[PATCH 00/11] EFI runtime services virtual mapping, vN++

[PATCH 00/11] EFI runtime services virtual mapping, vN++

[Borislav Petkov]

From: Borislav Petkov <bp@suse.de>

Hi all,

here's maybe the final version of the patchset, no major changes since
the last time but cosmetic and cleanups and tidying as requested by Matt
and others.

Patches also at:

git://git.kernel.org/pub/scm/linux/kernel/git/bp/bp.git#efi

The previous announcement:

here's finally a new version of the runtime services VA mapping patchset
which hopefully implements hpa's idea of statically mapping EFI runtime
regions in a top-down manner starting at -4Gb virtual.

We're also using a different pagetable so as not to pollute kernel
address space. For that, we switch to that table before doing an EFI
call, and afterwards we switch back to the previous one.

To the patches:

1-2 are simple cleanups which Matt probably can take now

3-10 add the machinery to map regions into an arbitrary PGD. Those I've
split deliberately into very small bites so that they can be reviewed
more thoroughly and easily for my pagetable skills are pretty basic.

11 is the actual patch which implements that mapping so that we can use
runtime services in kexec (which is the whole reason for this fuss :))

So please take a long hard look at those, hammer on them on your
boxes and let me know. They boot fine on my Dell UEFI box and in OVMF
(obviously :)).

Borislav Petkov (11):
  efi: Simplify EFI_DEBUG
  x86, pageattr: Lookup address in an arbitrary PGD
  x86, pageattr: Add a PGD pagetable populating function
  x86, pageattr: Add a PUD pagetable populating function
  x86, pageattr: Add a PMD pagetable populating function
  x86, pageattr: Add a PTE pagetable populating function
  x86, pageattr: Add a PUD error unwinding path
  x86, pageattr: Add last levels of error path
  x86, cpa: Map in an arbitrary pgd
  EFI: Runtime services virtual mapping
  efi: Check krealloc return value

 Documentation/kernel-parameters.txt  |   6 +
 Documentation/x86/x86_64/mm.txt      |   7 +
 arch/x86/include/asm/efi.h           |  64 +++--
 arch/x86/include/asm/pgtable_types.h |   3 +-
 arch/x86/mm/pageattr.c               | 461 +++++++++++++++++++++++++++++++++--
 arch/x86/platform/efi/efi.c          | 111 ++++++---
 arch/x86/platform/efi/efi_32.c       |   9 +-
 arch/x86/platform/efi/efi_64.c       | 109 +++++++++
 arch/x86/platform/efi/efi_stub_64.S  |  54 ++++
 include/linux/efi.h                  |   1 +
 10 files changed, 755 insertions(+), 70 deletions(-)

-- 
1.8.4

[PATCH 01/11] efi: Simplify EFI_DEBUG

[Borislav Petkov]

From: Borislav Petkov <bp@suse.de>

... and lose one #ifdef .. #endif sandwich.

Signed-off-by: Borislav Petkov <bp@suse.de>
---
 arch/x86/platform/efi/efi.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 1d3372ac9c66..f396163b0402 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -51,7 +51,7 @@
 #include <asm/x86_init.h>
 #include <asm/rtc.h>
 
-#define EFI_DEBUG	1
+#define EFI_DEBUG
 
 #define EFI_MIN_RESERVE 5120
 
@@ -398,9 +398,9 @@ int __init efi_memblock_x86_reserve_range(void)
 	return 0;
 }
 
-#if EFI_DEBUG
 static void __init print_efi_memmap(void)
 {
+#ifdef EFI_DEBUG
 	efi_memory_desc_t *md;
 	void *p;
 	int i;
@@ -415,8 +415,8 @@ static void __init print_efi_memmap(void)
 			md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT),
 			(md->num_pages >> (20 - EFI_PAGE_SHIFT)));
 	}
-}
 #endif  /*  EFI_DEBUG  */
+}
 
 void __init efi_reserve_boot_services(void)
 {
@@ -696,10 +696,7 @@ void __init efi_init(void)
 		x86_platform.set_wallclock = efi_set_rtc_mmss;
 	}
 #endif
-
-#if EFI_DEBUG
 	print_efi_memmap();
-#endif
 }
 
 void __init efi_late_init(void)
-- 
1.8.4

[PATCH 02/11] x86, pageattr: Lookup address in an arbitrary PGD

[Borislav Petkov]

From: Borislav Petkov <bp@suse.de>

This is preparatory work in order to be able to map pages into a
specified PGD and not implicitly and only into init_mm.

Signed-off-by: Borislav Petkov <bp@suse.de>
---
 arch/x86/mm/pageattr.c | 36 ++++++++++++++++++++++++++----------
 1 file changed, 26 insertions(+), 10 deletions(-)

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index bb32480c2d71..c53de62a1170 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -30,6 +30,7 @@
  */
 struct cpa_data {
 	unsigned long	*vaddr;
+	pgd_t		*pgd;
 	pgprot_t	mask_set;
 	pgprot_t	mask_clr;
 	int		numpages;
@@ -322,17 +323,9 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long address,
 	return prot;
 }
 
-/*
- * Lookup the page table entry for a virtual address. Return a pointer
- * to the entry and the level of the mapping.
- *
- * Note: We return pud and pmd either when the entry is marked large
- * or when the present bit is not set. Otherwise we would return a
- * pointer to a nonexisting mapping.
- */
-pte_t *lookup_address(unsigned long address, unsigned int *level)
+static pte_t *__lookup_address_in_pgd(pgd_t *pgd, unsigned long address,
+				      unsigned int *level)
 {
-	pgd_t *pgd = pgd_offset_k(address);
 	pud_t *pud;
 	pmd_t *pmd;
 
@@ -361,8 +354,31 @@ pte_t *lookup_address(unsigned long address, unsigned int *level)
 
 	return pte_offset_kernel(pmd, address);
 }
+
+/*
+ * Lookup the page table entry for a virtual address. Return a pointer
+ * to the entry and the level of the mapping.
+ *
+ * Note: We return pud and pmd either when the entry is marked large
+ * or when the present bit is not set. Otherwise we would return a
+ * pointer to a nonexisting mapping.
+ */
+pte_t *lookup_address(unsigned long address, unsigned int *level)
+{
+        return __lookup_address_in_pgd(pgd_offset_k(address), address, level);
+}
 EXPORT_SYMBOL_GPL(lookup_address);
 
+static pte_t *_lookup_address_cpa(struct cpa_data *cpa, unsigned long address,
+				  unsigned int *level)
+{
+        if (cpa->pgd)
+		return __lookup_address_in_pgd(cpa->pgd + pgd_index(address),
+					       address, level);
+
+        return lookup_address(address, level);
+}
+
 /*
  * This is necessary because __pa() does not work on some
  * kinds of memory, like vmalloc() or the alloc_remap()
-- 
1.8.4

[PATCH 05/11] x86, pageattr: Add a PMD pagetable populating function

[Borislav Petkov]

From: Borislav Petkov <bp@suse.de>

Handle PMD-level mappings the same as PUD ones.

Signed-off-by: Borislav Petkov <bp@suse.de>
---
 arch/x86/mm/pageattr.c | 82 +++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 81 insertions(+), 1 deletion(-)

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 81deca77b871..968398b023c0 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -666,6 +666,16 @@ static int split_large_page(pte_t *kpte, unsigned long address)
 	return 0;
 }
 
+static int alloc_pte_page(pmd_t *pmd)
+{
+	pte_t *pte = (pte_t *)get_zeroed_page(GFP_KERNEL | __GFP_NOTRACK);
+	if (!pte)
+		return -1;
+
+	set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE));
+	return 0;
+}
+
 static int alloc_pmd_page(pud_t *pud)
 {
 	pmd_t *pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL | __GFP_NOTRACK);
@@ -676,7 +686,77 @@ static int alloc_pmd_page(pud_t *pud)
 	return 0;
 }
 
-#define populate_pmd(cpa, start, end, pages, pud, pgprot)	(-1)
+#define populate_pte(cpa, start, end, pages, pmd, pgprot)	do {} while (0)
+
+static int populate_pmd(struct cpa_data *cpa,
+			unsigned long start, unsigned long end,
+			unsigned num_pages, pud_t *pud, pgprot_t pgprot)
+{
+	unsigned int cur_pages = 0;
+	pmd_t *pmd;
+
+	/*
+	 * Not on a 2M boundary?
+	 */
+	if (start & (PMD_SIZE - 1)) {
+		unsigned long pre_end = start + (num_pages << PAGE_SHIFT);
+		unsigned long next_page = (start + PMD_SIZE) & PMD_MASK;
+
+		pre_end   = min_t(unsigned long, pre_end, next_page);
+		cur_pages = (pre_end - start) >> PAGE_SHIFT;
+		cur_pages = min_t(unsigned int, num_pages, cur_pages);
+
+		/*
+		 * Need a PTE page?
+		 */
+		pmd = pmd_offset(pud, start);
+		if (pmd_none(*pmd))
+			if (alloc_pte_page(pmd))
+				return -1;
+
+		populate_pte(cpa, start, pre_end, cur_pages, pmd, pgprot);
+
+		start = pre_end;
+	}
+
+	/*
+	 * We mapped them all?
+	 */
+	if (num_pages == cur_pages)
+		return cur_pages;
+
+	while (end - start >= PMD_SIZE) {
+
+		/*
+		 * We cannot use a 1G page so allocate a PMD page if needed.
+		 */
+		if (pud_none(*pud))
+			if (alloc_pmd_page(pud))
+				return -1;
+
+		pmd = pmd_offset(pud, start);
+
+		set_pmd(pmd, __pmd(cpa->pfn | _PAGE_PSE | massage_pgprot(pgprot)));
+
+		start	  += PMD_SIZE;
+		cpa->pfn  += PMD_SIZE;
+		cur_pages += PMD_SIZE >> PAGE_SHIFT;
+	}
+
+	/*
+	 * Map trailing 4K pages.
+	 */
+	if (start < end) {
+		pmd = pmd_offset(pud, start);
+		if (pmd_none(*pmd))
+			if (alloc_pte_page(pmd))
+				return -1;
+
+		populate_pte(cpa, start, end, num_pages - cur_pages,
+			     pmd, pgprot);
+	}
+	return num_pages;
+}
 
 static int populate_pud(struct cpa_data *cpa, unsigned long start, pgd_t *pgd,
 			pgprot_t pgprot)
-- 
1.8.4

