The dcdbas driver is used to call SMI handlers for both, dcdbas and
dell-smbios-smm. Both drivers allocate a buffer for communicating
with the SMI handler. The physical buffer address is then passed to
the called SMI handler via %ebx.
Unfortunately this doesn't work when running in Xen dom0, as the
physical address obtained via virt_to_phys() is only a guest physical
address, and not a machine physical address as needed by SMI.
The problem in dcdbas is easy to correct, as dcdbas is using
dma_alloc_coherent() for allocating the buffer, and the machine
physical address is available via the DMA address returned in the DMA
handle.
In order to avoid duplicating the buffer allocation code in
dell-smbios-smm, add a generic buffer allocation function to dcdbas
and use it for both drivers. This is especially fine regarding driver
dependencies, as dell-smbios-smm is already calling dcdbas to generate
the SMI request.
Cc: [email protected]
Signed-off-by: Juergen Gross <[email protected]>
---
drivers/platform/x86/dell/dcdbas.c | 127 +++++++++++---------
drivers/platform/x86/dell/dcdbas.h | 9 ++
drivers/platform/x86/dell/dell-smbios-smm.c | 14 ++-
3 files changed, 87 insertions(+), 63 deletions(-)
diff --git a/drivers/platform/x86/dell/dcdbas.c b/drivers/platform/x86/dell/dcdbas.c
index 5e63d6225048..02bcac619018 100644
--- a/drivers/platform/x86/dell/dcdbas.c
+++ b/drivers/platform/x86/dell/dcdbas.c
@@ -40,13 +40,10 @@
static struct platform_device *dcdbas_pdev;
-static u8 *smi_data_buf;
-static dma_addr_t smi_data_buf_handle;
-static unsigned long smi_data_buf_size;
static unsigned long max_smi_data_buf_size = MAX_SMI_DATA_BUF_SIZE;
-static u32 smi_data_buf_phys_addr;
static DEFINE_MUTEX(smi_data_lock);
static u8 *bios_buffer;
+static struct smi_buffer smi_buf;
static unsigned int host_control_action;
static unsigned int host_control_smi_type;
@@ -54,23 +51,49 @@ static unsigned int host_control_on_shutdown;
static bool wsmt_enabled;
+int dcdbas_smi_alloc(struct smi_buffer *smi_buffer, unsigned long size)
+{
+ smi_buffer->virt = dma_alloc_coherent(&dcdbas_pdev->dev, size,
+ &smi_buffer->dma, GFP_KERNEL);
+ if (!smi_buffer->virt) {
+ dev_dbg(&dcdbas_pdev->dev,
+ "%s: failed to allocate memory size %lu\n",
+ __func__, size);
+ return -ENOMEM;
+ }
+ smi_buffer->size = size;
+
+ dev_dbg(&dcdbas_pdev->dev, "%s: phys: %x size: %lu\n",
+ __func__, (u32)smi_buffer->dma, smi_buffer->size);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(dcdbas_smi_alloc);
+
+void dcdbas_smi_free(struct smi_buffer *smi_buffer)
+{
+ if (!smi_buffer->virt)
+ return;
+
+ dev_dbg(&dcdbas_pdev->dev, "%s: phys: %x size: %lu\n",
+ __func__, (u32)smi_buffer->dma, smi_buffer->size);
+ dma_free_coherent(&dcdbas_pdev->dev, smi_buffer->size,
+ smi_buffer->virt, smi_buffer->dma);
+ smi_buffer->virt = NULL;
+ smi_buffer->dma = 0;
+ smi_buffer->size = 0;
+}
+EXPORT_SYMBOL_GPL(dcdbas_smi_free);
+
/**
* smi_data_buf_free: free SMI data buffer
*/
static void smi_data_buf_free(void)
{
- if (!smi_data_buf || wsmt_enabled)
+ if (!smi_buf.virt || wsmt_enabled)
return;
- dev_dbg(&dcdbas_pdev->dev, "%s: phys: %x size: %lu\n",
- __func__, smi_data_buf_phys_addr, smi_data_buf_size);
-
- dma_free_coherent(&dcdbas_pdev->dev, smi_data_buf_size, smi_data_buf,
- smi_data_buf_handle);
- smi_data_buf = NULL;
- smi_data_buf_handle = 0;
- smi_data_buf_phys_addr = 0;
- smi_data_buf_size = 0;
+ dcdbas_smi_free(&smi_buf);
}
/**
@@ -78,39 +101,29 @@ static void smi_data_buf_free(void)
*/
static int smi_data_buf_realloc(unsigned long size)
