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From: Bo Gan <ganboing@gmail.com>
To: opensbi@lists.infradead.org
Cc: linmin@eswincomputing.com, pinkesh.vaghela@einfochips.com,
	gaohan@iscas.ac.cn, samuel@sholland.org, wangxiang@iscas.ac.cn
Subject: [PATCH v3 1/4] lib: sbi: allow platform to override PMP (un)configuration
Date: Thu, 20 Nov 2025 01:34:37 -0800	[thread overview]
Message-ID: <20251120093440.4533-2-ganboing@gmail.com> (raw)
In-Reply-To: <20251120093440.4533-1-ganboing@gmail.com>

Platform sometimes wants to override the entire PMP (un)config phase,
not just performing additional work for each individual PMP entry. This
allows platforms to insert SoC/core specific PMP entries in a way that
works together with the existing ones set by lib/ code, not conflicting.
platform can also choose to merge or skip memory regions in a reasonable
way in case there's a shortage of PMP entries.

In addition, logic for determining flags in `sbi_hart_oldpmp_configure`
is abstracted out as sbi_domain_get_oldpmp_flags, analogous to the
`sbi_domain_get_smepmp_flags` for smepmp. so platform with traditional
PMP can leverage it in its own `pmp_configure`

Signed-off-by: Bo Gan <ganboing@gmail.com>
---
 include/sbi/sbi_domain.h     |  7 +++++
 include/sbi/sbi_hart.h       |  3 ++
 include/sbi/sbi_platform.h   | 53 ++++++++++++++++++++++++++++++++++++
 lib/sbi/sbi_domain.c         | 21 ++++++++++++++
 lib/sbi/sbi_domain_context.c | 11 +-------
 lib/sbi/sbi_hart.c           | 45 ++++++++++++++++++------------
 6 files changed, 113 insertions(+), 27 deletions(-)

diff --git a/include/sbi/sbi_domain.h b/include/sbi/sbi_domain.h
index 1196d609..3360e090 100644
--- a/include/sbi/sbi_domain.h
+++ b/include/sbi/sbi_domain.h
@@ -253,6 +253,13 @@ void sbi_domain_memregion_init(unsigned long addr,
 				unsigned long flags,
 				struct sbi_domain_memregion *reg);
 
+/**
+ * Return the oldpmp pmpcfg LRWX encoding for the flags in @reg.
+ *
+ * @param reg pointer to memory region; its flags field encodes permissions.
+ */
+unsigned int sbi_domain_get_oldpmp_flags(struct sbi_domain_memregion *reg);
+
 /**
  * Return the Smepmp pmpcfg LRWX encoding for the flags in @reg.
  *
diff --git a/include/sbi/sbi_hart.h b/include/sbi/sbi_hart.h
index e66dd52f..c0bf79e0 100644
--- a/include/sbi/sbi_hart.h
+++ b/include/sbi/sbi_hart.h
@@ -133,6 +133,8 @@ struct sbi_hart_features {
 };
 
 struct sbi_scratch;
+struct sbi_domain;
+struct sbi_domain_memregion;
 
 int sbi_hart_reinit(struct sbi_scratch *scratch);
 int sbi_hart_init(struct sbi_scratch *scratch, bool cold_boot);
@@ -147,6 +149,7 @@ unsigned int sbi_hart_pmp_log2gran(struct sbi_scratch *scratch);
 unsigned int sbi_hart_pmp_addrbits(struct sbi_scratch *scratch);
 unsigned int sbi_hart_mhpm_bits(struct sbi_scratch *scratch);
 bool sbi_hart_smepmp_is_fw_region(unsigned int pmp_idx);
+void sbi_hart_pmp_unconfigure(struct sbi_scratch *scratch);
 int sbi_hart_pmp_configure(struct sbi_scratch *scratch);
 int sbi_hart_map_saddr(unsigned long base, unsigned long size);
 int sbi_hart_unmap_saddr(void);
diff --git a/include/sbi/sbi_platform.h b/include/sbi/sbi_platform.h
index d75c12de..a53e1797 100644
--- a/include/sbi/sbi_platform.h
+++ b/include/sbi/sbi_platform.h
@@ -146,6 +146,18 @@ struct sbi_platform_operations {
 			unsigned long log2len);
 	/** platform specific pmp disable on current HART */
 	void (*pmp_disable)(unsigned int n);
+
+	/** platform pmp configure override on current HART */
+	int (*pmp_configure)(unsigned int pmp_count,
+			     unsigned int pmp_log2gran,
+			     unsigned long pmp_addr_max);
+	/**
+	 * You need both pmp_configure/unconfigure to properly
+	 * provide platform override
+	 */
+
+	/** platform pmp unconfigure override on current HART */
+	void (*pmp_unconfigure)(void);
 };
 
