[PATCH v3 0/6] generic early_ioremap support

[PATCH v3 0/6] generic early_ioremap support

[Mark Salter]

This patch series takes the common bits from the x86 early ioremap
implementation and creates a generic implementation which may be used
by other architectures. The early ioremap interfaces are intended for
situations where boot code needs to make temporary virtual mappings
before the normal ioremap interfaces are available. Typically, this
means before paging_init() has run.

These patches are layered on top of generic fixmap patches which
were discussed here (and are in the akpm tree):

  http://lkml.org/lkml/2013/11/25/474

This is version 3 of the patch series. These patches (and underlying
fixmap patches) may be found at:

  git://github.com/mosalter/linux.git (early-ioremap-v3 branch)

Changes from version 2:

  * Added some Acks

  * Incorporated a patch from Dave Young to change the signature
    of early_memremap() (dropping __iomem from returned pointer)
    which is the first patch in a larger series:

        https://lkml.org/lkml/2013/12/22/69

    This allows the change of just the x86 function signature
    to be bisected.

Changes from version 1:

  * Moved the generic code into linux/mm instead of linux/lib

  * Have early_memremap() return normal pointer instead of __iomem
    This is in response to sparse warning cleanups being made in
    an unrelated patch series:

        https://lkml.org/lkml/2013/12/22/69

  * Added arm64 patch to call init_mem_pgprot() earlier so that
    the pgprot macros are valid in time for early_ioremap use

  * Added validity checking for early_ioremap pgd, pud, and pmd
    in arm64

Dave Young (1):
  x86/mm: sparse warning fix for early_memremap

Mark Salter (5):
  mm: create generic early_ioremap() support
  x86: use generic early_ioremap
  arm: add early_ioremap support
  arm64: initialize pgprot info earlier in boot
  arm64: add early_ioremap support

 Documentation/arm64/memory.txt      |   4 +-
 arch/arm/Kconfig                    |  11 ++
 arch/arm/include/asm/Kbuild         |   1 +
 arch/arm/include/asm/fixmap.h       |  18 +++
 arch/arm/include/asm/io.h           |   1 +
 arch/arm/kernel/setup.c             |   3 +
 arch/arm/mm/Makefile                |   1 +
 arch/arm/mm/early_ioremap.c         |  93 ++++++++++++++
 arch/arm/mm/mmu.c                   |   2 +
 arch/arm64/Kconfig                  |   1 +
 arch/arm64/include/asm/Kbuild       |   1 +
 arch/arm64/include/asm/fixmap.h     |  68 ++++++++++
 arch/arm64/include/asm/io.h         |   1 +
 arch/arm64/include/asm/memory.h     |   2 +-
 arch/arm64/include/asm/mmu.h        |   1 +
 arch/arm64/kernel/early_printk.c    |   8 +-
 arch/arm64/kernel/head.S            |   9 +-
 arch/arm64/kernel/setup.c           |   4 +
 arch/arm64/mm/ioremap.c             |  85 ++++++++++++
 arch/arm64/mm/mmu.c                 |  44 +------
 arch/x86/Kconfig                    |   1 +
 arch/x86/include/asm/Kbuild         |   1 +
 arch/x86/include/asm/fixmap.h       |   6 +
 arch/x86/include/asm/io.h           |  14 +-
 arch/x86/mm/ioremap.c               | 224 +-------------------------------
 arch/x86/mm/pgtable_32.c            |   2 +-
 include/asm-generic/early_ioremap.h |  41 ++++++
 mm/Kconfig                          |   3 +
 mm/Makefile                         |   1 +
 mm/early_ioremap.c                  | 249 ++++++++++++++++++++++++++++++++++++
 30 files changed, 611 insertions(+), 289 deletions(-)
 create mode 100644 arch/arm/mm/early_ioremap.c
 create mode 100644 arch/arm64/include/asm/fixmap.h
 create mode 100644 include/asm-generic/early_ioremap.h
 create mode 100644 mm/early_ioremap.c

-- 
1.8.3.1

[PATCH v3 1/6] x86/mm: sparse warning fix for early_memremap

[Mark Salter]

From: Dave Young <dyoung@redhat.com>

There's a lot of sparse warnings for code like below:
void *a = early_memremap(phys_addr, size);

early_memremap intend to map kernel memory with ioremap facility, the return
pointer should be a kernel ram pointer instead of iomem one.

For making the function clearer and supressing sparse warnings this patch
do below two things:
1. cast to (__force void *) for the return value of early_memremap
2. add early_memunmap function and pass (__force void __iomem *) to iounmap

>From Boris:
> Ingo told me yesterday, it makes sense too. I'd guess we can try it.
> FWIW, all callers of early_memremap use the memory they get remapped as
> normal memory so we should be safe.

Signed-off-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Mark Salter <msalter@redhat.com>
---
 arch/x86/include/asm/io.h |  3 ++-
 arch/x86/mm/ioremap.c     | 10 +++++++---
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h
index 34f69cb..1db414f 100644
--- a/arch/x86/include/asm/io.h
+++ b/arch/x86/include/asm/io.h
@@ -325,9 +325,10 @@ extern void early_ioremap_init(void);
 extern void early_ioremap_reset(void);
 extern void __iomem *early_ioremap(resource_size_t phys_addr,
 				   unsigned long size);
-extern void __iomem *early_memremap(resource_size_t phys_addr,
+extern void *early_memremap(resource_size_t phys_addr,
 				    unsigned long size);
 extern void early_iounmap(void __iomem *addr, unsigned long size);
+extern void early_memunmap(void *addr, unsigned long size);
 extern void fixup_early_ioremap(void);
 extern bool is_early_ioremap_ptep(pte_t *ptep);
 
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 799580c..bbb4504 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -562,10 +562,9 @@ early_ioremap(resource_size_t phys_addr, unsigned long size)
 }
 
 /* Remap memory */
-void __init __iomem *
-early_memremap(resource_size_t phys_addr, unsigned long size)
+void __init *early_memremap(resource_size_t phys_addr, unsigned long size)
 {
-	return __early_ioremap(phys_addr, size, PAGE_KERNEL);
+	return (__force void *)__early_ioremap(phys_addr, size, PAGE_KERNEL);
 }
 
 void __init early_iounmap(void __iomem *addr, unsigned long size)
@@ -620,3 +619,8 @@ void __init early_iounmap(void __iomem *addr, unsigned long size)
 	}
 	prev_map[slot] = NULL;
 }
+
+void __init early_memunmap(void *addr, unsigned long size)
+{
+	early_iounmap((__force void __iomem *)addr, size);
+}
-- 
1.8.3.1

[PATCH v3 2/6] mm: create generic early_ioremap() support

[Mark Salter]

This patch creates a generic implementation of early_ioremap() support
based on the existing x86 implementation. early_ioremp() is useful for
early boot code which needs to temporarily map I/O or memory regions
before normal mapping functions such as ioremap() are available.

Signed-off-by: Mark Salter <msalter@redhat.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
CC: x86@kernel.org
CC: linux-arm-kernel@lists.infradead.org
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Arnd Bergmann <arnd@arndb.de>
CC: Ingo Molnar <mingo@kernel.org>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: "H. Peter Anvin" <hpa@zytor.com>
CC: Russell King <linux@arm.linux.org.uk>
CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Will Deacon <will.deacon@arm.com>
---
 include/asm-generic/early_ioremap.h |  41 ++++++
 mm/Kconfig                          |   3 +
 mm/Makefile                         |   1 +
 mm/early_ioremap.c                  | 249 ++++++++++++++++++++++++++++++++++++
 4 files changed, 294 insertions(+)
 create mode 100644 include/asm-generic/early_ioremap.h
 create mode 100644 mm/early_ioremap.c

diff --git a/include/asm-generic/early_ioremap.h b/include/asm-generic/early_ioremap.h
new file mode 100644
index 0000000..d43e187
--- /dev/null
+++ b/include/asm-generic/early_ioremap.h
@@ -0,0 +1,41 @@
+#ifndef _ASM_EARLY_IOREMAP_H_
+#define _ASM_EARLY_IOREMAP_H_
+
+#include <linux/types.h>
+
+#ifdef CONFIG_GENERIC_EARLY_IOREMAP
+/*
+ * early_ioremap() and early_iounmap() are for temporary early boot-time
+ * mappings, before the real ioremap() is functional.
+ */
+extern void __iomem *early_ioremap(resource_size_t phys_addr,
+				   unsigned long size);
+extern void *early_memremap(resource_size_t phys_addr,
+			    unsigned long size);
+extern void early_iounmap(void __iomem *addr, unsigned long size);
+extern void early_memunmap(void *addr, unsigned long size);
+
+/* Arch-specific initialization */
+extern void early_ioremap_init(void);
+
+/* Generic initialization called by architecture code */
+extern void early_ioremap_setup(void);
+
+/*
+ * Called as last step in paging_init() so library can act
+ * accordingly for subsequent map/unmap requests.
+ */
+extern void early_ioremap_reset(void);
+
+/*
+ * Weak function called by early_ioremap_reset(). It does nothing, but
+ * architectures may provide their own version to do any needed cleanups.
+ */
+extern void early_ioremap_shutdown(void);
+#else
+static inline void early_ioremap_init(void) { }
+static inline void early_ioremap_setup(void) { }
+static inline void early_ioremap_reset(void) { }
+#endif
+
+#endif /* _ASM_EARLY_IOREMAP_H_ */
diff --git a/mm/Kconfig b/mm/Kconfig
index 723bbe0..0dcebf2a 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -552,3 +552,6 @@ config MEM_SOFT_DIRTY
 	  it can be cleared by hands.
 
