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SubjectRe: [patch v2] x86, UV: integer wrap bug in uv_hub_ipi_value()


Am 02.12.2012 11:44, schrieb Dan Carpenter:
> This is a static checker fix. The problem is that we store the bits
> from "uv_apicid_hibits" into "apicid" (the high 16 bits) but then we
> shift it 16 bit to the left. "apicid" is an int so it wraps and we lose
> them.
>
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> v2: Style fix. Don't use ulong.
>
> I don't have this hardware so I can't test it. There may also be other
> bugs which this patch does not addressed. These files are only compiled
> on x86_64 and "unsigned long" is used throughout to mean 64 bits.
>
> diff --git a/arch/x86/include/asm/uv/uv_hub.h b/arch/x86/include/asm/uv/uv_hub.h
> index 21f7385..e7a83d5 100644
> --- a/arch/x86/include/asm/uv/uv_hub.h
> +++ b/arch/x86/include/asm/uv/uv_hub.h
> @@ -577,7 +577,7 @@ static unsigned long uv_hub_ipi_value(int apicid, int vector, int mode)
> {
> apicid |= uv_apicid_hibits;
> return (1UL << UVH_IPI_INT_SEND_SHFT) |
> - ((apicid) << UVH_IPI_INT_APIC_ID_SHFT) |
> + ((unsigned long)apicid << UVH_IPI_INT_APIC_ID_SHFT) |
> (mode << UVH_IPI_INT_DELIVERY_MODE_SHFT) |
> (vector << UVH_IPI_INT_VECTOR_SHFT);
> }
> diff --git a/arch/x86/kernel/apic/x2apic_uv_x.c b/arch/x86/kernel/apic/x2apic_uv_x.c
> index 8cfade9..6d93b2f 100644
> --- a/arch/x86/kernel/apic/x2apic_uv_x.c
> +++ b/arch/x86/kernel/apic/x2apic_uv_x.c
> @@ -194,13 +194,13 @@ static int __cpuinit uv_wakeup_secondary(int phys_apicid, unsigned long start_ri
> pnode = uv_apicid_to_pnode(phys_apicid);
> phys_apicid |= uv_apicid_hibits;
> val = (1UL << UVH_IPI_INT_SEND_SHFT) |
> - (phys_apicid << UVH_IPI_INT_APIC_ID_SHFT) |
> + ((unsigned long)phys_apicid << UVH_IPI_INT_APIC_ID_SHFT) |
> ((start_rip << UVH_IPI_INT_VECTOR_SHFT) >> 12) |
> APIC_DM_INIT;
> uv_write_global_mmr64(pnode, UVH_IPI_INT, val);
>
> val = (1UL << UVH_IPI_INT_SEND_SHFT) |
> - (phys_apicid << UVH_IPI_INT_APIC_ID_SHFT) |
> + ((unsigned long)phys_apicid << UVH_IPI_INT_APIC_ID_SHFT) |
> ((start_rip << UVH_IPI_INT_VECTOR_SHFT) >> 12) |
> APIC_DM_STARTUP;
> uv_write_global_mmr64(pnode, UVH_IPI_INT, val);

making this more readable is hard but what is about:

val=(1UL << UVH_IPI_INT_SEND_SHFT) |
((unsigned long)phys_apicid << UVH_IPI_INT_APIC_ID_SHFT) |
((start_rip << UVH_IPI_INT_VECTOR_SHFT) >> 12);

uv_write_global_mmr64(pnode, UVH_IPI_INT, val|APIC_DM_INIT);

uv_write_global_mmr64(pnode, UVH_IPI_INT, val|APIC_DM_STARTUP);


just my 2 cents,
re
wh

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