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ppc/kvm: Replace ACCESS_ONCE with READ_ONCE
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ACCESS_ONCE does not work reliably on non-scalar types. For
example gcc 4.6 and 4.7 might remove the volatile tag for such
accesses during the SRA (scalar replacement of aggregates) step
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145)

Change the ppc/kvm code to replace ACCESS_ONCE with READ_ONCE.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Alexander Graf <agraf@suse.de>
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Christian Borntraeger committed Jan 19, 2015
1 parent b1940cd commit 5ee0761
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Showing 2 changed files with 12 additions and 12 deletions.
8 changes: 4 additions & 4 deletions arch/powerpc/kvm/book3s_hv_rm_xics.c
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Original file line number Diff line number Diff line change
Expand Up @@ -152,7 +152,7 @@ static void icp_rm_down_cppr(struct kvmppc_xics *xics, struct kvmppc_icp *icp,
* in virtual mode.
*/
do {
old_state = new_state = ACCESS_ONCE(icp->state);
old_state = new_state = READ_ONCE(icp->state);

/* Down_CPPR */
new_state.cppr = new_cppr;
Expand Down Expand Up @@ -211,7 +211,7 @@ unsigned long kvmppc_rm_h_xirr(struct kvm_vcpu *vcpu)
* pending priority
*/
do {
old_state = new_state = ACCESS_ONCE(icp->state);
old_state = new_state = READ_ONCE(icp->state);

xirr = old_state.xisr | (((u32)old_state.cppr) << 24);
if (!old_state.xisr)
Expand Down Expand Up @@ -277,7 +277,7 @@ int kvmppc_rm_h_ipi(struct kvm_vcpu *vcpu, unsigned long server,
* whenever the MFRR is made less favored.
*/
do {
old_state = new_state = ACCESS_ONCE(icp->state);
old_state = new_state = READ_ONCE(icp->state);

/* Set_MFRR */
new_state.mfrr = mfrr;
Expand Down Expand Up @@ -352,7 +352,7 @@ int kvmppc_rm_h_cppr(struct kvm_vcpu *vcpu, unsigned long cppr)
icp_rm_clr_vcpu_irq(icp->vcpu);

do {
old_state = new_state = ACCESS_ONCE(icp->state);
old_state = new_state = READ_ONCE(icp->state);

reject = 0;
new_state.cppr = cppr;
Expand Down
16 changes: 8 additions & 8 deletions arch/powerpc/kvm/book3s_xics.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -327,7 +327,7 @@ static bool icp_try_to_deliver(struct kvmppc_icp *icp, u32 irq, u8 priority,
icp->server_num);

do {
old_state = new_state = ACCESS_ONCE(icp->state);
old_state = new_state = READ_ONCE(icp->state);

*reject = 0;

Expand Down Expand Up @@ -512,7 +512,7 @@ static void icp_down_cppr(struct kvmppc_xics *xics, struct kvmppc_icp *icp,
* in virtual mode.
*/
do {
old_state = new_state = ACCESS_ONCE(icp->state);
old_state = new_state = READ_ONCE(icp->state);

/* Down_CPPR */
new_state.cppr = new_cppr;
Expand Down Expand Up @@ -567,7 +567,7 @@ static noinline unsigned long kvmppc_h_xirr(struct kvm_vcpu *vcpu)
* pending priority
*/
do {
old_state = new_state = ACCESS_ONCE(icp->state);
old_state = new_state = READ_ONCE(icp->state);

xirr = old_state.xisr | (((u32)old_state.cppr) << 24);
if (!old_state.xisr)
Expand Down Expand Up @@ -634,7 +634,7 @@ static noinline int kvmppc_h_ipi(struct kvm_vcpu *vcpu, unsigned long server,
* whenever the MFRR is made less favored.
*/
do {
old_state = new_state = ACCESS_ONCE(icp->state);
old_state = new_state = READ_ONCE(icp->state);

/* Set_MFRR */
new_state.mfrr = mfrr;
Expand Down Expand Up @@ -679,7 +679,7 @@ static int kvmppc_h_ipoll(struct kvm_vcpu *vcpu, unsigned long server)
if (!icp)
return H_PARAMETER;
}
state = ACCESS_ONCE(icp->state);
state = READ_ONCE(icp->state);
kvmppc_set_gpr(vcpu, 4, ((u32)state.cppr << 24) | state.xisr);
kvmppc_set_gpr(vcpu, 5, state.mfrr);
return H_SUCCESS;
Expand Down Expand Up @@ -721,7 +721,7 @@ static noinline void kvmppc_h_cppr(struct kvm_vcpu *vcpu, unsigned long cppr)
BOOK3S_INTERRUPT_EXTERNAL_LEVEL);

do {
old_state = new_state = ACCESS_ONCE(icp->state);
old_state = new_state = READ_ONCE(icp->state);

reject = 0;
new_state.cppr = cppr;
Expand Down Expand Up @@ -885,7 +885,7 @@ static int xics_debug_show(struct seq_file *m, void *private)
if (!icp)
continue;

state.raw = ACCESS_ONCE(icp->state.raw);
state.raw = READ_ONCE(icp->state.raw);
seq_printf(m, "cpu server %#lx XIRR:%#x PPRI:%#x CPPR:%#x MFRR:%#x OUT:%d NR:%d\n",
icp->server_num, state.xisr,
state.pending_pri, state.cppr, state.mfrr,
Expand Down Expand Up @@ -1082,7 +1082,7 @@ int kvmppc_xics_set_icp(struct kvm_vcpu *vcpu, u64 icpval)
* the ICS states before the ICP states.
*/
do {
old_state = ACCESS_ONCE(icp->state);
old_state = READ_ONCE(icp->state);

if (new_state.mfrr <= old_state.mfrr) {
resend = false;
Expand Down

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