 	  See Documentation/vm/soft-dirty.txt for more details.
+
+config GENERIC_EARLY_IOREMAP
+	bool
diff --git a/mm/Makefile b/mm/Makefile
index 305d10a..4e102e9 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -60,3 +60,4 @@ obj-$(CONFIG_DEBUG_KMEMLEAK_TEST) += kmemleak-test.o
 obj-$(CONFIG_CLEANCACHE) += cleancache.o
 obj-$(CONFIG_MEMORY_ISOLATION) += page_isolation.o
 obj-$(CONFIG_ZBUD)	+= zbud.o
+obj-$(CONFIG_GENERIC_EARLY_IOREMAP) += early_ioremap.o
diff --git a/mm/early_ioremap.c b/mm/early_ioremap.c
new file mode 100644
index 0000000..8c1ac48
--- /dev/null
+++ b/mm/early_ioremap.c
@@ -0,0 +1,249 @@
+/*
+ * Provide common bits of early_ioremap() support for architectures needing
+ * temporary mappings during boot before ioremap() is available.
+ *
+ * This is mostly a direct copy of the x86 early_ioremap implementation.
+ *
+ * (C) Copyright 1995 1996 Linus Torvalds
+ *
+ */
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+#include <linux/vmalloc.h>
+#include <asm/fixmap.h>
+
+static int early_ioremap_debug __initdata;
+
+static int __init early_ioremap_debug_setup(char *str)
+{
+	early_ioremap_debug = 1;
+
+	return 0;
+}
+early_param("early_ioremap_debug", early_ioremap_debug_setup);
+
+static int after_paging_init __initdata;
+
+void __init __attribute__((weak)) early_ioremap_shutdown(void)
+{
+}
+
+void __init early_ioremap_reset(void)
+{
+	early_ioremap_shutdown();
+	after_paging_init = 1;
+}
+
+/*
+ * Generally, ioremap() is available after paging_init() has been called.
+ * Architectures wanting to allow early_ioremap after paging_init() can
+ * define __late_set_fixmap and __late_clear_fixmap to do the right thing.
+ */
+#ifndef __late_set_fixmap
+static inline void __init __late_set_fixmap(enum fixed_addresses idx,
+					    phys_addr_t phys, pgprot_t prot)
+{
+	BUG();
+}
+#endif
+
+#ifndef __late_clear_fixmap
+static inline void __init __late_clear_fixmap(enum fixed_addresses idx)
+{
+	BUG();
+}
+#endif
+
+static void __iomem *prev_map[FIX_BTMAPS_SLOTS] __initdata;
+static unsigned long prev_size[FIX_BTMAPS_SLOTS] __initdata;
+static unsigned long slot_virt[FIX_BTMAPS_SLOTS] __initdata;
+
+void __init early_ioremap_setup(void)
+{
+	int i;
+
+	for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
+		if (prev_map[i]) {
+			WARN_ON(1);
+			break;
+		}
+	}
+
+	for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
+		slot_virt[i] = __fix_to_virt(FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*i);
+}
+
+static int __init check_early_ioremap_leak(void)
+{
+	int count = 0;
+	int i;
+
+	for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
+		if (prev_map[i])
+			count++;
+
+	if (!count)
+		return 0;
+	WARN(1, KERN_WARNING
+	       "Debug warning: early ioremap leak of %d areas detected.\n",
+		count);
+	pr_warn("please boot with early_ioremap_debug and report the dmesg.\n");
+
+	return 1;
+}
+late_initcall(check_early_ioremap_leak);
+
+static void __init __iomem *
+__early_ioremap(resource_size_t phys_addr, unsigned long size, pgprot_t prot)
+{
+	unsigned long offset;
+	resource_size_t last_addr;
+	unsigned int nrpages;
+	enum fixed_addresses idx;
+	int i, slot;
+
+	WARN_ON(system_state != SYSTEM_BOOTING);
+
+	slot = -1;
+	for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
+		if (!prev_map[i]) {
+			slot = i;
+			break;
+		}
+	}
+
+	if (slot < 0) {
+		pr_info("%s(%08llx, %08lx) not found slot\n",
+			__func__, (u64)phys_addr, size);
+		WARN_ON(1);
+		return NULL;
+	}
+
+	if (early_ioremap_debug) {
+		pr_info("%s(%08llx, %08lx) [%d] => ",
+			__func__, (u64)phys_addr, size, slot);
+		dump_stack();
+	}
+
+	/* Don't allow wraparound or zero size */
+	last_addr = phys_addr + size - 1;
+	if (!size || last_addr < phys_addr) {
+		WARN_ON(1);
+		return NULL;
+	}
+
+	prev_size[slot] = size;
+	/*
+	 * Mappings have to be page-aligned
+	 */
+	offset = phys_addr & ~PAGE_MASK;
+	phys_addr &= PAGE_MASK;
+	size = PAGE_ALIGN(last_addr + 1) - phys_addr;
+
+	/*
+	 * Mappings have to fit in the FIX_BTMAP area.
+	 */
+	nrpages = size >> PAGE_SHIFT;
+	if (nrpages > NR_FIX_BTMAPS) {
+		WARN_ON(1);
+		return NULL;
+	}
+
+	/*
+	 * Ok, go for it..
+	 */
+	idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot;
+	while (nrpages > 0) {
+		if (after_paging_init)
+			__late_set_fixmap(idx, phys_addr, prot);
+		else
+			__early_set_fixmap(idx, phys_addr, prot);
+		phys_addr += PAGE_SIZE;
+		--idx;
+		--nrpages;
+	}
+	if (early_ioremap_debug)
+		pr_cont("%08lx + %08lx\n", offset, slot_virt[slot]);
+
+	prev_map[slot] = (void __iomem *)(offset + slot_virt[slot]);
+	return prev_map[slot];
+}
+
+/* Remap an IO device */
+void __init __iomem *
+early_ioremap(resource_size_t phys_addr, unsigned long size)
+{
+	return __early_ioremap(phys_addr, size, FIXMAP_PAGE_IO);
+}
+
+/* Remap memory */
+void __init *
+early_memremap(resource_size_t phys_addr, unsigned long size)
+{
+	return (__force void *)__early_ioremap(phys_addr, size,
+					       FIXMAP_PAGE_NORMAL);
+}
+
+void __init early_iounmap(void __iomem *addr, unsigned long size)
+{
+	unsigned long virt_addr;
+	unsigned long offset;
+	unsigned int nrpages;
+	enum fixed_addresses idx;
+	int i, slot;
+
+	slot = -1;
+	for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
+		if (prev_map[i] == addr) {
+			slot = i;
+			break;
+		}
+	}
+
+	if (slot < 0) {
+		pr_info("early_iounmap(%p, %08lx) not found slot\n",
+			addr, size);
+		WARN_ON(1);
+		return;
+	}
+
+	if (prev_size[slot] != size) {
+		pr_info("early_iounmap(%p, %08lx) [%d] size not consistent %08lx\n",
+			addr, size, slot, prev_size[slot]);
+		WARN_ON(1);
+		return;
+	}
+
+	if (early_ioremap_debug) {
+		pr_info("early_iounmap(%p, %08lx) [%d]\n", addr,
+			size, slot);
+		dump_stack();
+	}
+
+	virt_addr = (unsigned long)addr;
+	if (virt_addr < fix_to_virt(FIX_BTMAP_BEGIN)) {
+		WARN_ON(1);
+		return;
+	}
+	offset = virt_addr & ~PAGE_MASK;
+	nrpages = PAGE_ALIGN(offset + size) >> PAGE_SHIFT;
+
+	idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot;
+	while (nrpages > 0) {
+		if (after_paging_init)
+			__late_clear_fixmap(idx);
+		else
+			__early_set_fixmap(idx, 0, FIXMAP_PAGE_CLEAR);
+		--idx;
+		--nrpages;
+	}
+	prev_map[slot] = NULL;
+}
+
+void __init early_memunmap(void *addr, unsigned long size)
+{
+	early_iounmap((__force void __iomem *)addr, size);
+}
-- 
1.8.3.1

[PATCH v3 3/6] x86: use generic early_ioremap

[Mark Salter]

Move x86 over to the generic early ioremap implementation.

Signed-off-by: Mark Salter <msalter@redhat.com>
CC: x86@kernel.org
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Arnd Bergmann <arnd@arndb.de>
CC: Ingo Molnar <mingo@kernel.org>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: "H. Peter Anvin" <hpa@zytor.com>
---
 arch/x86/Kconfig              |   1 +
 arch/x86/include/asm/Kbuild   |   1 +
 arch/x86/include/asm/fixmap.h |   6 ++
 arch/x86/include/asm/io.h     |  15 +--
 arch/x86/mm/ioremap.c         | 228 +-----------------------------------------
 arch/x86/mm/pgtable_32.c      |   2 +-
 6 files changed, 13 insertions(+), 240 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 0952ecd..50e1eab 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -125,6 +125,7 @@ config X86
 	select RTC_LIB
 	select HAVE_DEBUG_STACKOVERFLOW
 	select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
+	select GENERIC_EARLY_IOREMAP
 
 config INSTRUCTION_DECODER
 	def_bool y
diff --git a/arch/x86/include/asm/Kbuild b/arch/x86/include/asm/Kbuild
index 7f66985..203f5f9 100644
--- a/arch/x86/include/asm/Kbuild
+++ b/arch/x86/include/asm/Kbuild
@@ -5,3 +5,4 @@ genhdr-y += unistd_64.h
 genhdr-y += unistd_x32.h
 
 generic-y += clkdev.h
+generic-y += early_ioremap.h
diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h
index 7252cd3..e5f236d 100644
--- a/arch/x86/include/asm/fixmap.h
+++ b/arch/x86/include/asm/fixmap.h
@@ -177,5 +177,11 @@ static inline void __set_fixmap(enum fixed_addresses idx,
 
 #include <asm-generic/fixmap.h>
 
+#define __late_set_fixmap(idx, phys, flags) __set_fixmap(idx, phys, flags)
+#define __late_clear_fixmap(idx) __set_fixmap(idx, 0, __pgprot(0))
+
+void __early_set_fixmap(enum fixed_addresses idx,
+			phys_addr_t phys, pgprot_t flags);
+
 #endif /* !__ASSEMBLY__ */
 #endif /* _ASM_X86_FIXMAP_H */
diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h
index 1db414f..aae7010 100644
--- a/arch/x86/include/asm/io.h
+++ b/arch/x86/include/asm/io.h
@@ -39,6 +39,7 @@
 #include <linux/string.h>
 #include <linux/compiler.h>
 #include <asm/page.h>
+#include <asm/early_ioremap.h>
 
