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Re: [Qemu-arm] [PATCH] [PATCH] Allow AArch64 processors to boot from a k
From: |
Peter Maydell |
Subject: |
Re: [Qemu-arm] [PATCH] [PATCH] Allow AArch64 processors to boot from a kernel placed over 4GB. |
Date: |
Tue, 27 Nov 2018 10:43:31 +0000 |
On Mon, 26 Nov 2018 at 19:15, Perez Blanco, Ricardo (Nokia -
BE/Antwerp) <address@hidden> wrote:
>
> Some machine based on AArch64 can have its main memory over 4GBs. With
> the current path, these machines can support "-kernel" in qemu
>
> Signed-off-by: Ricardo Perez Blanco <address@hidden>
Hi; I think it would be worth noting in the commit message that
this doesn't affect any machines QEMU currently emulates.
> ---
> hw/arm/boot.c | 12 +++++++++---
> 1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/hw/arm/boot.c b/hw/arm/boot.c
> index 586baa9b64..183c5860bd 100644
> --- a/hw/arm/boot.c
> +++ b/hw/arm/boot.c
> @@ -64,7 +64,9 @@ typedef enum {
> FIXUP_BOARDID, /* overwrite with board ID number */
> FIXUP_BOARD_SETUP, /* overwrite with board specific setup code address
> */
> FIXUP_ARGPTR, /* overwrite with pointer to kernel args */
> + FIXUP_ARGPTR_HIGHER_32BITS, /* overwrite with pointer to kernel
> args (higher 32 bits) */
> FIXUP_ENTRYPOINT, /* overwrite with kernel entry point */
> + FIXUP_ENTRYPOINT_HIGHER_32BITS, /* overwrite with kernel entry point
> (higher 32 bits) */
I recommend naming these FIXUP_ARGPTR_HI and FIXUP_ENTRYPOINT_HI.
As a second followup patch we can then rename FIXUP_ARGPTR and
FIXUP_ENTRYPOINT to FIXUP_ARGPTR_LO and FIXUP_ENTRYPOINT_LO.
> FIXUP_GIC_CPU_IF, /* overwrite with GIC CPU interface address */
> FIXUP_BOOTREG, /* overwrite with boot register address */
> FIXUP_DSB, /* overwrite with correct DSB insn for cpu */
> @@ -84,9 +86,9 @@ static const ARMInsnFixup bootloader_aarch64[] = {
> { 0x58000084 }, /* ldr x4, entry ; Load the lower 32-bits of kernel
> entry */
> { 0xd61f0080 }, /* br x4 ; Jump to the kernel entry point */
> { 0, FIXUP_ARGPTR }, /* arg: .word @DTB Lower 32-bits */
> - { 0 }, /* .word @DTB Higher 32-bits */
> + { 0, FIXUP_ARGPTR_HIGHER_32BITS}, /* .word @DTB Higher 32-bits */
> { 0, FIXUP_ENTRYPOINT }, /* entry: .word @Kernel Entry Lower 32-bits */
> - { 0 }, /* .word @Kernel Entry Higher 32-bits */
> + { 0, FIXUP_ENTRYPOINT_HIGHER_32BITS }, /* .word @Kernel Entry Higher
> 32-bits */
> { 0, FIXUP_TERMINATOR }
> };
>
> @@ -175,7 +177,9 @@ static void write_bootloader(const char *name, hwaddr
> addr,
> case FIXUP_BOARDID:
> case FIXUP_BOARD_SETUP:
> case FIXUP_ARGPTR:
> + case FIXUP_ARGPTR_HIGHER_32BITS:
> case FIXUP_ENTRYPOINT:
> + case FIXUP_ENTRYPOINT_HIGHER_32BITS:
> case FIXUP_GIC_CPU_IF:
> case FIXUP_BOOTREG:
> case FIXUP_DSB:
> @@ -939,7 +943,6 @@ static uint64_t load_aarch64_image(const char *filename,
> hwaddr mem_base,
> }
> }
> }
> -
> *entry = mem_base + kernel_load_offset;
> rom_add_blob_fixed_as(filename, buffer, size, *entry, as);
>
Stray whitespace change.
> @@ -1153,8 +1156,10 @@ void arm_load_kernel(ARMCPU *cpu, struct arm_boot_info
> *info)
> info->dtb_start = QEMU_ALIGN_UP(info->initrd_start + initrd_size,
> align);
> fixupcontext[FIXUP_ARGPTR] = info->dtb_start;
> + fixupcontext[FIXUP_ARGPTR_HIGHER_32BITS] = info->dtb_start >> 32;
> } else {
> fixupcontext[FIXUP_ARGPTR] = info->loader_start +
> KERNEL_ARGS_ADDR;
> + fixupcontext[FIXUP_ARGPTR_HIGHER_32BITS] = (info->loader_start +
> KERNEL_ARGS_ADDR) >> 32;
> if (info->ram_size >= (1ULL << 32)) {
> error_report("RAM size must be less than 4GB to boot"
> " Linux kernel using ATAGS (try passing a
> device tree"
> @@ -1163,6 +1168,7 @@ void arm_load_kernel(ARMCPU *cpu, struct arm_boot_info
> *info)
> }
> }
> fixupcontext[FIXUP_ENTRYPOINT] = entry;
> + fixupcontext[FIXUP_ENTRYPOINT_HIGHER_32BITS] = entry >> 32;
>
> write_bootloader("bootloader", info->loader_start,
> primary_loader, fixupcontext, as);
> --
Otherwise the patch looks good.
thanks
-- PMM