Re: Boot with EFI stub fails on VMWare during decompression

[Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>]

On Fri, 16 Jan, at 11:03:44AM, Bruno Prémont wrote:
> Register dump:
> rax            0x1000   4096
> rbx            0x23f78cb        37714123
> rcx            0x0      0
> rdx            0x0      0
> rsi            0x0      0
> rdi            0x23f7863        37714019
> rbp            0x1a363b4        0x1a363b4
> rsp            0x2404b20        0x2404b20
> r8             0x2404ee0        37768928
> r9             0x4      4
> r10            0x3      3
> r11            0x9      9
> r12            0x13dcbbc        20827068
> r13            0x1e000000       503316480      (this seems to point to decompressed kernel)

[...]
 
> while on the failing one I get (just enough efi_printk to cause kernel to boot):
> [    0.000000] efi: EFI v2.30 by VMware, Inc.
> [    0.000000] efi:  SMBIOS=0x1ffaf000  ACPI 2.0=0x1ff9f000 
> [    0.000000] efi: mem00: [ACPI Memory NVS    |   |  |  |  |   |WB|WT|WC|UC] range=[0x0000000000000000-0x0000000000001000) (0MB)

[..]

> [    0.000000] efi: mem23: [Boot Data          |   |  |  |  |   |WB|WT|WC|UC] range=[0x000000001dee8000-0x000000001e547000) (6MB)

Oops. It sure looks like the EFI boot stub is trashing an EFI boot data
region. That would certainly explain the memory corruption you're seeing
(since the firmware assumes no one else is touch its data areas).

By any chance have you modified CONFIG_PHYSICAL_START in your .config?

The suspect code is probably this from
arch/x86/boot/compressed/head_64.S:

---

	/*
	 * Compute the decompressed kernel start address.  It is where
	 * we were loaded at aligned to a 2M boundary. %rbp contains the
	 * decompressed kernel start address.
	 *
	 * If it is a relocatable kernel then decompress and run the kernel
	 * from load address aligned to 2MB addr, otherwise decompress and
	 * run the kernel from LOAD_PHYSICAL_ADDR
	 *
	 * We cannot rely on the calculation done in 32-bit mode, since we
	 * may have been invoked via the 64-bit entry point.
	 */

	/* Start with the delta to where the kernel will run at. */
#ifdef CONFIG_RELOCATABLE
	leaq	startup_32(%rip) /* - $startup_32 */, %rbp
	movl	BP_kernel_alignment(%rsi), %eax
	decl	%eax
	addq	%rax, %rbp
	notq	%rax
	andq	%rax, %rbp
	cmpq	$LOAD_PHYSICAL_ADDR, %rbp
	jge	1f
#endif
	movq	$LOAD_PHYSICAL_ADDR, %rbp
1:

You may want to snoop around this code to make sure that we're not
making some crazy calculation mistakes wrt where we decompress the
kernel.

-- 
Matt Fleming, Intel Open Source Technology Center