 #define build_mmio_read(name, size, type, reg, barrier) \
 static inline type name(const volatile void __iomem *addr) \
@@ -316,20 +317,6 @@ extern int ioremap_change_attr(unsigned long vaddr, unsigned long size,
 				unsigned long prot_val);
 extern void __iomem *ioremap_wc(resource_size_t offset, unsigned long size);
 
-/*
- * early_ioremap() and early_iounmap() are for temporary early boot-time
- * mappings, before the real ioremap() is functional.
- * A boot-time mapping is currently limited to at most 16 pages.
- */
-extern void early_ioremap_init(void);
-extern void early_ioremap_reset(void);
-extern void __iomem *early_ioremap(resource_size_t phys_addr,
-				   unsigned long size);
-extern void *early_memremap(resource_size_t phys_addr,
-				    unsigned long size);
-extern void early_iounmap(void __iomem *addr, unsigned long size);
-extern void early_memunmap(void *addr, unsigned long size);
-extern void fixup_early_ioremap(void);
 extern bool is_early_ioremap_ptep(pte_t *ptep);
 
 #ifdef CONFIG_XEN
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index bbb4504..597ac15 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -328,17 +328,6 @@ void unxlate_dev_mem_ptr(unsigned long phys, void *addr)
 	return;
 }
 
-static int __initdata early_ioremap_debug;
-
-static int __init early_ioremap_debug_setup(char *str)
-{
-	early_ioremap_debug = 1;
-
-	return 0;
-}
-early_param("early_ioremap_debug", early_ioremap_debug_setup);
-
-static __initdata int after_paging_init;
 static pte_t bm_pte[PAGE_SIZE/sizeof(pte_t)] __page_aligned_bss;
 
 static inline pmd_t * __init early_ioremap_pmd(unsigned long addr)
@@ -362,18 +351,11 @@ bool __init is_early_ioremap_ptep(pte_t *ptep)
 	return ptep >= &bm_pte[0] && ptep < &bm_pte[PAGE_SIZE/sizeof(pte_t)];
 }
 
-static unsigned long slot_virt[FIX_BTMAPS_SLOTS] __initdata;
-
 void __init early_ioremap_init(void)
 {
 	pmd_t *pmd;
-	int i;
 
-	if (early_ioremap_debug)
-		printk(KERN_INFO "early_ioremap_init()\n");
-
-	for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
-		slot_virt[i] = __fix_to_virt(FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*i);
+	early_ioremap_setup();
 
 	pmd = early_ioremap_pmd(fix_to_virt(FIX_BTMAP_BEGIN));
 	memset(bm_pte, 0, sizeof(bm_pte));
@@ -402,13 +384,8 @@ void __init early_ioremap_init(void)
 	}
 }
 
-void __init early_ioremap_reset(void)
-{
-	after_paging_init = 1;
-}
-
-static void __init __early_set_fixmap(enum fixed_addresses idx,
-				      phys_addr_t phys, pgprot_t flags)
+void __init __early_set_fixmap(enum fixed_addresses idx,
+			       phys_addr_t phys, pgprot_t flags)
 {
 	unsigned long addr = __fix_to_virt(idx);
 	pte_t *pte;
@@ -425,202 +402,3 @@ static void __init __early_set_fixmap(enum fixed_addresses idx,
 		pte_clear(&init_mm, addr, pte);
 	__flush_tlb_one(addr);
 }
-
-static inline void __init early_set_fixmap(enum fixed_addresses idx,
-					   phys_addr_t phys, pgprot_t prot)
-{
-	if (after_paging_init)
-		__set_fixmap(idx, phys, prot);
-	else
-		__early_set_fixmap(idx, phys, prot);
-}
-
-static inline void __init early_clear_fixmap(enum fixed_addresses idx)
-{
-	if (after_paging_init)
-		clear_fixmap(idx);
-	else
-		__early_set_fixmap(idx, 0, __pgprot(0));
-}
-
-static void __iomem *prev_map[FIX_BTMAPS_SLOTS] __initdata;
-static unsigned long prev_size[FIX_BTMAPS_SLOTS] __initdata;
-
-void __init fixup_early_ioremap(void)
-{
-	int i;
-
-	for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
-		if (prev_map[i]) {
-			WARN_ON(1);
-			break;
-		}
-	}
-
-	early_ioremap_init();
-}
-
-static int __init check_early_ioremap_leak(void)
-{
-	int count = 0;
-	int i;
-
-	for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
-		if (prev_map[i])
-			count++;
-
-	if (!count)
-		return 0;
-	WARN(1, KERN_WARNING
-	       "Debug warning: early ioremap leak of %d areas detected.\n",
-		count);
-	printk(KERN_WARNING
-		"please boot with early_ioremap_debug and report the dmesg.\n");
-
-	return 1;
-}
-late_initcall(check_early_ioremap_leak);
-
-static void __init __iomem *
-__early_ioremap(resource_size_t phys_addr, unsigned long size, pgprot_t prot)
-{
-	unsigned long offset;
-	resource_size_t last_addr;
-	unsigned int nrpages;
-	enum fixed_addresses idx;
-	int i, slot;
-
-	WARN_ON(system_state != SYSTEM_BOOTING);
-
-	slot = -1;
-	for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
-		if (!prev_map[i]) {
-			slot = i;
-			break;
-		}
-	}
-
-	if (slot < 0) {
-		printk(KERN_INFO "%s(%08llx, %08lx) not found slot\n",
-		       __func__, (u64)phys_addr, size);
-		WARN_ON(1);
-		return NULL;
-	}
-
-	if (early_ioremap_debug) {
-		printk(KERN_INFO "%s(%08llx, %08lx) [%d] => ",
-		       __func__, (u64)phys_addr, size, slot);
-		dump_stack();
-	}
-
-	/* Don't allow wraparound or zero size */
-	last_addr = phys_addr + size - 1;
-	if (!size || last_addr < phys_addr) {
-		WARN_ON(1);
-		return NULL;
-	}
-
-	prev_size[slot] = size;
-	/*
-	 * Mappings have to be page-aligned
-	 */
-	offset = phys_addr & ~PAGE_MASK;
-	phys_addr &= PAGE_MASK;
-	size = PAGE_ALIGN(last_addr + 1) - phys_addr;
-
-	/*
-	 * Mappings have to fit in the FIX_BTMAP area.
-	 */
-	nrpages = size >> PAGE_SHIFT;
-	if (nrpages > NR_FIX_BTMAPS) {
-		WARN_ON(1);
-		return NULL;
-	}
-
-	/*
-	 * Ok, go for it..
-	 */
-	idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot;
-	while (nrpages > 0) {
-		early_set_fixmap(idx, phys_addr, prot);
-		phys_addr += PAGE_SIZE;
-		--idx;
-		--nrpages;
-	}
-	if (early_ioremap_debug)
-		printk(KERN_CONT "%08lx + %08lx\n", offset, slot_virt[slot]);
-
-	prev_map[slot] = (void __iomem *)(offset + slot_virt[slot]);
-	return prev_map[slot];
-}
-
-/* Remap an IO device */
-void __init __iomem *
-early_ioremap(resource_size_t phys_addr, unsigned long size)
-{
-	return __early_ioremap(phys_addr, size, PAGE_KERNEL_IO);
-}
-
-/* Remap memory */
-void __init *early_memremap(resource_size_t phys_addr, unsigned long size)
-{
-	return (__force void *)__early_ioremap(phys_addr, size, PAGE_KERNEL);
-}
-
-void __init early_iounmap(void __iomem *addr, unsigned long size)
-{
-	unsigned long virt_addr;
-	unsigned long offset;
-	unsigned int nrpages;
-	enum fixed_addresses idx;
-	int i, slot;
-
-	slot = -1;
-	for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
-		if (prev_map[i] == addr) {
-			slot = i;
-			break;
-		}
-	}
-
-	if (slot < 0) {
-		printk(KERN_INFO "early_iounmap(%p, %08lx) not found slot\n",
-			 addr, size);
-		WARN_ON(1);
-		return;
-	}
-
-	if (prev_size[slot] != size) {
-		printk(KERN_INFO "early_iounmap(%p, %08lx) [%d] size not consistent %08lx\n",
-			 addr, size, slot, prev_size[slot]);
-		WARN_ON(1);
-		return;
-	}
-
-	if (early_ioremap_debug) {
-		printk(KERN_INFO "early_iounmap(%p, %08lx) [%d]\n", addr,
-		       size, slot);
-		dump_stack();
-	}
-
-	virt_addr = (unsigned long)addr;
-	if (virt_addr < fix_to_virt(FIX_BTMAP_BEGIN)) {
-		WARN_ON(1);
-		return;
-	}
-	offset = virt_addr & ~PAGE_MASK;
-	nrpages = PAGE_ALIGN(offset + size) >> PAGE_SHIFT;
-
-	idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot;
-	while (nrpages > 0) {
-		early_clear_fixmap(idx);
-		--idx;
-		--nrpages;
-	}
-	prev_map[slot] = NULL;
-}
-
-void __init early_memunmap(void *addr, unsigned long size)
-{
-	early_iounmap((__force void __iomem *)addr, size);
-}
diff --git a/arch/x86/mm/pgtable_32.c b/arch/x86/mm/pgtable_32.c
index a69bcb8..4dd8cf6 100644
--- a/arch/x86/mm/pgtable_32.c
+++ b/arch/x86/mm/pgtable_32.c
@@ -127,7 +127,7 @@ static int __init parse_reservetop(char *arg)
 
 	address = memparse(arg, &arg);
 	reserve_top_address(address);
-	fixup_early_ioremap();
+	early_ioremap_init();
 	return 0;
 }
 early_param("reservetop", parse_reservetop);
-- 
1.8.3.1