 /** Platform default per-HART stack size for exception/interrupt handling */
@@ -666,6 +678,47 @@ static inline void sbi_platform_pmp_disable(const struct sbi_platform *plat,
 		sbi_platform_ops(plat)->pmp_disable(n);
 }
 
+/**
+ * Check if platform wants to override PMP (un)configuration
+ *
+ * @param plat pointer to struct sbi_platform
+ */
+static inline bool sbi_platform_pmp_override(const struct sbi_platform *plat)
+{
+	return plat &&
+		sbi_platform_ops(plat)->pmp_configure &&
+		sbi_platform_ops(plat)->pmp_unconfigure;
+}
+
+/**
+ * Platform PMP configuration override
+ *
+ * @param plat pointer to struct sbi_platform
+ * @param pmp_count number of PMP entries
+ * @param pmp_log2gran PMP granularity
+ * @param pmp_addr_max largest value pmpaddr(x) can hold
+ */
+static inline int sbi_platform_pmp_configure(const struct sbi_platform *plat,
+					     unsigned int pmp_count,
+					     unsigned int pmp_log2gran,
+					     unsigned long pmp_addr_max)
+{
+	return sbi_platform_ops(plat)->pmp_configure(pmp_count,
+						     pmp_log2gran,
+						     pmp_addr_max);
+}
+
+/**
+ * Platform PMP unconfiguration override
+ *
+ * @param plat pointer to struct sbi_platform
+ */
+static inline void sbi_platform_pmp_unconfigure(
+					const struct sbi_platform *plat)
+{
+	return sbi_platform_ops(plat)->pmp_unconfigure();
+}
+
 #endif
 
 #endif
diff --git a/lib/sbi/sbi_domain.c b/lib/sbi/sbi_domain.c
index da0f0557..32e4c882 100644
--- a/lib/sbi/sbi_domain.c
+++ b/lib/sbi/sbi_domain.c
@@ -122,6 +122,27 @@ void sbi_domain_memregion_init(unsigned long addr,
 	}
 }
 
+unsigned int sbi_domain_get_oldpmp_flags(struct sbi_domain_memregion *reg)
+{
+	unsigned int pmp_flags = 0;
+
+	/*
+	 * If permissions are to be enforced for all modes on
+	 * this region, the lock bit should be set.
+	 */
+	if (reg->flags & SBI_DOMAIN_MEMREGION_ENF_PERMISSIONS)
+		pmp_flags |= PMP_L;
+
+	if (reg->flags & SBI_DOMAIN_MEMREGION_SU_READABLE)
+		pmp_flags |= PMP_R;
+	if (reg->flags & SBI_DOMAIN_MEMREGION_SU_WRITABLE)
+		pmp_flags |= PMP_W;
+	if (reg->flags & SBI_DOMAIN_MEMREGION_SU_EXECUTABLE)
+		pmp_flags |= PMP_X;
+
+	return pmp_flags;
+}
+
 unsigned int sbi_domain_get_smepmp_flags(struct sbi_domain_memregion *reg)
 {
 	unsigned int pmp_flags = 0;
diff --git a/lib/sbi/sbi_domain_context.c b/lib/sbi/sbi_domain_context.c
index 74ad25e8..ea7f741b 100644
--- a/lib/sbi/sbi_domain_context.c
+++ b/lib/sbi/sbi_domain_context.c
@@ -102,7 +102,6 @@ static int switch_to_next_domain_context(struct hart_context *ctx,
 	struct sbi_trap_context *trap_ctx;
 	struct sbi_domain *current_dom, *target_dom;
 	struct sbi_scratch *scratch = sbi_scratch_thishart_ptr();
-	unsigned int pmp_count = sbi_hart_pmp_count(scratch);
 
 	if (!ctx || !dom_ctx || ctx == dom_ctx)
 		return SBI_EINVAL;
@@ -120,15 +119,7 @@ static int switch_to_next_domain_context(struct hart_context *ctx,
 	sbi_hartmask_set_hartindex(hartindex, &target_dom->assigned_harts);
 	spin_unlock(&target_dom->assigned_harts_lock);
 
-	/* Reconfigure PMP settings for the new domain */
-	for (int i = 0; i < pmp_count; i++) {
-		/* Don't revoke firmware access permissions */
-		if (sbi_hart_smepmp_is_fw_region(i))
-			continue;
-
-		sbi_platform_pmp_disable(sbi_platform_thishart_ptr(), i);
-		pmp_disable(i);
-	}
+	sbi_hart_pmp_unconfigure(scratch);
 	sbi_hart_pmp_configure(scratch);
 
