* [Qemu-devel] [PATCH v2] hw/arm/boot: take Linux/arm64 TEXT_OFFSET header field into account
@ 2017-03-13 14:17 Ard Biesheuvel
2017-03-20 11:13 ` Peter Maydell
0 siblings, 1 reply; 4+ messages in thread
From: Ard Biesheuvel @ 2017-03-13 14:17 UTC (permalink / raw)
To: qemu-devel, peter.maydell; +Cc: mark.rutland, Ard Biesheuvel
The arm64 boot protocol stipulates that the kernel must be loaded
TEXT_OFFSET bytes beyond a 2 MB aligned base address, where TEXT_OFFSET
could be any 4 KB multiple between 0 and 2 MB, and whose value can be
found in the header of the Image file.
So after attempts to load the arm64 kernel image as an ELF file or as a
U-Boot image have failed (both of which have their own way of specifying
the load offset), try to determine the TEXT_OFFSET from the image after
loading it but before mapping it as a ROM mapping into the guest address
space.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
v2: split off AArch64 specific loader logic regarding gzipped/raw and variable
load offset into a separate helper function, which removes the need for
loading the image twice
hw/arm/boot.c | 64 ++++++++++++++++----
1 file changed, 53 insertions(+), 11 deletions(-)
diff --git a/hw/arm/boot.c b/hw/arm/boot.c
index ff621e4b6a4b..c2720c80460f 100644
--- a/hw/arm/boot.c
+++ b/hw/arm/boot.c
@@ -31,6 +31,9 @@
#define KERNEL_LOAD_ADDR 0x00010000
#define KERNEL64_LOAD_ADDR 0x00080000
+#define ARM64_TEXT_OFFSET_OFFSET 8
+#define ARM64_MAGIC_OFFSET 56
+
typedef enum {
FIXUP_NONE = 0, /* do nothing */
FIXUP_TERMINATOR, /* end of insns */
@@ -768,6 +771,49 @@ static uint64_t arm_load_elf(struct arm_boot_info *info, uint64_t *pentry,
return ret;
}
+static uint64_t load_aarch64_image(const char *filename, hwaddr mem_base,
+ hwaddr *entry)
+{
+ hwaddr kernel_load_offset = KERNEL64_LOAD_ADDR;
+ uint8_t *buffer;
+ int size;
+
+ /* On aarch64, it's the bootloader's job to uncompress the kernel. */
+ size = load_image_gzipped_buffer(filename, LOAD_IMAGE_MAX_GUNZIP_BYTES,
+ &buffer);
+
+ if (size < 0) {
+ gsize len;
+
+ /* Load as raw file otherwise */
+ if (!g_file_get_contents(filename, (char **)&buffer, &len, NULL)) {
+ return -1;
+ }
+ size = len;
+ }
+
+ /* check the arm64 magic header value -- very old kernels may not have it */
+ if (memcmp(buffer + ARM64_MAGIC_OFFSET, "ARM\x64", 4) == 0) {
+ uint64_t hdrvals[2];
+
+ /* The arm64 Image header has text_offset and image_size fields at 8 and
+ * 16 bytes into the Image header, respectively. The text_offset field
+ * is only valid if the image_size is non-zero.
