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>
--- 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_mas
#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:
--- a/xen/arch/x86/cpu/common.c
+++ b/xen/arch/x86/cpu/common.c
@@ -119,7 +119,7 @@ static const struct cpu_dev __initconst_
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)
{
--- 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_m
#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,
On 16/01/2024 4:53 pm, Jan Beulich wrote: > 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> > > --- 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_mas > #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 If we gain more of these, I suspect we'll want a wrapper for it. Irritatingly you can't pass parameters into global asm, because the nice way to do this would be an _ASM_PTR in a pushsection. ~Andrew
On 01.02.2024 22:12, Andrew Cooper wrote: > On 16/01/2024 4:53 pm, Jan Beulich wrote: >> 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> Thanks. >> --- 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_mas >> #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 > > If we gain more of these, I suspect we'll want a wrapper for it. > > Irritatingly you can't pass parameters into global asm, because the nice > way to do this would be an _ASM_PTR in a pushsection. While I'm not convinced resorting to asm() here would indeed be a good thing, for very many years I've been carrying a gcc change to permit exactly this. I don't even recall anymore why it wasn't liked upstream. Jan
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