[PATCH v4] powerpc/mm: dump block address translation on book3s/32

[Christophe Leroy <christophe.leroy@c-s.fr>]

This patch adds a debugfs file to dump block address translation:

~# cat /sys/kernel/debug/powerpc/block_address_translation
---[ Instruction Block Address Translations ]---
0:         -
1:         -
2: 0xc0000000-0xcfffffff 0x00000000 Kernel EXEC coherent
3: 0xd0000000-0xdfffffff 0x10000000 Kernel EXEC coherent
4:         -
5:         -
6:         -
7:         -

---[ Data Block Address Translations ]---
0:         -
1:         -
2: 0xc0000000-0xcfffffff 0x00000000 Kernel RW coherent
3: 0xd0000000-0xdfffffff 0x10000000 Kernel RW coherent
4:         -
5:         -
6:         -
7:         -

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
 v4: Moved it in debugfs/powerpc
     Added __init to bats_init()

 v3: Fixed PHYS_BAT_ADDR() when !CONFIG_PHYS_64BIT
     Cosmetic changes to have it look more like kernel_page_table with ---[ xxx ]---
     Removed unnecessary includes
     Using CPU feature to know if it is a 601 instead of SPRN_PVR

 v2: Fixed phys address display for CONFIG_PHYS_64BIT

 arch/powerpc/include/asm/book3s/32/mmu-hash.h |   4 +
 arch/powerpc/mm/Makefile                      |   2 +-
 arch/powerpc/mm/dump_bats.c                   | 173 ++++++++++++++++++++++++++
 3 files changed, 178 insertions(+), 1 deletion(-)
 create mode 100644 arch/powerpc/mm/dump_bats.c

diff --git a/arch/powerpc/include/asm/book3s/32/mmu-hash.h b/arch/powerpc/include/asm/book3s/32/mmu-hash.h
index e38c91388c40..35a990ca7173 100644
--- a/arch/powerpc/include/asm/book3s/32/mmu-hash.h
+++ b/arch/powerpc/include/asm/book3s/32/mmu-hash.h
@@ -34,8 +34,12 @@
 #define BAT_PHYS_ADDR(x) ((u32)((x & 0x00000000fffe0000ULL) | \
 				((x & 0x0000000e00000000ULL) >> 24) | \
 				((x & 0x0000000100000000ULL) >> 30)))
+#define PHYS_BAT_ADDR(x) (((u64)(x) & 0x00000000fffe0000ULL) | \
+			  (((u64)(x) << 24) & 0x0000000e00000000ULL) | \
+			  (((u64)(x) << 30) & 0x0000000100000000ULL))
 #else
 #define BAT_PHYS_ADDR(x) (x)
+#define PHYS_BAT_ADDR(x) ((x) & 0xfffe0000)
 #endif
 
