From 51bba8edef90cf579dba16de912d3ef809fe1d77 Mon Sep 17 00:00:00 2001
From: Hari Bathini <hbathini@linux.ibm.com>
Date: Wed, 11 Sep 2019 20:21:46 +0530
Subject: [PATCH] powerpc/fadump: support copying multiple kernel boot memory
 regions

References: jsc#PM-1318 jsc#SLE-9099 jsc#SLE-9176
Patch-mainline: v5.4-rc1
Git-commit: 51bba8edef90cf579dba16de912d3ef809fe1d77

Firmware uses a 32-bit field for size while copying/backing-up memory
during MPIPL. So, the maximum value that could be represented with
a PAGE_SIZE aligned 32-bit field will be the maximum copy size for a
region but FADump capture kernel usually needs more memory than that
to be preserved to avoid running into out of memory errors.

So, request firmware to copy multiple kernel boot memory regions
instead of just one (which worked fine for pseries as 64-bit field
was used for size there).

Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/156821350193.5656.3664853158523582019.stgit@hbathini.in.ibm.com
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
 arch/powerpc/platforms/powernv/opal-fadump.c | 34 ++++++++++++++++----
 1 file changed, 27 insertions(+), 7 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/opal-fadump.c b/arch/powerpc/platforms/powernv/opal-fadump.c
index b53007e82190..a4b96a7a5d6c 100644
--- a/arch/powerpc/platforms/powernv/opal-fadump.c
+++ b/arch/powerpc/platforms/powernv/opal-fadump.c
@@ -26,6 +26,8 @@ static int opal_fadump_unregister(struct fw_dump *fadump_conf);
 static void opal_fadump_update_config(struct fw_dump *fadump_conf,
 				      const struct opal_fadump_mem_struct *fdm)
 {
+	pr_debug("Boot memory regions count: %d\n", fdm->region_cnt);
+
 	/*
 	 * The destination address of the first boot memory region is the
 	 * destination address of boot memory regions.
@@ -48,16 +50,34 @@ static void opal_fadump_init_metadata(struct opal_fadump_mem_struct *fdm)
 
 static u64 opal_fadump_init_mem_struct(struct fw_dump *fadump_conf)
 {
-	u64 addr = fadump_conf->reserve_dump_area_start;
+	int max_copy_size, cur_size, size;
+	u64 src_addr, dest_addr;
 
 	opal_fdm = __va(fadump_conf->kernel_metadata);
 	opal_fadump_init_metadata(opal_fdm);
 
-	opal_fdm->region_cnt = 1;
-	opal_fdm->rgn[0].src	= 0;
-	opal_fdm->rgn[0].dest	= addr;
-	opal_fdm->rgn[0].size	= fadump_conf->boot_memory_size;
-	addr += fadump_conf->boot_memory_size;
+	/*
+	 * Firmware supports 32-bit field for size. Align it to PAGE_SIZE
+	 * and request firmware to copy multiple kernel boot memory regions.
+	 */
+	max_copy_size = _ALIGN_DOWN(U32_MAX, PAGE_SIZE);
+
+	/* Boot memory regions */
+	src_addr = 0;
+	dest_addr = fadump_conf->reserve_dump_area_start;
+	size = fadump_conf->boot_memory_size;
+	while (size) {
+		cur_size = size > max_copy_size ? max_copy_size : size;
+
+		opal_fdm->rgn[opal_fdm->region_cnt].src  = src_addr;
+		opal_fdm->rgn[opal_fdm->region_cnt].dest = dest_addr;
+		opal_fdm->rgn[opal_fdm->region_cnt].size = cur_size;
+
+		opal_fdm->region_cnt++;
+		dest_addr	+= cur_size;
+		src_addr	+= cur_size;
+		size		-= cur_size;
+	}
 
 	/*
 	 * Kernel metadata is passed to f/w and retrieved in capture kerenl.
@@ -68,7 +88,7 @@ static u64 opal_fadump_init_mem_struct(struct fw_dump *fadump_conf)
 
 	opal_fadump_update_config(fadump_conf, opal_fdm);
 
-	return addr;
+	return dest_addr;
 }
 
 static u64 opal_fadump_get_metadata_size(void)
-- 
2.23.0