[PATCH 03/11] x86, pageattr: Add a PGD pagetable populating function

[Borislav Petkov]

From: Borislav Petkov <bp-l3A5Bk7waGM@public.gmane.org>

This allocates, if necessary, and populates the corresponding PGD entry
with a PUD page. The next population level is a dummy macro which will
be removed by the next patch and it is added here to keep the patch
small and easily reviewable but not break bisection, at the same time.

Signed-off-by: Borislav Petkov <bp-l3A5Bk7waGM@public.gmane.org>
---
 arch/x86/mm/pageattr.c | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index c53de62a1170..4b47ae0602e1 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -666,6 +666,45 @@ static int split_large_page(pte_t *kpte, unsigned long address)
 	return 0;
 }
 
+#define populate_pud(cpa, addr, pgd, pgprot)	(-1)
+
+/*
+ * Restrictions for kernel page table do not necessarily apply when mapping in
+ * an alternate PGD.
+ */
+static int populate_pgd(struct cpa_data *cpa, unsigned long addr)
+{
+	pgprot_t pgprot = __pgprot(_KERNPG_TABLE);
+	bool allocd_pgd = false;
+	pgd_t *pgd_entry;
+	pud_t *pud = NULL;	/* shut up gcc */
+	int ret;
+
+	pgd_entry = cpa->pgd + pgd_index(addr);
+
+	/*
+	 * Allocate a PUD page and hand it down for mapping.
+	 */
+	if (pgd_none(*pgd_entry)) {
+		pud = (pud_t *)get_zeroed_page(GFP_KERNEL | __GFP_NOTRACK);
+		if (!pud)
+			return -1;
+
+		set_pgd(pgd_entry, __pgd(__pa(pud) | _KERNPG_TABLE));
+		allocd_pgd = true;
+	}
+
+	pgprot_val(pgprot) &= ~pgprot_val(cpa->mask_clr);
+	pgprot_val(pgprot) |=  pgprot_val(cpa->mask_set);
+
+	ret = populate_pud(cpa, addr, pgd_entry, pgprot);
+	if (ret < 0)
+		return ret;
+
+	cpa->numpages = ret;
+	return 0;
+}
+
 static int __cpa_process_fault(struct cpa_data *cpa, unsigned long vaddr,
 			       int primary)
 {
-- 
1.8.4

[PATCH 04/11] x86, pageattr: Add a PUD pagetable populating function

[Borislav Petkov]

From: Borislav Petkov <bp-l3A5Bk7waGM@public.gmane.org>

Add the next level of the pagetable populating function, we handle
chunks around a 1G boundary by mapping them with the lower level
functions - otherwise we use 1G pages for the mappings, thus using as
less amount of pagetable pages as possible.

Signed-off-by: Borislav Petkov <bp-l3A5Bk7waGM@public.gmane.org>
---
 arch/x86/mm/pageattr.c | 87 +++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 86 insertions(+), 1 deletion(-)

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 4b47ae0602e1..81deca77b871 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -666,7 +666,92 @@ static int split_large_page(pte_t *kpte, unsigned long address)
 	return 0;
 }
 
-#define populate_pud(cpa, addr, pgd, pgprot)	(-1)
+static int alloc_pmd_page(pud_t *pud)
+{
+	pmd_t *pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL | __GFP_NOTRACK);
+	if (!pmd)
+		return -1;
+
+	set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
+	return 0;
+}
+
+#define populate_pmd(cpa, start, end, pages, pud, pgprot)	(-1)
+
+static int populate_pud(struct cpa_data *cpa, unsigned long start, pgd_t *pgd,
+			pgprot_t pgprot)
+{
+	pud_t *pud;
+	unsigned long end;
+	int cur_pages = 0;
+
+	end = start + (cpa->numpages << PAGE_SHIFT);
+
+	/*
+	 * Not on a Gb page boundary? => map everything up to it with
+	 * smaller pages.
+	 */
+	if (start & (PUD_SIZE - 1)) {
+		unsigned long pre_end;
+		unsigned long next_page = (start + PUD_SIZE) & PUD_MASK;
+
+		pre_end   = min_t(unsigned long, end, next_page);
+		cur_pages = (pre_end - start) >> PAGE_SHIFT;
+		cur_pages = min_t(int, (int)cpa->numpages, cur_pages);
+
+		pud = pud_offset(pgd, start);
+
+		/*
+		 * Need a PMD page?
+		 */
+		if (pud_none(*pud))
+			if (alloc_pmd_page(pud))
+				return -1;
+
+		cur_pages = populate_pmd(cpa, start, pre_end, cur_pages,
+					 pud, pgprot);
+		if (cur_pages < 0)
+			return cur_pages;
+
+		start = pre_end;
+	}
+
+	/* We mapped them all? */
+	if (cpa->numpages == cur_pages)
+		return cur_pages;
+
+	pud = pud_offset(pgd, start);
+
+	/*
+	 * Map everything starting from the Gb boundary, possibly with 1G pages
+	 */
+	while (end - start >= PUD_SIZE) {
+		set_pud(pud, __pud(cpa->pfn | _PAGE_PSE | massage_pgprot(pgprot)));
+
+		start	  += PUD_SIZE;
+		cpa->pfn  += PUD_SIZE;
+		cur_pages += PUD_SIZE >> PAGE_SHIFT;
+		pud++;
+	}
+
+	/* Map trailing leftover */
+	if (start < end) {
+		int tmp;
+
+		pud = pud_offset(pgd, start);
+		if (pud_none(*pud))
+			if (alloc_pmd_page(pud))
+				return -1;
+
+		tmp = populate_pmd(cpa, start, end, cpa->numpages - cur_pages,
+				   pud, pgprot);
+		if (tmp < 0)
+			return cur_pages;
+
+		cur_pages += tmp;
+	}
+	return cur_pages;
+}
 
 /*
  * Restrictions for kernel page table do not necessarily apply when mapping in
-- 
1.8.4

[PATCH 06/11] x86, pageattr: Add a PTE pagetable populating function

[Borislav Petkov]

From: Borislav Petkov <bp-l3A5Bk7waGM@public.gmane.org>

Handle last level by unconditionally writing the PTEs into the PTE page
while paying attention to the NX bit.

Signed-off-by: Borislav Petkov <bp-l3A5Bk7waGM@public.gmane.org>
---
 arch/x86/mm/pageattr.c | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 968398b023c0..2a1308a8c072 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -686,7 +686,27 @@ static int alloc_pmd_page(pud_t *pud)
 	return 0;
 }
 
-#define populate_pte(cpa, start, end, pages, pmd, pgprot)	do {} while (0)
+static void populate_pte(struct cpa_data *cpa,
+			 unsigned long start, unsigned long end,
+			 unsigned num_pages, pmd_t *pmd, pgprot_t pgprot)
+{
+	pte_t *pte;
+
+	pte = pte_offset_kernel(pmd, start);
+
+	while (num_pages-- && start < end) {
+
+		/* deal with the NX bit */
+		if (!(pgprot_val(pgprot) & _PAGE_NX))
+			cpa->pfn &= ~_PAGE_NX;
+
+		set_pte(pte, pfn_pte(cpa->pfn >> PAGE_SHIFT, pgprot));
+
+		start	 += PAGE_SIZE;
+		cpa->pfn += PAGE_SIZE;
+		pte++;
+	}
+}
 
 static int populate_pmd(struct cpa_data *cpa,
 			unsigned long start, unsigned long end,
-- 
1.8.4

[PATCH 07/11] x86, pageattr: Add a PUD error unwinding path

[Borislav Petkov]

From: Borislav Petkov <bp-l3A5Bk7waGM@public.gmane.org>

In case we encounter an error during the mapping of a region, we want to
unwind what we've established so far exactly the way we did the mapping.
This is the PUD part kept deliberately small for easier review.

