linux-kernel - [GIT PULL] EFI fix

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Message-ID: <20181130062102.GA51809@gmail.com>
Date:   Fri, 30 Nov 2018 07:21:02 +0100
From:   Ingo Molnar <mingo@...nel.org>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     linux-kernel@...r.kernel.org,
        Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        Matt Fleming <matt@...eblueprint.co.uk>,
        Thomas Gleixner <tglx@...utronix.de>,
        Borislav Petkov <bp@...en8.de>,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>,
        Andrew Morton <akpm@...ux-foundation.org>
Subject: [GIT PULL] EFI fix

Linus,

Please pull the latest efi-urgent-for-linus git tree from:

   git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git efi-urgent-for-linus

   # HEAD: 976b489120cdab2b1b3a41ffa14661db43d58190 efi: Prevent GICv3 WARN() by mapping the memreserve table before first use

An arm64 warning fix.

 Thanks,

	Ingo

------------------>
Ard Biesheuvel (1):
      efi: Prevent GICv3 WARN() by mapping the memreserve table before first use


 drivers/firmware/efi/efi.c | 36 ++++++++++++++++++++++++++----------
 1 file changed, 26 insertions(+), 10 deletions(-)

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index fad7c62cfc0e..415849bab233 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -969,13 +969,33 @@ bool efi_is_table_address(unsigned long phys_addr)
 static DEFINE_SPINLOCK(efi_mem_reserve_persistent_lock);
 static struct linux_efi_memreserve *efi_memreserve_root __ro_after_init;
 
-int efi_mem_reserve_persistent(phys_addr_t addr, u64 size)
+static int __init efi_memreserve_map_root(void)
+{
+	if (efi.mem_reserve == EFI_INVALID_TABLE_ADDR)
+		return -ENODEV;
+
+	efi_memreserve_root = memremap(efi.mem_reserve,
+				       sizeof(*efi_memreserve_root),
+				       MEMREMAP_WB);
+	if (WARN_ON_ONCE(!efi_memreserve_root))
+		return -ENOMEM;
+	return 0;
+}
+
+int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size)
 {
 	struct linux_efi_memreserve *rsv;
+	int rc;
 
-	if (!efi_memreserve_root)
+	if (efi_memreserve_root == (void *)ULONG_MAX)
 		return -ENODEV;
 
+	if (!efi_memreserve_root) {
+		rc = efi_memreserve_map_root();
+		if (rc)
+			return rc;
+	}
+
 	rsv = kmalloc(sizeof(*rsv), GFP_ATOMIC);
 	if (!rsv)
 		return -ENOMEM;
@@ -993,14 +1013,10 @@ int efi_mem_reserve_persistent(phys_addr_t addr, u64 size)
 
 static int __init efi_memreserve_root_init(void)
 {
-	if (efi.mem_reserve == EFI_INVALID_TABLE_ADDR)
-		return -ENODEV;
-
-	efi_memreserve_root = memremap(efi.mem_reserve,
-				       sizeof(*efi_memreserve_root),
-				       MEMREMAP_WB);
-	if (!efi_memreserve_root)
-		return -ENOMEM;
+	if (efi_memreserve_root)
+		return 0;
+	if (efi_memreserve_map_root())
+		efi_memreserve_root = (void *)ULONG_MAX;
 	return 0;
 }
 early_initcall(efi_memreserve_root_init);