powerpc/pseries/fadump: add support for multiple boot memory regions

Currently, fadump on pseries assumes a single boot memory region even
though f/w supports more than one boot memory region. Add support for
more boot memory regions to make the implementation flexible for any
enhancements that introduce other region types. For this, rtas memory
structure for fadump is updated to have multiple boot memory regions
instead of just one. Additionally, methods responsible for creating
the fadump memory structure during both the first and second kernel
boot have been modified to take these multiple boot memory regions
into account. Also, a new callback has been added to the fadump_ops
structure to get the maximum boot memory regions supported by the
platform.
Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240509115755.519982-2-hbathini@linux.ibm.com

arch/powerpc/include/asm/fadump-internal.h

@@ -156,6 +156,7 @@ struct fadump_ops {
 				      struct seq_file *m);
 	void	(*fadump_trigger)(struct fadump_crash_info_header *fdh,
 				  const char *msg);
+	int	(*fadump_max_boot_mem_rgns)(void);
 };
 
 /* Helper functions */
@@ -163,7 +164,6 @@ s32 __init fadump_setup_cpu_notes_buf(u32 num_cpus);
 void fadump_free_cpu_notes_buf(void);
 u32 *__init fadump_regs_to_elf_notes(u32 *buf, struct pt_regs *regs);
 void __init fadump_update_elfcore_header(char *bufp);
-bool is_fadump_boot_mem_contiguous(void);
 bool is_fadump_reserved_mem_contiguous(void);
 
 #else /* !CONFIG_PRESERVE_FA_DUMP */

arch/powerpc/kernel/fadump.c

@@ -220,28 +220,6 @@ static bool is_fadump_mem_area_contiguous(u64 d_start, u64 d_end)
 	return ret;
 }
 
-/*
- * Returns true, if there are no holes in boot memory area,
- * false otherwise.
- */
-bool is_fadump_boot_mem_contiguous(void)
-{
-	unsigned long d_start, d_end;
-	bool ret = false;
-	int i;
-
-	for (i = 0; i < fw_dump.boot_mem_regs_cnt; i++) {
-		d_start = fw_dump.boot_mem_addr[i];
-		d_end   = d_start + fw_dump.boot_mem_sz[i];
-
-		ret = is_fadump_mem_area_contiguous(d_start, d_end);
-		if (!ret)
-			break;
-	}
-
-	return ret;
-}
-
 /*
  * Returns true, if there are no holes in reserved memory area,
  * false otherwise.
@@ -381,10 +359,11 @@ static unsigned long __init get_fadump_area_size(void)
 static int __init add_boot_mem_region(unsigned long rstart,
 				      unsigned long rsize)
 {
+	int max_boot_mem_rgns = fw_dump.ops->fadump_max_boot_mem_rgns();
 	int i = fw_dump.boot_mem_regs_cnt++;
 
-	if (fw_dump.boot_mem_regs_cnt > FADUMP_MAX_MEM_REGS) {
-		fw_dump.boot_mem_regs_cnt = FADUMP_MAX_MEM_REGS;
+	if (fw_dump.boot_mem_regs_cnt > max_boot_mem_rgns) {
+		fw_dump.boot_mem_regs_cnt = max_boot_mem_rgns;
 		return 0;
 	}
 

arch/powerpc/platforms/powernv/opal-fadump.c

@@ -599,6 +599,12 @@ static void opal_fadump_trigger(struct fadump_crash_info_header *fdh,
 		pr_emerg("No backend support for MPIPL!\n");
 }
 
+/* FADUMP_MAX_MEM_REGS or lower */
+static int opal_fadump_max_boot_mem_rgns(void)
+{
+	return FADUMP_MAX_MEM_REGS;
+}
+
 static struct fadump_ops opal_fadump_ops = {
 	.fadump_init_mem_struct		= opal_fadump_init_mem_struct,
 	.fadump_get_metadata_size	= opal_fadump_get_metadata_size,
@@ -611,6 +617,7 @@ static struct fadump_ops opal_fadump_ops = {
 	.fadump_process			= opal_fadump_process,
 	.fadump_region_show		= opal_fadump_region_show,
 	.fadump_trigger			= opal_fadump_trigger,
+	.fadump_max_boot_mem_rgns	= opal_fadump_max_boot_mem_rgns,
 };
 
 void __init opal_fadump_dt_scan(struct fw_dump *fadump_conf, u64 node)

arch/powerpc/platforms/pseries/rtas-fadump.h

@@ -29,6 +29,15 @@
 /* Dump status flag */
 #define RTAS_FADUMP_ERROR_FLAG		0x2000
 
+/*
+ * The Firmware Assisted Dump Memory structure supports a maximum of 10 sections
+ * in the dump memory structure. Presently, first two sections are used for
+ * CPU and HPTE data, while the remaining eight sections can be used for
+ * boot memory regions.
+ */
+#define MAX_SECTIONS				10
+#define RTAS_FADUMP_MAX_BOOT_MEM_REGS		8
+
 /* Kernel Dump section info */
 struct rtas_fadump_section {
 	__be32	request_flag;
@@ -61,20 +70,15 @@ struct rtas_fadump_section_header {
  * Firmware Assisted dump memory structure. This structure is required for
  * registering future kernel dump with power firmware through rtas call.
  *
- * No disk dump option. Hence disk dump path string section is not included.
+ * In version 1, the platform permits one section header, dump-disk path
+ * and ten sections.
+ *
+ * Note: No disk dump option. Hence disk dump path string section is not
+ * included.
  */
 struct rtas_fadump_mem_struct {
 	struct rtas_fadump_section_header	header;
-
-	/* Kernel dump sections */
-	struct rtas_fadump_section		cpu_state_data;
-	struct rtas_fadump_section		hpte_region;
-
-	/*
-	 * TODO: Extend multiple boot memory regions support in the kernel
-	 *       for this platform.
-	 */
-	struct rtas_fadump_section		rmr_region;
+	struct rtas_fadump_section		rgn[MAX_SECTIONS];
 };
 
 /*