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

[tip-bot2 for Peter Zijlstra]

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

Commit-ID:     f4afb713e5c3a4419ba7aaecc31a8c8bd91d13fb
Gitweb:        https://git.kernel.org/tip/f4afb713e5c3a4419ba7aaecc31a8c8bd91d13fb
Author:        Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate:    Thu, 24 Jun 2021 11:41:15 +02:00
Committer:     Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Fri, 17 Sep 2021 13:12:34 +02:00

x86/xen: Make get_debugreg() noinstr

vmlinux.o: warning: objtool: pv_ops[1]: xen_get_debugreg
vmlinux.o: warning: objtool: pv_ops[1]: native_get_debugreg
vmlinux.o: warning: objtool: exc_debug()+0x25: call to pv_ops[1]() leaves .noinstr.text section

Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Juergen Gross <jgross@xxxxxxxx>
Link: https://lore.kernel.org/r/20210624095148.625523645@xxxxxxxxxxxxx
---
 arch/x86/include/asm/paravirt.h      | 2 +-
 arch/x86/include/asm/xen/hypercall.h | 2 +-
 arch/x86/kernel/paravirt.c           | 8 ++++++--
 arch/x86/xen/enlighten_pv.c          | 2 +-
 4 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index be82b52..f48465c 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -113,7 +113,7 @@ static inline void __cpuid(unsigned int *eax, unsigned int *ebx,
 /*
  * These special macros can be used to get or set a debugging register
  */
-static inline unsigned long paravirt_get_debugreg(int reg)
+static __always_inline unsigned long paravirt_get_debugreg(int reg)
 {
 	return PVOP_CALL1(unsigned long, cpu.get_debugreg, reg);
 }
diff --git a/arch/x86/include/asm/xen/hypercall.h b/arch/x86/include/asm/xen/hypercall.h
index 454b208..af92202 100644
--- a/arch/x86/include/asm/xen/hypercall.h
+++ b/arch/x86/include/asm/xen/hypercall.h
@@ -314,7 +314,7 @@ HYPERVISOR_set_debugreg(int reg, unsigned long value)
 	return _hypercall2(int, set_debugreg, reg, value);
 }
 
-static inline unsigned long
+static __always_inline unsigned long
 HYPERVISOR_get_debugreg(int reg)
 {
 	return _hypercall1(unsigned long, get_debugreg, reg);
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index fc2cf2b..8af526c 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -228,6 +228,11 @@ static noinstr void pv_native_write_cr2(unsigned long val)
 {
 	native_write_cr2(val);
 }
+
+static noinstr unsigned long pv_native_get_debugreg(int regno)
+{
+	return native_get_debugreg(regno);
+}
 #endif
 
 enum paravirt_lazy_mode paravirt_get_lazy_mode(void)
@@ -254,7 +259,7 @@ struct paravirt_patch_template pv_ops = {
 
 #ifdef CONFIG_PARAVIRT_XXL
 	.cpu.cpuid		= native_cpuid,
-	.cpu.get_debugreg	= native_get_debugreg,
+	.cpu.get_debugreg	= pv_native_get_debugreg,
 	.cpu.set_debugreg	= native_set_debugreg,
 	.cpu.read_cr0		= native_read_cr0,
 	.cpu.write_cr0		= native_write_cr0,
@@ -382,7 +387,6 @@ struct paravirt_patch_template pv_ops = {
 
 #ifdef CONFIG_PARAVIRT_XXL
 /* At this point, native_get/set_debugreg has real function entries */
-NOKPROBE_SYMBOL(native_get_debugreg);
 NOKPROBE_SYMBOL(native_set_debugreg);
 NOKPROBE_SYMBOL(native_load_idt);
 
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 753f637..273e1fa 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -316,7 +316,7 @@ static void xen_set_debugreg(int reg, unsigned long val)
 	HYPERVISOR_set_debugreg(reg, val);
 }
 
-static unsigned long xen_get_debugreg(int reg)
+static noinstr unsigned long xen_get_debugreg(int reg)
 {
 	return HYPERVISOR_get_debugreg(reg);
 }