[PATCH v3 4/6] arm: add early_ioremap support

[Mark Salter]

This patch uses the generic early_ioremap code to implement
early_ioremap for ARM. The ARM-specific bits come mostly from
an earlier patch from Leif Lindholm <leif.lindholm@linaro.org>
here:

  https://lkml.org/lkml/2013/10/3/279

Signed-off-by: Mark Salter <msalter@redhat.com>
Tested-by: Leif Lindholm <leif.lindholm@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
CC: linux-arm-kernel@lists.infradead.org
CC: Russell King <linux@arm.linux.org.uk>
CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Will Deacon <will.deacon@arm.com>
CC: Arnd Bergmann <arnd@arndb.de>
---
 arch/arm/Kconfig              | 11 +++++
 arch/arm/include/asm/Kbuild   |  1 +
 arch/arm/include/asm/fixmap.h | 18 +++++++++
 arch/arm/include/asm/io.h     |  1 +
 arch/arm/kernel/setup.c       |  3 ++
 arch/arm/mm/Makefile          |  1 +
 arch/arm/mm/early_ioremap.c   | 93 +++++++++++++++++++++++++++++++++++++++++++
 arch/arm/mm/mmu.c             |  2 +
 8 files changed, 130 insertions(+)
 create mode 100644 arch/arm/mm/early_ioremap.c

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index c1f1a7e..78a79a6a 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1842,6 +1842,17 @@ config UACCESS_WITH_MEMCPY
 	  However, if the CPU data cache is using a write-allocate mode,
 	  this option is unlikely to provide any performance gain.
 
+config EARLY_IOREMAP
+	depends on MMU
+	bool "Provide early_ioremap() support for kernel initialization."
+	select GENERIC_EARLY_IOREMAP
+	help
+	  Provide a mechanism for kernel initialisation code to temporarily
+	  map, in a highmem-agnostic way, memory pages in before ioremap()
+	  and friends are available (before paging_init() has run). It uses
+	  the same virtual memory range as kmap so all early mappings must
+	  be unapped before paging_init() is called.
+
 config SECCOMP
 	bool
 	prompt "Enable seccomp to safely compute untrusted bytecode"
diff --git a/arch/arm/include/asm/Kbuild b/arch/arm/include/asm/Kbuild
index c38b58c..49ec506 100644
--- a/arch/arm/include/asm/Kbuild
+++ b/arch/arm/include/asm/Kbuild
@@ -4,6 +4,7 @@ generic-y += auxvec.h
 generic-y += bitsperlong.h
 generic-y += cputime.h
 generic-y += current.h
+generic-y += early_ioremap.h
 generic-y += emergency-restart.h
 generic-y += errno.h
 generic-y += exec.h
diff --git a/arch/arm/include/asm/fixmap.h b/arch/arm/include/asm/fixmap.h
index 68ea615..e92b7a4 100644
--- a/arch/arm/include/asm/fixmap.h
+++ b/arch/arm/include/asm/fixmap.h
@@ -21,8 +21,26 @@ enum fixed_addresses {
 	FIX_KMAP_BEGIN,
 	FIX_KMAP_END = (FIXADDR_TOP - FIXADDR_START) >> PAGE_SHIFT,
 	__end_of_fixed_addresses
+/*
+ * 224 temporary boot-time mappings, used by early_ioremap(),
+ * before ioremap() is functional.
+ *
+ * (P)re-using the FIXADDR region, which is used for highmem
+ * later on, and statically aligned to 1MB.
+ */
+#define NR_FIX_BTMAPS		32
+#define FIX_BTMAPS_SLOTS	7
+#define TOTAL_FIX_BTMAPS	(NR_FIX_BTMAPS * FIX_BTMAPS_SLOTS)
+#define FIX_BTMAP_END		FIX_KMAP_BEGIN
+#define FIX_BTMAP_BEGIN		(FIX_BTMAP_END + TOTAL_FIX_BTMAPS - 1)
 };
 
+#define FIXMAP_PAGE_NORMAL (L_PTE_MT_WRITEBACK | L_PTE_YOUNG | L_PTE_PRESENT)
+#define FIXMAP_PAGE_IO (L_PTE_MT_DEV_NONSHARED | L_PTE_YOUNG | L_PTE_PRESENT)
+
+extern void __early_set_fixmap(enum fixed_addresses idx,
+			       phys_addr_t phys, pgprot_t flags);
+
 #include <asm-generic/fixmap.h>
 
 #endif
diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h
index fbeb39c..6b2cc53 100644
--- a/arch/arm/include/asm/io.h
+++ b/arch/arm/include/asm/io.h
@@ -28,6 +28,7 @@
 #include <asm/byteorder.h>
 #include <asm/memory.h>
 #include <asm-generic/pci_iomap.h>
+#include <asm/early_ioremap.h>
 #include <xen/xen.h>
 
 /*
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 987a7f5..038fb75 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -36,6 +36,7 @@
 #include <asm/cpu.h>
 #include <asm/cputype.h>
 #include <asm/elf.h>
+#include <asm/io.h>
 #include <asm/procinfo.h>
 #include <asm/psci.h>
 #include <asm/sections.h>
@@ -887,6 +888,8 @@ void __init setup_arch(char **cmdline_p)
 
 	parse_early_param();
 
+	early_ioremap_init();
+
 	sort(&meminfo.bank, meminfo.nr_banks, sizeof(meminfo.bank[0]), meminfo_cmp, NULL);
 
 	early_paging_init(mdesc, lookup_processor_type(read_cpuid_id()));
diff --git a/arch/arm/mm/Makefile b/arch/arm/mm/Makefile
index ecfe6e5..fea855e 100644
--- a/arch/arm/mm/Makefile
+++ b/arch/arm/mm/Makefile
@@ -15,6 +15,7 @@ endif
 obj-$(CONFIG_MODULES)		+= proc-syms.o
 
 obj-$(CONFIG_ALIGNMENT_TRAP)	+= alignment.o
+obj-$(CONFIG_EARLY_IOREMAP)	+= early_ioremap.o
 obj-$(CONFIG_HIGHMEM)		+= highmem.o
 obj-$(CONFIG_HUGETLB_PAGE)	+= hugetlbpage.o
 
diff --git a/arch/arm/mm/early_ioremap.c b/arch/arm/mm/early_ioremap.c
new file mode 100644
index 0000000..c3e2bf2
--- /dev/null
+++ b/arch/arm/mm/early_ioremap.c
@@ -0,0 +1,93 @@
+/*
+ * early_ioremap() support for ARM
+ *
+ * Based on existing support in arch/x86/mm/ioremap.c
+ *
+ * Restrictions: currently only functional before paging_init()
+ */
+
+#include <linux/init.h>
+#include <linux/io.h>
+
+#include <asm/fixmap.h>
+#include <asm/pgalloc.h>
+#include <asm/pgtable.h>
+#include <asm/tlbflush.h>
+
+#include <asm/mach/map.h>
+
+static pte_t bm_pte[PTRS_PER_PTE] __aligned(PTE_HWTABLE_SIZE) __initdata;
+
+static inline pmd_t * __init early_ioremap_pmd(unsigned long addr)
+{
+	unsigned int index = pgd_index(addr);
+	pgd_t *pgd = cpu_get_pgd() + index;
+	pud_t *pud = pud_offset(pgd, addr);
+	pmd_t *pmd = pmd_offset(pud, addr);
+
+	return pmd;
+}
+
+static inline pte_t * __init early_ioremap_pte(unsigned long addr)
+{
+	return &bm_pte[pte_index(addr)];
+}
+
+void __init early_ioremap_init(void)
+{
+	pmd_t *pmd;
+
+	pmd = early_ioremap_pmd(fix_to_virt(FIX_BTMAP_BEGIN));
+
+	pmd_populate_kernel(NULL, pmd, bm_pte);
+
+	/*
+	 * Make sure we don't span multiple pmds.
+	 */
+	BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT)
+		     != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT));
+
+	if (pmd != early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END))) {
+		WARN_ON(1);
+		pr_warn("pmd %p != %p\n",
+			pmd, early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END)));
+		pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
+			fix_to_virt(FIX_BTMAP_BEGIN));
+		pr_warn("fix_to_virt(FIX_BTMAP_END):   %08lx\n",
+			fix_to_virt(FIX_BTMAP_END));
+		pr_warn("FIX_BTMAP_END:       %d\n", FIX_BTMAP_END);
+		pr_warn("FIX_BTMAP_BEGIN:     %d\n", FIX_BTMAP_BEGIN);
+	}
+
+	early_ioremap_setup();
+}
+
+void __init __early_set_fixmap(enum fixed_addresses idx,
+			       phys_addr_t phys, pgprot_t flags)
+{
+	unsigned long addr = __fix_to_virt(idx);
+	pte_t *pte;
+	u64 desc;
+
+	if (idx > FIX_KMAP_END) {
+		BUG();
+		return;
+	}
+	pte = early_ioremap_pte(addr);
+
+	if (pgprot_val(flags))
+		set_pte_at(NULL, 0xfff00000, pte,
+			   pfn_pte(phys >> PAGE_SHIFT, flags));
+	else
+		pte_clear(NULL, addr, pte);
+	flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
+	desc = *pte;
+}
+
+void __init
+early_ioremap_shutdown(void)
+{
+	pmd_t *pmd;
+	pmd = early_ioremap_pmd(fix_to_virt(FIX_BTMAP_BEGIN));
+	pmd_clear(pmd);
+}
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 580ef2d..bef59b9 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -34,6 +34,7 @@
 #include <asm/mach/arch.h>
 #include <asm/mach/map.h>
 #include <asm/mach/pci.h>
+#include <asm/early_ioremap.h>
 
 #include "mm.h"
 #include "tcm.h"
@@ -1405,6 +1406,7 @@ void __init paging_init(const struct machine_desc *mdesc)
 {
 	void *zero_page;
 
+	early_ioremap_reset();
 	build_mem_type_table();
 	prepare_page_table();
 	map_lowmem();
-- 
1.8.3.1

[PATCH v3 5/6] arm64: initialize pgprot info earlier in boot

[Mark Salter]

Presently, paging_init() calls init_mem_pgprot() to initialize pgprot
values used by macros such as PAGE_KERNEL, PAGE_KERNEL_EXEC, etc. The
new fixmap and early_ioremap support also needs to use these macros
before paging_init() is called. This patch moves the init_mem_pgprot()
call out of paging_init() and into setup_arch() so that pgprot_default
gets initialized in time for fixmap and early_ioremap.