{
- void *buf;
- dma_addr_t handle;
+ struct smi_buffer tmp;
+ int ret;
- if (smi_data_buf_size >= size)
+ if (smi_buf.size >= size)
return 0;
if (size > max_smi_data_buf_size)
return -EINVAL;
/* new buffer is needed */
- buf = dma_alloc_coherent(&dcdbas_pdev->dev, size, &handle, GFP_KERNEL);
- if (!buf) {
- dev_dbg(&dcdbas_pdev->dev,
- "%s: failed to allocate memory size %lu\n",
- __func__, size);
- return -ENOMEM;
- }
- /* memory zeroed by dma_alloc_coherent */
+ ret = dcdbas_smi_alloc(&tmp, size);
+ if (ret)
+ return ret;
- if (smi_data_buf)
- memcpy(buf, smi_data_buf, smi_data_buf_size);
+ /* memory zeroed by dma_alloc_coherent */
+ if (smi_buf.virt)
+ memcpy(tmp.virt, smi_buf.virt, smi_buf.size);
/* free any existing buffer */
smi_data_buf_free();
/* set up new buffer for use */
- smi_data_buf = buf;
- smi_data_buf_handle = handle;
- smi_data_buf_phys_addr = (u32) virt_to_phys(buf);
- smi_data_buf_size = size;
-
- dev_dbg(&dcdbas_pdev->dev, "%s: phys: %x size: %lu\n",
- __func__, smi_data_buf_phys_addr, smi_data_buf_size);
+ smi_buf = tmp;
return 0;
}
@@ -119,14 +132,14 @@ static ssize_t smi_data_buf_phys_addr_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
- return sprintf(buf, "%x\n", smi_data_buf_phys_addr);
+ return sprintf(buf, "%x\n", (u32)smi_buf.dma);
}
static ssize_t smi_data_buf_size_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
- return sprintf(buf, "%lu\n", smi_data_buf_size);
+ return sprintf(buf, "%lu\n", smi_buf.size);
}
static ssize_t smi_data_buf_size_store(struct device *dev,
@@ -155,8 +168,8 @@ static ssize_t smi_data_read(struct file *filp, struct kobject *kobj,
ssize_t ret;
mutex_lock(&smi_data_lock);
- ret = memory_read_from_buffer(buf, count, &pos, smi_data_buf,
- smi_data_buf_size);
+ ret = memory_read_from_buffer(buf, count, &pos, smi_buf.virt,
+ smi_buf.size);
mutex_unlock(&smi_data_lock);
return ret;
}
@@ -176,7 +189,7 @@ static ssize_t smi_data_write(struct file *filp, struct kobject *kobj,
if (ret)
goto out;
- memcpy(smi_data_buf + pos, buf, count);
+ memcpy(smi_buf.virt + pos, buf, count);
ret = count;
out:
mutex_unlock(&smi_data_lock);
@@ -306,11 +319,11 @@ static ssize_t smi_request_store(struct device *dev,
mutex_lock(&smi_data_lock);
- if (smi_data_buf_size < sizeof(struct smi_cmd)) {
+ if (smi_buf.size < sizeof(struct smi_cmd)) {
ret = -ENODEV;
goto out;
}
- smi_cmd = (struct smi_cmd *)smi_data_buf;
+ smi_cmd = (struct smi_cmd *)smi_buf.virt;
switch (val) {
case 2:
@@ -326,20 +339,20 @@ static ssize_t smi_request_store(struct device *dev,
* Provide physical address of command buffer field within
* the struct smi_cmd to BIOS.
*
- * Because the address that smi_cmd (smi_data_buf) points to
+ * Because the address that smi_cmd (smi_buf.virt) points to
* will be from memremap() of a non-memory address if WSMT
* is present, we can't use virt_to_phys() on smi_cmd, so
* we have to use the physical address that was saved when
* the virtual address for smi_cmd was received.
*/
- smi_cmd->ebx = smi_data_buf_phys_addr +
+ smi_cmd->ebx = (u32)smi_buf.dma +
offsetof(struct smi_cmd, command_buffer);
ret = dcdbas_smi_request(smi_cmd);
if (!ret)
ret = count;
break;
case 0:
- memset(smi_data_buf, 0, smi_data_buf_size);
+ memset(smi_buf.virt, 0, smi_buf.size);
ret = count;
break;
default:
@@ -356,7 +369,7 @@ EXPORT_SYMBOL(dcdbas_smi_request);
/**
* host_control_smi: generate host control SMI
*
- * Caller must set up the host control command in smi_data_buf.
+ * Caller must set up the host control command in smi_buf.virt.