+ */
+ memcpy(&hdrvals, buffer + ARM64_TEXT_OFFSET_OFFSET, sizeof(hdrvals));
+ if (hdrvals[1] != 0) {
+ kernel_load_offset = le64_to_cpu(hdrvals[0]);
+ }
+ }
+
+ *entry = mem_base + kernel_load_offset;
+ rom_add_blob_fixed(filename, buffer, size, *entry);
+
+ g_free(buffer);
+
+ return size;
+}
+
static void arm_load_kernel_notify(Notifier *notifier, void *data)
{
CPUState *cs;
@@ -776,7 +822,7 @@ static void arm_load_kernel_notify(Notifier *notifier, void *data)
int is_linux = 0;
uint64_t elf_entry, elf_low_addr, elf_high_addr;
int elf_machine;
- hwaddr entry, kernel_load_offset;
+ hwaddr entry;
static const ARMInsnFixup *primary_loader;
ArmLoadKernelNotifier *n = DO_UPCAST(ArmLoadKernelNotifier,
notifier, notifier);
@@ -841,14 +887,12 @@ static void arm_load_kernel_notify(Notifier *notifier, void *data)
if (arm_feature(&cpu->env, ARM_FEATURE_AARCH64)) {
primary_loader = bootloader_aarch64;
- kernel_load_offset = KERNEL64_LOAD_ADDR;
elf_machine = EM_AARCH64;
} else {
primary_loader = bootloader;
if (!info->write_board_setup) {
primary_loader += BOOTLOADER_NO_BOARD_SETUP_OFFSET;
}
- kernel_load_offset = KERNEL_LOAD_ADDR;
elf_machine = EM_ARM;
}
@@ -900,17 +944,15 @@ static void arm_load_kernel_notify(Notifier *notifier, void *data)
kernel_size = load_uimage(info->kernel_filename, &entry, NULL,
&is_linux, NULL, NULL);
}
- /* On aarch64, it's the bootloader's job to uncompress the kernel. */
if (arm_feature(&cpu->env, ARM_FEATURE_AARCH64) && kernel_size < 0) {
- entry = info->loader_start + kernel_load_offset;
- kernel_size = load_image_gzipped(info->kernel_filename, entry,
- info->ram_size - kernel_load_offset);
+ kernel_size = load_aarch64_image(info->kernel_filename,
+ info->loader_start, &entry);
is_linux = 1;
- }
- if (kernel_size < 0) {
- entry = info->loader_start + kernel_load_offset;
+ } else if (kernel_size < 0) {
+ /* 32-bit ARM */
+ entry = info->loader_start + KERNEL_LOAD_ADDR;
kernel_size = load_image_targphys(info->kernel_filename, entry,
- info->ram_size - kernel_load_offset);
+ info->ram_size - KERNEL_LOAD_ADDR);
is_linux = 1;
}
if (kernel_size < 0) {
--
2.7.4
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [Qemu-devel] [PATCH v2] hw/arm/boot: take Linux/arm64 TEXT_OFFSET header field into account
2017-03-13 14:17 [Qemu-devel] [PATCH v2] hw/arm/boot: take Linux/arm64 TEXT_OFFSET header field into account Ard Biesheuvel
@ 2017-03-20 11:13 ` Peter Maydell
2017-03-20 11:15 ` Ard Biesheuvel
2017-04-04 11:45 ` Peter Maydell
0 siblings, 2 replies; 4+ messages in thread
From: Peter Maydell @ 2017-03-20 11:13 UTC (permalink / raw)
To: Ard Biesheuvel; +Cc: QEMU Developers, Mark Rutland
On 13 March 2017 at 14:17, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
> The arm64 boot protocol stipulates that the kernel must be loaded
> TEXT_OFFSET bytes beyond a 2 MB aligned base address, where TEXT_OFFSET
> could be any 4 KB multiple between 0 and 2 MB, and whose value can be
> found in the header of the Image file.
>
> So after attempts to load the arm64 kernel image as an ELF file or as a
> U-Boot image have failed (both of which have their own way of specifying
> the load offset), try to determine the TEXT_OFFSET from the image after
> loading it but before mapping it as a ROM mapping into the guest address
> space.