Signed-off-by: Mark Salter <msalter@redhat.com>
CC: linux-arm-kernel@lists.infradead.org
CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Will Deacon <will.deacon@arm.com>
---
 arch/arm64/include/asm/mmu.h | 1 +
 arch/arm64/kernel/setup.c    | 2 ++
 arch/arm64/mm/mmu.c          | 3 +--
 3 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/mmu.h b/arch/arm64/include/asm/mmu.h
index 2494fc0..f600d40 100644
--- a/arch/arm64/include/asm/mmu.h
+++ b/arch/arm64/include/asm/mmu.h
@@ -27,5 +27,6 @@ typedef struct {
 extern void paging_init(void);
 extern void setup_mm_for_reboot(void);
 extern void __iomem *early_io_map(phys_addr_t phys, unsigned long virt);
+extern void init_mem_pgprot(void);
 
 #endif
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index bd9bbd0..029ecfe 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -221,6 +221,8 @@ void __init setup_arch(char **cmdline_p)
 
 	*cmdline_p = boot_command_line;
 
+	init_mem_pgprot();
+
 	parse_early_param();
 
 	arm64_memblock_init();
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index f557ebb..541c782 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -125,7 +125,7 @@ early_param("cachepolicy", early_cachepolicy);
 /*
  * Adjust the PMD section entries according to the CPU in use.
  */
-static void __init init_mem_pgprot(void)
+void __init init_mem_pgprot(void)
 {
 	pteval_t default_pgprot;
 	int i;
@@ -349,7 +349,6 @@ void __init paging_init(void)
 {
 	void *zero_page;
 
-	init_mem_pgprot();
 	map_mem();
 
 	/*
-- 
1.8.3.1

[PATCH v3 6/6] arm64: add early_ioremap support

[Mark Salter]

Add support for early IO or memory mappings which are needed
before the normal ioremap() is usable. This also adds fixmap
support for permanent fixed mappings such as that used by the
earlyprintk device register region.

Signed-off-by: Mark Salter <msalter@redhat.com>
CC: linux-arm-kernel@lists.infradead.org
CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Will Deacon <will.deacon@arm.com>
---
 Documentation/arm64/memory.txt   |  4 +-
 arch/arm64/Kconfig               |  1 +
 arch/arm64/include/asm/Kbuild    |  1 +
 arch/arm64/include/asm/fixmap.h  | 68 ++++++++++++++++++++++++++++++++
 arch/arm64/include/asm/io.h      |  1 +
 arch/arm64/include/asm/memory.h  |  2 +-
 arch/arm64/kernel/early_printk.c |  8 +++-
 arch/arm64/kernel/head.S         |  9 ++---
 arch/arm64/kernel/setup.c        |  2 +
 arch/arm64/mm/ioremap.c          | 85 ++++++++++++++++++++++++++++++++++++++++
 arch/arm64/mm/mmu.c              | 41 -------------------
 11 files changed, 170 insertions(+), 52 deletions(-)
 create mode 100644 arch/arm64/include/asm/fixmap.h

diff --git a/Documentation/arm64/memory.txt b/Documentation/arm64/memory.txt
index 5e054bf..953c81e 100644
--- a/Documentation/arm64/memory.txt
+++ b/Documentation/arm64/memory.txt
@@ -35,7 +35,7 @@ ffffffbc00000000	ffffffbdffffffff	   8GB		vmemmap
 
 ffffffbe00000000	ffffffbffbbfffff	  ~8GB		[guard, future vmmemap]
 
-ffffffbffbc00000	ffffffbffbdfffff	   2MB		earlyprintk device
+ffffffbffbc00000	ffffffbffbdfffff	   2MB		fixed mappings
 
 ffffffbffbe00000	ffffffbffbe0ffff	  64KB		PCI I/O space
 
@@ -60,7 +60,7 @@ fffffdfc00000000	fffffdfdffffffff	   8GB		vmemmap
 
 fffffdfe00000000	fffffdfffbbfffff	  ~8GB		[guard, future vmmemap]
 
-fffffdfffbc00000	fffffdfffbdfffff	   2MB		earlyprintk device
+fffffdfffbc00000	fffffdfffbdfffff	   2MB		fixed mappings
 
 fffffdfffbe00000	fffffdfffbe0ffff	  64KB		PCI I/O space
 
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 6d4dd22..e66a317 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -12,6 +12,7 @@ config ARM64
 	select CLONE_BACKWARDS
 	select COMMON_CLK
 	select GENERIC_CLOCKEVENTS
+	select GENERIC_EARLY_IOREMAP
 	select GENERIC_IOMAP
 	select GENERIC_IRQ_PROBE
 	select GENERIC_IRQ_SHOW
diff --git a/arch/arm64/include/asm/Kbuild b/arch/arm64/include/asm/Kbuild
index 519f89f..b7f99a3 100644
--- a/arch/arm64/include/asm/Kbuild
+++ b/arch/arm64/include/asm/Kbuild
@@ -10,6 +10,7 @@ generic-y += delay.h
 generic-y += div64.h
 generic-y += dma.h
 generic-y += emergency-restart.h
+generic-y += early_ioremap.h
 generic-y += errno.h
 generic-y += ftrace.h
 generic-y += hw_irq.h
diff --git a/arch/arm64/include/asm/fixmap.h b/arch/arm64/include/asm/fixmap.h
new file mode 100644
index 0000000..7ad4f29
--- /dev/null
+++ b/arch/arm64/include/asm/fixmap.h
@@ -0,0 +1,68 @@
+/*
+ * fixmap.h: compile-time virtual memory allocation
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 1998 Ingo Molnar
+ * Copyright (C) 2013 Mark Salter <msalter@redhat.com>
+ *
+ * Adapted from arch/x86_64 version.
+ *
+ */
+
+#ifndef _ASM_ARM64_FIXMAP_H
+#define _ASM_ARM64_FIXMAP_H
+
+#ifndef __ASSEMBLY__
+#include <linux/kernel.h>
+#include <asm/page.h>
+
+/*
+ * Here we define all the compile-time 'special' virtual
+ * addresses. The point is to have a constant address at
+ * compile time, but to set the physical address only
+ * in the boot process.
+ *
+ * These 'compile-time allocated' memory buffers are
+ * page-sized. Use set_fixmap(idx,phys) to associate
+ * physical memory with fixmap indices.
+ *
+ */
+enum fixed_addresses {
+	FIX_EARLYCON,
+	__end_of_permanent_fixed_addresses,
+
+	/*
+	 * Temporary boot-time mappings, used by early_ioremap(),
+	 * before ioremap() is functional.
+	 */
+#ifdef CONFIG_ARM64_64K_PAGES
+#define NR_FIX_BTMAPS		4
+#else
+#define NR_FIX_BTMAPS		64
+#endif
+#define FIX_BTMAPS_SLOTS	7
+#define TOTAL_FIX_BTMAPS	(NR_FIX_BTMAPS * FIX_BTMAPS_SLOTS)
+
+	FIX_BTMAP_END = __end_of_permanent_fixed_addresses,
+	FIX_BTMAP_BEGIN = FIX_BTMAP_END + TOTAL_FIX_BTMAPS - 1,
+	__end_of_fixed_addresses
+};
+
+#define FIXADDR_SIZE	(__end_of_permanent_fixed_addresses << PAGE_SHIFT)
+#define FIXADDR_START	(FIXADDR_TOP - FIXADDR_SIZE)
+
+#define FIXMAP_PAGE_NORMAL PAGE_KERNEL_EXEC
+#define FIXMAP_PAGE_IO     __pgprot(PROT_DEVICE_nGnRE)
+
+extern void __early_set_fixmap(enum fixed_addresses idx,
+			       phys_addr_t phys, pgprot_t flags);
+
+#define __set_fixmap __early_set_fixmap
+
+#include <asm-generic/fixmap.h>
+
+#endif /* !__ASSEMBLY__ */
+#endif /* _ASM_ARM64_FIXMAP_H */
diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h
index 5727697..1e34831 100644
--- a/arch/arm64/include/asm/io.h
+++ b/arch/arm64/include/asm/io.h
@@ -27,6 +27,7 @@
 #include <asm/byteorder.h>
 #include <asm/barrier.h>
 #include <asm/pgtable.h>
+#include <asm/early_ioremap.h>
 
 #include <xen/xen.h>
 
diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index 3776217..50a97df 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -49,7 +49,7 @@
 #define PAGE_OFFSET		(UL(0xffffffffffffffff) << (VA_BITS - 1))
 #define MODULES_END		(PAGE_OFFSET)
 #define MODULES_VADDR		(MODULES_END - SZ_64M)
-#define EARLYCON_IOBASE		(MODULES_VADDR - SZ_4M)
+#define FIXADDR_TOP		(MODULES_VADDR - SZ_2M - PAGE_SIZE)
 #define TASK_SIZE_64		(UL(1) << VA_BITS)
 
 #ifdef CONFIG_COMPAT
diff --git a/arch/arm64/kernel/early_printk.c b/arch/arm64/kernel/early_printk.c
index fbb6e18..850d9a4 100644
--- a/arch/arm64/kernel/early_printk.c
+++ b/arch/arm64/kernel/early_printk.c
@@ -26,6 +26,8 @@
 #include <linux/amba/serial.h>
 #include <linux/serial_reg.h>
 