Signed-off-by: Borislav Petkov <bp-l3A5Bk7waGM@public.gmane.org>
---
 arch/x86/mm/pageattr.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 58 insertions(+), 2 deletions(-)

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 2a1308a8c072..1cbdbbc35b47 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -666,6 +666,51 @@ static int split_large_page(pte_t *kpte, unsigned long address)
 	return 0;
 }
 
+#define unmap_pmd_range(pud, start, pre_end)		do {} while (0)
+
+static void unmap_pud_range(pgd_t *pgd, unsigned long start, unsigned long end)
+{
+	pud_t *pud = pud_offset(pgd, start);
+
+	/*
+	 * Not on a GB page boundary?
+	 */
+	if (start & (PUD_SIZE - 1)) {
+		unsigned long next_page = (start + PUD_SIZE) & PUD_MASK;
+		unsigned long pre_end	= min_t(unsigned long, end, next_page);
+
+		unmap_pmd_range(pud, start, pre_end);
+
+		start = pre_end;
+		pud++;
+	}
+
+	/*
+	 * Try to unmap in 1G chunks?
+	 */
+	while (end - start >= PUD_SIZE) {
+
+		if (pud_large(*pud))
+			pud_clear(pud);
+		else
+			unmap_pmd_range(pud, start, start + PUD_SIZE);
+
+		start += PUD_SIZE;
+		pud++;
+	}
+
+	/*
+	 * 2M leftovers?
+	 */
+	if (start < end)
+		unmap_pmd_range(pud, start, end);
+
+	/*
+	 * No need to try to free the PUD page because we'll free it in
+	 * populate_pgd's error path
+	 */
+}
+
 static int alloc_pte_page(pmd_t *pmd)
 {
 	pte_t *pte = (pte_t *)get_zeroed_page(GFP_KERNEL | __GFP_NOTRACK);
@@ -883,9 +928,20 @@ static int populate_pgd(struct cpa_data *cpa, unsigned long addr)
 	pgprot_val(pgprot) |=  pgprot_val(cpa->mask_set);
 
 	ret = populate_pud(cpa, addr, pgd_entry, pgprot);
-	if (ret < 0)
-		return ret;
+	if (ret < 0) {
+		unmap_pud_range(pgd_entry, addr,
+				addr + (cpa->numpages << PAGE_SHIFT));
 
+		if (allocd_pgd) {
+			/*
+			 * If I allocated this PUD page, I can just as well
+			 * free it in this error path.
+			 */
+			pgd_clear(pgd_entry);
+			free_page((unsigned long)pud);
+		}
+		return ret;
+	}
 	cpa->numpages = ret;
 	return 0;
 }
-- 
1.8.4

[PATCH 08/11] x86, pageattr: Add last levels of error path

[Borislav Petkov]

From: Borislav Petkov <bp-l3A5Bk7waGM@public.gmane.org>

We try to free the pagetable pages once we've unmapped our portion.

Signed-off-by: Borislav Petkov <bp-l3A5Bk7waGM@public.gmane.org>
---
 arch/x86/mm/pageattr.c | 94 +++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 93 insertions(+), 1 deletion(-)

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 1cbdbbc35b47..db8ace29514f 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -666,7 +666,99 @@ static int split_large_page(pte_t *kpte, unsigned long address)
 	return 0;
 }
 
-#define unmap_pmd_range(pud, start, pre_end)		do {} while (0)
+static bool try_to_free_pte_page(pte_t *pte)
+{
+	int i;
+
+	for (i = 0; i < PTRS_PER_PTE; i++)
+		if (!pte_none(pte[i]))
+			return false;
+
+	free_page((unsigned long)pte);
+	return true;
+}
+
+static bool try_to_free_pmd_page(pmd_t *pmd)
+{
+	int i;
+
+	for (i = 0; i < PTRS_PER_PMD; i++)
+		if (!pmd_none(pmd[i]))
+			return false;
+
+	free_page((unsigned long)pmd);
+	return true;
+}
+
+static bool unmap_pte_range(pmd_t *pmd, unsigned long start, unsigned long end)
+{
+	pte_t *pte = pte_offset_kernel(pmd, start);
+
+	while (start < end) {
+		set_pte(pte, __pte(0));
+
+		start += PAGE_SIZE;
+		pte++;
+	}
+
+	if (try_to_free_pte_page((pte_t *)pmd_page_vaddr(*pmd))) {
+		pmd_clear(pmd);
+		return true;
+	}
+	return false;
+}
+
+static void __unmap_pmd_range(pud_t *pud, pmd_t *pmd,
+			      unsigned long start, unsigned long end)
+{
+	if (unmap_pte_range(pmd, start, end))
+		if (try_to_free_pmd_page((pmd_t *)pud_page_vaddr(*pud)))
+			pud_clear(pud);
+}
+
+static void unmap_pmd_range(pud_t *pud, unsigned long start, unsigned long end)
+{
+	pmd_t *pmd = pmd_offset(pud, start);
+
+	/*
+	 * Not on a 2MB page boundary?
+	 */
+	if (start & (PMD_SIZE - 1)) {
+		unsigned long next_page = (start + PMD_SIZE) & PMD_MASK;
+		unsigned long pre_end = min_t(unsigned long, end, next_page);
+
+		__unmap_pmd_range(pud, pmd, start, pre_end);
+
+		start = pre_end;
+		pmd++;
+	}
+
+	/*
+	 * Try to unmap in 2M chunks.
+	 */
+	while (end - start >= PMD_SIZE) {
+		if (pmd_large(*pmd))
+			pmd_clear(pmd);
+		else
+			__unmap_pmd_range(pud, pmd, start, start + PMD_SIZE);
+
+		start += PMD_SIZE;
+		pmd++;
+	}
+
+	/*
+	 * 4K leftovers?
+	 */
+	if (start < end)
+		return __unmap_pmd_range(pud, pmd, start, end);
+
+	/*
+	 * Try again to free the PMD page if haven't succeeded above.
+	 */
+	if (!pud_none(*pud))
+		if (try_to_free_pmd_page((pmd_t *)pud_page_vaddr(*pud)))
+			pud_clear(pud);
+}
 
 static void unmap_pud_range(pgd_t *pgd, unsigned long start, unsigned long end)
 {
-- 
1.8.4

[PATCH 09/11] x86, cpa: Map in an arbitrary pgd

[Borislav Petkov]

From: Borislav Petkov <bp@suse.de>

Add the ability to map pages in an arbitrary pgd. This wires in the
remaining stuff so that there's a new interface with which you can map a
region into an arbitrary PGD.

Signed-off-by: Borislav Petkov <bp@suse.de>
---
 arch/x86/mm/pageattr.c | 53 +++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 46 insertions(+), 7 deletions(-)

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index db8ace29514f..b3b19f46c016 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -453,7 +453,7 @@ try_preserve_large_page(pte_t *kpte, unsigned long address,
 	 * Check for races, another CPU might have split this page
 	 * up already:
 	 */
-	tmp = lookup_address(address, &level);
+	tmp = _lookup_address_cpa(cpa, address, &level);
 	if (tmp != kpte)
 		goto out_unlock;
 
@@ -559,7 +559,8 @@ out_unlock:
 }
 
 static int
-__split_large_page(pte_t *kpte, unsigned long address, struct page *base)
+__split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address,
+		   struct page *base)
 {
 	pte_t *pbase = (pte_t *)page_address(base);
 	unsigned long pfn, pfninc = 1;
@@ -572,7 +573,7 @@ __split_large_page(pte_t *kpte, unsigned long address, struct page *base)
 	 * Check for races, another CPU might have split this page
 	 * up for us already:
 	 */
-	tmp = lookup_address(address, &level);
+	tmp = _lookup_address_cpa(cpa, address, &level);
 	if (tmp != kpte) {
 		spin_unlock(&pgd_lock);
 		return 1;
@@ -648,7 +649,8 @@ __split_large_page(pte_t *kpte, unsigned long address, struct page *base)
 	return 0;
 }
 
-static int split_large_page(pte_t *kpte, unsigned long address)
+static int split_large_page(struct cpa_data *cpa, pte_t *kpte,
+			    unsigned long address)
 {
 	struct page *base;
 
@@ -660,7 +662,7 @@ static int split_large_page(pte_t *kpte, unsigned long address)
 	if (!base)
 		return -ENOMEM;
 
-	if (__split_large_page(kpte, address, base))
+	if (__split_large_page(cpa, kpte, address, base))
 		__free_page(base);
 
 	return 0;
@@ -1041,6 +1043,9 @@ static int populate_pgd(struct cpa_data *cpa, unsigned long addr)
 static int __cpa_process_fault(struct cpa_data *cpa, unsigned long vaddr,
 			       int primary)
 {
+	if (cpa->pgd)
+		return populate_pgd(cpa, vaddr);
+
 	/*
 	 * Ignore all non primary paths.
 	 */
@@ -1085,7 +1090,7 @@ static int __change_page_attr(struct cpa_data *cpa, int primary)
 	else
 		address = *cpa->vaddr;
 repeat:
-	kpte = lookup_address(address, &level);
+	kpte = _lookup_address_cpa(cpa, address, &level);
 	if (!kpte)
 		return __cpa_process_fault(cpa, address, primary);
 
@@ -1149,7 +1154,7 @@ repeat:
 	/*
 	 * We have to split the large page:
 	 */
-	err = split_large_page(kpte, address);
+	err = split_large_page(cpa, kpte, address);
 	if (!err) {
 		/*
 	 	 * Do a global flush tlb after splitting the large page
@@ -1298,6 +1303,8 @@ static int change_page_attr_set_clr(unsigned long *addr, int numpages,
 	int ret, cache, checkalias;
 	unsigned long baddr = 0;
 