 struct ppc_bat {
diff --git a/arch/powerpc/mm/Makefile b/arch/powerpc/mm/Makefile
index 1adc3d8a89cc..20c537a5c436 100644
--- a/arch/powerpc/mm/Makefile
+++ b/arch/powerpc/mm/Makefile
@@ -47,7 +47,7 @@ ifdef CONFIG_PPC_PTDUMP
 obj-$(CONFIG_4xx)		+= dump_linuxpagetables-generic.o
 obj-$(CONFIG_PPC_8xx)		+= dump_linuxpagetables-8xx.o
 obj-$(CONFIG_PPC_BOOK3E_MMU)	+= dump_linuxpagetables-generic.o
-obj-$(CONFIG_PPC_BOOK3S_32)	+= dump_linuxpagetables-generic.o
+obj-$(CONFIG_PPC_BOOK3S_32)	+= dump_linuxpagetables-generic.o dump_bats.o
 obj-$(CONFIG_PPC_BOOK3S_64)	+= dump_linuxpagetables-book3s64.o
 endif
 obj-$(CONFIG_PPC_HTDUMP)	+= dump_hashpagetable.o
diff --git a/arch/powerpc/mm/dump_bats.c b/arch/powerpc/mm/dump_bats.c
new file mode 100644
index 000000000000..a0d23e96e841
--- /dev/null
+++ b/arch/powerpc/mm/dump_bats.c
@@ -0,0 +1,173 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2018, Christophe Leroy CS S.I.
+ * <christophe.leroy@c-s.fr>
+ *
+ * This dumps the content of BATS
+ */
+
+#include <asm/debugfs.h>
+#include <asm/pgtable.h>
+#include <asm/cpu_has_feature.h>
+
+static char *pp_601(int k, int pp)
+{
+	if (pp == 0)
+		return k ? "NA" : "RWX";
+	if (pp == 1)
+		return k ? "ROX" : "RWX";
+	if (pp == 2)
+		return k ? "RWX" : "RWX";
+	return k ? "ROX" : "ROX";
+}
+
+static void bat_show_601(struct seq_file *m, int idx, u32 lower, u32 upper)
+{
+	u32 blpi = upper & 0xfffe0000;
+	u32 k = (upper >> 2) & 3;
+	u32 pp = upper & 3;
+	phys_addr_t pbn = PHYS_BAT_ADDR(lower);
+	u32 bsm = lower & 0x3ff;
+	u32 size = (bsm + 1) << 17;
+
+	seq_printf(m, "%d: ", idx);
+	if (!(lower & 0x40)) {
+		seq_puts(m, "        -\n");
+		return;
+	}
+
+	seq_printf(m, "0x%08x-0x%08x ", blpi, blpi + size - 1);
+#ifdef CONFIG_PHYS_64BIT
+	seq_printf(m, "0x%016llx ", pbn);
+#else
+	seq_printf(m, "0x%08x ", pbn);
+#endif
+
+	seq_printf(m, "Kernel %s User %s", pp_601(k & 2, pp), pp_601(k & 1, pp));
+
+	if (lower & _PAGE_WRITETHRU)
+		seq_puts(m, "write through ");
+	if (lower & _PAGE_NO_CACHE)
+		seq_puts(m, "no cache ");
+	if (lower & _PAGE_COHERENT)
+		seq_puts(m, "coherent ");
+	seq_puts(m, "\n");
+}
+
+#define BAT_SHOW_601(_m, _n, _l, _u) bat_show_601(_m, _n, mfspr(_l), mfspr(_u))
+
+static int bats_show_601(struct seq_file *m, void *v)
+{
+	seq_puts(m, "---[ Block Address Translation ]---\n");
+
+	BAT_SHOW_601(m, 0, SPRN_IBAT0L, SPRN_IBAT0U);
+	BAT_SHOW_601(m, 1, SPRN_IBAT1L, SPRN_IBAT1U);
+	BAT_SHOW_601(m, 2, SPRN_IBAT2L, SPRN_IBAT2U);
+	BAT_SHOW_601(m, 3, SPRN_IBAT3L, SPRN_IBAT3U);
+
+	return 0;
+}
+
+static void bat_show_603(struct seq_file *m, int idx, u32 lower, u32 upper, bool is_d)
+{
+	u32 bepi = upper & 0xfffe0000;
+	u32 bl = (upper >> 2) & 0x7ff;
+	u32 k = upper & 3;
+	phys_addr_t brpn = PHYS_BAT_ADDR(lower);
