Hi Aiden,
On Fri, Aug 30, 2019 at 5:31 AM Park, Aiden aiden.park@intel.com wrote:
Hi Heinrich and Bin,
-----Original Message----- From: Heinrich Schuchardt [mailto:xypron.glpk@gmx.de] Sent: Wednesday, August 28, 2019 10:16 PM To: Bin Meng bmeng.cn@gmail.com; Park, Aiden aiden.park@intel.com Cc: Simon Glass sjg@chromium.org; u-boot@lists.denx.de; Alexander Graf agraf@csgraf.de Subject: Re: [PATCH 1/1] x86: efi_loader: Fix invalid address return from efi_alloc()
On 8/29/19 5:36 AM, Bin Meng wrote:
+Heinrich,
On Wed, Aug 28, 2019 at 2:35 AM Park, Aiden aiden.park@intel.com wrote:
This issue can be seen on 32bit operation when one of E820_RAM type entries is greater than 4GB memory space.
The efi_alloc() finds a free memory in the conventional memory which is greater than 4GB. But, it does type cast to 32bit address space and eventually returns invalid address.
Signed-off-by: Aiden Park aiden.park@intel.com
arch/x86/lib/e820.c | 22 +++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-)
diff --git a/arch/x86/lib/e820.c b/arch/x86/lib/e820.c index d6ae2c4e9d..3e93931231 100644 --- a/arch/x86/lib/e820.c +++ b/arch/x86/lib/e820.c @@ -41,11 +41,15 @@ void efi_add_known_memory(void) { struct e820_entry e820[E820MAX]; unsigned int i, num;
u64 start, pages;
u64 start, pages, ram_top; int type; num = install_e820_map(ARRAY_SIZE(e820), e820);ram_top = (u64)gd->ram_top & ~EFI_PAGE_MASK;if (!ram_top)So for the logic here to work, gd->ram_top is already zero in 32-bit, right? I was wondering how U-Boot could boot on such target?
If in 32bit mode RAM addresses up to 2^32-1 are available, gd->ram_top is 0 due to overflow.
ram_top = 0x100000000ULL;In this special case we correct the value to 4GB.
for (i = 0; i < num; ++i) { start = e820[i].addr; pages = ALIGN(e820[i].size, EFI_PAGE_SIZE) >>EFI_PAGE_SHIFT; @@ -70,6 +74,22 @@ void efi_add_known_memory(void) }
efi_add_memory_map(start, pages, type, false);
if (type == EFI_CONVENTIONAL_MEMORY) {u64 end = start + (pages << EFI_PAGE_SHIFT);/* reserve the memory region greater than ram_top */if (ram_top < start) {efi_add_memory_map(start, pages,EFI_BOOT_SERVICES_DATA,true);Heinrich, could you please review the changes here?
These lines are verbatim copies of what we have in lib/efi_loader/efi_memory.c. Function wise this is ok.
But this creates code duplication. Most of what is in this loop and in the loop in lib/efi_loader/efi_memory.c (starting at /* Remove partial pages */) could be put into a separate common function.
Aiden, do you want to give a try?
I have a quick question here. Do we really need to override efi_add_known_memory() in arch/x86/lib/e820.c? I think the original weak function would be okay for x86 arch as well.
Yep, I see the generic one provided by the EFI loader is using gd->bd->bi_dram[i] to populate the EFI memory. The only handles EFI_CONVENTIONAL_MEMORY, but for x86, it may have EFI_ACPI_RECLAIM_MEMORY and EFI_ACPI_MEMORY_NVS which gd->bd->bi_dram[i] does not distinguish normal memory usage and these special ones. Hence I think we still need the x86 specific one.
But as Heinrich mentioned, there might be some room to refactor the codes a little bit to share as much common parts as possible.
Regards, Bin