diff options
| -rw-r--r-- | arch/x86/platform/pvh/head.S | 30 |
1 files changed, 18 insertions, 12 deletions
diff --git a/arch/x86/platform/pvh/head.S b/arch/x86/platform/pvh/head.S index e6f39d77f0b4..4733a5f467b8 100644 --- a/arch/x86/platform/pvh/head.S +++ b/arch/x86/platform/pvh/head.S @@ -6,7 +6,9 @@ .code32 .text +#ifdef CONFIG_X86_32 #define _pa(x) ((x) - __START_KERNEL_map) +#endif #define rva(x) ((x) - pvh_start_xen) #include <linux/elfnote.h> @@ -72,8 +74,7 @@ SYM_CODE_START(pvh_start_xen) movl $0, %esp leal rva(gdt)(%ebp), %eax - leal rva(gdt_start)(%ebp), %ecx - movl %ecx, 2(%eax) + addl %eax, 2(%eax) lgdt (%eax) mov $PVH_DS_SEL,%eax @@ -103,10 +104,23 @@ SYM_CODE_START(pvh_start_xen) btsl $_EFER_LME, %eax wrmsr + /* + * Reuse the non-relocatable symbol emitted for the ELF note to + * subtract the build time physical address of pvh_start_xen() from + * its actual runtime address, without relying on absolute 32-bit ELF + * relocations, as these are not supported by the linker when running + * in -pie mode, and should be avoided in .head.text in general. + */ mov %ebp, %ebx - subl $_pa(pvh_start_xen), %ebx /* offset */ + subl rva(xen_elfnote_phys32_entry)(%ebp), %ebx jz .Lpagetable_done + /* + * Store the resulting load offset in phys_base. __pa() needs + * phys_base set to calculate the hypercall page in xen_pvh_init(). + */ + movl %ebx, rva(phys_base)(%ebp) + /* Fixup page-tables for relocation. */ leal rva(pvh_init_top_pgt)(%ebp), %edi movl $PTRS_PER_PGD, %ecx @@ -165,14 +179,6 @@ SYM_CODE_START(pvh_start_xen) xor %edx, %edx wrmsr - /* - * Calculate load offset and store in phys_base. __pa() needs - * phys_base set to calculate the hypercall page in xen_pvh_init(). - */ - movq %rbp, %rbx - subq $_pa(pvh_start_xen), %rbx - movq %rbx, phys_base(%rip) - /* Call xen_prepare_pvh() via the kernel virtual mapping */ leaq xen_prepare_pvh(%rip), %rax subq phys_base(%rip), %rax @@ -218,7 +224,7 @@ SYM_CODE_END(pvh_start_xen) .balign 8 SYM_DATA_START_LOCAL(gdt) .word gdt_end - gdt_start - 1 - .long _pa(gdt_start) /* x86-64 will overwrite if relocated. */ + .long gdt_start - gdt .word 0 SYM_DATA_END(gdt) SYM_DATA_START_LOCAL(gdt_start) |