x86/xen: Rework the xen_{cpu,irq,mmu}_opsarrays

In order to allow objtool to make sense of all the various paravirt
functions, it needs to either parse whole pv_ops[] tables, or observe
individual assignments in the form:

  bf87:       48 c7 05 00 00 00 00 00 00 00 00        movq   $0x0,0x0(%rip)
    bf92 <xen_init_spinlocks+0x5f>
    bf8a: R_X86_64_PC32     pv_ops+0x268

As is, xen_cpu_ops[] is at offset +0 in pv_ops[] and could thus be
parsed as a 'normal' pv_ops[] table, however xen_irq_ops[] and
xen_mmu_ops[] are not.

Worse, both the latter two are compiled into the individual assignment
for by current GCC, but that's not something one can rely on.

Therefore, convert all three into full pv_ops[] tables. This has the
benefit of not needing to teach objtool about the offsets and
resulting in more conservative code-gen.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20210624095149.057262522@infradead.org

1 files changed, 46 insertions, 44 deletions

diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c
index f3cafe56fbe5..b9a4f797ec1a 100644
--- a/arch/x86/xen/mmu_pv.c
+++ b/arch/x86/xen/mmu_pv.c
@@ -2076,67 +2076,69 @@ static void xen_leave_lazy_mmu(void)
 	preempt_enable();
 }
 
-static const struct pv_mmu_ops xen_mmu_ops __initconst = {
-	.read_cr2 = __PV_IS_CALLEE_SAVE(xen_read_cr2),
-	.write_cr2 = xen_write_cr2,
+static const typeof(pv_ops) xen_mmu_ops __initconst = {
+	.mmu = {
+		.read_cr2 = __PV_IS_CALLEE_SAVE(xen_read_cr2),
+		.write_cr2 = xen_write_cr2,
 
-	.read_cr3 = xen_read_cr3,
-	.write_cr3 = xen_write_cr3_init,
+		.read_cr3 = xen_read_cr3,
+		.write_cr3 = xen_write_cr3_init,
 
-	.flush_tlb_user = xen_flush_tlb,
-	.flush_tlb_kernel = xen_flush_tlb,
-	.flush_tlb_one_user = xen_flush_tlb_one_user,
-	.flush_tlb_multi = xen_flush_tlb_multi,
-	.tlb_remove_table = tlb_remove_table,
+		.flush_tlb_user = xen_flush_tlb,
+		.flush_tlb_kernel = xen_flush_tlb,
+		.flush_tlb_one_user = xen_flush_tlb_one_user,
+		.flush_tlb_multi = xen_flush_tlb_multi,
+		.tlb_remove_table = tlb_remove_table,
 
-	.pgd_alloc = xen_pgd_alloc,
-	.pgd_free = xen_pgd_free,
+		.pgd_alloc = xen_pgd_alloc,
+		.pgd_free = xen_pgd_free,
 
-	.alloc_pte = xen_alloc_pte_init,
-	.release_pte = xen_release_pte_init,
-	.alloc_pmd = xen_alloc_pmd_init,
-	.release_pmd = xen_release_pmd_init,
+		.alloc_pte = xen_alloc_pte_init,
+		.release_pte = xen_release_pte_init,
+		.alloc_pmd = xen_alloc_pmd_init,
+		.release_pmd = xen_release_pmd_init,
 
-	.set_pte = xen_set_pte_init,
-	.set_pmd = xen_set_pmd_hyper,
+		.set_pte = xen_set_pte_init,
+		.set_pmd = xen_set_pmd_hyper,
 
-	.ptep_modify_prot_start = xen_ptep_modify_prot_start,
-	.ptep_modify_prot_commit = xen_ptep_modify_prot_commit,
+		.ptep_modify_prot_start = xen_ptep_modify_prot_start,
+		.ptep_modify_prot_commit = xen_ptep_modify_prot_commit,
 
-	.pte_val = PV_CALLEE_SAVE(xen_pte_val),
-	.pgd_val = PV_CALLEE_SAVE(xen_pgd_val),
+		.pte_val = PV_CALLEE_SAVE(xen_pte_val),
+		.pgd_val = PV_CALLEE_SAVE(xen_pgd_val),
 
-	.make_pte = PV_CALLEE_SAVE(xen_make_pte_init),
-	.make_pgd = PV_CALLEE_SAVE(xen_make_pgd),
+		.make_pte = PV_CALLEE_SAVE(xen_make_pte_init),
+		.make_pgd = PV_CALLEE_SAVE(xen_make_pgd),
 
-	.set_pud = xen_set_pud_hyper,
+		.set_pud = xen_set_pud_hyper,
 
-	.make_pmd = PV_CALLEE_SAVE(xen_make_pmd),
-	.pmd_val = PV_CALLEE_SAVE(xen_pmd_val),
+		.make_pmd = PV_CALLEE_SAVE(xen_make_pmd),
+		.pmd_val = PV_CALLEE_SAVE(xen_pmd_val),
 
-	.pud_val = PV_CALLEE_SAVE(xen_pud_val),
-	.make_pud = PV_CALLEE_SAVE(xen_make_pud),
-	.set_p4d = xen_set_p4d_hyper,
+		.pud_val = PV_CALLEE_SAVE(xen_pud_val),
+		.make_pud = PV_CALLEE_SAVE(xen_make_pud),
+		.set_p4d = xen_set_p4d_hyper,
 
-	.alloc_pud = xen_alloc_pmd_init,
-	.release_pud = xen_release_pmd_init,
+		.alloc_pud = xen_alloc_pmd_init,
+		.release_pud = xen_release_pmd_init,
 
 #if CONFIG_PGTABLE_LEVELS >= 5
-	.p4d_val = PV_CALLEE_SAVE(xen_p4d_val),
-	.make_p4d = PV_CALLEE_SAVE(xen_make_p4d),
+		.p4d_val = PV_CALLEE_SAVE(xen_p4d_val),
+		.make_p4d = PV_CALLEE_SAVE(xen_make_p4d),
 #endif
 
-	.activate_mm = xen_activate_mm,
-	.dup_mmap = xen_dup_mmap,
-	.exit_mmap = xen_exit_mmap,
+		.activate_mm = xen_activate_mm,
+		.dup_mmap = xen_dup_mmap,
+		.exit_mmap = xen_exit_mmap,
 
-	.lazy_mode = {
-		.enter = paravirt_enter_lazy_mmu,
-		.leave = xen_leave_lazy_mmu,
-		.flush = paravirt_flush_lazy_mmu,
-	},
+		.lazy_mode = {
+			.enter = paravirt_enter_lazy_mmu,
+			.leave = xen_leave_lazy_mmu,
+			.flush = paravirt_flush_lazy_mmu,
+		},
 
-	.set_fixmap = xen_set_fixmap,
+		.set_fixmap = xen_set_fixmap,
+	},
 };
 
 void __init xen_init_mmu_ops(void)
@@ -2144,7 +2146,7 @@ void __init xen_init_mmu_ops(void)
 	x86_init.paging.pagetable_init = xen_pagetable_init;
 	x86_init.hyper.init_after_bootmem = xen_after_bootmem;
 
-	pv_ops.mmu = xen_mmu_ops;
+	pv_ops.mmu = xen_mmu_ops.mmu;
 
 	memset(dummy_mapping, 0xff, PAGE_SIZE);
 }