*/
static int host_control_smi(void)
{
@@ -367,14 +380,14 @@ static int host_control_smi(void)
s8 cmd_status;
u8 index;
- apm_cmd = (struct apm_cmd *)smi_data_buf;
+ apm_cmd = (struct apm_cmd *)smi_buf.virt;
apm_cmd->status = ESM_STATUS_CMD_UNSUCCESSFUL;
switch (host_control_smi_type) {
case HC_SMITYPE_TYPE1:
spin_lock_irqsave(&rtc_lock, flags);
/* write SMI data buffer physical address */
- data = (u8 *)&smi_data_buf_phys_addr;
+ data = (u8 *)&smi_buf.dma;
for (index = PE1300_CMOS_CMD_STRUCT_PTR;
index < (PE1300_CMOS_CMD_STRUCT_PTR + 4);
index++, data++) {
@@ -405,7 +418,7 @@ static int host_control_smi(void)
case HC_SMITYPE_TYPE3:
spin_lock_irqsave(&rtc_lock, flags);
/* write SMI data buffer physical address */
- data = (u8 *)&smi_data_buf_phys_addr;
+ data = (u8 *)&smi_buf.dma;
for (index = PE1400_CMOS_CMD_STRUCT_PTR;
index < (PE1400_CMOS_CMD_STRUCT_PTR + 4);
index++, data++) {
@@ -450,7 +463,7 @@ static int host_control_smi(void)
* This function is called by the driver after the system has
* finished shutting down if the user application specified a
* host control action to perform on shutdown. It is safe to
- * use smi_data_buf at this point because the system has finished
+ * use smi_buf.virt at this point because the system has finished
* shutting down and no userspace apps are running.
*/
static void dcdbas_host_control(void)
@@ -464,18 +477,18 @@ static void dcdbas_host_control(void)
action = host_control_action;
host_control_action = HC_ACTION_NONE;
- if (!smi_data_buf) {
+ if (!smi_buf.virt) {
dev_dbg(&dcdbas_pdev->dev, "%s: no SMI buffer\n", __func__);
return;
}
- if (smi_data_buf_size < sizeof(struct apm_cmd)) {
+ if (smi_buf.size < sizeof(struct apm_cmd)) {
dev_dbg(&dcdbas_pdev->dev, "%s: SMI buffer too small\n",
__func__);
return;
}
- apm_cmd = (struct apm_cmd *)smi_data_buf;
+ apm_cmd = (struct apm_cmd *)smi_buf.virt;
/* power off takes precedence */
if (action & HC_ACTION_HOST_CONTROL_POWEROFF) {
@@ -583,11 +596,11 @@ static int dcdbas_check_wsmt(void)
return -ENOMEM;
}
- /* First 8 bytes is for a semaphore, not part of the smi_data_buf */
- smi_data_buf_phys_addr = bios_buf_paddr + 8;
- smi_data_buf = bios_buffer + 8;
- smi_data_buf_size = remap_size - 8;
- max_smi_data_buf_size = smi_data_buf_size;
+ /* First 8 bytes is for a semaphore, not part of the smi_buf.virt */
+ smi_buf.dma = bios_buf_paddr + 8;
+ smi_buf.virt = bios_buffer + 8;
+ smi_buf.size = remap_size - 8;
+ max_smi_data_buf_size = smi_buf.size;
wsmt_enabled = true;
dev_info(&dcdbas_pdev->dev,
"WSMT found, using firmware-provided SMI buffer.\n");
diff --git a/drivers/platform/x86/dell/dcdbas.h b/drivers/platform/x86/dell/dcdbas.h
index c3cca5433525..942a23ddded0 100644
--- a/drivers/platform/x86/dell/dcdbas.h
+++ b/drivers/platform/x86/dell/dcdbas.h
@@ -105,5 +105,14 @@ struct smm_eps_table {
u64 num_of_4k_pages;
} __packed;
+struct smi_buffer {
+ u8 *virt;
+ unsigned long size;
+ dma_addr_t dma;
+};
+
+int dcdbas_smi_alloc(struct smi_buffer *smi_buffer, unsigned long size);
+void dcdbas_smi_free(struct smi_buffer *smi_buffer);
+
#endif /* _DCDBAS_H_ */
diff --git a/drivers/platform/x86/dell/dell-smbios-smm.c b/drivers/platform/x86/dell/dell-smbios-smm.c
index 320c032418ac..4d375985c85f 100644
--- a/drivers/platform/x86/dell/dell-smbios-smm.c
+++ b/drivers/platform/x86/dell/dell-smbios-smm.c
@@ -20,6 +20,7 @@
static int da_command_address;
static int da_command_code;
+static struct smi_buffer smi_buf;
static struct calling_interface_buffer *buffer;
static struct platform_device *platform_device;
static DEFINE_MUTEX(smm_mutex);
@@ -57,7 +58,7 @@ static int dell_smbios_smm_call(struct calling_interface_buffer *input)
command.magic = SMI_CMD_MAGIC;
command.command_address = da_command_address;
command.command_code = da_command_code;
- command.ebx = virt_to_phys(buffer);
+ command.ebx = smi_buf.dma;
command.ecx = 0x42534931;
mutex_lock(&smm_mutex);
@@ -101,9 +102,10 @@ int init_dell_smbios_smm(void)
* Allocate buffer below 4GB for SMI data--only 32-bit physical addr
* is passed to SMI handler.
