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Subject[tip: x86/platform] x86/platform/uv: Account for UV Hubless in is_uvX_hub Ops
The following commit has been merged into the x86/platform branch of tip:

Commit-ID: 4fb7d08707565d27ec84a364d011043ade8c38b4
Gitweb: https://git.kernel.org/tip/4fb7d08707565d27ec84a364d011043ade8c38b4
Author: Mike Travis <mike.travis@hpe.com>
AuthorDate: Tue, 10 Sep 2019 09:58:47 -05:00
Committer: Ingo Molnar <mingo@kernel.org>
CommitterDate: Mon, 07 Oct 2019 13:42:11 +02:00

x86/platform/uv: Account for UV Hubless in is_uvX_hub Ops

The references in the is_uvX_hub() function uses the hub_info pointer
which will be NULL when the system is hubless. This change avoids
that NULL dereference. It is also an optimization in performance.

Signed-off-by: Mike Travis <mike.travis@hpe.com>
Reviewed-by: Steve Wahl <steve.wahl@hpe.com>
Reviewed-by: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Hedi Berriche <hedi.berriche@hpe.com>
Cc: Justin Ernst <justin.ernst@hpe.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russ Anderson <russ.anderson@hpe.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190910145840.294981941@stormcage.eag.rdlabs.hpecorp.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/include/asm/uv/uv_hub.h | 61 ++++++++++---------------------
1 file changed, 20 insertions(+), 41 deletions(-)

diff --git a/arch/x86/include/asm/uv/uv_hub.h b/arch/x86/include/asm/uv/uv_hub.h
index 44cf6d6..950cd13 100644
--- a/arch/x86/include/asm/uv/uv_hub.h
+++ b/arch/x86/include/asm/uv/uv_hub.h
@@ -19,6 +19,7 @@
#include <linux/topology.h>
#include <asm/types.h>
#include <asm/percpu.h>
+#include <asm/uv/uv.h>
#include <asm/uv/uv_mmrs.h>
#include <asm/uv/bios.h>
#include <asm/irq_vectors.h>
@@ -243,83 +244,61 @@ static inline int uv_hub_info_check(int version)
#define UV4_HUB_REVISION_BASE 7
#define UV4A_HUB_REVISION_BASE 8 /* UV4 (fixed) rev 2 */

-#ifdef UV1_HUB_IS_SUPPORTED
+/* WARNING: UVx_HUB_IS_SUPPORTED defines are deprecated and will be removed */
static inline int is_uv1_hub(void)
{
- return uv_hub_info->hub_revision < UV2_HUB_REVISION_BASE;
-}
+#ifdef UV1_HUB_IS_SUPPORTED
+ return is_uv_hubbed(uv(1));
#else
-static inline int is_uv1_hub(void)
-{
return 0;
-}
#endif
+}

-#ifdef UV2_HUB_IS_SUPPORTED
static inline int is_uv2_hub(void)
{
- return ((uv_hub_info->hub_revision >= UV2_HUB_REVISION_BASE) &&
- (uv_hub_info->hub_revision < UV3_HUB_REVISION_BASE));
-}
+#ifdef UV2_HUB_IS_SUPPORTED
+ return is_uv_hubbed(uv(2));
#else
-static inline int is_uv2_hub(void)
-{
return 0;
-}
#endif
+}

-#ifdef UV3_HUB_IS_SUPPORTED
static inline int is_uv3_hub(void)
{
- return ((uv_hub_info->hub_revision >= UV3_HUB_REVISION_BASE) &&
- (uv_hub_info->hub_revision < UV4_HUB_REVISION_BASE));
-}
+#ifdef UV3_HUB_IS_SUPPORTED
+ return is_uv_hubbed(uv(3));
#else
-static inline int is_uv3_hub(void)
-{
return 0;
-}
#endif
+}

/* First test "is UV4A", then "is UV4" */
-#ifdef UV4A_HUB_IS_SUPPORTED
-static inline int is_uv4a_hub(void)
-{
- return (uv_hub_info->hub_revision >= UV4A_HUB_REVISION_BASE);
-}
-#else
static inline int is_uv4a_hub(void)
{
+#ifdef UV4A_HUB_IS_SUPPORTED
+ if (is_uv_hubbed(uv(4)))
+ return (uv_hub_info->hub_revision == UV4A_HUB_REVISION_BASE);
+#endif
return 0;
}
-#endif

-#ifdef UV4_HUB_IS_SUPPORTED
static inline int is_uv4_hub(void)
{
- return uv_hub_info->hub_revision >= UV4_HUB_REVISION_BASE;
-}
+#ifdef UV4_HUB_IS_SUPPORTED
+ return is_uv_hubbed(uv(4));
#else
-static inline int is_uv4_hub(void)
-{
return 0;
-}
#endif
+}

static inline int is_uvx_hub(void)
{
- if (uv_hub_info->hub_revision >= UV2_HUB_REVISION_BASE)
- return uv_hub_info->hub_revision;
-
- return 0;
+ return (is_uv_hubbed(-2) >= uv(2));
}

static inline int is_uv_hub(void)
{
-#ifdef UV1_HUB_IS_SUPPORTED
- return uv_hub_info->hub_revision;
-#endif
- return is_uvx_hub();
+ return is_uv1_hub() || is_uvx_hub();
}

union uvh_apicid {
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