linux-kernel - [PATCH 1/3] KVM: arm64: fix override-init warnings in W=1 builds

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Message-ID: <20240712110332.10970-2-sebott@redhat.com>
Date: Fri, 12 Jul 2024 13:03:30 +0200
From: Sebastian Ott <sebott@...hat.com>
To: linux-arm-kernel@...ts.infradead.org,
	kvmarm@...ts.linux.dev,
	linux-kernel@...r.kernel.org
Cc: Marc Zyngier <maz@...nel.org>,
	Oliver Upton <oliver.upton@...ux.dev>,
	James Morse <james.morse@....com>,
	Suzuki K Poulose <suzuki.poulose@....com>,
	Catalin Marinas <catalin.marinas@....com>,
	Will Deacon <will@...nel.org>,
	Zenghui Yu <yuzenghui@...wei.com>
Subject: [PATCH 1/3] KVM: arm64: fix override-init warnings in W=1 builds

Remove double initializations in cases where that's easily possible
- like extra NULL initialization in static global structures. In the
other cases just silence -Woverride-init.

To fix warnings like the following:
arch/arm64/kvm/hyp/vhe/switch.c:271:43: warning: initialized field overwritten [-Woverride-init]
  271 |         [ESR_ELx_EC_CP15_32]            = kvm_hyp_handle_cp15_32,
      |                                           ^~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Sebastian Ott <sebott@...hat.com>
---
 arch/arm64/kvm/handle_exit.c     | 5 +++++
 arch/arm64/kvm/hyp/nvhe/switch.c | 6 ++----
 arch/arm64/kvm/hyp/vhe/switch.c  | 3 +--
 arch/arm64/kvm/sys_regs.c        | 5 +++++
 4 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
index d7c2990e7c9e..2c049746657c 100644
--- a/arch/arm64/kvm/handle_exit.c
+++ b/arch/arm64/kvm/handle_exit.c
@@ -291,6 +291,9 @@ static int handle_svc(struct kvm_vcpu *vcpu)
 	return 1;
 }
 
+__diag_push();
+__diag_ignore_all("-Woverride-init", "Allow field overrides in exit_handlers");
+
 static exit_handle_fn arm_exit_handlers[] = {
 	[0 ... ESR_ELx_EC_MAX]	= kvm_handle_unknown_ec,
 	[ESR_ELx_EC_WFx]	= kvm_handle_wfx,
@@ -319,6 +322,8 @@ static exit_handle_fn arm_exit_handlers[] = {
 	[ESR_ELx_EC_PAC]	= kvm_handle_ptrauth,
 };
 
+__diag_pop();
+
 static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu)
 {
 	u64 esr = kvm_vcpu_get_esr(vcpu);
diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c
index 6af179c6356d..bf49afc01542 100644
--- a/arch/arm64/kvm/hyp/nvhe/switch.c
+++ b/arch/arm64/kvm/hyp/nvhe/switch.c
@@ -200,8 +200,7 @@ static void kvm_hyp_save_fpsimd_host(struct kvm_vcpu *vcpu)
 	}
 }
 
-static const exit_handler_fn hyp_exit_handlers[] = {
-	[0 ... ESR_ELx_EC_MAX]		= NULL,
+static const exit_handler_fn hyp_exit_handlers[ESR_ELx_EC_MAX + 1] = {
 	[ESR_ELx_EC_CP15_32]		= kvm_hyp_handle_cp15_32,
 	[ESR_ELx_EC_SYS64]		= kvm_hyp_handle_sysreg,
 	[ESR_ELx_EC_SVE]		= kvm_hyp_handle_fpsimd,
@@ -212,8 +211,7 @@ static const exit_handler_fn hyp_exit_handlers[] = {
 	[ESR_ELx_EC_MOPS]		= kvm_hyp_handle_mops,
 };
 
-static const exit_handler_fn pvm_exit_handlers[] = {
-	[0 ... ESR_ELx_EC_MAX]		= NULL,
+static const exit_handler_fn pvm_exit_handlers[ESR_ELx_EC_MAX + 1] = {
 	[ESR_ELx_EC_SYS64]		= kvm_handle_pvm_sys64,
 	[ESR_ELx_EC_SVE]		= kvm_handle_pvm_restricted,
 	[ESR_ELx_EC_FP_ASIMD]		= kvm_hyp_handle_fpsimd,
diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c
index 77010b76c150..4e4ff2bd51c9 100644
--- a/arch/arm64/kvm/hyp/vhe/switch.c
+++ b/arch/arm64/kvm/hyp/vhe/switch.c
@@ -415,8 +415,7 @@ static bool kvm_hyp_handle_sysreg_vhe(struct kvm_vcpu *vcpu, u64 *exit_code)
 	return kvm_hyp_handle_sysreg(vcpu, exit_code);
 }
 
-static const exit_handler_fn hyp_exit_handlers[] = {
-	[0 ... ESR_ELx_EC_MAX]		= NULL,
+static const exit_handler_fn hyp_exit_handlers[ESR_ELx_EC_MAX + 1] = {
 	[ESR_ELx_EC_CP15_32]		= kvm_hyp_handle_cp15_32,
 	[ESR_ELx_EC_SYS64]		= kvm_hyp_handle_sysreg_vhe,
 	[ESR_ELx_EC_SVE]		= kvm_hyp_handle_fpsimd,
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index c90324060436..00fb6f1e9a48 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -2255,6 +2255,9 @@ static bool access_zcr_el2(struct kvm_vcpu *vcpu,
 	return true;
 }
 
+__diag_push();
+__diag_ignore_all("-Woverride-init", "Allow field overrides in sys_reg_descs");
+
 /*
  * Architected system registers.
  * Important: Must be sorted ascending by Op0, Op1, CRn, CRm, Op2
@@ -2803,6 +2806,8 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	EL2_REG(SP_EL2, NULL, reset_unknown, 0),
 };
 
+__diag_pop();
+
 static bool kvm_supported_tlbi_s12_op(struct kvm_vcpu *vpcu, u32 instr)
 {
 	struct kvm *kvm = vpcu->kvm;
-- 
2.42.0