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From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Sami Tolvanen <samitolvanen@google.com>,
        Sedat Dilek <sedat.dilek@gmail.com>,
        Borislav Petkov <bp@alien8.de>, Borislav Petkov <bp@suse.de>,
        Sasha Levin <sashal@kernel.org>, linux-pci@vger.kernel.org,
        clang-built-linux@googlegroups.com
Subject: [PATCH AUTOSEL 5.4 077/130] x86/pci: Fix the function type for check_reserved_t
Date:   Tue, 22 Dec 2020 21:17:20 -0500
Message-Id: <20201223021813.2791612-77-sashal@kernel.org>
In-Reply-To: <20201223021813.2791612-1-sashal@kernel.org>
References: <20201223021813.2791612-1-sashal@kernel.org>
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From: Sami Tolvanen <samitolvanen@google.com>

[ Upstream commit 83321c335dccba262a57378361d63da96b8166d6 ]

e820__mapped_all() is passed as a callback to is_mmconf_reserved(),
which expects a function of type:

  typedef bool (*check_reserved_t)(u64 start, u64 end, unsigned type);

However, e820__mapped_all() accepts enum e820_type as the last argument
and this type mismatch trips indirect call checking with Clang's
Control-Flow Integrity (CFI).

As is_mmconf_reserved() only passes enum e820_type values for the
type argument, change the typedef and the unused type argument in
is_acpi_reserved() to enum e820_type to fix the type mismatch.

Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20201130193900.456726-1-samitolvanen@google.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/pci/mmconfig-shared.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/pci/mmconfig-shared.c b/arch/x86/pci/mmconfig-shared.c
index 6fa42e9c4e6fa..234998f196d4d 100644
--- a/arch/x86/pci/mmconfig-shared.c
+++ b/arch/x86/pci/mmconfig-shared.c
@@ -425,7 +425,7 @@ static acpi_status find_mboard_resource(acpi_handle handle, u32 lvl,
 	return AE_OK;
 }
 
-static bool is_acpi_reserved(u64 start, u64 end, unsigned not_used)
+static bool is_acpi_reserved(u64 start, u64 end, enum e820_type not_used)
 {
 	struct resource mcfg_res;
 
@@ -442,7 +442,7 @@ static bool is_acpi_reserved(u64 start, u64 end, unsigned not_used)
 	return mcfg_res.flags;
 }
 
-typedef bool (*check_reserved_t)(u64 start, u64 end, unsigned type);
+typedef bool (*check_reserved_t)(u64 start, u64 end, enum e820_type type);
 
 static bool __ref is_mmconf_reserved(check_reserved_t is_reserved,
 				     struct pci_mmcfg_region *cfg,
-- 
2.27.0