[U-Boot] [PATCH 1/1] efi_loader: fix bug in efi_add_known_memory

[Heinrich Schuchardt]

In efi_add_known_memory the start address is correctly rounded
up to a mulitple of EFI_PAGE_SIZE.
By this rounding we may loose up to EFI_PAGE_MASK bytes.
The current code does not take this loss of available memory
into account when calculating the number of pages.

Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
---
 lib/efi_loader/efi_memory.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/lib/efi_loader/efi_memory.c b/lib/efi_loader/efi_memory.c
index c1a080e2e9..38b0e1d808 100644
--- a/lib/efi_loader/efi_memory.c
+++ b/lib/efi_loader/efi_memory.c
@@ -444,8 +444,14 @@ __weak void efi_add_known_memory(void)
 		u64 ram_start = gd->bd->bi_dram[i].start;
 		u64 ram_size = gd->bd->bi_dram[i].size;
 		u64 start = (ram_start + EFI_PAGE_MASK) & ~EFI_PAGE_MASK;
-		u64 pages = (ram_size + EFI_PAGE_MASK) >> EFI_PAGE_SHIFT;
+		u64 pages;
 
+		if (ram_size <= EFI_PAGE_MASK)
+			continue;
+		pages = (ram_start + ram_size - start + EFI_PAGE_MASK) >>
+			EFI_PAGE_SHIFT;
+		if (pages == 0)
+			continue;
 		efi_add_memory_map(start, pages, EFI_CONVENTIONAL_MEMORY,
 				   false);
 	}
-- 
2.11.0