*/
- buffer = (void *)__get_free_page(GFP_KERNEL | GFP_DMA32);
- if (!buffer)
- return -ENOMEM;
+ ret = dcdbas_smi_alloc(&smi_buf, PAGE_SIZE);
+ if (ret)
+ return ret;
+ buffer = (void *)smi_buf.virt;
dmi_walk(find_cmd_address, NULL);
@@ -138,7 +140,7 @@ int init_dell_smbios_smm(void)
fail_wsmt:
fail_platform_device_alloc:
- free_page((unsigned long)buffer);
+ dcdbas_smi_free(&smi_buf);
return ret;
}
@@ -147,6 +149,6 @@ void exit_dell_smbios_smm(void)
if (platform_device) {
dell_smbios_unregister_device(&platform_device->dev);
platform_device_unregister(platform_device);
- free_page((unsigned long)buffer);
+ dcdbas_smi_free(&smi_buf);
}
}
--
2.34.1
From: Juergen Gross
> Sent: 18 March 2022 16:56
>
> On 18.03.22 16:22, David Laight wrote:
> > From: Juergen Gross
> >> Sent: 18 March 2022 15:10
> >>
> >> The dcdbas driver is used to call SMI handlers for both, dcdbas and
> >> dell-smbios-smm. Both drivers allocate a buffer for communicating
> >> with the SMI handler. The physical buffer address is then passed to
> >> the called SMI handler via %ebx.
> >>
> >> Unfortunately this doesn't work when running in Xen dom0, as the
> >> physical address obtained via virt_to_phys() is only a guest physical
> >> address, and not a machine physical address as needed by SMI.
> >
> > The physical address from virt_to_phy() is always wrong.
> > That is the physical address the cpu has for the memory.
> > What you want is the address the dma master interface needs to use.
> > That can be different for a physical system - no need for virtualisation.
> >
> > On x86 they do usually match, but anything with a full iommu
> > will need completely different addresses.
>
> Yes, thanks for reminding me of that.
>
> The SMI handler is running on the cpu, right? So using the DMA
> address is wrong in case of an IOMMU. I really need the machine
> physical address.
That ought to be handled by the 'dev' parameter to dma_alloc_coherent().
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
From: Juergen Gross
> Sent: 18 March 2022 15:10
>
> The dcdbas driver is used to call SMI handlers for both, dcdbas and
> dell-smbios-smm. Both drivers allocate a buffer for communicating
> with the SMI handler. The physical buffer address is then passed to
> the called SMI handler via %ebx.
>
> Unfortunately this doesn't work when running in Xen dom0, as the
> physical address obtained via virt_to_phys() is only a guest physical
> address, and not a machine physical address as needed by SMI.
The physical address from virt_to_phy() is always wrong.
That is the physical address the cpu has for the memory.
What you want is the address the dma master interface needs to use.
That can be different for a physical system - no need for virtualisation.
On x86 they do usually match, but anything with a full iommu
will need completely different addresses.
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
On 18.03.22 16:22, David Laight wrote:
> From: Juergen Gross
>> Sent: 18 March 2022 15:10
>>
>> The dcdbas driver is used to call SMI handlers for both, dcdbas and
>> dell-smbios-smm. Both drivers allocate a buffer for communicating
>> with the SMI handler. The physical buffer address is then passed to
>> the called SMI handler via %ebx.
>>
>> Unfortunately this doesn't work when running in Xen dom0, as the
>> physical address obtained via virt_to_phys() is only a guest physical
>> address, and not a machine physical address as needed by SMI.
>
> The physical address from virt_to_phy() is always wrong.
> That is the physical address the cpu has for the memory.
> What you want is the address the dma master interface needs to use.
> That can be different for a physical system - no need for virtualisation.
>
> On x86 they do usually match, but anything with a full iommu
> will need completely different addresses.
Yes, thanks for reminding me of that.
The SMI handler is running on the cpu, right? So using the DMA
address is wrong in case of an IOMMU. I really need the machine
physical address.
