The kernel will align itself to the nearest boundary specified by the kernel_alignment field in the bzImage header. If the kernel is loaded to an address which is not sufficiently aligned, it will therefore use memory beyond that indicated solely by the init_size field.
The PE/COFF headers now include a .bss section to describe the requirements of the init_size field, but do not currently expose the alignment requirement. Consequently, a kernel loaded via the PE entry point may still end up overwriting unexpected areas of memory. Fix by exposing the desired alignment via the SectionAlignment field in the PE/COFF headers. Despite its name, this field provides an overall alignment requirement for the loaded file. (Naturally, the FileAlignment field describes the alignment for individual sections.) There is no way in the PE/COFF headers to express the concept of min_alignment; we therefore do not expose the minimum (as opposed to preferred) alignment. Signed-off-by: Michael Brown <[email protected]> --- arch/x86/boot/header.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S index 7a6d43a..16ef025 100644 --- a/arch/x86/boot/header.S +++ b/arch/x86/boot/header.S @@ -154,7 +154,7 @@ extra_header_fields: #else .quad 0 # ImageBase #endif - .long 0x20 # SectionAlignment + .long CONFIG_PHYSICAL_ALIGN # SectionAlignment .long 0x20 # FileAlignment .word 0 # MajorOperatingSystemVersion .word 0 # MinorOperatingSystemVersion -- 1.8.4.5 -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