+	memset(&cpa, 0, sizeof(cpa));
+
 	/*
 	 * Check, if we are requested to change a not supported
 	 * feature:
@@ -1744,6 +1751,7 @@ static int __set_pages_p(struct page *page, int numpages)
 {
 	unsigned long tempaddr = (unsigned long) page_address(page);
 	struct cpa_data cpa = { .vaddr = &tempaddr,
+				.pgd = NULL,
 				.numpages = numpages,
 				.mask_set = __pgprot(_PAGE_PRESENT | _PAGE_RW),
 				.mask_clr = __pgprot(0),
@@ -1762,6 +1770,7 @@ static int __set_pages_np(struct page *page, int numpages)
 {
 	unsigned long tempaddr = (unsigned long) page_address(page);
 	struct cpa_data cpa = { .vaddr = &tempaddr,
+				.pgd = NULL,
 				.numpages = numpages,
 				.mask_set = __pgprot(0),
 				.mask_clr = __pgprot(_PAGE_PRESENT | _PAGE_RW),
@@ -1822,6 +1831,36 @@ bool kernel_page_present(struct page *page)
 
 #endif /* CONFIG_DEBUG_PAGEALLOC */
 
+int kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, unsigned long address,
+			    unsigned numpages, unsigned long page_flags)
+{
+	int retval = -EINVAL;
+
+	struct cpa_data cpa = {
+		.vaddr = &address,
+		.pfn = pfn,
+		.pgd = pgd,
+		.numpages = numpages,
+		.mask_set = __pgprot(0),
+		.mask_clr = __pgprot(0),
+		.flags = 0,
+	};
+
+	if (!(__supported_pte_mask & _PAGE_NX))
+		goto out;
+
+	if (!(page_flags & _PAGE_NX))
+		cpa.mask_clr = __pgprot(_PAGE_NX);
+
+	cpa.mask_set = __pgprot(_PAGE_PRESENT | page_flags);
+
+	retval = __change_page_attr_set_clr(&cpa, 0);
+	__flush_tlb_all();
+
+out:
+	return retval;
+}
+
 /*
  * The testcases use internal knowledge of the implementation that shouldn't
  * be exposed to the rest of the kernel. Include these directly here.
-- 
1.8.4

[PATCH 10/11] EFI: Runtime services virtual mapping

[Borislav Petkov]

From: Borislav Petkov <bp@suse.de>

We map the EFI regions needed for runtime services non-contiguously,
with preserved alignment on virtual addresses starting from -4G down
for a total max space of 64G. This way, we provide for stable runtime
services addresses across kernels so that a kexec'd kernel can still use
them.

Thus, they're mapped in a separate pagetable so that we don't pollute
the kernel namespace.

Add an efi= kernel command line parameter for passing miscellaneous
options and chicken bits from the command line.

While at it, add 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...).

Also, add the UEFI RT VA space to Documentation/x86/x86_64/mm.txt.

Signed-off-by: Borislav Petkov <bp@suse.de>
---
 Documentation/kernel-parameters.txt  |   6 ++
 Documentation/x86/x86_64/mm.txt      |   7 +++
 arch/x86/include/asm/efi.h           |  64 ++++++++++++++------
 arch/x86/include/asm/pgtable_types.h |   3 +-
 arch/x86/platform/efi/efi.c          |  94 +++++++++++++++++++++---------
 arch/x86/platform/efi/efi_32.c       |   9 ++-
 arch/x86/platform/efi/efi_64.c       | 109 +++++++++++++++++++++++++++++++++++
 arch/x86/platform/efi/efi_stub_64.S  |  54 +++++++++++++++++
 include/linux/efi.h                  |   1 +
 9 files changed, 300 insertions(+), 47 deletions(-)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 7f9d4f53882c..57603f2d7e86 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -833,6 +833,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 	edd=		[EDD]
 			Format: {"off" | "on" | "skip[mbr]"}
 
+	efi=		[EFI]
+			Format: { "old_map" }
+			old_map [X86-64]: switch to the old ioremap-based EFI
+			runtime services mapping. 32-bit still uses this one by
+			default.
+
 	efi_no_storage_paranoia [EFI; X86]
 			Using this parameter you can use more than 50% of
 			your efi variable storage. Use this parameter only if
diff --git a/Documentation/x86/x86_64/mm.txt b/Documentation/x86/x86_64/mm.txt
index 881582f75c9c..c584a51add15 100644
--- a/Documentation/x86/x86_64/mm.txt
+++ b/Documentation/x86/x86_64/mm.txt
@@ -28,4 +28,11 @@ reference.
 Current X86-64 implementations only support 40 bits of address space,
 but we support up to 46 bits. This expands into MBZ space in the page tables.
 
+->trampoline_pgd:
+
+We map EFI runtime services in the aforementioned PGD in the virtual
+range of 64Gb (arbitrarily set, can be raised if needed)
+
+0xffffffef00000000 - 0xffffffff00000000
+
 -Andi Kleen, Jul 2004
diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
index 0062a0125041..ee86179f8ca7 100644
--- a/arch/x86/include/asm/efi.h
+++ b/arch/x86/include/asm/efi.h
@@ -1,6 +1,24 @@
 #ifndef _ASM_X86_EFI_H
 #define _ASM_X86_EFI_H
 
+/*
+ * We map the EFI regions needed for runtime services non-contiguously,
+ * with preserved alignment on virtual addresses starting from -4G down
+ * for a total max space of 64G. This way, we provide for stable runtime
+ * services addresses across kernels so that a kexec'd kernel can still
+ * use them.
+ *
+ * This is the main reason why we're doing stable VA mappings for RT
+ * services.
+ *
+ * This flag is used in conjuction 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...).
+ */
+#define EFI_OLD_MEMMAP		EFI_ARCH_1
+
 #ifdef CONFIG_X86_32
 
 #define EFI_LOADER_SIGNATURE	"EL32"
@@ -69,24 +87,31 @@ extern u64 efi_call6(void *fp, u64 arg1, u64 arg2, u64 arg3,
 	efi_call6((f), (u64)(a1), (u64)(a2), (u64)(a3),		\
 		  (u64)(a4), (u64)(a5), (u64)(a6))
 
+#define _efi_call_virtX(x, f, ...)					\
+({									\
+	efi_status_t __s;						\
+									\
+	efi_sync_low_kernel_mappings();					\
+	preempt_disable();						\
+	__s = efi_call##x((void *)efi.systab->runtime->f, __VA_ARGS__);	\
+	preempt_enable();						\
+	__s;								\
+})
+
 #define efi_call_virt0(f)				\
-	efi_call0((efi.systab->runtime->f))
-#define efi_call_virt1(f, a1)					\
-	efi_call1((efi.systab->runtime->f), (u64)(a1))
-#define efi_call_virt2(f, a1, a2)					\
-	efi_call2((efi.systab->runtime->f), (u64)(a1), (u64)(a2))
-#define efi_call_virt3(f, a1, a2, a3)					\
-	efi_call3((efi.systab->runtime->f), (u64)(a1), (u64)(a2), \
-		  (u64)(a3))
-#define efi_call_virt4(f, a1, a2, a3, a4)				\
-	efi_call4((efi.systab->runtime->f), (u64)(a1), (u64)(a2), \
-		  (u64)(a3), (u64)(a4))
-#define efi_call_virt5(f, a1, a2, a3, a4, a5)				\
-	efi_call5((efi.systab->runtime->f), (u64)(a1), (u64)(a2), \
-		  (u64)(a3), (u64)(a4), (u64)(a5))
-#define efi_call_virt6(f, a1, a2, a3, a4, a5, a6)			\
-	efi_call6((efi.systab->runtime->f), (u64)(a1), (u64)(a2), \
-		  (u64)(a3), (u64)(a4), (u64)(a5), (u64)(a6))
+	_efi_call_virtX(0, f)
+#define efi_call_virt1(f, a1)				\
+	_efi_call_virtX(1, f, (u64)(a1))
+#define efi_call_virt2(f, a1, a2)			\
+	_efi_call_virtX(2, f, (u64)(a1), (u64)(a2))
+#define efi_call_virt3(f, a1, a2, a3)			\
+	_efi_call_virtX(3, f, (u64)(a1), (u64)(a2), (u64)(a3))
+#define efi_call_virt4(f, a1, a2, a3, a4)		\
+	_efi_call_virtX(4, f, (u64)(a1), (u64)(a2), (u64)(a3), (u64)(a4))
+#define efi_call_virt5(f, a1, a2, a3, a4, a5)		\
+	_efi_call_virtX(5, f, (u64)(a1), (u64)(a2), (u64)(a3), (u64)(a4), (u64)(a5))
+#define efi_call_virt6(f, a1, a2, a3, a4, a5, a6)	\
+	_efi_call_virtX(6, f, (u64)(a1), (u64)(a2), (u64)(a3), (u64)(a4), (u64)(a5), (u64)(a6))
 
 extern void __iomem *efi_ioremap(unsigned long addr, unsigned long size,
 				 u32 type, u64 attribute);
@@ -95,12 +120,17 @@ extern void __iomem *efi_ioremap(unsigned long addr, unsigned long size,
 
 extern int add_efi_memmap;
 extern unsigned long x86_efi_facility;
+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_map_region(efi_memory_desc_t *md);
+extern void efi_sync_low_kernel_mappings(void);
+extern void efi_setup_page_tables(void);
+extern void __init old_map_region(efi_memory_desc_t *md);
 
