2022-07-05 14:42:49

by Quentin Perret

Subject: [PATCH] KVM: arm64: Don't return from void function

Although harmless, the return statement in kvm_unexpected_el2_exception
is rather confusing as the function itself has a void return type. The
C standard is also pretty clear that "A return statement with an
expression shall not appear in a function whose return type is void".
Given that this return statement does not seem to add any actual value,
let's not pointlessly violate the standard.

Build-tested with GCC 10 and CLANG 13 for good measure, the disassembled
code is identical with or without the return statement.

Fixes: e9ee186bb735 ("KVM: arm64: Add kvm_extable for vaxorcism code")
Signed-off-by: Quentin Perret <[email protected]>
---
arch/arm64/kvm/hyp/nvhe/switch.c | 2 +-
arch/arm64/kvm/hyp/vhe/switch.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c
index 6db801db8f27..925b34b7708d 100644
--- a/arch/arm64/kvm/hyp/nvhe/switch.c
+++ b/arch/arm64/kvm/hyp/nvhe/switch.c
@@ -386,5 +386,5 @@ asmlinkage void __noreturn hyp_panic_bad_stack(void)

asmlinkage void kvm_unexpected_el2_exception(void)
{
- return __kvm_unexpected_el2_exception();
+ __kvm_unexpected_el2_exception();
}
diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c
index 969f20daf97a..390af1a6a9b4 100644
--- a/arch/arm64/kvm/hyp/vhe/switch.c
+++ b/arch/arm64/kvm/hyp/vhe/switch.c
@@ -249,5 +249,5 @@ void __noreturn hyp_panic(void)

asmlinkage void kvm_unexpected_el2_exception(void)
{
- return __kvm_unexpected_el2_exception();
+ __kvm_unexpected_el2_exception();
}
--
2.37.0.rc0.161.g10f37bed90-goog

2022-07-06 09:07:27

by Marc Zyngier

Subject: Re: [PATCH] KVM: arm64: Don't return from void function

On Tue, 5 Jul 2022 14:23:10 +0000, Quentin Perret wrote:
> Although harmless, the return statement in kvm_unexpected_el2_exception
> is rather confusing as the function itself has a void return type. The
> C standard is also pretty clear that "A return statement with an
> expression shall not appear in a function whose return type is void".
> Given that this return statement does not seem to add any actual value,
> let's not pointlessly violate the standard.
>
> [...]

Applied to kvm-arm64/misc-5.20, thanks!

[1/1] KVM: arm64: Don't return from void function
commit: 1c3ace2b8b3995d3213c5e2d2aca01a0577a3b0f

Cheers,

M.
--
Marc Zyngier <[email protected]>