[xen stable-4.18] x86/APIC: finish genapic conversion to altcall

[patchbot@xxxxxxx]

commit 6b8ee350885c20673585953719210d415ee96a4a
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Wed Jan 17 10:41:52 2024 +0100
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Tue Apr 9 16:45:01 2024 +0100

    x86/APIC: finish genapic conversion to altcall
    
    While .probe() doesn't need fiddling with for being run only very early,
    init_apic_ldr() wants converting too despite not being on a frequently
    executed path: This way all pre-filled struct genapic instances can
    become __initconst_cf_clobber, thus allowing to eliminate 15 more ENDBR
    during the 2nd phase of alternatives patching.
    
    While fiddling with section annotations here, also move "genapic" itself
    to .data.ro_after_init.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    (cherry picked from commit b1cc53753cba4c3253f2e1093a3a6a9a828314bf)
---
 xen/arch/x86/genapic/bigsmp.c                     | 2 +-
 xen/arch/x86/genapic/default.c                    | 2 +-
 xen/arch/x86/genapic/probe.c                      | 2 +-
 xen/arch/x86/genapic/x2apic.c                     | 6 +++---
 xen/arch/x86/include/asm/mach-generic/mach_apic.h | 2 +-
 5 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/xen/arch/x86/genapic/bigsmp.c b/xen/arch/x86/genapic/bigsmp.c
index 2000383ab0..7219ec53b0 100644
--- a/xen/arch/x86/genapic/bigsmp.c
+++ b/xen/arch/x86/genapic/bigsmp.c
@@ -41,7 +41,7 @@ static int __init cf_check probe_bigsmp(void)
        return def_to_bigsmp;
 } 
 
-const struct genapic __initconstrel apic_bigsmp = {
+const struct genapic __initconst_cf_clobber apic_bigsmp = {
        APIC_INIT("bigsmp", probe_bigsmp),
        GENAPIC_PHYS
 };
diff --git a/xen/arch/x86/genapic/default.c b/xen/arch/x86/genapic/default.c
index 2c63c1f917..a968836a18 100644
--- a/xen/arch/x86/genapic/default.c
+++ b/xen/arch/x86/genapic/default.c
@@ -14,7 +14,7 @@
 #include <asm/io_apic.h>
 
 /* should be called last. */
-const struct genapic __initconstrel apic_default = {
+const struct genapic __initconst_cf_clobber apic_default = {
        APIC_INIT("default", NULL),
        GENAPIC_FLAT
 };
diff --git a/xen/arch/x86/genapic/probe.c b/xen/arch/x86/genapic/probe.c
index ad57912f50..10ceeae4d2 100644
--- a/xen/arch/x86/genapic/probe.c
+++ b/xen/arch/x86/genapic/probe.c
@@ -16,7 +16,7 @@
 #include <asm/mach-generic/mach_apic.h>
 #include <asm/setup.h>
 
-struct genapic __read_mostly genapic;
+struct genapic __ro_after_init genapic;
 
 static const struct genapic *const __initconstrel apic_probe[] = {
        &apic_bigsmp, 
diff --git a/xen/arch/x86/genapic/x2apic.c b/xen/arch/x86/genapic/x2apic.c
index b88c7a96fe..371dd100c7 100644
--- a/xen/arch/x86/genapic/x2apic.c
+++ b/xen/arch/x86/genapic/x2apic.c
@@ -158,7 +158,7 @@ static void cf_check send_IPI_mask_x2apic_cluster(
     local_irq_restore(flags);
 }
 
-static const struct genapic __initconstrel apic_x2apic_phys = {
+static const struct genapic __initconst_cf_clobber apic_x2apic_phys = {
     APIC_INIT("x2apic_phys", NULL),
     .int_delivery_mode = dest_Fixed,
     .int_dest_mode = 0 /* physical delivery */,
@@ -169,7 +169,7 @@ static const struct genapic __initconstrel apic_x2apic_phys 
= {
     .send_IPI_self = send_IPI_self_x2apic
 };
 
-static const struct genapic __initconstrel apic_x2apic_cluster = {
+static const struct genapic __initconst_cf_clobber apic_x2apic_cluster = {
     APIC_INIT("x2apic_cluster", NULL),
     .int_delivery_mode = dest_LowestPrio,
     .int_dest_mode = 1 /* logical delivery */,
@@ -187,7 +187,7 @@ static const struct genapic __initconstrel 
apic_x2apic_cluster = {
  * IPIs to be more efficiently delivered by not having to perform an ICR write
  * for each target CPU.
  */
-static const struct genapic __initconstrel apic_x2apic_mixed = {
+static const struct genapic __initconst_cf_clobber apic_x2apic_mixed = {
     APIC_INIT("x2apic_mixed", NULL),
 
     /*
diff --git a/xen/arch/x86/include/asm/mach-generic/mach_apic.h 
b/xen/arch/x86/include/asm/mach-generic/mach_apic.h
index cf8b31b6e0..c0d8b232c9 100644
--- a/xen/arch/x86/include/asm/mach-generic/mach_apic.h
+++ b/xen/arch/x86/include/asm/mach-generic/mach_apic.h
@@ -10,7 +10,7 @@
 #define INT_DELIVERY_MODE (genapic.int_delivery_mode)
 #define INT_DEST_MODE (genapic.int_dest_mode)
 #define TARGET_CPUS ((const typeof(cpu_online_map) *)&cpu_online_map)
-#define init_apic_ldr (genapic.init_apic_ldr)
+#define init_apic_ldr() alternative_vcall(genapic.init_apic_ldr)
 #define cpu_mask_to_apicid(mask) ({ \
        /* \
         * There are a number of places where the address of a local variable \
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.18