+#include <asm/fixmap.h>
+
 static void __iomem *early_base;
 static void (*printch)(char ch);
 
@@ -141,8 +143,10 @@ static int __init setup_early_printk(char *buf)
 	}
 	/* no options parsing yet */
 
-	if (paddr)
-		early_base = early_io_map(paddr, EARLYCON_IOBASE);
+	if (paddr) {
+		set_fixmap_io(FIX_EARLYCON, paddr);
+		early_base = (void __iomem *)fix_to_virt(FIX_EARLYCON);
+	}
 
 	printch = match->printch;
 	early_console = &early_console_dev;
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index c68cca5..4b47dcb 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -412,7 +412,7 @@ ENDPROC(__calc_phys_offset)
  *   - identity mapping to enable the MMU (low address, TTBR0)
  *   - first few MB of the kernel linear mapping to jump to once the MMU has
  *     been enabled, including the FDT blob (TTBR1)
- *   - UART mapping if CONFIG_EARLY_PRINTK is enabled (TTBR1)
+ *   - pgd entry for fixed mappings (TTBR1)
  */
 __create_page_tables:
 	pgtbl	x25, x26, x24			// idmap_pg_dir and swapper_pg_dir addresses
@@ -465,15 +465,12 @@ __create_page_tables:
 	sub	x6, x6, #1			// inclusive range
 	create_block_map x0, x7, x3, x5, x6
 1:
-#ifdef CONFIG_EARLY_PRINTK
 	/*
-	 * Create the pgd entry for the UART mapping. The full mapping is done
-	 * later based earlyprintk kernel parameter.
+	 * Create the pgd entry for the fixed mappings.
 	 */
-	ldr	x5, =EARLYCON_IOBASE		// UART virtual address
+	ldr	x5, =FIXADDR_TOP		// Fixed mapping virtual address
 	add	x0, x26, #2 * PAGE_SIZE		// section table address
 	create_pgd_entry x26, x0, x5, x6, x7
-#endif
 	ret
 ENDPROC(__create_page_tables)
 	.ltorg
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 029ecfe..5516f54 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -42,6 +42,7 @@
 #include <linux/of_fdt.h>
 #include <linux/of_platform.h>
 
+#include <asm/fixmap.h>
 #include <asm/cputype.h>
 #include <asm/elf.h>
 #include <asm/cputable.h>
@@ -222,6 +223,7 @@ void __init setup_arch(char **cmdline_p)
 	*cmdline_p = boot_command_line;
 
 	init_mem_pgprot();
+	early_ioremap_init();
 
 	parse_early_param();
 
diff --git a/arch/arm64/mm/ioremap.c b/arch/arm64/mm/ioremap.c
index 2bb1d58..7ec3283 100644
--- a/arch/arm64/mm/ioremap.c
+++ b/arch/arm64/mm/ioremap.c
@@ -25,6 +25,10 @@
 #include <linux/vmalloc.h>
 #include <linux/io.h>
 
+#include <asm/fixmap.h>
+#include <asm/tlbflush.h>
+#include <asm/pgalloc.h>
+
 static void __iomem *__ioremap_caller(phys_addr_t phys_addr, size_t size,
 				      pgprot_t prot, void *caller)
 {
@@ -98,3 +102,84 @@ void __iomem *ioremap_cache(phys_addr_t phys_addr, size_t size)
 				__builtin_return_address(0));
 }
 EXPORT_SYMBOL(ioremap_cache);
+
+#ifndef CONFIG_ARM64_64K_PAGES
+static pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss;
+#endif
+
+static inline pmd_t * __init early_ioremap_pmd(unsigned long addr)
+{
+	pgd_t *pgd;
+	pud_t *pud;
+
+	pgd = pgd_offset_k(addr);
+	BUG_ON(pgd_none(*pgd) || pgd_bad(*pgd));
+
+	pud = pud_offset(pgd, addr);
+	BUG_ON(pud_none(*pud) || pud_bad(*pud));
+
+	return pmd_offset(pud, addr);
+}
+
+static inline pte_t * __init early_ioremap_pte(unsigned long addr)
+{
+	pmd_t *pmd = early_ioremap_pmd(addr);
+
+	BUG_ON(pmd_none(*pmd) || pmd_bad(*pmd));
+
+	return pte_offset_kernel(pmd, addr);
+}
+
+void __init early_ioremap_init(void)
+{
+	pmd_t *pmd;
+
+	pmd = early_ioremap_pmd(fix_to_virt(FIX_BTMAP_BEGIN));
+#ifndef CONFIG_ARM64_64K_PAGES
+	/* need to populate pmd for 4k pagesize only */
+	pmd_populate_kernel(&init_mm, pmd, bm_pte);
+#endif
+	/*
+	 * The boot-ioremap range spans multiple pmds, for which
+	 * we are not prepared:
+	 */
+	BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT)
+		     != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT));
+
+	if (pmd != early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END))) {
+		WARN_ON(1);
+		pr_warn("pmd %p != %p\n",
+			pmd, early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END)));
+		pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
+			fix_to_virt(FIX_BTMAP_BEGIN));
+		pr_warn("fix_to_virt(FIX_BTMAP_END):   %08lx\n",
+			fix_to_virt(FIX_BTMAP_END));
+
+		pr_warn("FIX_BTMAP_END:       %d\n", FIX_BTMAP_END);
+		pr_warn("FIX_BTMAP_BEGIN:     %d\n",
+			FIX_BTMAP_BEGIN);
+	}
+
+	early_ioremap_setup();
+}
+
+void __init __early_set_fixmap(enum fixed_addresses idx,
+			       phys_addr_t phys, pgprot_t flags)
+{
+	unsigned long addr = __fix_to_virt(idx);
+	pte_t *pte;
+
+	if (idx >= __end_of_fixed_addresses) {
+		BUG();
+		return;
+	}
+
+	pte = early_ioremap_pte(addr);
+
+	if (pgprot_val(flags))
+		set_pte(pte, pfn_pte(phys >> PAGE_SHIFT, flags));
+	else {
+		pte_clear(&init_mm, addr, pte);
+		flush_tlb_kernel_range(addr, addr+PAGE_SIZE);
+	}
+}
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 541c782..7b345e3 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -252,47 +252,6 @@ static void __init create_mapping(phys_addr_t phys, unsigned long virt,
 	} while (pgd++, addr = next, addr != end);
 }
 
-#ifdef CONFIG_EARLY_PRINTK
-/*
- * Create an early I/O mapping using the pgd/pmd entries already populated
- * in head.S as this function is called too early to allocated any memory. The
- * mapping size is 2MB with 4KB pages or 64KB or 64KB pages.
- */
-void __iomem * __init early_io_map(phys_addr_t phys, unsigned long virt)
-{
-	unsigned long size, mask;
-	bool page64k = IS_ENABLED(CONFIG_ARM64_64K_PAGES);
-	pgd_t *pgd;
-	pud_t *pud;
-	pmd_t *pmd;
-	pte_t *pte;
-
-	/*
-	 * No early pte entries with !ARM64_64K_PAGES configuration, so using
-	 * sections (pmd).
-	 */
-	size = page64k ? PAGE_SIZE : SECTION_SIZE;
-	mask = ~(size - 1);
-
-	pgd = pgd_offset_k(virt);
-	pud = pud_offset(pgd, virt);
-	if (pud_none(*pud))
-		return NULL;
-	pmd = pmd_offset(pud, virt);
-
-	if (page64k) {
-		if (pmd_none(*pmd))
-			return NULL;
-		pte = pte_offset_kernel(pmd, virt);
-		set_pte(pte, __pte((phys & mask) | PROT_DEVICE_nGnRE));
-	} else {
-		set_pmd(pmd, __pmd((phys & mask) | PROT_SECT_DEVICE_nGnRE));
-	}
-
-	return (void __iomem *)((virt & mask) + (phys & ~mask));
-}
-#endif
-
 static void __init map_mem(void)
 {
 	struct memblock_region *reg;
-- 
1.8.3.1

Re: [PATCH v3 4/6] arm: add early_ioremap support

[Russell King - ARM Linux]

On Thu, Jan 09, 2014 at 10:50:31PM -0500, Mark Salter wrote:
> +#define FIXMAP_PAGE_NORMAL (L_PTE_MT_WRITEBACK | L_PTE_YOUNG | L_PTE_PRESENT)
> +#define FIXMAP_PAGE_IO (L_PTE_MT_DEV_NONSHARED | L_PTE_YOUNG | L_PTE_PRESENT)

Doesn't this also want L_PTE_XN for at least IO mappings - maybe for the
normal too if no code is expected to be run from it.

-- 
FTTC broadband for 0.8mile line: 5.8Mbps down 500kbps up.  Estimation
in database were 13.1 to 19Mbit for a good line, about 7.5+ for a bad.
Estimate before purchase was "up to 13.2Mbit".

Re: [PATCH v3 4/6] arm: add early_ioremap support

[Rob Herring]

On Thu, Jan 9, 2014 at 9:50 PM, Mark Salter <msalter@redhat.com> wrote:
> This patch uses the generic early_ioremap code to implement
> early_ioremap for ARM. The ARM-specific bits come mostly from
> an earlier patch from Leif Lindholm <leif.lindholm@linaro.org>
> here:
>
>   https://lkml.org/lkml/2013/10/3/279

I think this will be useful to implement an arm64 style earlycon for
arm as the current DEBUG_LL doesn't really work with multi-platform
kernels. I started on this and quickly realized I needed the fixmap
support.

