_t efi_SecureBoot_name[] = {
-	'S', 'e', 'c', 'u', 'r', 'e', 'B', 'o', 'o', 't', 0
-};
-static const efi_char16_t efi_SetupMode_name[] = {
-	'S', 'e', 't', 'u', 'p', 'M', 'o', 'd', 'e', 0
-};
+static const efi_char16_t efi_SecureBoot_name[] = L"SecureBoot";
+static const efi_char16_t efi_SetupMode_name[] = L"SetupMode";
 
 /* SHIM variables */
 static const efi_guid_t shim_guid = EFI_SHIM_LOCK_GUID;
-static efi_char16_t const shim_MokSBState_name[] = {
-	'M', 'o', 'k', 'S', 'B', 'S', 't', 'a', 't', 'e', 0
-};
+static const efi_char16_t shim_MokSBState_name[] = L"MokSBState";
 
 #define get_efi_var(name, vendor, ...) \
 	efi_call_runtime(get_variable, \
diff --git a/drivers/firmware/efi/libstub/tpm.c b/drivers/firmware/efi/libstub/tpm.c
index da661bf8cb96..2298560cea72 100644
--- a/drivers/firmware/efi/libstub/tpm.c
+++ b/drivers/firmware/efi/libstub/tpm.c
@@ -16,11 +16,8 @@
 #include "efistub.h"
 
 #ifdef CONFIG_RESET_ATTACK_MITIGATION
-static const efi_char16_t efi_MemoryOverWriteRequest_name[] = {
-	'M', 'e', 'm', 'o', 'r', 'y', 'O', 'v', 'e', 'r', 'w', 'r', 'i', 't',
-	'e', 'R', 'e', 'q', 'u', 'e', 's', 't', 'C', 'o', 'n', 't', 'r', 'o',
-	'l', 0
-};
+static const efi_char16_t efi_MemoryOverWriteRequest_name[] =
+	L"MemoryOverwriteRequestControl";
 
 #define MEMORY_ONLY_RESET_CONTROL_GUID \
 	EFI_GUID(0xe20939be, 0x32d4, 0x41be, 0xa1, 0x50, 0x89, 0x7f, 0x85, 0xd4, 0x98, 0x29)