Hi Stefano,
On 10/8/19 2:14 AM, Stefano Stabellini wrote:
The size of buf is calculated wrongly: the number is 64bit, not 32bit.
While the variable mpdir_aff is 64-bit, we only write the first 32-bit
in the property reg (#address-cells == 1 and fdt_property_cell()). So
what needs to be modified is the format here.
Also, looking the CPU bindings (see
linux/Documentation/devicetree/bindings/arm/cpus.yaml), technically only
the bits [23:0] of the mpidr should be used. The rest is zeroed.
This is ok because vcpuid_to_vaffinity() is always returning a value
following the requirements above. However, for correctness, this may
want to be fixed.
Also the number is printed as a hexadecimal number, so we need 8 bytes
for 32bit, not 10 bytes.
As a result, it should be sizeof("cpu@") + 16 bytes for a 64-bit number
+ 1 byte for \0. Total = 21.
Fixes: fafd682c3e (xen/arm: Create a fake cpus node in dom0 device tree)
I am afraid this is not fixing this patch:
snprintf(buf, sizeof(buf), "cpu@%u", cpu);
So the 10 bytes were actually correct back then.
The problem was introduced by commit c81a791d34 "xen/arm: Set 'reg' of
cpu node for dom0 to match MPIDR's affinity".
Signed-off-by: Stefano Stabellini <[email protected]>
---
Changes in v2:
- patch added
---
xen/arch/arm/domain_build.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 921b054520..60923a7051 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -788,8 +788,8 @@ static int __init make_cpus_node(const struct domain *d,
void *fdt)
unsigned int cpu;
const void *compatible = NULL;
u32 len;
- /* Placeholder for cpu@ + a 32-bit number + \0 */
- char buf[15];
+ /* Placeholder for cpu@ + a 64-bit number + \0 */
+ char buf[21];
u32 clock_frequency;
bool clock_valid;
uint64_t mpidr_aff;
Cheers,
--
Julien Grall
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