From: Anders Roxell anders.roxell@linaro.org
commit 3d584a3c85d6fe2cf878f220d4ad7145e7f89218 upstream.
When fall-through warnings was enabled by default, commit d93512ef0f0e ("Makefile: Globally enable fall-through warning"), the following warnings was starting to show up:
In file included from ../arch/arm64/include/asm/kvm_emulate.h:19, from ../arch/arm64/kvm/regmap.c:13: ../arch/arm64/kvm/regmap.c: In function ‘vcpu_write_spsr32’: ../arch/arm64/include/asm/kvm_hyp.h:31:3: warning: this statement may fall through [-Wimplicit-fallthrough=] asm volatile(ALTERNATIVE(__msr_s(r##nvh, "%x0"), \ ^~~ ../arch/arm64/include/asm/kvm_hyp.h:46:31: note: in expansion of macro ‘write_sysreg_elx’ #define write_sysreg_el1(v,r) write_sysreg_elx(v, r, _EL1, _EL12) ^~~~~~~~~~~~~~~~ ../arch/arm64/kvm/regmap.c:180:3: note: in expansion of macro ‘write_sysreg_el1’ write_sysreg_el1(v, SYS_SPSR); ^~~~~~~~~~~~~~~~ ../arch/arm64/kvm/regmap.c:181:2: note: here case KVM_SPSR_ABT: ^~~~ In file included from ../arch/arm64/include/asm/cputype.h:132, from ../arch/arm64/include/asm/cache.h:8, from ../include/linux/cache.h:6, from ../include/linux/printk.h:9, from ../include/linux/kernel.h:15, from ../include/asm-generic/bug.h:18, from ../arch/arm64/include/asm/bug.h:26, from ../include/linux/bug.h:5, from ../include/linux/mmdebug.h:5, from ../include/linux/mm.h:9, from ../arch/arm64/kvm/regmap.c:11: ../arch/arm64/include/asm/sysreg.h:837:2: warning: this statement may fall through [-Wimplicit-fallthrough=] asm volatile("msr " __stringify(r) ", %x0" \ ^~~ ../arch/arm64/kvm/regmap.c:182:3: note: in expansion of macro ‘write_sysreg’ write_sysreg(v, spsr_abt); ^~~~~~~~~~~~ ../arch/arm64/kvm/regmap.c:183:2: note: here case KVM_SPSR_UND: ^~~~
Rework to add a 'break;' in the swich-case since it didn't have that, leading to an interresting set of bugs.
Cc: stable@vger.kernel.org # v4.17+ Fixes: a892819560c4 ("KVM: arm64: Prepare to handle deferred save/restore of 32-bit registers") Signed-off-by: Anders Roxell anders.roxell@linaro.org [maz: reworked commit message, fixed stable range] Signed-off-by: Marc Zyngier maz@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/arm64/kvm/regmap.c | 5 +++++ 1 file changed, 5 insertions(+)
--- a/arch/arm64/kvm/regmap.c +++ b/arch/arm64/kvm/regmap.c @@ -189,13 +189,18 @@ void vcpu_write_spsr32(struct kvm_vcpu * switch (spsr_idx) { case KVM_SPSR_SVC: write_sysreg_el1(v, spsr); + break; case KVM_SPSR_ABT: write_sysreg(v, spsr_abt); + break; case KVM_SPSR_UND: write_sysreg(v, spsr_und); + break; case KVM_SPSR_IRQ: write_sysreg(v, spsr_irq); + break; case KVM_SPSR_FIQ: write_sysreg(v, spsr_fiq); + break; } }