[tip: objtool/core] x86/xen: Make set_debugreg() noinstr

tip-bot2 for Peter Zijlstra
2021-09-17T12:58:40Z

The following commit has been merged into the objtool/core branch of tip:

Commit-ID: 7361fac0465ba96ec8f7559459e3c70818ba6c78
Gitweb: https://git.kernel.org/tip/7361fac0465ba96ec8f7559459e3c70818ba6c78
Author: Peter Zijlstra <peterz@infradead.org>
AuthorDate: Thu, 24 Jun 2021 11:41:16 +02:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Fri, 17 Sep 2021 13:14:39 +02:00

x86/xen: Make set_debugreg() noinstr

vmlinux.o: warning: objtool: pv_ops[2]: xen_set_debugreg
vmlinux.o: warning: objtool: pv_ops[2]: native_set_debugreg
vmlinux.o: warning: objtool: exc_debug()+0x3b: call to pv_ops[2]() leaves .noinstr.text section

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20210624095148.687755639@infradead.org
---
arch/x86/include/asm/paravirt.h | 2 +-
arch/x86/include/asm/xen/hypercall.h | 2 +-
arch/x86/kernel/paravirt.c | 9 ++++++---
arch/x86/xen/enlighten_pv.c | 2 +-
4 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index f48465c..34da790 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -118,7 +118,7 @@ static __always_inline unsigned long paravirt_get_debugreg(int reg)
return PVOP_CALL1(unsigned long, cpu.get_debugreg, reg);
}
#define get_debugreg(var, reg) var = paravirt_get_debugreg(reg)
-static inline void set_debugreg(unsigned long val, int reg)
+static __always_inline void set_debugreg(unsigned long val, int reg)
{
PVOP_VCALL2(cpu.set_debugreg, reg, val);
}
diff --git a/arch/x86/include/asm/xen/hypercall.h b/arch/x86/include/asm/xen/hypercall.h
index af92202..990b8aa 100644
--- a/arch/x86/include/asm/xen/hypercall.h
+++ b/arch/x86/include/asm/xen/hypercall.h
@@ -308,7 +308,7 @@ HYPERVISOR_platform_op(struct xen_platform_op *op)
return _hypercall1(int, platform_op, op);
}

-static inline int
+static __always_inline int
HYPERVISOR_set_debugreg(int reg, unsigned long value)
{
return _hypercall2(int, set_debugreg, reg, value);
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index 8af526c..cdaf862 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -233,6 +233,11 @@ static noinstr unsigned long pv_native_get_debugreg(int regno)
{
return native_get_debugreg(regno);
}
+
+static noinstr void pv_native_set_debugreg(int regno, unsigned long val)
+{
+ native_set_debugreg(regno, val);
+}
#endif

enum paravirt_lazy_mode paravirt_get_lazy_mode(void)
@@ -260,7 +265,7 @@ struct paravirt_patch_template pv_ops = {
#ifdef CONFIG_PARAVIRT_XXL
.cpu.cpuid = native_cpuid,
.cpu.get_debugreg = pv_native_get_debugreg,
- .cpu.set_debugreg = native_set_debugreg,
+ .cpu.set_debugreg = pv_native_set_debugreg,
.cpu.read_cr0 = native_read_cr0,
.cpu.write_cr0 = native_write_cr0,
.cpu.write_cr4 = native_write_cr4,
@@ -386,8 +391,6 @@ struct paravirt_patch_template pv_ops = {
};

#ifdef CONFIG_PARAVIRT_XXL
-/* At this point, native_get/set_debugreg has real function entries */
-NOKPROBE_SYMBOL(native_set_debugreg);
NOKPROBE_SYMBOL(native_load_idt);

void (*paravirt_iret)(void) = native_iret;
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 273e1fa..2b1a8ba 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -311,7 +311,7 @@ static void __init xen_init_capabilities(void)
}
}

-static void xen_set_debugreg(int reg, unsigned long val)
+static noinstr void xen_set_debugreg(int reg, unsigned long val)
{
HYPERVISOR_set_debugreg(reg, val);
}