Juergen
Hi,
On 3/18/22 23:28, David Laight wrote:
> From: Juergen Gross
>> Sent: 18 March 2022 16:56
>>
>> On 18.03.22 16:22, David Laight wrote:
>>> From: Juergen Gross
>>>> Sent: 18 March 2022 15:10
>>>>
>>>> The dcdbas driver is used to call SMI handlers for both, dcdbas and
>>>> dell-smbios-smm. Both drivers allocate a buffer for communicating
>>>> with the SMI handler. The physical buffer address is then passed to
>>>> the called SMI handler via %ebx.
>>>>
>>>> Unfortunately this doesn't work when running in Xen dom0, as the
>>>> physical address obtained via virt_to_phys() is only a guest physical
>>>> address, and not a machine physical address as needed by SMI.
>>>
>>> The physical address from virt_to_phy() is always wrong.
>>> That is the physical address the cpu has for the memory.
>>> What you want is the address the dma master interface needs to use.
>>> That can be different for a physical system - no need for virtualisation.
>>>
>>> On x86 they do usually match, but anything with a full iommu
>>> will need completely different addresses.
>>
>> Yes, thanks for reminding me of that.
>>
>> The SMI handler is running on the cpu, right? So using the DMA
>> address is wrong in case of an IOMMU. I really need the machine
>> physical address.
>
> That ought to be handled by the 'dev' parameter to dma_alloc_coherent().
>
> David
I must admit that I'm not too familiar with all the intricate details
of the DMA API here.
So does this mean that the patch in its original form is good as is
and should be merged?
An Acked-by or Reviewed-by from someone more familiar with the DMA
APIs would be helpful.
Regards,
Hans
Hi,
On 3/18/22 16:09, Juergen Gross wrote:
> The dcdbas driver is used to call SMI handlers for both, dcdbas and
> dell-smbios-smm. Both drivers allocate a buffer for communicating
> with the SMI handler. The physical buffer address is then passed to
> the called SMI handler via %ebx.
>
> Unfortunately this doesn't work when running in Xen dom0, as the
> physical address obtained via virt_to_phys() is only a guest physical
> address, and not a machine physical address as needed by SMI.
>
> The problem in dcdbas is easy to correct, as dcdbas is using
> dma_alloc_coherent() for allocating the buffer, and the machine
> physical address is available via the DMA address returned in the DMA
> handle.
>
> In order to avoid duplicating the buffer allocation code in
> dell-smbios-smm, add a generic buffer allocation function to dcdbas
> and use it for both drivers. This is especially fine regarding driver
> dependencies, as dell-smbios-smm is already calling dcdbas to generate
> the SMI request.
>
> Cc: [email protected]
> Signed-off-by: Juergen Gross <[email protected]>
Thank you for your patch, I've applied this patch to my review-hans
branch:
https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/log/?h=review-hans
Note it will show up in my review-hans branch once I've pushed my
local branch there, which might take a while.
Once I've run some tests on this branch the patches there will be
added to the platform-drivers-x86/for-next branch and eventually
will be included in the pdx86 pull-request to Linus for the next
merge-window.
Regards,
Hans
> ---
> drivers/platform/x86/dell/dcdbas.c | 127 +++++++++++---------
> drivers/platform/x86/dell/dcdbas.h | 9 ++
> drivers/platform/x86/dell/dell-smbios-smm.c | 14 ++-
> 3 files changed, 87 insertions(+), 63 deletions(-)
>
> diff --git a/drivers/platform/x86/dell/dcdbas.c b/drivers/platform/x86/dell/dcdbas.c
> index 5e63d6225048..02bcac619018 100644
> --- a/drivers/platform/x86/dell/dcdbas.c
> +++ b/drivers/platform/x86/dell/dcdbas.c
> @@ -40,13 +40,10 @@
>
> static struct platform_device *dcdbas_pdev;
