linux-kernel - [PATCH v3 1/3] x86/platform/uv: Update NMI Handler for UV5

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Message-Id: <20220318224304.174967-2-mike.travis@hpe.com>
Date:   Fri, 18 Mar 2022 17:43:02 -0500
From:   Mike Travis <mike.travis@....com>
To:     Borislav Petkov <bp@...en8.de>, Ingo Molnar <mingo@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Steve Wahl <steve.wahl@....com>, x86@...nel.org
Cc:     Mike Travis <mike.travis@....com>,
        Dimitri Sivanich <dimitri.sivanich@....com>,
        Andy Shevchenko <andy@...radead.org>,
        Darren Hart <dvhart@...radead.org>,
        "H. Peter Anvin" <hpa@...or.com>,
        Russ Anderson <russ.anderson@....com>,
        linux-kernel@...r.kernel.org, platform-driver-x86@...r.kernel.org
Subject: [PATCH v3 1/3] x86/platform/uv: Update NMI Handler for UV5

Update NMI handler to interface with UV5 hardware. This involves changing
the EVENT_OCCURRED MMR used by the hardware and removes the check for
which NMI function is supported by UV BIOS.  The newer NMI function is
assumed supported on UV5 and above.

Signed-off-by: Mike Travis <mike.travis@....com>
Reviewed-by: Dimitri Sivanich <dimitri.sivanich@....com>
Reviewed-by: Steve Wahl <steve.wahl@....com>
---
v3: Fix mistake in UVH_EXTIO_INT0_BROADCAST check.
    Use true/false in setting bool flag.
v2: Use bool flag to assume NMI support for UV5 and above.
---
 arch/x86/platform/uv/uv_nmi.c | 21 +++++++++++----------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/arch/x86/platform/uv/uv_nmi.c b/arch/x86/platform/uv/uv_nmi.c
index 1e9ff28bc2e0..6d2e9ae8576b 100644
--- a/arch/x86/platform/uv/uv_nmi.c
+++ b/arch/x86/platform/uv/uv_nmi.c
@@ -244,8 +244,10 @@ static inline bool uv_nmi_action_is(const char *action)
 /* Setup which NMI support is present in system */
 static void uv_nmi_setup_mmrs(void)
 {
+	bool nmi_supported = false;
+
 	/* First determine arch specific MMRs to handshake with BIOS */
-	if (UVH_EVENT_OCCURRED0_EXTIO_INT0_MASK) {
+	if (UVH_EVENT_OCCURRED0_EXTIO_INT0_MASK) {	/* UV2,3,4 setup */
 		uvh_nmi_mmrx = UVH_EVENT_OCCURRED0;
 		uvh_nmi_mmrx_clear = UVH_EVENT_OCCURRED0_ALIAS;
 		uvh_nmi_mmrx_shift = UVH_EVENT_OCCURRED0_EXTIO_INT0_SHFT;
@@ -255,26 +257,25 @@ static void uv_nmi_setup_mmrs(void)
 		uvh_nmi_mmrx_req = UVH_BIOS_KERNEL_MMR_ALIAS_2;
 		uvh_nmi_mmrx_req_shift = 62;
 
-	} else if (UVH_EVENT_OCCURRED1_EXTIO_INT0_MASK) {
+	} else if (UVH_EVENT_OCCURRED1_EXTIO_INT0_MASK) { /* UV5+ setup */
 		uvh_nmi_mmrx = UVH_EVENT_OCCURRED1;
 		uvh_nmi_mmrx_clear = UVH_EVENT_OCCURRED1_ALIAS;
 		uvh_nmi_mmrx_shift = UVH_EVENT_OCCURRED1_EXTIO_INT0_SHFT;
 		uvh_nmi_mmrx_type = "OCRD1-EXTIO_INT0";
 
-		uvh_nmi_mmrx_supported = UVH_EXTIO_INT0_BROADCAST;
-		uvh_nmi_mmrx_req = UVH_BIOS_KERNEL_MMR_ALIAS_2;
-		uvh_nmi_mmrx_req_shift = 62;
+		nmi_supported = true;		/* assume sync valid on UV5+ */
+		uvh_nmi_mmrx_req = 0;		/* no request bit to clear */
 
 	} else {
-		pr_err("UV:%s:cannot find EVENT_OCCURRED*_EXTIO_INT0\n",
-			__func__);
+		pr_err("UV:%s:NMI support not available on this system\n", __func__);
 		return;
 	}
 
 	/* Then find out if new NMI is supported */
-	if (likely(uv_read_local_mmr(uvh_nmi_mmrx_supported))) {
-		uv_write_local_mmr(uvh_nmi_mmrx_req,
-					1UL << uvh_nmi_mmrx_req_shift);
+	if (likely(nmi_supported) || (uv_read_local_mmr(uvh_nmi_mmrx_supported))) {
+		if (uvh_nmi_mmrx_req)
+			uv_write_local_mmr(uvh_nmi_mmrx_req,
+						1UL << uvh_nmi_mmrx_req_shift);
 		nmi_mmr = uvh_nmi_mmrx;
 		nmi_mmr_clear = uvh_nmi_mmrx_clear;
 		nmi_mmr_pending = 1UL << uvh_nmi_mmrx_shift;
-- 
2.26.2