powerpc/fadump: allocate memory for additional parameters early

Memory for passing additional parameters to fadump capture kernel
is allocated during subsys_initcall level, using memblock. But
as slab is already available by this time, allocation happens via
the buddy allocator. This may work for radix MMU but is likely to
fail in most cases for hash MMU as hash MMU needs this memory in
the first memory block for it to be accessible in real mode in the
capture kernel (second boot). So, allocate memory for additional
parameters area as soon as MMU mode is obvious.

Fixes: 683eab94da75 ("powerpc/fadump: setup additional parameters for dump capture kernel")
Reported-by: Venkat Rao Bagalkote <[email protected]>
Closes: https://lore.kernel.org/lkml/[email protected]/T/#u
Signed-off-by: Hari Bathini <[email protected]>
Signed-off-by: Sourabh Jain <[email protected]>
Tested-by: Venkat Rao Bagalkote <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://patch.msgid.link/[email protected]

1 files changed, 10 insertions, 5 deletions

diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
index c42f89862893..5583017bbfbc 100644
--- a/arch/powerpc/kernel/fadump.c
+++ b/arch/powerpc/kernel/fadump.c
@@ -1587,6 +1587,12 @@ static void __init fadump_init_files(void)
 		return;
 	}
 
+	if (fw_dump.param_area) {
+		rc = sysfs_create_file(fadump_kobj, &bootargs_append_attr.attr);
+		if (rc)
+			pr_err("unable to create bootargs_append sysfs file (%d)\n", rc);
+	}
+
 	debugfs_create_file("fadump_region", 0444, arch_debugfs_dir, NULL,
 			    &fadump_region_fops);
 
@@ -1741,7 +1747,7 @@ err_out:
  * Reserve memory to store additional parameters to be passed
  * for fadump/capture kernel.
  */
-static void __init fadump_setup_param_area(void)
+void __init fadump_setup_param_area(void)
 {
 	phys_addr_t range_start, range_end;
 
@@ -1749,7 +1755,7 @@ static void __init fadump_setup_param_area(void)
 		return;
 
 	/* This memory can't be used by PFW or bootloader as it is shared across kernels */
-	if (radix_enabled()) {
+	if (early_radix_enabled()) {
 		/*
 		 * Anywhere in the upper half should be good enough as all memory
 		 * is accessible in real mode.
@@ -1777,12 +1783,12 @@ static void __init fadump_setup_param_area(void)
 						       COMMAND_LINE_SIZE,
 						       range_start,
 						       range_end);
-	if (!fw_dump.param_area || sysfs_create_file(fadump_kobj, &bootargs_append_attr.attr)) {
+	if (!fw_dump.param_area) {
 		pr_warn("WARNING: Could not setup area to pass additional parameters!\n");
 		return;
 	}
 
-	memset(phys_to_virt(fw_dump.param_area), 0, COMMAND_LINE_SIZE);
+	memset((void *)fw_dump.param_area, 0, COMMAND_LINE_SIZE);
 }
 
 /*
@@ -1808,7 +1814,6 @@ int __init setup_fadump(void)
 	}
 	/* Initialize the kernel dump memory structure and register with f/w */
 	else if (fw_dump.reserve_dump_area_size) {
-		fadump_setup_param_area();
 		fw_dump.ops->fadump_init_mem_struct(&fw_dump);
 		register_fadump();
 	}