>
> -static u8 *smi_data_buf;
> -static dma_addr_t smi_data_buf_handle;
> -static unsigned long smi_data_buf_size;
> static unsigned long max_smi_data_buf_size = MAX_SMI_DATA_BUF_SIZE;
> -static u32 smi_data_buf_phys_addr;
> static DEFINE_MUTEX(smi_data_lock);
> static u8 *bios_buffer;
> +static struct smi_buffer smi_buf;
>
> static unsigned int host_control_action;
> static unsigned int host_control_smi_type;
> @@ -54,23 +51,49 @@ static unsigned int host_control_on_shutdown;
>
> static bool wsmt_enabled;
>
> +int dcdbas_smi_alloc(struct smi_buffer *smi_buffer, unsigned long size)
> +{
> + smi_buffer->virt = dma_alloc_coherent(&dcdbas_pdev->dev, size,
> + &smi_buffer->dma, GFP_KERNEL);
> + if (!smi_buffer->virt) {
> + dev_dbg(&dcdbas_pdev->dev,
> + "%s: failed to allocate memory size %lu\n",
> + __func__, size);
> + return -ENOMEM;
> + }
> + smi_buffer->size = size;
> +
> + dev_dbg(&dcdbas_pdev->dev, "%s: phys: %x size: %lu\n",
> + __func__, (u32)smi_buffer->dma, smi_buffer->size);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(dcdbas_smi_alloc);
> +
> +void dcdbas_smi_free(struct smi_buffer *smi_buffer)
> +{
> + if (!smi_buffer->virt)
> + return;
> +
> + dev_dbg(&dcdbas_pdev->dev, "%s: phys: %x size: %lu\n",
> + __func__, (u32)smi_buffer->dma, smi_buffer->size);
> + dma_free_coherent(&dcdbas_pdev->dev, smi_buffer->size,
> + smi_buffer->virt, smi_buffer->dma);
> + smi_buffer->virt = NULL;
> + smi_buffer->dma = 0;
> + smi_buffer->size = 0;
> +}
> +EXPORT_SYMBOL_GPL(dcdbas_smi_free);
> +
> /**
> * smi_data_buf_free: free SMI data buffer
> */
> static void smi_data_buf_free(void)
> {
> - if (!smi_data_buf || wsmt_enabled)
> + if (!smi_buf.virt || wsmt_enabled)
> return;
>
> - dev_dbg(&dcdbas_pdev->dev, "%s: phys: %x size: %lu\n",
> - __func__, smi_data_buf_phys_addr, smi_data_buf_size);
> -
> - dma_free_coherent(&dcdbas_pdev->dev, smi_data_buf_size, smi_data_buf,
> - smi_data_buf_handle);
> - smi_data_buf = NULL;
> - smi_data_buf_handle = 0;
> - smi_data_buf_phys_addr = 0;
> - smi_data_buf_size = 0;
> + dcdbas_smi_free(&smi_buf);
> }
>
> /**
> @@ -78,39 +101,29 @@ static void smi_data_buf_free(void)
> */
> static int smi_data_buf_realloc(unsigned long size)
> {
> - void *buf;
> - dma_addr_t handle;
> + struct smi_buffer tmp;
> + int ret;
>
> - if (smi_data_buf_size >= size)
> + if (smi_buf.size >= size)
> return 0;
>
> if (size > max_smi_data_buf_size)
> return -EINVAL;
>
> /* new buffer is needed */
> - buf = dma_alloc_coherent(&dcdbas_pdev->dev, size, &handle, GFP_KERNEL);
> - if (!buf) {
> - dev_dbg(&dcdbas_pdev->dev,
> - "%s: failed to allocate memory size %lu\n",
> - __func__, size);
> - return -ENOMEM;
> - }
> - /* memory zeroed by dma_alloc_coherent */
> + ret = dcdbas_smi_alloc(&tmp, size);
> + if (ret)
> + return ret;
>
> - if (smi_data_buf)
> - memcpy(buf, smi_data_buf, smi_data_buf_size);
> + /* memory zeroed by dma_alloc_coherent */
> + if (smi_buf.virt)
> + memcpy(tmp.virt, smi_buf.virt, smi_buf.size);
>
> /* free any existing buffer */
> smi_data_buf_free();
>
> /* set up new buffer for use */
> - smi_data_buf = buf;
> - smi_data_buf_handle = handle;
> - smi_data_buf_phys_addr = (u32) virt_to_phys(buf);
> - smi_data_buf_size = size;
> -
> - dev_dbg(&dcdbas_pdev->dev, "%s: phys: %x size: %lu\n",
> - __func__, smi_data_buf_phys_addr, smi_data_buf_size);
> + smi_buf = tmp;
>
> return 0;
> }
> @@ -119,14 +132,14 @@ static ssize_t smi_data_buf_phys_addr_show(struct device *dev,
> struct device_attribute *attr,
> char *buf)
> {
> - return sprintf(buf, "%x\n", smi_data_buf_phys_addr);
> + return sprintf(buf, "%x\n", (u32)smi_buf.dma);
> }
>
> static ssize_t smi_data_buf_size_show(struct device *dev,