 #ifdef CONFIG_EFI
 
diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index f4843e031131..028e28b6fc2c 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -379,7 +379,8 @@ static inline void update_page_count(int level, unsigned long pages) { }
  */
 extern pte_t *lookup_address(unsigned long address, unsigned int *level);
 extern phys_addr_t slow_virt_to_phys(void *__address);
-
+extern int kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, unsigned long address,
+				   unsigned numpages, unsigned long page_flags);
 #endif	/* !__ASSEMBLY__ */
 
 #endif /* _ASM_X86_PGTABLE_DEFS_H */
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index f396163b0402..b453069236fd 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -12,6 +12,8 @@
  *	Bibo Mao <bibo.mao@intel.com>
  *	Chandramouli Narayanan <mouli@linux.intel.com>
  *	Huang Ying <ying.huang@intel.com>
+ * Copyright (C) 2013 SuSE Labs
+ *	Borislav Petkov <bp@suse.de> - runtime services VA mapping
  *
  * Copied from efi_32.c to eliminate the duplicated code between EFI
  * 32/64 support code. --ying 2007-10-26
@@ -745,21 +747,56 @@ void efi_memory_uc(u64 addr, unsigned long size)
 	set_memory_uc(addr, npages);
 }
 
+void __init old_map_region(efi_memory_desc_t *md)
+{
+	u64 start_pfn, end_pfn, end;
+	unsigned long size;
+	void *va;
+
+	start_pfn = PFN_DOWN(md->phys_addr);
+	size	  = md->num_pages << PAGE_SHIFT;
+	end	  = md->phys_addr + size;
+	end_pfn   = PFN_UP(end);
+
+	if (pfn_range_is_mapped(start_pfn, end_pfn)) {
+		va = __va(md->phys_addr);
+
+		if (!(md->attribute & EFI_MEMORY_WB))
+			efi_memory_uc((u64)(unsigned long)va, size);
+	} else
+		va = efi_ioremap(md->phys_addr, size,
+				 md->type, md->attribute);
+
+	md->virt_addr = (u64) (unsigned long) va;
+	if (!va)
+		pr_err("ioremap of 0x%llX failed!\n",
+		       (unsigned long long)md->phys_addr);
+}
+
 /*
  * This function will switch the EFI runtime services to virtual mode.
- * Essentially, look through the EFI memmap and map every region that
- * has the runtime attribute bit set in its memory descriptor and update
- * that memory descriptor with the virtual address obtained from ioremap().
- * This enables the runtime services to be called without having to
+ * Essentially, we look through the EFI memmap and map every region that
+ * has the runtime attribute bit set in its memory descriptor into the
+ * ->trampoline_pgd page table using a top-down VA allocation scheme.
+ *
+ * The old method which used to update that memory descriptor with the
+ * virtual address obtained from ioremap() is still supported when the
+ * kernel is booted with efi=old_map on its command line. Same old
+ * method enabled the runtime services to be called without having to
  * thunk back into physical mode for every invocation.
+ *
+ * The new method does a pagetable switch in a preemption-safe manner
+ * so that we're in a different address space when calling a runtime
+ * function. For function arguments passing we do copy the PGDs of the
+ * kernel page table into ->trampoline_pgd prior to each call.
  */
 void __init efi_enter_virtual_mode(void)
 {
 	efi_memory_desc_t *md, *prev_md = NULL;
-	efi_status_t status;
+	void *p, *new_memmap = NULL;
 	unsigned long size;
-	u64 end, systab, start_pfn, end_pfn;
-	void *p, *va, *new_memmap = NULL;
+	efi_status_t status;
+	u64 end, systab;
 	int count = 0;
 
 	efi.systab = NULL;
@@ -768,7 +805,6 @@ void __init efi_enter_virtual_mode(void)
 	 * We don't do virtual mode, since we don't do runtime services, on
 	 * non-native EFI
 	 */
-
 	if (!efi_is_native()) {
 		efi_unmap_memmap();
 		return;
@@ -799,6 +835,7 @@ void __init efi_enter_virtual_mode(void)
 			continue;
 		}
 		prev_md = md;
+
 	}
 
 	for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
@@ -808,33 +845,18 @@ void __init efi_enter_virtual_mode(void)
 		    md->type != EFI_BOOT_SERVICES_DATA)
 			continue;
 
+		efi_map_region(md);
+
 		size = md->num_pages << EFI_PAGE_SHIFT;
 		end = md->phys_addr + size;
 
-		start_pfn = PFN_DOWN(md->phys_addr);
-		end_pfn = PFN_UP(end);
-		if (pfn_range_is_mapped(start_pfn, end_pfn)) {
-			va = __va(md->phys_addr);
-
-			if (!(md->attribute & EFI_MEMORY_WB))
-				efi_memory_uc((u64)(unsigned long)va, size);
-		} else
-			va = efi_ioremap(md->phys_addr, size,
-					 md->type, md->attribute);
-
-		md->virt_addr = (u64) (unsigned long) va;
-
-		if (!va) {
-			pr_err("ioremap of 0x%llX failed!\n",
-			       (unsigned long long)md->phys_addr);
-			continue;
-		}
-
 		systab = (u64) (unsigned long) efi_phys.systab;
 		if (md->phys_addr <= systab && systab < end) {
 			systab += md->virt_addr - md->phys_addr;
+
 			efi.systab = (efi_system_table_t *) (unsigned long) systab;
 		}
+
 		new_memmap = krealloc(new_memmap,
 				      (count + 1) * memmap.desc_size,
 				      GFP_KERNEL);
@@ -845,6 +867,9 @@ void __init efi_enter_virtual_mode(void)
 
 	BUG_ON(!efi.systab);
 
+	efi_setup_page_tables();
+	efi_sync_low_kernel_mappings();
+
 	status = phys_efi_set_virtual_address_map(
 		memmap.desc_size * count,
 		memmap.desc_size,
@@ -877,7 +902,8 @@ void __init efi_enter_virtual_mode(void)
 	efi.query_variable_info = virt_efi_query_variable_info;
 	efi.update_capsule = virt_efi_update_capsule;
 	efi.query_capsule_caps = virt_efi_query_capsule_caps;
-	if (__supported_pte_mask & _PAGE_NX)
+
+	if (efi_enabled(EFI_OLD_MEMMAP) && (__supported_pte_mask & _PAGE_NX))
 		runtime_code_page_mkexec();
 
 	kfree(new_memmap);
@@ -1007,3 +1033,15 @@ efi_status_t efi_query_variable_store(u32 attributes, unsigned long size)
 	return EFI_SUCCESS;
 }
 EXPORT_SYMBOL_GPL(efi_query_variable_store);
+
+static int __init parse_efi_cmdline(char *str)
+{
+	if (*str == '=')
+		str++;
+
+	if (!strncmp(str, "old_map", 7))
+		set_bit(EFI_OLD_MEMMAP, &x86_efi_facility);
+
+	return 0;
+}
+early_param("efi", parse_efi_cmdline);
diff --git a/arch/x86/platform/efi/efi_32.c b/arch/x86/platform/efi/efi_32.c
index 40e446941dd7..e94557cf5487 100644
--- a/arch/x86/platform/efi/efi_32.c
+++ b/arch/x86/platform/efi/efi_32.c
@@ -37,9 +37,16 @@
  * claim EFI runtime service handler exclusively and to duplicate a memory in
  * low memory space say 0 - 3G.
  */
-
 static unsigned long efi_rt_eflags;
 
+void efi_sync_low_kernel_mappings(void) {}
+void efi_setup_page_tables(void) {}
+
+void __init efi_map_region(efi_memory_desc_t *md)
+{
+	old_map_region(md);
+}
+
 void efi_call_phys_prelog(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 39a0e7f1f0a3..bf286c386d33 100644
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -38,10 +38,28 @@
 #include <asm/efi.h>
 #include <asm/cacheflush.h>
 #include <asm/fixmap.h>
+#include <asm/realmode.h>
 
 static pgd_t *save_pgd __initdata;
 static unsigned long efi_flags __initdata;
 
+/*
+ * We allocate runtime services regions bottom-up, starting from -4G, i.e.
+ * 0xffff_ffff_0000_0000 and limit EFI VA mapping space to 64G.
+ */
+static u64 efi_va	= -4 * (1UL << 30);
+#define EFI_VA_END	(-68 * (1UL << 30))
+
+/*
+ * Scratch space used for switching the pagetable in the EFI stub
+ */
+struct efi_scratch {
+	u64 r15;
+	u64 prev_cr3;
+	pgd_t *efi_pgt;
+	bool use_pgd;
+};
+
 static void __init early_code_mapping_set_exec(int executable)
 {
 	efi_memory_desc_t *md;
@@ -65,6 +83,9 @@ void __init efi_call_phys_prelog(void)
 	int pgd;
 	int n_pgds;
 
+	if (!efi_enabled(EFI_OLD_MEMMAP))
+		return;
+
 	early_code_mapping_set_exec(1);
 	local_irq_save(efi_flags);
 