+	u32 size = (bl + 1) << 17;
+
+	seq_printf(m, "%d: ", idx);
+	if (k == 0) {
+		seq_puts(m, "        -\n");
+		return;
+	}
+
+	seq_printf(m, "0x%08x-0x%08x ", bepi, bepi + size - 1);
+#ifdef CONFIG_PHYS_64BIT
+	seq_printf(m, "0x%016llx ", brpn);
+#else
+	seq_printf(m, "0x%08x ", brpn);
+#endif
+
+	if (k == 1)
+		seq_puts(m, "User ");
+	else if (k == 2)
+		seq_puts(m, "Kernel ");
+	else
+		seq_puts(m, "Kernel/User ");
+
+	if (lower & BPP_RX)
+		seq_puts(m, is_d ? "RO " : "EXEC ");
+	else if (lower & BPP_RW)
+		seq_puts(m, is_d ? "RW " : "EXEC ");
+	else
+		seq_puts(m, is_d ? "NA " : "NX   ");
+
+	if (lower & _PAGE_WRITETHRU)
+		seq_puts(m, "write through ");
+	if (lower & _PAGE_NO_CACHE)
+		seq_puts(m, "no cache ");
+	if (lower & _PAGE_COHERENT)
+		seq_puts(m, "coherent ");
+	if (lower & _PAGE_GUARDED)
+		seq_puts(m, "guarded ");
+	seq_puts(m, "\n");
+}
+
+#define BAT_SHOW_603(_m, _n, _l, _u, _d) bat_show_603(_m, _n, mfspr(_l), mfspr(_u), _d)
+
+static int bats_show_603(struct seq_file *m, void *v)
+{
+	seq_puts(m, "---[ Instruction Block Address Translation ]---\n");
+
+	BAT_SHOW_603(m, 0, SPRN_IBAT0L, SPRN_IBAT0U, false);
+	BAT_SHOW_603(m, 1, SPRN_IBAT1L, SPRN_IBAT1U, false);
+	BAT_SHOW_603(m, 2, SPRN_IBAT2L, SPRN_IBAT2U, false);
+	BAT_SHOW_603(m, 3, SPRN_IBAT3L, SPRN_IBAT3U, false);
+	if (mmu_has_feature(MMU_FTR_USE_HIGH_BATS)) {
+		BAT_SHOW_603(m, 4, SPRN_IBAT4L, SPRN_IBAT4U, false);
+		BAT_SHOW_603(m, 5, SPRN_IBAT5L, SPRN_IBAT5U, false);
+		BAT_SHOW_603(m, 6, SPRN_IBAT6L, SPRN_IBAT6U, false);
+		BAT_SHOW_603(m, 7, SPRN_IBAT7L, SPRN_IBAT7U, false);
+	}
+
+	seq_puts(m, "\n---[ Data Block Address Translation ]---\n");
+
+	BAT_SHOW_603(m, 0, SPRN_DBAT0L, SPRN_DBAT0U, true);
+	BAT_SHOW_603(m, 1, SPRN_DBAT1L, SPRN_DBAT1U, true);
+	BAT_SHOW_603(m, 2, SPRN_DBAT2L, SPRN_DBAT2U, true);
+	BAT_SHOW_603(m, 3, SPRN_DBAT3L, SPRN_DBAT3U, true);
+	if (mmu_has_feature(MMU_FTR_USE_HIGH_BATS)) {
+		BAT_SHOW_603(m, 4, SPRN_DBAT4L, SPRN_DBAT4U, true);
+		BAT_SHOW_603(m, 5, SPRN_DBAT5L, SPRN_DBAT5U, true);
+		BAT_SHOW_603(m, 6, SPRN_DBAT6L, SPRN_DBAT6U, true);
+		BAT_SHOW_603(m, 7, SPRN_DBAT7L, SPRN_DBAT7U, true);
+	}
+
+	return 0;
+}
+
+static int bats_open(struct inode *inode, struct file *file)
+{
+	if (cpu_has_feature(CPU_FTR_601))
+		return single_open(file, bats_show_601, NULL);
+
+	return single_open(file, bats_show_603, NULL);
+}
+
+static const struct file_operations bats_fops = {
+	.open		= bats_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static int __init bats_init(void)
+{
+	struct dentry *debugfs_file;
+
+	debugfs_file = debugfs_create_file("block_address_translation", 0400,
+					   powerpc_debugfs_root, NULL, &bats_fops);
+	return debugfs_file ? 0 : -ENOMEM;
+}
+device_initcall(bats_init);
-- 
2.13.3