> struct device_attribute *attr,
> char *buf)
> {
> - return sprintf(buf, "%lu\n", smi_data_buf_size);
> + return sprintf(buf, "%lu\n", smi_buf.size);
> }
>
> static ssize_t smi_data_buf_size_store(struct device *dev,
> @@ -155,8 +168,8 @@ static ssize_t smi_data_read(struct file *filp, struct kobject *kobj,
> ssize_t ret;
>
> mutex_lock(&smi_data_lock);
> - ret = memory_read_from_buffer(buf, count, &pos, smi_data_buf,
> - smi_data_buf_size);
> + ret = memory_read_from_buffer(buf, count, &pos, smi_buf.virt,
> + smi_buf.size);
> mutex_unlock(&smi_data_lock);
> return ret;
> }
> @@ -176,7 +189,7 @@ static ssize_t smi_data_write(struct file *filp, struct kobject *kobj,
> if (ret)
> goto out;
>
> - memcpy(smi_data_buf + pos, buf, count);
> + memcpy(smi_buf.virt + pos, buf, count);
> ret = count;
> out:
> mutex_unlock(&smi_data_lock);
> @@ -306,11 +319,11 @@ static ssize_t smi_request_store(struct device *dev,
>
> mutex_lock(&smi_data_lock);
>
> - if (smi_data_buf_size < sizeof(struct smi_cmd)) {
> + if (smi_buf.size < sizeof(struct smi_cmd)) {
> ret = -ENODEV;
> goto out;
> }
> - smi_cmd = (struct smi_cmd *)smi_data_buf;
> + smi_cmd = (struct smi_cmd *)smi_buf.virt;
>
> switch (val) {
> case 2:
> @@ -326,20 +339,20 @@ static ssize_t smi_request_store(struct device *dev,
> * Provide physical address of command buffer field within
> * the struct smi_cmd to BIOS.
> *
> - * Because the address that smi_cmd (smi_data_buf) points to
> + * Because the address that smi_cmd (smi_buf.virt) points to
> * will be from memremap() of a non-memory address if WSMT
> * is present, we can't use virt_to_phys() on smi_cmd, so
> * we have to use the physical address that was saved when
> * the virtual address for smi_cmd was received.
> */
> - smi_cmd->ebx = smi_data_buf_phys_addr +
> + smi_cmd->ebx = (u32)smi_buf.dma +
> offsetof(struct smi_cmd, command_buffer);
> ret = dcdbas_smi_request(smi_cmd);
> if (!ret)
> ret = count;
> break;
> case 0:
> - memset(smi_data_buf, 0, smi_data_buf_size);
> + memset(smi_buf.virt, 0, smi_buf.size);
> ret = count;
> break;
> default:
> @@ -356,7 +369,7 @@ EXPORT_SYMBOL(dcdbas_smi_request);
> /**
> * host_control_smi: generate host control SMI
> *
> - * Caller must set up the host control command in smi_data_buf.
> + * Caller must set up the host control command in smi_buf.virt.
> */
> static int host_control_smi(void)
> {
> @@ -367,14 +380,14 @@ static int host_control_smi(void)
> s8 cmd_status;
> u8 index;
>
> - apm_cmd = (struct apm_cmd *)smi_data_buf;
> + apm_cmd = (struct apm_cmd *)smi_buf.virt;
> apm_cmd->status = ESM_STATUS_CMD_UNSUCCESSFUL;
>
> switch (host_control_smi_type) {
> case HC_SMITYPE_TYPE1:
> spin_lock_irqsave(&rtc_lock, flags);
> /* write SMI data buffer physical address */
> - data = (u8 *)&smi_data_buf_phys_addr;
> + data = (u8 *)&smi_buf.dma;
> for (index = PE1300_CMOS_CMD_STRUCT_PTR;
> index < (PE1300_CMOS_CMD_STRUCT_PTR + 4);
> index++, data++) {
> @@ -405,7 +418,7 @@ static int host_control_smi(void)
> case HC_SMITYPE_TYPE3:
> spin_lock_irqsave(&rtc_lock, flags);
> /* write SMI data buffer physical address */
> - data = (u8 *)&smi_data_buf_phys_addr;
> + data = (u8 *)&smi_buf.dma;
> for (index = PE1400_CMOS_CMD_STRUCT_PTR;
> index < (PE1400_CMOS_CMD_STRUCT_PTR + 4);
> index++, data++) {
> @@ -450,7 +463,7 @@ static int host_control_smi(void)
> * This function is called by the driver after the system has
> * finished shutting down if the user application specified a
> * host control action to perform on shutdown. It is safe to
> - * use smi_data_buf at this point because the system has finished
> + * use smi_buf.virt at this point because the system has finished
> * shutting down and no userspace apps are running.