@@ -86,6 +107,10 @@ void __init efi_call_phys_epilog(void)
 	 */
 	int pgd;
 	int n_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT) , PGDIR_SIZE);
+
+	if (!efi_enabled(EFI_OLD_MEMMAP))
+		return;
+
 	for (pgd = 0; pgd < n_pgds; pgd++)
 		set_pgd(pgd_offset_k(pgd * PGDIR_SIZE), save_pgd[pgd]);
 	kfree(save_pgd);
@@ -94,6 +119,90 @@ void __init efi_call_phys_epilog(void)
 	early_code_mapping_set_exec(0);
 }
 
+/*
+ * Add low kernel mappings for passing arguments to EFI functions.
+ */
+void efi_sync_low_kernel_mappings(void)
+{
+	unsigned num_pgds;
+	pgd_t *pgd = (pgd_t *)__va(real_mode_header->trampoline_pgd);
+
+	if (efi_enabled(EFI_OLD_MEMMAP))
+		return;
+
+	num_pgds = pgd_index(MODULES_END - 1) - pgd_index(PAGE_OFFSET);
+
+	memcpy(pgd + pgd_index(PAGE_OFFSET),
+		init_mm.pgd + pgd_index(PAGE_OFFSET),
+		sizeof(pgd_t) * num_pgds);
+}
+
+void efi_setup_page_tables(void)
+{
+	efi_scratch.efi_pgt = (pgd_t *)(unsigned long)real_mode_header->trampoline_pgd;
+
+	if (!efi_enabled(EFI_OLD_MEMMAP))
+		efi_scratch.use_pgd = true;
+}
+
+static void __init __map_region(efi_memory_desc_t *md, u64 va)
+{
+	pgd_t *pgd = (pgd_t *)__va(real_mode_header->trampoline_pgd);
+	unsigned long pf = 0, size;
+	u64 end;
+
+	if (!(md->attribute & EFI_MEMORY_WB))
+		pf |= _PAGE_PCD;
+
+	size = md->num_pages << PAGE_SHIFT;
+	end  = va + size;
+
+	if (kernel_map_pages_in_pgd(pgd, md->phys_addr, va, md->num_pages, pf))
+		pr_warn("Error mapping PA 0x%llx -> VA 0x%llx!\n",
+			   md->phys_addr, va);
+}
+
+void __init efi_map_region(efi_memory_desc_t *md)
+{
+	unsigned long size = md->num_pages << PAGE_SHIFT;
+	u64 pa = md->phys_addr;
+
+	if (efi_enabled(EFI_OLD_MEMMAP))
+		return old_map_region(md);
+
+	/*
+	 * Make sure the 1:1 mappings are present as a catch-all for b0rked
+	 * firmware which doesn't update all internal pointers after switching
+	 * to virtual mode and would otherwise crap on us.
+	 */
+	__map_region(md, md->phys_addr);
+
+	efi_va -= size;
+
+	/* Is PA 2M-aligned? */
+	if (!(pa & (PMD_SIZE - 1))) {
+		efi_va &= PMD_MASK;
+	} else {
+		u64 pa_offset = pa & (PMD_SIZE - 1);
+		u64 prev_va = efi_va;
+
+		/* get us the same offset within this 2M page */
+		efi_va = (efi_va & PMD_MASK) + pa_offset;
+
+		if (efi_va > prev_va)
+			efi_va -= PMD_SIZE;
+	}
+
+	if (efi_va < EFI_VA_END) {
+		pr_warn(FW_WARN "VA address range overflow!\n");
+		return;
+	}
+
+	/* Do the VA map */
+	__map_region(md, efi_va);
+	md->virt_addr = efi_va;
+}
+
 void __iomem *__init efi_ioremap(unsigned long phys_addr, unsigned long size,
 				 u32 type, u64 attribute)
 {
diff --git a/arch/x86/platform/efi/efi_stub_64.S b/arch/x86/platform/efi/efi_stub_64.S
index 4c07ccab8146..88073b140298 100644
--- a/arch/x86/platform/efi/efi_stub_64.S
+++ b/arch/x86/platform/efi/efi_stub_64.S
@@ -34,10 +34,47 @@
 	mov %rsi, %cr0;			\
 	mov (%rsp), %rsp
 
+	/* stolen from gcc */
+	.macro FLUSH_TLB_ALL
+	movq %r15, efi_scratch(%rip)
+	movq %r14, efi_scratch+8(%rip)
+	movq %cr4, %r15
+	movq %r15, %r14
+	andb $0x7f, %r14b
+	movq %r14, %cr4
+	movq %r15, %cr4
+	movq efi_scratch+8(%rip), %r14
+	movq efi_scratch(%rip), %r15
+	.endm
+
+	.macro SWITCH_PGT
+	cmpb $0, efi_scratch+24(%rip)
+	je 1f
+	movq %r15, efi_scratch(%rip)		# r15
+	# save previous CR3
+	movq %cr3, %r15
+	movq %r15, efi_scratch+8(%rip)		# prev_cr3
+	movq efi_scratch+16(%rip), %r15		# EFI pgt
+	movq %r15, %cr3
+	1:
+	.endm
+
+	.macro RESTORE_PGT
+	cmpb $0, efi_scratch+24(%rip)
+	je 2f
+	movq efi_scratch+8(%rip), %r15
+	movq %r15, %cr3
+	movq efi_scratch(%rip), %r15
+	FLUSH_TLB_ALL
+	2:
+	.endm
+
 ENTRY(efi_call0)
 	SAVE_XMM
 	subq $32, %rsp
+	SWITCH_PGT
 	call *%rdi
+	RESTORE_PGT
 	addq $32, %rsp
 	RESTORE_XMM
 	ret
@@ -47,7 +84,9 @@ ENTRY(efi_call1)
 	SAVE_XMM
 	subq $32, %rsp
 	mov  %rsi, %rcx
+	SWITCH_PGT
 	call *%rdi
+	RESTORE_PGT
 	addq $32, %rsp
 	RESTORE_XMM
 	ret
@@ -57,7 +96,9 @@ ENTRY(efi_call2)
 	SAVE_XMM
 	subq $32, %rsp
 	mov  %rsi, %rcx
+	SWITCH_PGT
 	call *%rdi
+	RESTORE_PGT
 	addq $32, %rsp
 	RESTORE_XMM
 	ret
@@ -68,7 +109,9 @@ ENTRY(efi_call3)
 	subq $32, %rsp
 	mov  %rcx, %r8
 	mov  %rsi, %rcx
+	SWITCH_PGT
 	call *%rdi
+	RESTORE_PGT
 	addq $32, %rsp
 	RESTORE_XMM
 	ret
@@ -80,7 +123,9 @@ ENTRY(efi_call4)
 	mov %r8, %r9
 	mov %rcx, %r8
 	mov %rsi, %rcx
+	SWITCH_PGT
 	call *%rdi
+	RESTORE_PGT
 	addq $32, %rsp
 	RESTORE_XMM
 	ret
@@ -93,7 +138,9 @@ ENTRY(efi_call5)
 	mov %r8, %r9
 	mov %rcx, %r8
 	mov %rsi, %rcx
+	SWITCH_PGT
 	call *%rdi
+	RESTORE_PGT
 	addq $48, %rsp
 	RESTORE_XMM
 	ret
@@ -109,8 +156,15 @@ ENTRY(efi_call6)
 	mov %r8, %r9
 	mov %rcx, %r8
 	mov %rsi, %rcx
+	SWITCH_PGT
 	call *%rdi
+	RESTORE_PGT
 	addq $48, %rsp
 	RESTORE_XMM
 	ret
 ENDPROC(efi_call6)
+
+	.data
+ENTRY(efi_scratch)
+	.fill 3,8,0
+	.byte 0
diff --git a/include/linux/efi.h b/include/linux/efi.h
index bc5687d0f315..6c0ca528300c 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -653,6 +653,7 @@ extern int __init efi_setup_pcdp_console(char *);
 #define EFI_RUNTIME_SERVICES	3	/* Can we use runtime services? */
 #define EFI_MEMMAP		4	/* Can we use EFI memory map? */
 #define EFI_64BIT		5	/* Is the firmware 64-bit? */
+#define EFI_ARCH_1		6	/* First arch-specific bit */
 
 #ifdef CONFIG_EFI
 # ifdef CONFIG_X86
-- 
1.8.4

Re: [PATCH 10/11] EFI: Runtime services virtual mapping

[Dave Young]

On 10/31/13 at 05:25pm, Borislav Petkov wrote:
> From: Borislav Petkov <bp-l3A5Bk7waGM@public.gmane.org>
> 
> We map the EFI regions needed for runtime services non-contiguously,
> with preserved alignment on virtual addresses starting from -4G down
> for a total max space of 64G. This way, we provide for stable runtime
> services addresses across kernels so that a kexec'd kernel can still use
> them.
> 
> Thus, they're mapped in a separate pagetable so that we don't pollute
> the kernel namespace.
> 
> Add an efi= kernel command line parameter for passing miscellaneous
> options and chicken bits from the command line.
> 
> While at it, add 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...).
> 
> Also, add the UEFI RT VA space to Documentation/x86/x86_64/mm.txt.
> 
> Signed-off-by: Borislav Petkov <bp-l3A5Bk7waGM@public.gmane.org>
> ---
>  Documentation/kernel-parameters.txt  |   6 ++
>  Documentation/x86/x86_64/mm.txt      |   7 +++
>  arch/x86/include/asm/efi.h           |  64 ++++++++++++++------
>  arch/x86/include/asm/pgtable_types.h |   3 +-
>  arch/x86/platform/efi/efi.c          |  94 +++++++++++++++++++++---------
>  arch/x86/platform/efi/efi_32.c       |   9 ++-
>  arch/x86/platform/efi/efi_64.c       | 109 +++++++++++++++++++++++++++++++++++
>  arch/x86/platform/efi/efi_stub_64.S  |  54 +++++++++++++++++
>  include/linux/efi.h                  |   1 +
>  9 files changed, 300 insertions(+), 47 deletions(-)
> 

