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Subject[PATCH v3 19/20] ARM: LPAE: add support for ATAG_MEM64
Date
From: Will Deacon <will.deacon@arm.com>

LPAE provides support for memory banks with physical addresses of up
to 40 bits.

This patch adds a new atag, ATAG_MEM64, so that the Kernel can be
informed about memory that exists above the 4GB boundary.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---
arch/arm/include/asm/setup.h | 10 +++++++++-
arch/arm/kernel/compat.c | 4 ++--
arch/arm/kernel/setup.c | 12 +++++++++++-
3 files changed, 22 insertions(+), 4 deletions(-)
diff --git a/arch/arm/include/asm/setup.h b/arch/arm/include/asm/setup.h
index 5092118..fab849f 100644
--- a/arch/arm/include/asm/setup.h
+++ b/arch/arm/include/asm/setup.h
@@ -43,6 +43,13 @@ struct tag_mem32 {
__u32 start; /* physical start address */
};

+#define ATAG_MEM64 0x54420002
+
+struct tag_mem64 {
+ __u64 size;
+ __u64 start; /* physical start address */
+};
+
/* VGA text type displays */
#define ATAG_VIDEOTEXT 0x54410003

@@ -147,7 +154,8 @@ struct tag {
struct tag_header hdr;
union {
struct tag_core core;
- struct tag_mem32 mem;
+ struct tag_mem32 mem32;
+ struct tag_mem64 mem64;
struct tag_videotext videotext;
struct tag_ramdisk ramdisk;
struct tag_initrd initrd;
diff --git a/arch/arm/kernel/compat.c b/arch/arm/kernel/compat.c
index 9256523..f224d95 100644
--- a/arch/arm/kernel/compat.c
+++ b/arch/arm/kernel/compat.c
@@ -86,8 +86,8 @@ static struct tag * __init memtag(struct tag *tag, unsigned long start, unsigned
tag = tag_next(tag);
tag->hdr.tag = ATAG_MEM;
tag->hdr.size = tag_size(tag_mem32);
- tag->u.mem.size = size;
- tag->u.mem.start = start;
+ tag->u.mem32.size = size;
+ tag->u.mem32.start = start;

return tag;
}
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index eaa87d4..c7770e8 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -591,11 +591,21 @@ __tagtable(ATAG_CORE, parse_tag_core);

static int __init parse_tag_mem32(const struct tag *tag)
{
- return arm_add_memory(tag->u.mem.start, tag->u.mem.size);
+ return arm_add_memory(tag->u.mem32.start, tag->u.mem32.size);
}

__tagtable(ATAG_MEM, parse_tag_mem32);

+#ifdef CONFIG_PHYS_ADDR_T_64BIT
+static int __init parse_tag_mem64(const struct tag *tag)
+{
+ /* We only use 32-bits for the size. */
+ return arm_add_memory(tag->u.mem64.start, (unsigned long)tag->u.mem64.size);
+}
+
+__tagtable(ATAG_MEM64, parse_tag_mem64);
+#endif /* CONFIG_PHYS_ADDR_T_64BIT */
+
#if defined(CONFIG_VGA_CONSOLE) || defined(CONFIG_DUMMY_CONSOLE)
struct screen_info screen_info = {
.orig_video_lines = 30,

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