[PATCH rebased 2/2] powerpc: avoid adjusting memory_limit for capture kernel memory reservation

[Michal Suchanek]

From: Hari Bathini <hbathini at linux.ibm.com>

Currently, if memory_limit is specified and it overlaps with memory to
be reserved for capture kernel, memory_limit is adjusted to accommodate
capture kernel. With memory reservation for capture kernel moved later
(after enforcing memory limit), this adjustment no longer holds water.
So, avoid adjusting memory_limit and error out instead.

Signed-off-by: Hari Bathini <hbathini at linux.ibm.com>
Reviewed-by: Michal Suchanek <msuchanek at suse.de>
---
 arch/powerpc/kernel/fadump.c | 16 ----------------
 arch/powerpc/kexec/core.c    | 22 +++++++++++-----------
 2 files changed, 11 insertions(+), 27 deletions(-)

diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
index ff0114aeba9b..54d56ecadf1a 100644
--- a/arch/powerpc/kernel/fadump.c
+++ b/arch/powerpc/kernel/fadump.c
@@ -472,22 +472,6 @@ int __init fadump_reserve_mem(void)
 		}
 	}
 
-	/*
-	 * Calculate the memory boundary.
-	 * If memory_limit is less than actual memory boundary then reserve
-	 * the memory for fadump beyond the memory_limit and adjust the
-	 * memory_limit accordingly, so that the running kernel can run with
-	 * specified memory_limit.
-	 */
-	if (memory_limit && memory_limit < memblock_end_of_DRAM()) {
-		size = get_fadump_area_size();
-		if ((memory_limit + size) < memblock_end_of_DRAM())
-			memory_limit += size;
-		else
-			memory_limit = memblock_end_of_DRAM();
-		printk(KERN_INFO "Adjusted memory_limit for firmware-assisted"
-				" dump, now %#016llx\n", memory_limit);
-	}
 	if (memory_limit)
 		mem_boundary = memory_limit;
 	else
diff --git a/arch/powerpc/kexec/core.c b/arch/powerpc/kexec/core.c
index 078fe3d76feb..491e08d98c1b 100644
--- a/arch/powerpc/kexec/core.c
+++ b/arch/powerpc/kexec/core.c
@@ -126,10 +126,8 @@ void __init reserve_crashkernel(void)
 		crashk_res.end = crash_base + crash_size - 1;
 	}
 
-	if (crashk_res.end == crashk_res.start) {
-		crashk_res.start = crashk_res.end = 0;
-		return;
-	}
+	if (crashk_res.end == crashk_res.start)
+		goto error_out;
 
 	/* We might have got these values via the command line or the
 	 * device tree, either way sanitise them now. */
@@ -171,15 +169,13 @@ void __init reserve_crashkernel(void)
 	if (overlaps_crashkernel(__pa(_stext), _end - _stext)) {
 		printk(KERN_WARNING
 			"Crash kernel can not overlap current kernel\n");
-		crashk_res.start = crashk_res.end = 0;
-		return;
+		goto error_out;
 	}
 
 	/* Crash kernel trumps memory limit */
 	if (memory_limit && memory_limit <= crashk_res.end) {
-		memory_limit = crashk_res.end + 1;
-		printk("Adjusted memory limit for crashkernel, now 0x%llx\n",
-		       memory_limit);
+		pr_err("Crash kernel size can't exceed memory_limit\n");
+		goto error_out;
 	}
 
 	printk(KERN_INFO "Reserving %ldMB of memory at %ldMB "
@@ -191,9 +187,13 @@ void __init reserve_crashkernel(void)
 	if (!memblock_is_region_memory(crashk_res.start, crash_size) ||
 	    memblock_reserve(crashk_res.start, crash_size)) {
 		pr_err("Failed to reserve memory for crashkernel!\n");
-		crashk_res.start = crashk_res.end = 0;
-		return;
+		goto error_out;
 	}
+
+	return;
+error_out:
+	crashk_res.start = crashk_res.end = 0;
+	return;
 }
 
 int overlaps_crashkernel(unsigned long start, unsigned long size)
-- 
2.23.0