linux-kernel - [PATCH] mips: Move initrd_start check after initrd address sanitisation.

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Message-Id: <20230509172921.295700-1-liviu@dudau.co.uk>
Date:   Tue,  9 May 2023 18:29:21 +0100
From:   Liviu Dudau <liviu@...au.co.uk>
To:     Thomas Bogendoerfer <tsbogend@...ha.franken.de>
Cc:     Paul Burton <paulburton@...nel.org>,
        John Crispin <john@...ozen.org>,
        Arınç ÜNAL <arinc.unal@...nc9.com>,
        Sergio Paracuellos <sergio.paracuellos@...il.com>,
        linux-mips@...r.kernel.org, linux-kernel@...r.kernel.org,
        Liviu Dudau <liviu@...au.co.uk>
Subject: [PATCH] mips: Move initrd_start check after initrd address sanitisation.

PAGE_OFFSET is technically a virtual address so when checking the value of
initrd_start against it we should make sure that it has been sanitised from
the values passed by the bootloader. Without this change, even with a bootloader
that passes correct addresses for an initrd, we are failing to load it on MT7621
boards, for example.

Signed-off-by: Liviu Dudau <liviu@...au.co.uk>
---
 arch/mips/kernel/setup.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index febdc5564638e..c0e65135481b7 100644
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -158,10 +158,6 @@ static unsigned long __init init_initrd(void)
 		pr_err("initrd start must be page aligned\n");
 		goto disable;
 	}
-	if (initrd_start < PAGE_OFFSET) {
-		pr_err("initrd start < PAGE_OFFSET\n");
-		goto disable;
-	}
 
 	/*
 	 * Sanitize initrd addresses. For example firmware
@@ -174,6 +170,11 @@ static unsigned long __init init_initrd(void)
 	initrd_end = (unsigned long)__va(end);
 	initrd_start = (unsigned long)__va(__pa(initrd_start));
 
+	if (initrd_start < PAGE_OFFSET) {
+		pr_err("initrd start < PAGE_OFFSET\n");
+		goto disable;
+	}
+
 	ROOT_DEV = Root_RAM0;
 	return PFN_UP(end);
 disable:
-- 
2.40.0