Mailing List Archive

commit b6fad02a54da8c38a316eeebab22152f29ee0218
Author: Jan Beulich <jbeulich@suse.com>
AuthorDate: Mon Feb 5 10:44:46 2024 +0100
Commit: Andrew Cooper <andrew.cooper3@citrix.com>
CommitDate: Tue Apr 9 16:45:01 2024 +0100

x86: arrange for ENDBR zapping from <vendor>_ctxt_switch_masking()

While altcall is already used for them, the functions want announcing in
.init.rodata.cf_clobber, even if the resulting static variables aren't
otherwise used.

While doing this also move ctxt_switch_masking to .data.ro_after_init.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
(cherry picked from commit 044168fa3a65b6542bda5c21e373742de1bd5980)
---
xen/arch/x86/cpu/amd.c | 5 +++++
xen/arch/x86/cpu/common.c | 2 +-
xen/arch/x86/cpu/intel.c | 5 +++++
3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/cpu/amd.c b/xen/arch/x86/cpu/amd.c
index d43288ae97..808cda46bc 100644
--- a/xen/arch/x86/cpu/amd.c
+++ b/xen/arch/x86/cpu/amd.c
@@ -258,6 +258,11 @@ static void cf_check amd_ctxt_switch_masking(const struct vcpu *next)
#undef LAZY
}

+#ifdef CONFIG_XEN_IBT /* Announce the function to ENDBR clobbering logic. */
+static const typeof(ctxt_switch_masking) __initconst_cf_clobber __used csm =
+ amd_ctxt_switch_masking;
+#endif
+
/*
* Mask the features and extended features returned by CPUID. Parameters are
* set from the boot line via two methods:
diff --git a/xen/arch/x86/cpu/common.c b/xen/arch/x86/cpu/common.c
index 51509fece0..61e5e52151 100644
--- a/xen/arch/x86/cpu/common.c
+++ b/xen/arch/x86/cpu/common.c
@@ -119,7 +119,7 @@ static const struct cpu_dev default_cpu = {
static const struct cpu_dev *this_cpu = &default_cpu;

static DEFINE_PER_CPU(uint64_t, msr_misc_features);
-void (* __read_mostly ctxt_switch_masking)(const struct vcpu *next);
+void (* __ro_after_init ctxt_switch_masking)(const struct vcpu *next);

bool __init probe_cpuid_faulting(void)
{
diff --git a/xen/arch/x86/cpu/intel.c b/xen/arch/x86/cpu/intel.c
index aef8e4506c..19466b89e8 100644
--- a/xen/arch/x86/cpu/intel.c
+++ b/xen/arch/x86/cpu/intel.c
@@ -220,6 +220,11 @@ static void cf_check intel_ctxt_switch_masking(const struct vcpu *next)
#undef LAZY
}

+#ifdef CONFIG_XEN_IBT /* Announce the function to ENDBR clobbering logic. */
+static const typeof(ctxt_switch_masking) __initconst_cf_clobber __used csm =
+ intel_ctxt_switch_masking;
+#endif
+
/*
* opt_cpuid_mask_ecx/edx: cpuid.1[ecx, edx] feature mask.
* For example, E8400[Intel Core 2 Duo Processor series] ecx = 0x0008E3FD,
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.18