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[v4,01/22] of/fdt: make memblock minimum physical address arch configurable

Message ID 1453828249-14467-2-git-send-email-ard.biesheuvel@linaro.org
State Accepted
Commit 270522a04f7a9911983878fa37da467f9ff1c938
Headers show

Commit Message

Ard Biesheuvel Jan. 26, 2016, 5:10 p.m. UTC 
By default, early_init_dt_add_memory_arch() ignores memory below
the base of the kernel image since it won't be addressable via the
linear mapping. However, this is not appropriate anymore once we
decouple the kernel text mapping from the linear mapping, so archs
may want to drop the low limit entirely. So allow the minimum to be
overridden by setting MIN_MEMBLOCK_ADDR.

Acked-by: Mark Rutland <mark.rutland@arm.com>

Acked-by: Rob Herring <robh@kernel.org>

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

---
 drivers/of/fdt.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

-- 
2.5.0
diff mbox

Patch

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 655f79db7899..1f98156f8996 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -976,13 +976,16 @@  int __init early_init_dt_scan_chosen(unsigned long node, const char *uname,
 }
 
 #ifdef CONFIG_HAVE_MEMBLOCK
+#ifndef MIN_MEMBLOCK_ADDR
+#define MIN_MEMBLOCK_ADDR	__pa(PAGE_OFFSET)
+#endif
 #ifndef MAX_MEMBLOCK_ADDR
 #define MAX_MEMBLOCK_ADDR	((phys_addr_t)~0)
 #endif
 
 void __init __weak early_init_dt_add_memory_arch(u64 base, u64 size)
 {
-	const u64 phys_offset = __pa(PAGE_OFFSET);
+	const u64 phys_offset = MIN_MEMBLOCK_ADDR;
 
 	if (!PAGE_ALIGNED(base)) {
 		if (size < PAGE_SIZE - (base & ~PAGE_MASK)) {