grub2/0151-ieee1275-drop-HEAP_MAX_ADDR-HEAP_MIN_SIZE.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Daniel Axtens <dja@axtens.net>
Date: Wed, 14 Apr 2021 20:10:23 +1000
Subject: [PATCH] ieee1275: drop HEAP_MAX_ADDR, HEAP_MIN_SIZE

HEAP_MAX_ADDR is confusing. Currently it is set to 32MB, except
on ieee1275 on x86, where it is 64MB.

There is a comment which purports to explain it:

/* If possible, we will avoid claiming heap above this address, because it
   seems to cause relocation problems with OSes that link at 4 MiB */

This doesn't make a lot of sense when the constants are well above 4MB
already. It was not always this way. Prior to
commit 7b5d0fe4440c ("Increase heap limit") in 2010, HEAP_MAX_SIZE and
HEAP_MAX_ADDR were indeed 4MB. However, when the constants were increased
the comment was left unchanged.

It's been over a decade. It doesn't seem like we have problems with
claims over 4MB on powerpc or x86 ieee1275. (sparc does things completely
differently and never used the constant.)

Drop the constant and the check.

The only use of HEAP_MIN_SIZE was to potentially override the
HEAP_MAX_ADDR check. It is now unused. Remove it.

Signed-off-by: Daniel Axtens <dja@axtens.net>
---
 grub-core/kern/ieee1275/init.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/grub-core/kern/ieee1275/init.c b/grub-core/kern/ieee1275/init.c
index 85d50e2965f..8ce1a0f09ee 100644
--- a/grub-core/kern/ieee1275/init.c
+++ b/grub-core/kern/ieee1275/init.c
@@ -51,7 +51,7 @@
 #endif
 #include <grub/lockdown.h>
 
-/* The maximum heap size we're going to claim at boot. Not used by sparc. */
+/* The maximum heap size we're going to claim. Not used by sparc. */
 #ifdef __i386__
 #define HEAP_MAX_SIZE		(unsigned long) (64 * 1024 * 1024)
 #else /* __powerpc__ */