Merge patch series "RISC-V: Ensure Zicbom has a valid block size"

Andrew Jones <ajones@ventanamicro.com> says:

When a DT puts zicbom in the isa string, but does not provide a block
size, ALT_CMO_OP() will attempt to do cache operations on address
zero since the start address will be ANDed with zero. We can't simply
BUG() in riscv_init_cbom_blocksize() when we fail to find a block
size because the failure will happen before logging works, leaving
users to scratch their heads as to why the boot hung. Instead, ensure
Zicbom is disabled and output an error which will hopefully alert
people that the DT needs to be fixed. While at it, add a check that
the block size is a power-of-2 too.

* b4-shazam-merge:
  RISC-V: Ensure Zicbom has a valid block size
  RISC-V: Introduce riscv_isa_extension_check
  RISC-V: Improve use of isa2hwcap[]

Link: https://lore.kernel.org/r/20221129143447.49714-1-ajones@ventanamicro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

2 files changed, 38 insertions, 41 deletions

diff --git a/arch/riscv/mm/cacheflush.c b/arch/riscv/mm/cacheflush.c
index 062559c04fc3..3cc07ed45aeb 100644
--- a/arch/riscv/mm/cacheflush.c
+++ b/arch/riscv/mm/cacheflush.c
@@ -3,6 +3,7 @@
  * Copyright (C) 2017 SiFive
  */
 
+#include <linux/of.h>
 #include <asm/cacheflush.h>
 
 #ifdef CONFIG_SMP
@@ -93,3 +94,40 @@ void flush_icache_pte(pte_t pte)
 		flush_icache_all();
 }
 #endif /* CONFIG_MMU */
+
+unsigned int riscv_cbom_block_size;
+EXPORT_SYMBOL_GPL(riscv_cbom_block_size);
+
+void riscv_init_cbom_blocksize(void)
+{
+	struct device_node *node;
+	unsigned long cbom_hartid;
+	u32 val, probed_block_size;
+	int ret;
+
+	probed_block_size = 0;
+	for_each_of_cpu_node(node) {
+		unsigned long hartid;
+
+		ret = riscv_of_processor_hartid(node, &hartid);
+		if (ret)
+			continue;
+
+		/* set block-size for cbom extension if available */
+		ret = of_property_read_u32(node, "riscv,cbom-block-size", &val);
+		if (ret)
+			continue;
+
+		if (!probed_block_size) {
+			probed_block_size = val;
+			cbom_hartid = hartid;
+		} else {
+			if (probed_block_size != val)
+				pr_warn("cbom-block-size mismatched between harts %lu and %lu\n",
+					cbom_hartid, hartid);
+		}
+	}
+
+	if (probed_block_size)
+		riscv_cbom_block_size = probed_block_size;
+}
diff --git a/arch/riscv/mm/dma-noncoherent.c b/arch/riscv/mm/dma-noncoherent.c
index b0add983530a..d919efab6eba 100644
--- a/arch/riscv/mm/dma-noncoherent.c
+++ b/arch/riscv/mm/dma-noncoherent.c
@@ -8,13 +8,8 @@
 #include <linux/dma-direct.h>
 #include <linux/dma-map-ops.h>
 #include <linux/mm.h>
-#include <linux/of.h>
-#include <linux/of_device.h>
 #include <asm/cacheflush.h>
 
-unsigned int riscv_cbom_block_size;
-EXPORT_SYMBOL_GPL(riscv_cbom_block_size);
-
 static bool noncoherent_supported;
 
 void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
@@ -77,42 +72,6 @@ void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
 	dev->dma_coherent = coherent;
 }
 
-#ifdef CONFIG_RISCV_ISA_ZICBOM
-void riscv_init_cbom_blocksize(void)
-{
-	struct device_node *node;
-	unsigned long cbom_hartid;
-	u32 val, probed_block_size;
-	int ret;
-
-	probed_block_size = 0;
-	for_each_of_cpu_node(node) {
-		unsigned long hartid;
-
-		ret = riscv_of_processor_hartid(node, &hartid);
-		if (ret)
-			continue;
-
-		/* set block-size for cbom extension if available */
-		ret = of_property_read_u32(node, "riscv,cbom-block-size", &val);
-		if (ret)
-			continue;
-
-		if (!probed_block_size) {
-			probed_block_size = val;
-			cbom_hartid = hartid;
-		} else {
-			if (probed_block_size != val)
-				pr_warn("cbom-block-size mismatched between harts %lu and %lu\n",
-					cbom_hartid, hartid);
-		}
-	}
-
-	if (probed_block_size)
-		riscv_cbom_block_size = probed_block_size;
-}
-#endif
-
 void riscv_noncoherent_supported(void)
 {
 	WARN(!riscv_cbom_block_size,