 	/* Save current CSR context and restore target domain's CSR context */
diff --git a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c
index a91703b4..b39f4de9 100644
--- a/lib/sbi/sbi_hart.c
+++ b/lib/sbi/sbi_hart.c
@@ -448,23 +448,9 @@ static int sbi_hart_oldpmp_configure(struct sbi_scratch *scratch,
 		if (!is_valid_pmp_idx(pmp_count, pmp_idx))
 			return SBI_EFAIL;
 
-		pmp_flags = 0;
-
-		/*
-		 * If permissions are to be enforced for all modes on
-		 * this region, the lock bit should be set.
-		 */
-		if (reg->flags & SBI_DOMAIN_MEMREGION_ENF_PERMISSIONS)
-			pmp_flags |= PMP_L;
-
-		if (reg->flags & SBI_DOMAIN_MEMREGION_SU_READABLE)
-			pmp_flags |= PMP_R;
-		if (reg->flags & SBI_DOMAIN_MEMREGION_SU_WRITABLE)
-			pmp_flags |= PMP_W;
-		if (reg->flags & SBI_DOMAIN_MEMREGION_SU_EXECUTABLE)
-			pmp_flags |= PMP_X;
-
+		pmp_flags = sbi_domain_get_oldpmp_flags(reg);
 		pmp_addr = reg->base >> PMP_SHIFT;
+
 		if (pmp_log2gran <= reg->order && pmp_addr < pmp_addr_max) {
 			sbi_platform_pmp_set(sbi_platform_ptr(scratch),
 					     pmp_idx, reg->flags, pmp_flags,
@@ -528,12 +514,34 @@ int sbi_hart_unmap_saddr(void)
 	return pmp_disable(SBI_SMEPMP_RESV_ENTRY);
 }
 
+void sbi_hart_pmp_unconfigure(struct sbi_scratch *scratch)
+{
+	unsigned int pmp_count = sbi_hart_pmp_count(scratch);
+	const struct sbi_platform *plat = sbi_platform_ptr(scratch);
+
+	if (sbi_platform_pmp_override(plat)) {
+		sbi_platform_pmp_unconfigure(plat);
+		return;
+	}
+
+	/* Reconfigure PMP settings for the new domain */
+	for (unsigned int i = 0; i < pmp_count; i++) {
+		/* Don't revoke firmware access permissions */
+		if (sbi_hart_smepmp_is_fw_region(i))
+			continue;
+
+		sbi_platform_pmp_disable(sbi_platform_thishart_ptr(), i);
+		pmp_disable(i);
+	}
+}
+
 int sbi_hart_pmp_configure(struct sbi_scratch *scratch)
 {
 	int rc;
 	unsigned int pmp_bits, pmp_log2gran;
 	unsigned int pmp_count = sbi_hart_pmp_count(scratch);
 	unsigned long pmp_addr_max;
+	const struct sbi_platform *plat = sbi_platform_ptr(scratch);
 
 	if (!pmp_count)
 		return 0;
@@ -542,7 +550,10 @@ int sbi_hart_pmp_configure(struct sbi_scratch *scratch)
 	pmp_bits = sbi_hart_pmp_addrbits(scratch) - 1;
 	pmp_addr_max = (1UL << pmp_bits) | ((1UL << pmp_bits) - 1);
 
-	if (sbi_hart_has_extension(scratch, SBI_HART_EXT_SMEPMP))
+	if (sbi_platform_pmp_override(plat))
+		rc = sbi_platform_pmp_configure(plat, pmp_count,
+						pmp_log2gran, pmp_addr_max);
+	else if (sbi_hart_has_extension(scratch, SBI_HART_EXT_SMEPMP))
 		rc = sbi_hart_smepmp_configure(scratch, pmp_count,
 						pmp_log2gran, pmp_addr_max);
 	else
-- 
2.34.1


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  reply	other threads:[~2025-11-20  9:36 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-11-20  9:34 [PATCH v3 0/4] Initial ESWIN/EIC7700 support Bo Gan
2025-11-20  9:34 ` Bo Gan [this message]
2025-11-20  9:34 ` [PATCH v3 2/4] lib: sbi: give platform choice of using single memregion to cover OpenSBI Bo Gan
2025-12-01  8:11   ` Yu-Chien Peter Lin
2025-12-07  6:09     ` Bo Gan
2025-11-20  9:34 ` [PATCH v3 3/4] include: sbi_domain: make is_region_subset public Bo Gan
2025-11-20  9:34 ` [PATCH v3 4/4] platform: generic: eswin: add EIC7700 Bo Gan
2025-12-01  7:35   ` Yu-Chien Peter Lin
2025-12-01 22:15     ` Bo Gan
2025-11-26 14:23 ` [PATCH v3 0/4] Initial ESWIN/EIC7700 support Anup Patel
2025-11-26 22:56   ` Bo Gan
2025-12-07  6:12     ` Bo Gan
2025-12-07 16:02       ` Anup Patel

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