Hi,

This one still does not apply:

[dave@darkstar linux-2.6]$ git am ~/Mail/bp/new/*
Applying: efi: Simplify EFI_DEBUG
Applying: x86, pageattr: Lookup address in an arbitrary PGD
Applying: x86, pageattr: Add a PGD pagetable populating function
Applying: x86, pageattr: Add a PUD pagetable populating function
Applying: x86, pageattr: Add a PMD pagetable populating function
Applying: x86, pageattr: Add a PTE pagetable populating function
Applying: x86, pageattr: Add a PUD error unwinding path
Applying: x86, pageattr: Add last levels of error path
Applying: x86, cpa: Map in an arbitrary pgd
Applying: EFI: Runtime services virtual mapping
error: patch failed: arch/x86/platform/efi/efi.c:808
error: arch/x86/platform/efi/efi.c: patch does not apply
Patch failed at 0010 EFI: Runtime services virtual mapping
The copy of the patch that failed is found in:
   /home/dave/git/linux-2.6/.git/rebase-apply/patch
When you have resolved this problem, run "git am --resolved".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".

I found the reason, here is the diff of the efi.c
between (linus tree + matt next) and the one in matt next:

--- efi.c.linus-tree	2013-11-01 11:16:44.731554778 +0800
+++ efi.c.matt-next	2013-11-01 11:17:41.662316832 +0800
@@ -806,13 +806,10 @@ void __init efi_enter_virtual_mode(void)
 
 	for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
 		md = p;
-		if (!(md->attribute & EFI_MEMORY_RUNTIME)) {
-#ifdef CONFIG_X86_64
-			if (md->type != EFI_BOOT_SERVICES_CODE &&
-			    md->type != EFI_BOOT_SERVICES_DATA)
-#endif
-				continue;
-		}
+		if (!(md->attribute & EFI_MEMORY_RUNTIME) &&
+		    md->type != EFI_BOOT_SERVICES_CODE &&
+		    md->type != EFI_BOOT_SERVICES_DATA)
+			continue;
 
 		size = md->num_pages << EFI_PAGE_SHIFT;
 		end = md->phys_addr + size;

The conflict is caused by missing one commit in matt's efi next tree:

commit 700870119f49084da004ab588ea2b799689efaf7
Author: Josh Boyer <jwboyer-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Date:   Thu Apr 18 07:51:34 2013 -0700

    x86, efi: Don't map Boot Services on i386
    
    Add patch to fix 32bit EFI service mapping (rhbz 726701)
    
    Multiple people are reporting hitting the following WARNING on i386,
    
      WARNING: at arch/x86/mm/ioremap.c:102 __ioremap_caller+0x3d3/0x440()
      Modules linked in:
      Pid: 0, comm: swapper Not tainted 3.9.0-rc7+ #95

--
Thanks
Dave

Re: [PATCH 10/11] EFI: Runtime services virtual mapping

[Dave Young]

On 11/01/13 at 11:25am, Dave Young wrote:
> On 10/31/13 at 05:25pm, Borislav Petkov wrote:
> > From: Borislav Petkov <bp-l3A5Bk7waGM@public.gmane.org>
> > 
> > We map the EFI regions needed for runtime services non-contiguously,
> > with preserved alignment on virtual addresses starting from -4G down
> > for a total max space of 64G. This way, we provide for stable runtime
> > services addresses across kernels so that a kexec'd kernel can still use
> > them.
> > 
> > Thus, they're mapped in a separate pagetable so that we don't pollute
> > the kernel namespace.
> > 
> > Add an efi= kernel command line parameter for passing miscellaneous
> > options and chicken bits from the command line.
> > 
> > While at it, add 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...).
> > 
> > Also, add the UEFI RT VA space to Documentation/x86/x86_64/mm.txt.
> > 
> > Signed-off-by: Borislav Petkov <bp-l3A5Bk7waGM@public.gmane.org>
> > ---
> >  Documentation/kernel-parameters.txt  |   6 ++
> >  Documentation/x86/x86_64/mm.txt      |   7 +++
> >  arch/x86/include/asm/efi.h           |  64 ++++++++++++++------
> >  arch/x86/include/asm/pgtable_types.h |   3 +-
> >  arch/x86/platform/efi/efi.c          |  94 +++++++++++++++++++++---------
> >  arch/x86/platform/efi/efi_32.c       |   9 ++-
> >  arch/x86/platform/efi/efi_64.c       | 109 +++++++++++++++++++++++++++++++++++
> >  arch/x86/platform/efi/efi_stub_64.S  |  54 +++++++++++++++++
> >  include/linux/efi.h                  |   1 +
> >  9 files changed, 300 insertions(+), 47 deletions(-)
> > 
> 
> Hi,
> 
> This one still does not apply:
> 
> [dave@darkstar linux-2.6]$ git am ~/Mail/bp/new/*
> Applying: efi: Simplify EFI_DEBUG
> Applying: x86, pageattr: Lookup address in an arbitrary PGD
> Applying: x86, pageattr: Add a PGD pagetable populating function
> Applying: x86, pageattr: Add a PUD pagetable populating function
> Applying: x86, pageattr: Add a PMD pagetable populating function
> Applying: x86, pageattr: Add a PTE pagetable populating function
> Applying: x86, pageattr: Add a PUD error unwinding path
> Applying: x86, pageattr: Add last levels of error path
> Applying: x86, cpa: Map in an arbitrary pgd
> Applying: EFI: Runtime services virtual mapping
> error: patch failed: arch/x86/platform/efi/efi.c:808
> error: arch/x86/platform/efi/efi.c: patch does not apply
> Patch failed at 0010 EFI: Runtime services virtual mapping
> The copy of the patch that failed is found in:
>    /home/dave/git/linux-2.6/.git/rebase-apply/patch
> When you have resolved this problem, run "git am --resolved".
> If you prefer to skip this patch, run "git am --skip" instead.
> To restore the original branch and stop patching, run "git am --abort".
> 
> I found the reason, here is the diff of the efi.c
> between (linus tree + matt next) and the one in matt next:
> 
> --- efi.c.linus-tree	2013-11-01 11:16:44.731554778 +0800
> +++ efi.c.matt-next	2013-11-01 11:17:41.662316832 +0800
> @@ -806,13 +806,10 @@ void __init efi_enter_virtual_mode(void)
>  
>  	for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
>  		md = p;
> -		if (!(md->attribute & EFI_MEMORY_RUNTIME)) {
> -#ifdef CONFIG_X86_64
> -			if (md->type != EFI_BOOT_SERVICES_CODE &&
> -			    md->type != EFI_BOOT_SERVICES_DATA)
> -#endif
> -				continue;
> -		}
> +		if (!(md->attribute & EFI_MEMORY_RUNTIME) &&
> +		    md->type != EFI_BOOT_SERVICES_CODE &&
> +		    md->type != EFI_BOOT_SERVICES_DATA)
> +			continue;
>  
>  		size = md->num_pages << EFI_PAGE_SHIFT;
>  		end = md->phys_addr + size;
> 
> The conflict is caused by missing one commit in matt's efi next tree:
> 
> commit 700870119f49084da004ab588ea2b799689efaf7
> Author: Josh Boyer <jwboyer-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> Date:   Thu Apr 18 07:51:34 2013 -0700
> 
>     x86, efi: Don't map Boot Services on i386
>     
>     Add patch to fix 32bit EFI service mapping (rhbz 726701)
>     
>     Multiple people are reporting hitting the following WARNING on i386,
>     
>       WARNING: at arch/x86/mm/ioremap.c:102 __ioremap_caller+0x3d3/0x440()
>       Modules linked in:
>       Pid: 0, comm: swapper Not tainted 3.9.0-rc7+ #95

Rethinking about above commit, it is actually a workaround for
mapping boot service, I suspect the problem connect to the off-by-one
problem in boot service reserve function. Matt, idea?

--
Thanks
Dave

Re: [PATCH 10/11] EFI: Runtime services virtual mapping

[Matt Fleming]

On Fri, 01 Nov, at 11:35:08AM, Dave Young wrote:
> > The conflict is caused by missing one commit in matt's efi next tree:
> > 
> > commit 700870119f49084da004ab588ea2b799689efaf7
> > Author: Josh Boyer <jwboyer-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> > Date:   Thu Apr 18 07:51:34 2013 -0700
> > 
> >     x86, efi: Don't map Boot Services on i386
> >     
> >     Add patch to fix 32bit EFI service mapping (rhbz 726701)
> >     
> >     Multiple people are reporting hitting the following WARNING on i386,
> >     
> >       WARNING: at arch/x86/mm/ioremap.c:102 __ioremap_caller+0x3d3/0x440()
> >       Modules linked in:
> >       Pid: 0, comm: swapper Not tainted 3.9.0-rc7+ #95
> 
> Rethinking about above commit, it is actually a workaround for
> mapping boot service, I suspect the problem connect to the off-by-one
> problem in boot service reserve function. Matt, idea?

