@@ -9,7 +9,7 @@ extern void kexec_reloc(unsigned long reloc_code, unsigned long reloc_pt,
unsigned long ind_maddr, unsigned long entry_maddr,
unsigned long flags);
-extern unsigned int kexec_reloc_size;
+extern const char kexec_reloc_end[];
#endif
@@ -117,7 +117,7 @@ int machine_kexec_load(struct kexec_image *image)
}
code_page = __map_domain_page(image->control_code_page);
- memcpy(code_page, kexec_reloc, kexec_reloc_size);
+ memcpy(code_page, kexec_reloc, kexec_reloc_end - (char *)kexec_reloc);
unmap_domain_page(code_page);
/*
@@ -34,7 +34,7 @@ ENTRY(kexec_reloc)
movq %rcx, %rbp
/* Setup stack. */
- leaq (reloc_stack - kexec_reloc)(%rdi), %rsp
+ leaq (.Lreloc_stack_base - kexec_reloc)(%rdi), %rsp
/* Load reloc page table. */
movq %rsi, %cr3
@@ -175,10 +175,16 @@ compatibility_mode_far:
.long 0x00000000 /* set in call_32_bit above */
.word 0x0010
+ .type compatibility_mode_far, @object
+ .size compatibility_mode_far, . - compatibility_mode_far
+
compat_mode_gdt_desc:
.word .Lcompat_mode_gdt_end - compat_mode_gdt -1
.quad 0x0000000000000000 /* set in call_32_bit above */
+ .type compat_mode_gdt_desc, @object
+ .size compat_mode_gdt_desc, . - compat_mode_gdt_desc
+
.align 8
compat_mode_gdt:
.quad 0x0000000000000000 /* null */
@@ -186,16 +192,23 @@ compat_mode_gdt:
.quad 0x00cf9b000000ffff /* 0x0010 ring 0 code, compatibility */
.Lcompat_mode_gdt_end:
+ .type compat_mode_gdt, @object
+ .size compat_mode_gdt, . - compat_mode_gdt
+
compat_mode_idt:
.word 0 /* limit */
.long 0 /* base */
+ .type compat_mode_idt, @object
+ .size compat_mode_idt, . - compat_mode_idt
+
/*
* 16 words of stack are more than enough.
*/
- .fill 16,8,0
+ .align 8
reloc_stack:
+ .fill 16,8,0
+.Lreloc_stack_base:
- .globl kexec_reloc_size
-kexec_reloc_size:
- .long . - kexec_reloc
+ .type reloc_stack, @object
+ .size reloc_stack, . - reloc_stack
@@ -84,6 +84,7 @@ SECTIONS
_etextentry = .;
*(.text.kexec) /* Page aligned in the object file. */
+ kexec_reloc_end = .;
*(.text.cold)
*(.text.unlikely)
@@ -428,7 +429,7 @@ ASSERT(__2M_rwdata_end <= XEN_VIRT_END - XEN_VIRT_START + __XEN_VIRT_START -
"Xen image overlaps stubs area")
#ifdef CONFIG_KEXEC
-ASSERT(kexec_reloc_size - kexec_reloc <= PAGE_SIZE, "kexec_reloc is too large")
+ASSERT(kexec_reloc_end - kexec_reloc <= PAGE_SIZE, "kexec_reloc is too large")
#endif
/* The Multiboot setup paths relies on this to simplify superpage PTE creation. */
Scanning for embedded endbranch instructions involves parsing the .text disassembly. Data in the kexec trampoline has no ELF metadata, so objdump treats it as instructions and tries to disassemble. Convert: ffff82d040396108 <compatibility_mode_far>: ffff82d040396108: 00 00 add %al,(%rax) ffff82d04039610a: 00 00 add %al,(%rax) ffff82d04039610c: 10 00 adc %al,(%rax) ffff82d04039610e <compat_mode_gdt_desc>: ffff82d04039610e: 17 (bad) ... ffff82d040396118 <compat_mode_gdt>: ... ffff82d040396120: ff (bad) ffff82d040396121: ff 00 incl (%rax) ffff82d040396123: 00 00 add %al,(%rax) ffff82d040396125: 93 xchg %eax,%ebx ffff82d040396126: cf iret ffff82d040396127: 00 ff add %bh,%bh ffff82d040396129: ff 00 incl (%rax) ffff82d04039612b: 00 00 add %al,(%rax) ffff82d04039612d: 9b fwait ffff82d04039612e: cf iret ... ffff82d040396130 <compat_mode_idt>: ... ffff82d0403961b6 <kexec_reloc_size>: ffff82d0403961b6: b6 01 mov $0x1,%dh ... to: ffff82d040396108 <compatibility_mode_far>: ffff82d040396108: 00 00 00 00 10 00 ...... ffff82d04039610e <compat_mode_gdt_desc>: ffff82d04039610e: 17 00 00 00 00 00 00 00 00 00 .......... ffff82d040396118 <compat_mode_gdt>: ... ffff82d040396120: ff ff 00 00 00 93 cf 00 ff ff 00 00 00 9b cf 00 ................ ffff82d040396130 <compat_mode_idt>: ffff82d040396130: 00 00 00 00 00 00 ...... ffff82d040396136 <reloc_stack>: ... Most data just gains type and size metadata. The reloc_stack label is the wrong end of the data block to have a size, so move it to the lowest address and introduce .Lreloc_stack_base as a replacement. Also, fix the fact that it is misaligned by 2 bytes. While kexec_reloc_size could gain metadata, it's use in the linker assertion (while correct) is deeply confusing to follow. Drop it entirely, using a linker symbol instead to denote the end of the trampoline. No functional change. Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> --- CC: Jan Beulich <JBeulich@suse.com> CC: Roger Pau Monné <roger.pau@citrix.com> CC: Wei Liu <wl@xen.org> The remainder of the 32bit code has mode-invariant lengths, so disassembles safely as 64bit. The only differences come from 32/64bit implicit register sizes. v2.1: * New v2.2: * Fix stack alignment --- xen/arch/x86/include/asm/machine_kexec.h | 2 +- xen/arch/x86/machine_kexec.c | 2 +- xen/arch/x86/x86_64/kexec_reloc.S | 23 ++++++++++++++++++----- xen/arch/x86/xen.lds.S | 3 ++- 4 files changed, 22 insertions(+), 8 deletions(-)