linux-kernel - [PATCH v4 02/14] x86/boot: Add setup_indirect support in early_memremap_is_setup

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Date:   Fri, 27 Aug 2021 09:28:25 -0400
From:   Ross Philipson <ross.philipson@...cle.com>
To:     linux-kernel@...r.kernel.org, x86@...nel.org,
        iommu@...ts.linux-foundation.org, linux-integrity@...r.kernel.org,
        linux-doc@...r.kernel.org
Cc:     ross.philipson@...cle.com, dpsmith@...rtussolutions.com,
        tglx@...utronix.de, mingo@...hat.com, bp@...en8.de, hpa@...or.com,
        luto@...capital.net, kanth.ghatraju@...cle.com,
        trenchboot-devel@...glegroups.com
Subject: [PATCH v4 02/14] x86/boot: Add setup_indirect support in early_memremap_is_setup_data

The x86 boot documentation describes the setup_indirect structures and
how they are used. Only one of the two functions in ioremap.c that needed
to be modified to be aware of the introduction of setup_indirect
functionality was updated. This adds comparable support to the other
function where it was missing.

Fixes: b3c72fc9a78e ("x86/boot: Introduce setup_indirect")

Signed-off-by: Ross Philipson <ross.philipson@...cle.com>
---
 arch/x86/mm/ioremap.c | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index ab74e4f..f2b34c5 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -669,17 +669,34 @@ static bool __init early_memremap_is_setup_data(resource_size_t phys_addr,
 
 	paddr = boot_params.hdr.setup_data;
 	while (paddr) {
-		unsigned int len;
+		unsigned int len, size;
 
 		if (phys_addr == paddr)
 			return true;
 
 		data = early_memremap_decrypted(paddr, sizeof(*data));
+		size = sizeof(*data);
 
 		paddr_next = data->next;
 		len = data->len;
 
-		early_memunmap(data, sizeof(*data));
+		if ((phys_addr > paddr) && (phys_addr < (paddr + len))) {
+			early_memunmap(data, sizeof(*data));
+			return true;
+		}
+
+		if (data->type == SETUP_INDIRECT) {
+			size += len;
+			early_memunmap(data, sizeof(*data));
+			data = early_memremap_decrypted(paddr, size);
+
+			if (((struct setup_indirect *)data->data)->type != SETUP_INDIRECT) {
+				paddr = ((struct setup_indirect *)data->data)->addr;
+				len = ((struct setup_indirect *)data->data)->len;
+			}
+		}
+
+		early_memunmap(data, size);
 
 		if ((phys_addr > paddr) && (phys_addr < (paddr + len)))
 			return true;
-- 
1.8.3.1