Received-SPF: softfail (google.com: domain of transitioning linux-kernel-owner@vger.kernel.org does not designate 23.128.96.19 as permitted sender) client-ip=23.128.96.19;
Date:   Mon, 6 Jun 2022 17:16:36 +0800
From:   James Liu <james.liu@hpe.com>
To:     "rafael@kernel.org" <rafael@kernel.org>
Cc:     lenb@kernel.org, linux-acpi@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH v2] ACPI: OSL: Fix the memory mapping of an ACPI GAS that
 addresses a data structure
Message-ID: <20220606091636.GA47704@ubuntu-20.04.3>
References: <20220522214302.39024-1-james.liu@hpe.com>
 <PH7PR84MB1958F5A9F4F05EFE72A9E906E6A29@PH7PR84MB1958.NAMPRD84.PROD.OUTLOOK.COM>
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <PH7PR84MB1958F5A9F4F05EFE72A9E906E6A29@PH7PR84MB1958.NAMPRD84.PROD.OUTLOOK.COM>
Precedence: bulk

Hi Rafael, the reported warning (i.e., uninitialized local variable) in V1
by the robot has been fixed. Could you check V2 of this patch? Thanks.

> Subject: [PATCH v2] ACPI: OSL: Fix the memory mapping of an ACPI GAS that addresses a data structure 
> ?
> From: James Liu <james.liu@hpe.com>
> 
> ??? Modify acpi_os_map_generic_address() & acpi_os_unmap_generic_address()
> ??? to correctly handle cases that a GAS table (i.e., Table 5.1, ACPI 6.4)
> ??? is used to address a data structure; in the case, the GAS has the field
> ??? of "Register Bit Width" equal to 0.
> 
> ??? For example, "Injection Instruction Entry" (Table 18.25, ACPI 6.4) has
> ??? a RegisterRegion field that is a GAS that points to a data structure
> ??? SET_ERROR_TYPE_WITH_ADDRESS (Table 18.30), which is required when using
> ??? EINJ (Error Injection module).
> 
> ??? This fix preserves a fairly sufficient memory space (i.e. page size) to
> ??? store the data structure to prevent EINJ module from loading failure if
> ??? platform firmware can correctly support Injection Instruction Entry in
> ??? an EINJ table.
> 
> Signed-off-by: James Liu <james.liu@hpe.com>
> ---
> ?drivers/acpi/osl.c | 27 +++++++++++++++++++++++----
> ?1 file changed, 23 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
> index 45c5c0e45..99f987c8c 100644
> --- a/drivers/acpi/osl.c
> +++ b/drivers/acpi/osl.c
> @@ -452,14 +452,20 @@ EXPORT_SYMBOL_GPL(acpi_os_unmap_memory);
> ?
> ?void __iomem *acpi_os_map_generic_address(struct acpi_generic_address *gas)
> ?{
> -?????? u64 addr;
> +?????? u64 addr = 0;
> ?
> ???????? if (gas->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY)
> ???????????????? return NULL;
> ?
> +?????? /* Handle a case that GAS is used to address an ACPI data structure */
> +?????? if (!gas->bit_width) {
> +?????????????? pr_info("An ACPI data structure at 0x%llx is mapped\n", addr);
> +?????????????? return? acpi_os_map_iomem(addr, PAGE_SIZE);
> +?????? }
> +
> ???????? /* Handle possible alignment issues */
> ???????? memcpy(&addr, &gas->address, sizeof(addr));
> -?????? if (!addr || !gas->bit_width)
> +?????? if (!addr)
> ???????????????? return NULL;
> ?
> ???????? return acpi_os_map_iomem(addr, gas->bit_width / 8);
> @@ -468,15 +474,28 @@ EXPORT_SYMBOL(acpi_os_map_generic_address);
> ?
> ?void acpi_os_unmap_generic_address(struct acpi_generic_address *gas)
> ?{
> -?????? u64 addr;
> +?????? u64 addr = 0;
> ???????? struct acpi_ioremap *map;
> ?
> ???????? if (gas->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY)
> ???????????????? return;
> ?
> +?????? /* Handle a case that GAS is used to address an ACPI data structure */
> +?????? if (!gas->bit_width) {
> +?????????????? pr_info("An ACPI data structure at 0x%llx is unmapped\n", addr);
> +?????????????? mutex_lock(&acpi_ioremap_lock);
> +?????????????? map = acpi_map_lookup(addr, PAGE_SIZE);
> +?????????????? if (!map) {
> +?????????????????????? mutex_unlock(&acpi_ioremap_lock);
> +?????????????????????? return;
> +?????????????? }
> +?????????????? acpi_os_drop_map_ref(map);
> +?????????????? mutex_unlock(&acpi_ioremap_lock);
> +?????? }
> +
> ???????? /* Handle possible alignment issues */
> ???????? memcpy(&addr, &gas->address, sizeof(addr));
> -?????? if (!addr || !gas->bit_width)
> +?????? if (!addr)
> ???????????????? return;
> ?
> ???????? mutex_lock(&acpi_ioremap_lock);
> -- 
> 2.25.1