linux-kernel - [PATCH v4 2/3] powerpc/powernv: Introduce Self save support

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Message-Id: <7fe2bb491799f495e4d9fc54b617235c498119b1.1581505210.git.psampat@linux.ibm.com>
Date:   Wed, 12 Feb 2020 16:50:12 +0530
From:   Pratik Rajesh Sampat <psampat@...ux.ibm.com>
To:     linux-kernel@...r.kernel.org, linuxppc-dev@...abs.org,
        mpe@...erman.id.au, svaidy@...ux.ibm.com, ego@...ux.vnet.ibm.com,
        linuxram@...ibm.com, pratik.sampat@...ibm.com,
        psampat@...ux.ibm.com, pratik.r.sampat@...il.com
Subject: [PATCH v4 2/3] powerpc/powernv: Introduce Self save support

This commit introduces and leverages the Self save API which OPAL now
supports.

Add the new Self Save OPAL API call in the list of OPAL calls.
Implement the self saving of the SPRs based on the support populated
while respecting it's preferences.

This implementation allows mixing of support for the SPRs, which
means that a SPR can be self restored while another SPR be self saved if
they support and prefer it to be so.

Signed-off-by: Pratik Rajesh Sampat <psampat@...ux.ibm.com>
Reviewed-by: Ram Pai <linuxram@...ibm.com>
---
 arch/powerpc/include/asm/opal-api.h        |  3 ++-
 arch/powerpc/include/asm/opal.h            |  1 +
 arch/powerpc/platforms/powernv/idle.c      | 22 ++++++++++++++++++++++
 arch/powerpc/platforms/powernv/opal-call.c |  1 +
 4 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/include/asm/opal-api.h b/arch/powerpc/include/asm/opal-api.h
index c1f25a760eb1..1b6e1a68d431 100644
--- a/arch/powerpc/include/asm/opal-api.h
+++ b/arch/powerpc/include/asm/opal-api.h
@@ -214,7 +214,8 @@
 #define OPAL_SECVAR_GET				176
 #define OPAL_SECVAR_GET_NEXT			177
 #define OPAL_SECVAR_ENQUEUE_UPDATE		178
-#define OPAL_LAST				178
+#define OPAL_SLW_SELF_SAVE_REG			181
+#define OPAL_LAST				181
 
 #define QUIESCE_HOLD			1 /* Spin all calls at entry */
 #define QUIESCE_REJECT			2 /* Fail all calls with OPAL_BUSY */
diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h
index 9986ac34b8e2..389a85b63805 100644
--- a/arch/powerpc/include/asm/opal.h
+++ b/arch/powerpc/include/asm/opal.h
@@ -203,6 +203,7 @@ int64_t opal_handle_hmi(void);
 int64_t opal_handle_hmi2(__be64 *out_flags);
 int64_t opal_register_dump_region(uint32_t id, uint64_t start, uint64_t end);
 int64_t opal_unregister_dump_region(uint32_t id);
+int64_t opal_slw_self_save_reg(uint64_t cpu_pir, uint64_t sprn);
 int64_t opal_slw_set_reg(uint64_t cpu_pir, uint64_t sprn, uint64_t val);
 int64_t opal_config_cpu_idle_state(uint64_t state, uint64_t flag);
 int64_t opal_pci_set_phb_cxl_mode(uint64_t phb_id, uint64_t mode, uint64_t pe_number);
diff --git a/arch/powerpc/platforms/powernv/idle.c b/arch/powerpc/platforms/powernv/idle.c
index 03fe835aadd1..97aeb45e897b 100644
--- a/arch/powerpc/platforms/powernv/idle.c
+++ b/arch/powerpc/platforms/powernv/idle.c
@@ -279,6 +279,26 @@ static int pnv_self_save_restore_sprs(void)
 					if (rc != 0)
 						return rc;
 					break;
+				} else if (preferred & curr_spr.supported_mode
+					   & SELF_SAVE_STRICT) {
+					is_initialized = true;
+					if (curr_spr.spr == SPRN_HMEER &&
+					    cpu_thread_in_core(cpu) != 0) {
+						continue;
+					}
+					rc = opal_slw_self_save_reg(pir,
+								curr_spr.spr);
+					if (rc != 0)
+						return rc;
+					switch (curr_spr.spr) {
+					case SPRN_LPCR:
+						is_lpcr_self_save = true;
+						break;
+					case SPRN_PTCR:
+						is_ptcr_self_save = true;
+						break;
+					}
+					break;
 				}
 				preferred_sprs[index].preferred_mode =
 					preferred_sprs[index].preferred_mode >>
@@ -1159,6 +1179,8 @@ void pnv_program_cpu_hotplug_lpcr(unsigned int cpu, u64 lpcr_val)
 		if (!is_lpcr_self_save)
 			opal_slw_set_reg(pir, SPRN_LPCR,
 					 lpcr_val);
+		else
+			opal_slw_self_save_reg(pir, SPRN_LPCR);
 	}
 }
 
diff --git a/arch/powerpc/platforms/powernv/opal-call.c b/arch/powerpc/platforms/powernv/opal-call.c
index 5cd0f52d258f..11e0ceb90de0 100644
--- a/arch/powerpc/platforms/powernv/opal-call.c
+++ b/arch/powerpc/platforms/powernv/opal-call.c
@@ -223,6 +223,7 @@ OPAL_CALL(opal_handle_hmi,			OPAL_HANDLE_HMI);
 OPAL_CALL(opal_handle_hmi2,			OPAL_HANDLE_HMI2);
 OPAL_CALL(opal_config_cpu_idle_state,		OPAL_CONFIG_CPU_IDLE_STATE);
 OPAL_CALL(opal_slw_set_reg,			OPAL_SLW_SET_REG);
+OPAL_CALL(opal_slw_self_save_reg,		OPAL_SLW_SELF_SAVE_REG);
 OPAL_CALL(opal_register_dump_region,		OPAL_REGISTER_DUMP_REGION);
 OPAL_CALL(opal_unregister_dump_region,		OPAL_UNREGISTER_DUMP_REGION);
 OPAL_CALL(opal_pci_set_phb_cxl_mode,		OPAL_PCI_SET_PHB_CAPI_MODE);
-- 
2.17.1