>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
> v2: split off AArch64 specific loader logic regarding gzipped/raw and variable
> load offset into a separate helper function, which removes the need for
> loading the image twice
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Since we're due to tag rc1 tomorrow and this is kind of on the
border between bugfix and new feature, I think I'd rather
defer it to 2.10, unless you have a strong view that it should
go into 2.9.
thanks
-- PMM
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Qemu-devel] [PATCH v2] hw/arm/boot: take Linux/arm64 TEXT_OFFSET header field into account
2017-03-20 11:13 ` Peter Maydell
@ 2017-03-20 11:15 ` Ard Biesheuvel
2017-04-04 11:45 ` Peter Maydell
1 sibling, 0 replies; 4+ messages in thread
From: Ard Biesheuvel @ 2017-03-20 11:15 UTC (permalink / raw)
To: Peter Maydell; +Cc: QEMU Developers, Mark Rutland
On 20 March 2017 at 11:13, Peter Maydell <peter.maydell@linaro.org> wrote:
> On 13 March 2017 at 14:17, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
>> The arm64 boot protocol stipulates that the kernel must be loaded
>> TEXT_OFFSET bytes beyond a 2 MB aligned base address, where TEXT_OFFSET
>> could be any 4 KB multiple between 0 and 2 MB, and whose value can be
>> found in the header of the Image file.
>>
>> So after attempts to load the arm64 kernel image as an ELF file or as a
>> U-Boot image have failed (both of which have their own way of specifying
>> the load offset), try to determine the TEXT_OFFSET from the image after
>> loading it but before mapping it as a ROM mapping into the guest address
>> space.
>>
>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>> ---
>> v2: split off AArch64 specific loader logic regarding gzipped/raw and variable
>> load offset into a separate helper function, which removes the need for
>> loading the image twice
>
> Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
>
Thanks
> Since we're due to tag rc1 tomorrow and this is kind of on the
> border between bugfix and new feature, I think I'd rather
> defer it to 2.10, unless you have a strong view that it should
> go into 2.9.
>
I will leave that to you to decide, I don't feel strongly either way
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Qemu-devel] [PATCH v2] hw/arm/boot: take Linux/arm64 TEXT_OFFSET header field into account
2017-03-20 11:13 ` Peter Maydell
2017-03-20 11:15 ` Ard Biesheuvel
@ 2017-04-04 11:45 ` Peter Maydell
1 sibling, 0 replies; 4+ messages in thread
From: Peter Maydell @ 2017-04-04 11:45 UTC (permalink / raw)
To: Ard Biesheuvel; +Cc: QEMU Developers, Mark Rutland
On 20 March 2017 at 11:13, Peter Maydell <peter.maydell@linaro.org> wrote:
> On 13 March 2017 at 14:17, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
>> The arm64 boot protocol stipulates that the kernel must be loaded
>> TEXT_OFFSET bytes beyond a 2 MB aligned base address, where TEXT_OFFSET
>> could be any 4 KB multiple between 0 and 2 MB, and whose value can be
>> found in the header of the Image file.
>>
>> So after attempts to load the arm64 kernel image as an ELF file or as a
>> U-Boot image have failed (both of which have their own way of specifying
>> the load offset), try to determine the TEXT_OFFSET from the image after
>> loading it but before mapping it as a ROM mapping into the guest address
>> space.
>>
>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>> ---
>> v2: split off AArch64 specific loader logic regarding gzipped/raw and variable
>> load offset into a separate helper function, which removes the need for
>> loading the image twice
>
> Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
>
> Since we're due to tag rc1 tomorrow and this is kind of on the
> border between bugfix and new feature, I think I'd rather
> defer it to 2.10, unless you have a strong view that it should
> go into 2.9.
Since we're now at rc3 and I don't expect to need to do another
arm pull request before 2.9, I've put this patch into target-arm.next
for 2.10.
thanks
-- PMM
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2017-04-04 11:45 UTC | newest]
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2017-03-13 14:17 [Qemu-devel] [PATCH v2] hw/arm/boot: take Linux/arm64 TEXT_OFFSET header field into account Ard Biesheuvel
2017-03-20 11:13 ` Peter Maydell
2017-03-20 11:15 ` Ard Biesheuvel
2017-04-04 11:45 ` Peter Maydell
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