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Message-ID: <20190802053744.5519-1-clin@suse.com>
Date: Fri, 2 Aug 2019 05:38:54 +0000
From: Chester Lin <clin@...e.com>
To: "linux@...linux.org.uk" <linux@...linux.org.uk>,
"ard.biesheuvel@...aro.org" <ard.biesheuvel@...aro.org>,
"akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
"rppt@...ux.ibm.com" <rppt@...ux.ibm.com>,
"ren_guo@...ky.com" <ren_guo@...ky.com>,
Juergen Gross <JGross@...e.com>,
"geert@...ux-m68k.org" <geert@...ux-m68k.org>,
"mingo@...nel.org" <mingo@...nel.org>
CC: "linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-efi@...r.kernel.org" <linux-efi@...r.kernel.org>,
"guillaume.gardet@....com" <guillaume.gardet@....com>,
Chester Lin <clin@...e.com>, Joey Lee <JLee@...e.com>,
Gary Lin <GLin@...e.com>
Subject: [PATCH] efi/arm: fix allocation failure when reserving the kernel
base
In some cases the arm32 efistub could fail to allocate memory for
uncompressed kernel. For example, we got the following error message when
verifying EFI stub on Raspberry Pi-2 [kernel-5.2.1 + grub-2.04] :
EFI stub: Booting Linux Kernel...
EFI stub: ERROR: Unable to allocate memory for uncompressed kernel.
EFI stub: ERROR: Failed to relocate kernel
After checking the EFI memory map we found that the first page [0 - 0xfff]
had been reserved by Raspberry Pi-2's firmware, and the efistub tried to
set the dram base at 0, which was actually in a reserved region.
grub> lsefimmap
Type Physical start - end #Pages Size Attributes
reserved 0000000000000000-0000000000000fff 00000001 4KiB WB
conv-mem 0000000000001000-0000000007ef5fff 00007ef5 130004KiB WB
RT-data 0000000007ef6000-0000000007f09fff 00000014 80KiB RT WB
conv-mem 0000000007f0a000-000000002d871fff 00025968 615840KiB WB
.....
To avoid a reserved address, we have to ignore the memory regions which are
marked as EFI_RESERVED_TYPE, and only conventional memory regions can be
chosen. If the region before the kernel base is unaligned, it will be
marked as EFI_RESERVED_TYPE and let kernel ignore it so that memblock_limit
will not be sticked with a very low address such as 0x1000.
Signed-off-by: Chester Lin <clin@...e.com>
---
arch/arm/mm/mmu.c | 3 ++
drivers/firmware/efi/libstub/arm32-stub.c | 43 ++++++++++++++++++-----
2 files changed, 37 insertions(+), 9 deletions(-)
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index f3ce34113f89..909b11ba48d8 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -1184,6 +1184,9 @@ void __init adjust_lowmem_bounds(void)
phys_addr_t block_start = reg->base;
phys_addr_t block_end = reg->base + reg->size;
+ if (memblock_is_nomap(reg))
+ continue;
+
if (reg->base < vmalloc_limit) {
if (block_end > lowmem_limit)
/*
diff --git a/drivers/firmware/efi/libstub/arm32-stub.c b/drivers/firmware/efi/libstub/arm32-stub.c
index e8f7aefb6813..10d33d36df00 100644
--- a/drivers/firmware/efi/libstub/arm32-stub.c
+++ b/drivers/firmware/efi/libstub/arm32-stub.c
@@ -128,7 +128,7 @@ static efi_status_t reserve_kernel_base(efi_system_table_t *sys_table_arg,
for (l = 0; l < map_size; l += desc_size) {
efi_memory_desc_t *desc;
- u64 start, end;
+ u64 start, end, spare, kernel_base;
desc = (void *)memory_map + l;
start = desc->phys_addr;
@@ -144,27 +144,52 @@ static efi_status_t reserve_kernel_base(efi_system_table_t *sys_table_arg,
case EFI_BOOT_SERVICES_DATA:
/* Ignore types that are released to the OS anyway */
continue;
-
+ case EFI_RESERVED_TYPE:
+ /* Ignore reserved regions */
+ continue;
case EFI_CONVENTIONAL_MEMORY:
/*
* Reserve the intersection between this entry and the
* region.
*/
start = max(start, (u64)dram_base);
- end = min(end, (u64)dram_base + MAX_UNCOMP_KERNEL_SIZE);
+ kernel_base = round_up(start, PMD_SIZE);
+ spare = kernel_base - start;
+ end = min(end, kernel_base + MAX_UNCOMP_KERNEL_SIZE);
+
+ status = efi_call_early(allocate_pages,
+ EFI_ALLOCATE_ADDRESS,
+ EFI_LOADER_DATA,
+ MAX_UNCOMP_KERNEL_SIZE / EFI_PAGE_SIZE,
+ &kernel_base);
+ if (status != EFI_SUCCESS) {
+ pr_efi_err(sys_table_arg,
+ "reserve_kernel_base: alloc failed.\n");
+ goto out;
+ }
+ *reserve_addr = kernel_base;
+ if (!spare)
+ break;
+ /*
+ * If there's a gap between start and kernel_base,
+ * it needs be reserved so that the memblock_limit
+ * will not fall on a very low address when running
+ * adjust_lowmem_bounds(), wchich could eventually
+ * cause CMA reservation issue.
+ */
status = efi_call_early(allocate_pages,
EFI_ALLOCATE_ADDRESS,
- EFI_LOADER_DATA,
- (end - start) / EFI_PAGE_SIZE,
+ EFI_RESERVED_TYPE,
+ spare / EFI_PAGE_SIZE,
&start);
if (status != EFI_SUCCESS) {
pr_efi_err(sys_table_arg,
- "reserve_kernel_base(): alloc failed.\n");
+ "reserve spare-region failed\n");
goto out;
}
- break;
+ break;
case EFI_LOADER_CODE:
case EFI_LOADER_DATA:
/*
@@ -220,7 +245,7 @@ efi_status_t handle_kernel_image(efi_system_table_t *sys_table,
*image_size = image->image_size;
status = efi_relocate_kernel(sys_table, image_addr, *image_size,
*image_size,
- dram_base + MAX_UNCOMP_KERNEL_SIZE, 0);
+ *reserve_addr + MAX_UNCOMP_KERNEL_SIZE, 0);
if (status != EFI_SUCCESS) {
pr_efi_err(sys_table, "Failed to relocate kernel.\n");
efi_free(sys_table, *reserve_size, *reserve_addr);
@@ -233,7 +258,7 @@ efi_status_t handle_kernel_image(efi_system_table_t *sys_table,
* in memory. The kernel determines the base of DRAM from the
* address at which the zImage is loaded.
*/
- if (*image_addr + *image_size > dram_base + ZIMAGE_OFFSET_LIMIT) {
+ if (*image_addr + *image_size > *reserve_addr + ZIMAGE_OFFSET_LIMIT) {
pr_efi_err(sys_table, "Failed to relocate kernel, no low memory available.\n");
efi_free(sys_table, *reserve_size, *reserve_addr);
*reserve_size = 0;
--
2.22.0
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