> */
> static void dcdbas_host_control(void)
> @@ -464,18 +477,18 @@ static void dcdbas_host_control(void)
> action = host_control_action;
> host_control_action = HC_ACTION_NONE;
>
> - if (!smi_data_buf) {
> + if (!smi_buf.virt) {
> dev_dbg(&dcdbas_pdev->dev, "%s: no SMI buffer\n", __func__);
> return;
> }
>
> - if (smi_data_buf_size < sizeof(struct apm_cmd)) {
> + if (smi_buf.size < sizeof(struct apm_cmd)) {
> dev_dbg(&dcdbas_pdev->dev, "%s: SMI buffer too small\n",
> __func__);
> return;
> }
>
> - apm_cmd = (struct apm_cmd *)smi_data_buf;
> + apm_cmd = (struct apm_cmd *)smi_buf.virt;
>
> /* power off takes precedence */
> if (action & HC_ACTION_HOST_CONTROL_POWEROFF) {
> @@ -583,11 +596,11 @@ static int dcdbas_check_wsmt(void)
> return -ENOMEM;
> }
>
> - /* First 8 bytes is for a semaphore, not part of the smi_data_buf */
> - smi_data_buf_phys_addr = bios_buf_paddr + 8;
> - smi_data_buf = bios_buffer + 8;
> - smi_data_buf_size = remap_size - 8;
> - max_smi_data_buf_size = smi_data_buf_size;
> + /* First 8 bytes is for a semaphore, not part of the smi_buf.virt */
> + smi_buf.dma = bios_buf_paddr + 8;
> + smi_buf.virt = bios_buffer + 8;
> + smi_buf.size = remap_size - 8;
> + max_smi_data_buf_size = smi_buf.size;
> wsmt_enabled = true;
> dev_info(&dcdbas_pdev->dev,
> "WSMT found, using firmware-provided SMI buffer.\n");
> diff --git a/drivers/platform/x86/dell/dcdbas.h b/drivers/platform/x86/dell/dcdbas.h
> index c3cca5433525..942a23ddded0 100644
> --- a/drivers/platform/x86/dell/dcdbas.h
> +++ b/drivers/platform/x86/dell/dcdbas.h
> @@ -105,5 +105,14 @@ struct smm_eps_table {
> u64 num_of_4k_pages;
> } __packed;
>
> +struct smi_buffer {
> + u8 *virt;
> + unsigned long size;
> + dma_addr_t dma;
> +};
> +
> +int dcdbas_smi_alloc(struct smi_buffer *smi_buffer, unsigned long size);
> +void dcdbas_smi_free(struct smi_buffer *smi_buffer);
> +
> #endif /* _DCDBAS_H_ */
>
> diff --git a/drivers/platform/x86/dell/dell-smbios-smm.c b/drivers/platform/x86/dell/dell-smbios-smm.c
> index 320c032418ac..4d375985c85f 100644
> --- a/drivers/platform/x86/dell/dell-smbios-smm.c
> +++ b/drivers/platform/x86/dell/dell-smbios-smm.c
> @@ -20,6 +20,7 @@
>
> static int da_command_address;
> static int da_command_code;
> +static struct smi_buffer smi_buf;
> static struct calling_interface_buffer *buffer;
> static struct platform_device *platform_device;
> static DEFINE_MUTEX(smm_mutex);
> @@ -57,7 +58,7 @@ static int dell_smbios_smm_call(struct calling_interface_buffer *input)
> command.magic = SMI_CMD_MAGIC;
> command.command_address = da_command_address;
> command.command_code = da_command_code;
> - command.ebx = virt_to_phys(buffer);
> + command.ebx = smi_buf.dma;
> command.ecx = 0x42534931;
>
> mutex_lock(&smm_mutex);
> @@ -101,9 +102,10 @@ int init_dell_smbios_smm(void)
> * Allocate buffer below 4GB for SMI data--only 32-bit physical addr
> * is passed to SMI handler.
> */
> - buffer = (void *)__get_free_page(GFP_KERNEL | GFP_DMA32);
> - if (!buffer)
> - return -ENOMEM;
> + ret = dcdbas_smi_alloc(&smi_buf, PAGE_SIZE);
> + if (ret)
> + return ret;
> + buffer = (void *)smi_buf.virt;
>
> dmi_walk(find_cmd_address, NULL);
>
> @@ -138,7 +140,7 @@ int init_dell_smbios_smm(void)
>
> fail_wsmt:
> fail_platform_device_alloc:
> - free_page((unsigned long)buffer);
> + dcdbas_smi_free(&smi_buf);
> return ret;
> }
>
> @@ -147,6 +149,6 @@ void exit_dell_smbios_smm(void)
> if (platform_device) {
> dell_smbios_unregister_device(&platform_device->dev);
> platform_device_unregister(platform_device);
> - free_page((unsigned long)buffer);
> + dcdbas_smi_free(&smi_buf);
> }
> }