Date: Fri, 26 Jun 2015 07:12:17 +0000 (UTC) From: Roger Pau Monné <royger@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r284870 - in head/sys: amd64/amd64 conf Message-ID: <201506260712.t5Q7CHxo037686@svn.freebsd.org>
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Author: royger Date: Fri Jun 26 07:12:17 2015 New Revision: 284870 URL: https://svnweb.freebsd.org/changeset/base/284870 Log: amd64: set the correct LMA values The current linker script generates program headers with VMA == LMA: Entry point 0xffffffff802e7000 There are 6 program headers, starting at offset 64 Program Headers: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flags Align PHDR 0x0000000000000040 0xffffffff80200040 0xffffffff80200040 0x0000000000000150 0x0000000000000150 R E 8 INTERP 0x0000000000000190 0xffffffff80200190 0xffffffff80200190 0x000000000000000d 0x000000000000000d R 1 [Requesting program interpreter: /red/herring] LOAD 0x0000000000000000 0xffffffff80200000 0xffffffff80200000 0x00000000010559b0 0x00000000010559b0 R E 200000 LOAD 0x0000000001056000 0xffffffff81456000 0xffffffff81456000 0x0000000000132638 0x000000000052ecf8 RW 200000 DYNAMIC 0x0000000001056000 0xffffffff81456000 0xffffffff81456000 0x00000000000000d0 0x00000000000000d0 RW 8 GNU_STACK 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 RWE 8 This is fine for the FreeBSD loader, because it completely ignores p_paddr and instead uses p_vaddr with a hardcoded offset. Other loaders however acknowledge p_paddr (like the Xen ELF loader), in which case they will try to load the kernel at the wrong place. Fix this by adding an AT keyword to the first section specifying the physical address, other sections will follow suit, so it ends up looking like: Entry point 0xffffffff802e7000 There are 6 program headers, starting at offset 64 Program Headers: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flags Align PHDR 0x0000000000000040 0xffffffff80200040 0x0000000000200040 0x0000000000000150 0x0000000000000150 R E 8 INTERP 0x0000000000000190 0xffffffff80200190 0x0000000000200190 0x000000000000000d 0x000000000000000d R 1 [Requesting program interpreter: /red/herring] LOAD 0x0000000000000000 0xffffffff80200000 0x0000000000200000 0x00000000010559b0 0x00000000010559b0 R E 200000 LOAD 0x0000000001056000 0xffffffff81456000 0x0000000001456000 0x0000000000132638 0x000000000052ecf8 RW 200000 DYNAMIC 0x0000000001056000 0xffffffff81456000 0x0000000001456000 0x00000000000000d0 0x00000000000000d0 RW 8 GNU_STACK 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 RWE 8 Tested on bare metal using the native FreeBSD loader and grub2 from TRUEOS. Sponsored by: Citrix Systems R&D Reviewed by: kib Differential Revision: https://reviews.freebsd.org/D2783 Modified: head/sys/amd64/amd64/xen-locore.S head/sys/conf/ldscript.amd64 Modified: head/sys/amd64/amd64/xen-locore.S ============================================================================== --- head/sys/amd64/amd64/xen-locore.S Fri Jun 26 07:01:29 2015 (r284869) +++ head/sys/amd64/amd64/xen-locore.S Fri Jun 26 07:12:17 2015 (r284870) @@ -47,7 +47,7 @@ ELFNOTE(Xen, XEN_ELFNOTE_GUEST_VERSION, .asciz, __XSTRING(__FreeBSD_version)) ELFNOTE(Xen, XEN_ELFNOTE_XEN_VERSION, .asciz, "xen-3.0") ELFNOTE(Xen, XEN_ELFNOTE_VIRT_BASE, .quad, KERNBASE) - ELFNOTE(Xen, XEN_ELFNOTE_PADDR_OFFSET, .quad, KERNBASE) /* Xen honours elf->p_paddr; compensate for this */ + ELFNOTE(Xen, XEN_ELFNOTE_PADDR_OFFSET, .quad, 0) ELFNOTE(Xen, XEN_ELFNOTE_ENTRY, .quad, xen_start) ELFNOTE(Xen, XEN_ELFNOTE_HYPERCALL_PAGE, .quad, hypercall_page) ELFNOTE(Xen, XEN_ELFNOTE_HV_START_LOW, .quad, HYPERVISOR_VIRT_START) Modified: head/sys/conf/ldscript.amd64 ============================================================================== --- head/sys/conf/ldscript.amd64 Fri Jun 26 07:01:29 2015 (r284869) +++ head/sys/conf/ldscript.amd64 Fri Jun 26 07:12:17 2015 (r284870) @@ -8,7 +8,12 @@ SECTIONS /* Read-only sections, merged into text segment: */ kernphys = CONSTANT (MAXPAGESIZE); . = kernbase + kernphys + SIZEOF_HEADERS; - .interp : { *(.interp) } + /* + * Use the AT keyword in order to set the right LMA that contains + * the physical address where the section should be loaded. This is + * needed for the Xen loader which honours the LMA. + */ + .interp : AT (kernphys + SIZEOF_HEADERS) { *(.interp) } .hash : { *(.hash) } .gnu.hash : { *(.gnu.hash) } .dynsym : { *(.dynsym) }
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