On 7/22/19 11:19 PM, Michal Suchánek wrote:

On Fri, 28 Jun 2019 00:51:19 +0530
Hari Bathini [off-list ref] wrote:

quoted

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.

Can you split out the memory limit adjustment out of memory reservation
so it can still be adjusted?

Do you mean adjust the memory limit before we do the actual reservation ?

Thanks

Michal

quoted

Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
---
 arch/powerpc/kernel/fadump.c        |   16 ----------------
 arch/powerpc/kernel/machine_kexec.c |   22 +++++++++++-----------
 2 files changed, 11 insertions(+), 27 deletions(-)

diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
index 4eab972..a784695 100644
--- a/arch/powerpc/kernel/fadump.c
+++ b/arch/powerpc/kernel/fadump.c

@@ -476,22 +476,6 @@ int __init fadump_reserve_mem(void)
 #endif
 	}
 
-	/*
-	 * 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)
 		memory_boundary = memory_limit;
 	else

diff --git a/arch/powerpc/kernel/machine_kexec.c b/arch/powerpc/kernel/machine_kexec.c
index c4ed328..fc5533b 100644
--- a/arch/powerpc/kernel/machine_kexec.c
+++ b/arch/powerpc/kernel/machine_kexec.c

@@ -125,10 +125,8 @@ 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. */

@@ -170,15 +168,13 @@ 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 "

@@ -190,9 +186,13 @@ 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)