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Subject[tip: objtool/core] x86/xen: Make get_debugreg() noinstr
The following commit has been merged into the objtool/core branch of tip:

Commit-ID: 737196b197f21326b96ba969a5b1205c90f25cdc
Gitweb: https://git.kernel.org/tip/737196b197f21326b96ba969a5b1205c90f25cdc
Author: Peter Zijlstra <peterz@infradead.org>
AuthorDate: Thu, 24 Jun 2021 11:41:15 +02:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Wed, 15 Sep 2021 15:51:49 +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@infradead.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20210624095148.625523645@infradead.org
---
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 78f08e1..9188ae1 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -248,13 +248,18 @@ 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);
+}
+
struct paravirt_patch_template pv_ops = {
/* Cpu ops. */
.cpu.io_delay = native_io_delay,

#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);
}
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