In case EFI not multiboot rolling back relocation is done in
efi_arch_post_exit_boot, called by efi_start however this is
not done in multiboot code path.
Do it also for this path to make it work correctly.
Signed-off-by: Frediano Ziglio <frediano.zig...@cloud.com>
---
xen/arch/x86/boot/head.S | 29 +++++++++++++++---
xen/arch/x86/boot/reloc.c | 63 ++++++++++++++++++++++++++++++++++++++-
2 files changed, 87 insertions(+), 5 deletions(-)
diff --git a/xen/arch/x86/boot/head.S b/xen/arch/x86/boot/head.S
index abfa3d82f7..75ac74a589 100644
--- a/xen/arch/x86/boot/head.S
+++ b/xen/arch/x86/boot/head.S
@@ -352,6 +352,7 @@ __efi64_mb2_start:
and $~15,%rsp
/* Save Multiboot2 magic on the stack. */
+ shlq $32, %rax
push %rax
/* Save EFI ImageHandle on the stack. */
@@ -382,11 +383,24 @@ __efi64_mb2_start:
/* Just pop an item from the stack. */
pop %rax
- /* Restore Multiboot2 magic. */
- pop %rax
+ /* Prepare stack for relocation call */
+ subq $16, %rsp
+ lea l2_bootmap(%rip), %ecx
+ movl %ecx, 16(%rsp)
+ lea l3_bootmap(%rip), %ecx
+ movl %ecx, 12(%rsp)
+ lea __base_relocs_end(%rip), %ecx
+ movl %ecx, 8(%rsp)
+ lea __base_relocs_start(%rip), %ecx
+ movl %ecx, 4(%rsp)
+ lea __image_base__(%rip),%rsi
+ movl %esi, (%rsp)
+ movabsq $__XEN_VIRT_START, %rcx
+ subq %rsi, %rcx
+ push %rcx
- /* Jump to trampoline_setup after switching CPU to x86_32 mode. */
- lea trampoline_setup(%rip),%r15
+ /* Jump to trampoline_efi_setup after switching CPU to x86_32 mode. */
+ lea trampoline_efi_setup(%rip),%r15
x86_32_switch:
mov %r15,%rdi
@@ -557,6 +571,12 @@ __start:
and $~(MULTIBOOT2_TAG_ALIGN-1),%ecx
jmp .Lmb2_tsize
+trampoline_efi_setup:
+ movb $1, %al
+ call reloc
+ pop %eax
+ jmp trampoline_setup
+
trampoline_bios_setup:
/*
* Called on legacy BIOS platforms only.
@@ -627,6 +647,7 @@ trampoline_setup:
push %ecx /* Bottom-most low-memory stack address. */
push %ebx /* Multiboot / PVH information address. */
push %eax /* Magic number. */
+ movb $0, %al
call reloc
#ifdef CONFIG_PVH_GUEST
cmpb $0, sym_esi(pvh_boot)
diff --git a/xen/arch/x86/boot/reloc.c b/xen/arch/x86/boot/reloc.c
index 4033557481..3aa97a99d0 100644
--- a/xen/arch/x86/boot/reloc.c
+++ b/xen/arch/x86/boot/reloc.c
@@ -23,7 +23,9 @@ asm (
" .text \n"
" .globl _start \n"
"_start: \n"
- " jmp reloc \n"
+ " cmpb $0, %al \n"
+ " je reloc \n"
+ " jmp reloc_pe_back \n"
);
#include "defs.h"
@@ -375,6 +377,65 @@ void *__stdcall reloc(uint32_t magic, uint32_t in,
uint32_t trampoline,
}
}
+struct pe_base_relocs {
+ u32 rva;
+ u32 size;
+ u16 entries[];
+};
+
+#define PE_BASE_RELOC_ABS 0
+#define PE_BASE_RELOC_HIGHLOW 3
+#define PE_BASE_RELOC_DIR64 10
+
+void __stdcall reloc_pe_back(long long delta,
+ uint32_t xen_phys_start,
+ const struct pe_base_relocs *__base_relocs_start,
+ const struct pe_base_relocs *__base_relocs_end,
+ char *l3_bootmap, char *l2_bootmap)
+{
+ const struct pe_base_relocs *base_relocs;
+
+ for ( base_relocs = __base_relocs_start; base_relocs < __base_relocs_end; )
+ {
+ unsigned int i = 0, n;
+
+ n = (base_relocs->size - sizeof(*base_relocs)) /
+ sizeof(*base_relocs->entries);
+
+ /*
+ * Relevant l{2,3}_bootmap entries get initialized explicitly in
+ * efi_arch_memory_setup(), so we must not apply relocations there.
+ * l2_directmap's first slot, otoh, should be handled normally, as
+ * efi_arch_memory_setup() won't touch it (xen_phys_start should
+ * never be zero).
+ */
+ if ( xen_phys_start + base_relocs->rva == (unsigned long)l3_bootmap ||
+ xen_phys_start + base_relocs->rva == (unsigned long)l2_bootmap )
+ i = n;
+
+ for ( ; i < n; ++i )
+ {
+ unsigned long addr = xen_phys_start + base_relocs->rva +
+ (base_relocs->entries[i] & 0xfff);
+
+ switch ( base_relocs->entries[i] >> 12 )
+ {
+ case PE_BASE_RELOC_ABS:
+ break;
+ case PE_BASE_RELOC_HIGHLOW:
+ if ( delta )
+ *(u32 *)addr += delta;
+ break;
+ case PE_BASE_RELOC_DIR64:
+ if ( delta )
+ *(u64 *)addr += delta;
+ break;
+ }
+ }
+ base_relocs = (const void *)(base_relocs->entries + i + (i & 1));
+ }
+}
+
/*
* Local variables:
* mode: C
--
2.45.2