> Signed-off-by: Mark Salter <msalter@redhat.com>
> Tested-by: Leif Lindholm <leif.lindholm@linaro.org>
> Acked-by: Catalin Marinas <catalin.marinas@arm.com>
> CC: linux-arm-kernel@lists.infradead.org
> CC: Russell King <linux@arm.linux.org.uk>
> CC: Catalin Marinas <catalin.marinas@arm.com>
> CC: Will Deacon <will.deacon@arm.com>
> CC: Arnd Bergmann <arnd@arndb.de>
> ---
>  arch/arm/Kconfig              | 11 +++++
>  arch/arm/include/asm/Kbuild   |  1 +
>  arch/arm/include/asm/fixmap.h | 18 +++++++++
>  arch/arm/include/asm/io.h     |  1 +
>  arch/arm/kernel/setup.c       |  3 ++
>  arch/arm/mm/Makefile          |  1 +
>  arch/arm/mm/early_ioremap.c   | 93 +++++++++++++++++++++++++++++++++++++++++++
>  arch/arm/mm/mmu.c             |  2 +
>  8 files changed, 130 insertions(+)
>  create mode 100644 arch/arm/mm/early_ioremap.c
>
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index c1f1a7e..78a79a6a 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -1842,6 +1842,17 @@ config UACCESS_WITH_MEMCPY
>           However, if the CPU data cache is using a write-allocate mode,
>           this option is unlikely to provide any performance gain.
>
> +config EARLY_IOREMAP
> +       depends on MMU

Is it possible to implement a !MMU version of early_ioremap that
simply returns the phys address rather than have this dependency?

> +       bool "Provide early_ioremap() support for kernel initialization."
> +       select GENERIC_EARLY_IOREMAP
> +       help
> +         Provide a mechanism for kernel initialisation code to temporarily
> +         map, in a highmem-agnostic way, memory pages in before ioremap()
> +         and friends are available (before paging_init() has run). It uses
> +         the same virtual memory range as kmap so all early mappings must
> +         be unapped before paging_init() is called.
> +
>  config SECCOMP
>         bool
>         prompt "Enable seccomp to safely compute untrusted bytecode"
> diff --git a/arch/arm/include/asm/Kbuild b/arch/arm/include/asm/Kbuild
> index c38b58c..49ec506 100644
> --- a/arch/arm/include/asm/Kbuild
> +++ b/arch/arm/include/asm/Kbuild
> @@ -4,6 +4,7 @@ generic-y += auxvec.h
>  generic-y += bitsperlong.h
>  generic-y += cputime.h
>  generic-y += current.h
> +generic-y += early_ioremap.h
>  generic-y += emergency-restart.h
>  generic-y += errno.h
>  generic-y += exec.h
> diff --git a/arch/arm/include/asm/fixmap.h b/arch/arm/include/asm/fixmap.h
> index 68ea615..e92b7a4 100644
> --- a/arch/arm/include/asm/fixmap.h
> +++ b/arch/arm/include/asm/fixmap.h
> @@ -21,8 +21,26 @@ enum fixed_addresses {
>         FIX_KMAP_BEGIN,
>         FIX_KMAP_END = (FIXADDR_TOP - FIXADDR_START) >> PAGE_SHIFT,
>         __end_of_fixed_addresses
> +/*
> + * 224 temporary boot-time mappings, used by early_ioremap(),
> + * before ioremap() is functional.
> + *
> + * (P)re-using the FIXADDR region, which is used for highmem
> + * later on, and statically aligned to 1MB.
> + */
> +#define NR_FIX_BTMAPS          32
> +#define FIX_BTMAPS_SLOTS       7
> +#define TOTAL_FIX_BTMAPS       (NR_FIX_BTMAPS * FIX_BTMAPS_SLOTS)
> +#define FIX_BTMAP_END          FIX_KMAP_BEGIN
> +#define FIX_BTMAP_BEGIN                (FIX_BTMAP_END + TOTAL_FIX_BTMAPS - 1)
>  };
>
> +#define FIXMAP_PAGE_NORMAL (L_PTE_MT_WRITEBACK | L_PTE_YOUNG | L_PTE_PRESENT)
> +#define FIXMAP_PAGE_IO (L_PTE_MT_DEV_NONSHARED | L_PTE_YOUNG | L_PTE_PRESENT)
> +
> +extern void __early_set_fixmap(enum fixed_addresses idx,
> +                              phys_addr_t phys, pgprot_t flags);
> +
>  #include <asm-generic/fixmap.h>
>
>  #endif
> diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h
> index fbeb39c..6b2cc53 100644
> --- a/arch/arm/include/asm/io.h
> +++ b/arch/arm/include/asm/io.h
> @@ -28,6 +28,7 @@
>  #include <asm/byteorder.h>
>  #include <asm/memory.h>
>  #include <asm-generic/pci_iomap.h>
> +#include <asm/early_ioremap.h>
>  #include <xen/xen.h>
>
>  /*
> diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
> index 987a7f5..038fb75 100644
> --- a/arch/arm/kernel/setup.c
> +++ b/arch/arm/kernel/setup.c
> @@ -36,6 +36,7 @@
>  #include <asm/cpu.h>
>  #include <asm/cputype.h>
>  #include <asm/elf.h>
> +#include <asm/io.h>

Use linux/io.h?

>  #include <asm/procinfo.h>
>  #include <asm/psci.h>
>  #include <asm/sections.h>
> @@ -887,6 +888,8 @@ void __init setup_arch(char **cmdline_p)
>
>         parse_early_param();
>
> +       early_ioremap_init();
> +

This call would need to be before parse_early_param for the earlycon to work.

Rob

Re: [PATCH v3 4/6] arm: add early_ioremap support

[Catalin Marinas]

On Fri, Jan 10, 2014 at 04:11:03PM +0000, Rob Herring wrote:
> On Thu, Jan 9, 2014 at 9:50 PM, Mark Salter <msalter@redhat.com> wrote:
> > This patch uses the generic early_ioremap code to implement
> > early_ioremap for ARM. The ARM-specific bits come mostly from
> > an earlier patch from Leif Lindholm <leif.lindholm@linaro.org>
> > here:
> >
> >   https://lkml.org/lkml/2013/10/3/279
> 
> I think this will be useful to implement an arm64 style earlycon for
> arm as the current DEBUG_LL doesn't really work with multi-platform
> kernels. I started on this and quickly realized I needed the fixmap
> support.

It would be even better if you can make it more generic
(drivers/tty/serial/) and keep DEBUG_LL as a specialised case for
arch/arm (when !multi-platform).

-- 
Catalin

Re: [PATCH v3 4/6] arm: add early_ioremap support

[Rob Herring]

On Fri, Jan 10, 2014 at 10:58 AM, Catalin Marinas
<catalin.marinas@arm.com> wrote:
> On Fri, Jan 10, 2014 at 04:11:03PM +0000, Rob Herring wrote:
>> On Thu, Jan 9, 2014 at 9:50 PM, Mark Salter <msalter@redhat.com> wrote:
>> > This patch uses the generic early_ioremap code to implement
>> > early_ioremap for ARM. The ARM-specific bits come mostly from
>> > an earlier patch from Leif Lindholm <leif.lindholm@linaro.org>
>> > here:
>> >
>> >   https://lkml.org/lkml/2013/10/3/279
>>
>> I think this will be useful to implement an arm64 style earlycon for
>> arm as the current DEBUG_LL doesn't really work with multi-platform
>> kernels. I started on this and quickly realized I needed the fixmap
>> support.
>
> It would be even better if you can make it more generic
> (drivers/tty/serial/) and keep DEBUG_LL as a specialised case for
> arch/arm (when !multi-platform).

Y

Re: [PATCH v3 4/6] arm: add early_ioremap support

[Rob Herring]

On Fri, Jan 10, 2014 at 10:58 AM, Catalin Marinas
<catalin.marinas@arm.com> wrote:
> On Fri, Jan 10, 2014 at 04:11:03PM +0000, Rob Herring wrote:
>> On Thu, Jan 9, 2014 at 9:50 PM, Mark Salter <msalter@redhat.com> wrote:
>> > This patch uses the generic early_ioremap code to implement
>> > early_ioremap for ARM. The ARM-specific bits come mostly from
>> > an earlier patch from Leif Lindholm <leif.lindholm@linaro.org>
>> > here:
>> >
>> >   https://lkml.org/lkml/2013/10/3/279
>>
>> I think this will be useful to implement an arm64 style earlycon for
>> arm as the current DEBUG_LL doesn't really work with multi-platform
>> kernels. I started on this and quickly realized I needed the fixmap
>> support.
>
> It would be even better if you can make it more generic
> (drivers/tty/serial/) and keep DEBUG_LL as a specialised case for
> arch/arm (when !multi-platform).

Yes, probably can do that. Perhaps DEBUG_LL can go back to just really
early debug as Russell desires.

Rob

Re: [PATCH v3 4/6] arm: add early_ioremap support

[Stephen Boyd]

Just some minor nitpicks

On 01/09/14 19:50, Mark Salter wrote:
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index c1f1a7e..78a79a6a 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -1842,6 +1842,17 @@ config UACCESS_WITH_MEMCPY
>  	  However, if the CPU data cache is using a write-allocate mode,
>  	  this option is unlikely to provide any performance gain.
>  
> +config EARLY_IOREMAP
> +	depends on MMU
> +	bool "Provide early_ioremap() support for kernel initialization."

Please drop the full stop.

> +	select GENERIC_EARLY_IOREMAP
> +	help
> +	  Provide a mechanism for kernel initialisation code to temporarily
> +	  map, in a highmem-agnostic way, memory pages in before ioremap()
> +	  and friends are available (before paging_init() has run). It uses
> +	  the same virtual memory range as kmap so all early mappings must
> +	  be unapped before paging_init() is called.

s/unapped/unmapped/

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
hosted by The Linux Foundation

Re: [PATCH v3 4/6] arm: add early_ioremap support

[Mark Salter]

On Fri, 2014-01-10 at 10:11 -0600, Rob Herring wrote:
> On Thu, Jan 9, 2014 at 9:50 PM, Mark Salter <msalter@redhat.com> wrote:
> > +config EARLY_IOREMAP
> > +       depends on MMU
> 
> Is it possible to implement a !MMU version of early_ioremap that
> simply returns the phys address rather than have this dependency?

