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arm64: KVM: regmap: Fix unexpected switch fall-through

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commit 3d584a3c85 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: a892819560 ("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>
This commit is contained in:
Anders Roxell 2019-07-26 13:27:05 +02:00 • committed by Greg Kroah-Hartman
commit c8d95668c4
1 changed files with 5 additions and 0 deletions
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5
arch/arm64/kvm/regmap.c
View file

@ -189,13 +189,18 @@ void vcpu_write_spsr32(struct kvm_vcpu *vcpu, unsigned long v)
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;
}
}