No, it's not the same problem. And just to make absolutely sure I
reverted the above commit and applied your patch, but I still see the
WARN_ON() described above.

-- 
Matt Fleming, Intel Open Source Technology Center

Re: [PATCH 10/11] EFI: Runtime services virtual mapping

[Dave Young]

On 11/01/13 at 12:50pm, Matt Fleming wrote:
> On Fri, 01 Nov, at 11:35:08AM, Dave Young wrote:
> > > The conflict is caused by missing one commit in matt's efi next tree:
> > > 
> > > commit 700870119f49084da004ab588ea2b799689efaf7
> > > Author: Josh Boyer <jwboyer-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> > > Date:   Thu Apr 18 07:51:34 2013 -0700
> > > 
> > >     x86, efi: Don't map Boot Services on i386
> > >     
> > >     Add patch to fix 32bit EFI service mapping (rhbz 726701)
> > >     
> > >     Multiple people are reporting hitting the following WARNING on i386,
> > >     
> > >       WARNING: at arch/x86/mm/ioremap.c:102 __ioremap_caller+0x3d3/0x440()
> > >       Modules linked in:
> > >       Pid: 0, comm: swapper Not tainted 3.9.0-rc7+ #95
> > 
> > Rethinking about above commit, it is actually a workaround for
> > mapping boot service, I suspect the problem connect to the off-by-one
> > problem in boot service reserve function. Matt, idea?
> 
> No, it's not the same problem. And just to make absolutely sure I
> reverted the above commit and applied your patch, but I still see the
> WARN_ON() described above.

Ok, I'm wrong then, thanks for verifying..

Re: [PATCH 10/11] EFI: Runtime services virtual mapping

[Dave Young]

On 11/01/13 at 11:25am, Dave Young wrote:
> On 10/31/13 at 05:25pm, Borislav Petkov wrote:
> > From: Borislav Petkov <bp-l3A5Bk7waGM@public.gmane.org>
> > 
> > We map the EFI regions needed for runtime services non-contiguously,
> > with preserved alignment on virtual addresses starting from -4G down
> > for a total max space of 64G. This way, we provide for stable runtime
> > services addresses across kernels so that a kexec'd kernel can still use
> > them.
> > 
> > Thus, they're mapped in a separate pagetable so that we don't pollute
> > the kernel namespace.
> > 
> > Add an efi= kernel command line parameter for passing miscellaneous
> > options and chicken bits from the command line.
> > 
> > While at it, add 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...).
> > 
> > Also, add the UEFI RT VA space to Documentation/x86/x86_64/mm.txt.
> > 
> > Signed-off-by: Borislav Petkov <bp-l3A5Bk7waGM@public.gmane.org>
> > ---
> >  Documentation/kernel-parameters.txt  |   6 ++
> >  Documentation/x86/x86_64/mm.txt      |   7 +++
> >  arch/x86/include/asm/efi.h           |  64 ++++++++++++++------
> >  arch/x86/include/asm/pgtable_types.h |   3 +-
> >  arch/x86/platform/efi/efi.c          |  94 +++++++++++++++++++++---------
> >  arch/x86/platform/efi/efi_32.c       |   9 ++-
> >  arch/x86/platform/efi/efi_64.c       | 109 +++++++++++++++++++++++++++++++++++
> >  arch/x86/platform/efi/efi_stub_64.S  |  54 +++++++++++++++++
> >  include/linux/efi.h                  |   1 +
> >  9 files changed, 300 insertions(+), 47 deletions(-)
> > 
> 
> Hi,
> 
> This one still does not apply:
> 
> [dave@darkstar linux-2.6]$ git am ~/Mail/bp/new/*
> Applying: efi: Simplify EFI_DEBUG
> Applying: x86, pageattr: Lookup address in an arbitrary PGD
> Applying: x86, pageattr: Add a PGD pagetable populating function
> Applying: x86, pageattr: Add a PUD pagetable populating function
> Applying: x86, pageattr: Add a PMD pagetable populating function
> Applying: x86, pageattr: Add a PTE pagetable populating function
> Applying: x86, pageattr: Add a PUD error unwinding path
> Applying: x86, pageattr: Add last levels of error path
> Applying: x86, cpa: Map in an arbitrary pgd
> Applying: EFI: Runtime services virtual mapping
> error: patch failed: arch/x86/platform/efi/efi.c:808
> error: arch/x86/platform/efi/efi.c: patch does not apply
> Patch failed at 0010 EFI: Runtime services virtual mapping
> The copy of the patch that failed is found in:
>    /home/dave/git/linux-2.6/.git/rebase-apply/patch
> When you have resolved this problem, run "git am --resolved".
> If you prefer to skip this patch, run "git am --skip" instead.
> To restore the original branch and stop patching, run "git am --abort".
> 
> I found the reason, here is the diff of the efi.c
> between (linus tree + matt next) and the one in matt next:
> 
> --- efi.c.linus-tree	2013-11-01 11:16:44.731554778 +0800
> +++ efi.c.matt-next	2013-11-01 11:17:41.662316832 +0800
> @@ -806,13 +806,10 @@ void __init efi_enter_virtual_mode(void)
>  
>  	for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
>  		md = p;
> -		if (!(md->attribute & EFI_MEMORY_RUNTIME)) {
> -#ifdef CONFIG_X86_64
> -			if (md->type != EFI_BOOT_SERVICES_CODE &&
> -			    md->type != EFI_BOOT_SERVICES_DATA)
> -#endif
> -				continue;
> -		}
> +		if (!(md->attribute & EFI_MEMORY_RUNTIME) &&
> +		    md->type != EFI_BOOT_SERVICES_CODE &&
> +		    md->type != EFI_BOOT_SERVICES_DATA)
> +			continue;
>  
>  		size = md->num_pages << EFI_PAGE_SHIFT;
>  		end = md->phys_addr + size;
> 
> The conflict is caused by missing one commit in matt's efi next tree:
> 
> commit 700870119f49084da004ab588ea2b799689efaf7
> Author: Josh Boyer <jwboyer-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> Date:   Thu Apr 18 07:51:34 2013 -0700
> 
>     x86, efi: Don't map Boot Services on i386
>     
>     Add patch to fix 32bit EFI service mapping (rhbz 726701)
>     
>     Multiple people are reporting hitting the following WARNING on i386,
>     
>       WARNING: at arch/x86/mm/ioremap.c:102 __ioremap_caller+0x3d3/0x440()
>       Modules linked in:
>       Pid: 0, comm: swapper Not tainted 3.9.0-rc7+ #95

Hi, Matt

How should I handle this problem, would you take above commit or rebase efi
next branch?

--
Thanks
Dave

Re: [PATCH 10/11] EFI: Runtime services virtual mapping

[Matt Fleming]

On Sun, 03 Nov, at 08:31:15PM, Dave Young wrote:
> Hi, Matt
> 
> How should I handle this problem, would you take above commit or rebase efi
> next branch?

Dave, could you base your patches against the EFI 'master' branch? I've
rebased that branch on v3.12, which includes commit 700870119f49 ("x86,
efi: Don't map Boot Services on i386"), and merged everything from
'next'. Just note in the patch description which branch you've based
your work on and why in case I forget ;-)

Let me know if this causes any issues.

-- 
Matt Fleming, Intel Open Source Technology Center

[PATCH 11/11] efi: Check krealloc return value

[Borislav Petkov]

From: Borislav Petkov <bp@suse.de>

Check it just in case. We might just as well panic there because runtime
won't be functioning anyway.

Signed-off-by: Borislav Petkov <bp@suse.de>
---
 arch/x86/platform/efi/efi.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index b453069236fd..3fac4dee492f 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -860,6 +860,9 @@ void __init efi_enter_virtual_mode(void)
 		new_memmap = krealloc(new_memmap,
 				      (count + 1) * memmap.desc_size,
 				      GFP_KERNEL);
+		if (!new_memmap)
+			goto err_out;
+
 		memcpy(new_memmap + (count * memmap.desc_size), md,
 		       memmap.desc_size);
 		count++;
@@ -914,6 +917,11 @@ void __init efi_enter_virtual_mode(void)
 			 EFI_VARIABLE_BOOTSERVICE_ACCESS |
 			 EFI_VARIABLE_RUNTIME_ACCESS,
 			 0, NULL);
+
+	return;
+
+ err_out:
+	pr_err("Error reallocating memory, EFI runtime non-functional!\n");
 }
 
 /*
-- 
1.8.4

Re: [PATCH 00/11] EFI runtime services virtual mapping, vN++

[Matt Fleming]

On Thu, 31 Oct, at 05:24:58PM, Borislav Petkov wrote:
> From: Borislav Petkov <bp@suse.de>
> 
> Hi all,
> 
> here's maybe the final version of the patchset, no major changes since
> the last time but cosmetic and cleanups and tidying as requested by Matt
> and others.
> 
> Patches also at:
> 
> git://git.kernel.org/pub/scm/linux/kernel/git/bp/bp.git#efi

Thanks Borislav, I've merged this version in the EFI 'next' branch to
queue up for v3.14.

Good work!

-- 
Matt Fleming, Intel Open Source Technology Center