I don't think that would be too hard to do.

> 
> > +       bool "Provide early_ioremap() support for kernel initialization."
> > +       select GENERIC_EARLY_IOREMAP
> > +       help
> > +         Provide a mechanism for kernel initialisation code to temporarily
> > +         map, in a highmem-agnostic way, memory pages in before ioremap()
> > +         and friends are available (before paging_init() has run). It uses
> > +         the same virtual memory range as kmap so all early mappings must
> > +         be unapped before paging_init() is called.
> > +
> >  config SECCOMP
> >         bool
> >         prompt "Enable seccomp to safely compute untrusted bytecode"
> > diff --git a/arch/arm/include/asm/Kbuild b/arch/arm/include/asm/Kbuild
> > index c38b58c..49ec506 100644
> > --- a/arch/arm/include/asm/Kbuild
> > +++ b/arch/arm/include/asm/Kbuild
> > @@ -4,6 +4,7 @@ generic-y += auxvec.h
> >  generic-y += bitsperlong.h
> >  generic-y += cputime.h
> >  generic-y += current.h
> > +generic-y += early_ioremap.h
> >  generic-y += emergency-restart.h
> >  generic-y += errno.h
> >  generic-y += exec.h
> > diff --git a/arch/arm/include/asm/fixmap.h b/arch/arm/include/asm/fixmap.h
> > index 68ea615..e92b7a4 100644
> > --- a/arch/arm/include/asm/fixmap.h
> > +++ b/arch/arm/include/asm/fixmap.h
> > @@ -21,8 +21,26 @@ enum fixed_addresses {
> >         FIX_KMAP_BEGIN,
> >         FIX_KMAP_END = (FIXADDR_TOP - FIXADDR_START) >> PAGE_SHIFT,
> >         __end_of_fixed_addresses
> > +/*
> > + * 224 temporary boot-time mappings, used by early_ioremap(),
> > + * before ioremap() is functional.
> > + *
> > + * (P)re-using the FIXADDR region, which is used for highmem
> > + * later on, and statically aligned to 1MB.
> > + */
> > +#define NR_FIX_BTMAPS          32
> > +#define FIX_BTMAPS_SLOTS       7
> > +#define TOTAL_FIX_BTMAPS       (NR_FIX_BTMAPS * FIX_BTMAPS_SLOTS)
> > +#define FIX_BTMAP_END          FIX_KMAP_BEGIN
> > +#define FIX_BTMAP_BEGIN                (FIX_BTMAP_END + TOTAL_FIX_BTMAPS - 1)
> >  };
> >
> > +#define FIXMAP_PAGE_NORMAL (L_PTE_MT_WRITEBACK | L_PTE_YOUNG | L_PTE_PRESENT)
> > +#define FIXMAP_PAGE_IO (L_PTE_MT_DEV_NONSHARED | L_PTE_YOUNG | L_PTE_PRESENT)
> > +
> > +extern void __early_set_fixmap(enum fixed_addresses idx,
> > +                              phys_addr_t phys, pgprot_t flags);
> > +
> >  #include <asm-generic/fixmap.h>
> >
> >  #endif
> > diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h
> > index fbeb39c..6b2cc53 100644
> > --- a/arch/arm/include/asm/io.h
> > +++ b/arch/arm/include/asm/io.h
> > @@ -28,6 +28,7 @@
> >  #include <asm/byteorder.h>
> >  #include <asm/memory.h>
> >  #include <asm-generic/pci_iomap.h>
> > +#include <asm/early_ioremap.h>
> >  #include <xen/xen.h>
> >
> >  /*
> > diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
> > index 987a7f5..038fb75 100644
> > --- a/arch/arm/kernel/setup.c
> > +++ b/arch/arm/kernel/setup.c
> > @@ -36,6 +36,7 @@
> >  #include <asm/cpu.h>
> >  #include <asm/cputype.h>
> >  #include <asm/elf.h>
> > +#include <asm/io.h>
> 
> Use linux/io.h?

Yes.

> 
> >  #include <asm/procinfo.h>
> >  #include <asm/psci.h>
> >  #include <asm/sections.h>
> > @@ -887,6 +888,8 @@ void __init setup_arch(char **cmdline_p)
> >
> >         parse_early_param();
> >
> > +       early_ioremap_init();
> > +
> 
> This call would need to be before parse_early_param for the earlycon to work.

Yes, like arm64 does it.

Re: [PATCH v3 4/6] arm: add early_ioremap support

[Mark Salter]

On Fri, 2014-01-10 at 12:40 -0800, Stephen Boyd wrote:
> Just some minor nitpicks
> 
> On 01/09/14 19:50, Mark Salter wrote:
> > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> > index c1f1a7e..78a79a6a 100644
> > --- a/arch/arm/Kconfig
> > +++ b/arch/arm/Kconfig
> > @@ -1842,6 +1842,17 @@ config UACCESS_WITH_MEMCPY
> >  	  However, if the CPU data cache is using a write-allocate mode,
> >  	  this option is unlikely to provide any performance gain.
> >  
> > +config EARLY_IOREMAP
> > +	depends on MMU
> > +	bool "Provide early_ioremap() support for kernel initialization."
> 
> Please drop the full stop.
> 
> > +	select GENERIC_EARLY_IOREMAP
> > +	help
> > +	  Provide a mechanism for kernel initialisation code to temporarily
> > +	  map, in a highmem-agnostic way, memory pages in before ioremap()
> > +	  and friends are available (before paging_init() has run). It uses
> > +	  the same virtual memory range as kmap so all early mappings must
> > +	  be unapped before paging_init() is called.
> 
> s/unapped/unmapped/
> 

Will do. Thanks!

Re: [PATCH v3 4/6] arm: add early_ioremap support

[Laura Abbott]

On 1/9/2014 7:50 PM, Mark Salter wrote:
....
> diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
> index 987a7f5..038fb75 100644
> --- a/arch/arm/kernel/setup.c
> +++ b/arch/arm/kernel/setup.c
> @@ -36,6 +36,7 @@
>   #include <asm/cpu.h>
>   #include <asm/cputype.h>
>   #include <asm/elf.h>
> +#include <asm/io.h>
>   #include <asm/procinfo.h>
>   #include <asm/psci.h>
>   #include <asm/sections.h>
> @@ -887,6 +888,8 @@ void __init setup_arch(char **cmdline_p)
>
>   	parse_early_param();
>
> +	early_ioremap_init();
> +
>   	sort(&meminfo.bank, meminfo.nr_banks, sizeof(meminfo.bank[0]), meminfo_cmp, NULL);
>
>   	early_paging_init(mdesc, lookup_processor_type(read_cpuid_id()));

Any chance we could do this even earlier, say right after 
setup_processor? It would be nice to be able to do this while FDT 
scanning (I have a use case in mind, potential patches are in the works)

<snip>
> diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
> index 580ef2d..bef59b9 100644
> --- a/arch/arm/mm/mmu.c
> +++ b/arch/arm/mm/mmu.c
> @@ -34,6 +34,7 @@
>   #include <asm/mach/arch.h>
>   #include <asm/mach/map.h>
>   #include <asm/mach/pci.h>
> +#include <asm/early_ioremap.h>
>
>   #include "mm.h"
>   #include "tcm.h"
> @@ -1405,6 +1406,7 @@ void __init paging_init(const struct machine_desc *mdesc)
>   {
>   	void *zero_page;
>
> +	early_ioremap_reset();
>   	build_mem_type_table();
>   	prepare_page_table();
>   	map_lowmem();
>

Neither x86 nor arm64 get rid of existing mapping in paging_init. Is 
there a reason this needs to be here for arm? Are there concerns about 
alias mappings?

Thanks,
Laura

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
hosted by The Linux Foundation

Re: [PATCH v3 4/6] arm: add early_ioremap support

[Russell King - ARM Linux]

On Wed, Jan 15, 2014 at 04:32:03PM -0800, Laura Abbott wrote:
> Neither x86 nor arm64 get rid of existing mapping in paging_init. Is  
> there a reason this needs to be here for arm? Are there concerns about  
> alias mappings?

The early mappings we setup in the assembly code are imperfect - they're
an approximation.  We map just about enough memory to get the kernel
going, and we setup a mapping for the debug stuff using a section
mapping, which may not be appropriate.

The permissions too are a just chosen to get things going, and the
subsequent replacement of the page table entries is to fix all that up.
We really don't want any old entries left behind.

-- 
FTTC broadband for 0.8mile line: 5.8Mbps down 500kbps up.  Estimation
in database were 13.1 to 19Mbit for a good line, about 7.5+ for a bad.
Estimate before purchase was "up to 13.2Mbit".

Re: [PATCH v3 4/6] arm: add early_ioremap support

[Mark Salter]

On Wed, 2014-01-15 at 16:32 -0800, Laura Abbott wrote:
> On 1/9/2014 7:50 PM, Mark Salter wrote:
> ....
> > diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
> > index 987a7f5..038fb75 100644
> > --- a/arch/arm/kernel/setup.c
> > +++ b/arch/arm/kernel/setup.c
> > @@ -36,6 +36,7 @@
> >   #include <asm/cpu.h>
> >   #include <asm/cputype.h>
> >   #include <asm/elf.h>
> > +#include <asm/io.h>
> >   #include <asm/procinfo.h>
> >   #include <asm/psci.h>
> >   #include <asm/sections.h>
> > @@ -887,6 +888,8 @@ void __init setup_arch(char **cmdline_p)
> >
> >   	parse_early_param();
> >
> > +	early_ioremap_init();
> > +
> >   	sort(&meminfo.bank, meminfo.nr_banks, sizeof(meminfo.bank[0]), meminfo_cmp, NULL);
> >
> >   	early_paging_init(mdesc, lookup_processor_type(read_cpuid_id()));
> 
> Any chance we could do this even earlier, say right after 
> setup_processor? It would be nice to be able to do this while FDT 
> scanning (I have a use case in mind, potential patches are in the works)

It looks like that would work...