| Message ID | 3b881313-d96c-0395-05f3-dd612b7e440f@gmail.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Delegated to: | Andy Shevchenko |
| Headers | show |
On Thu, Jun 14, 2018 at 6:45 PM, Stuart Hayes <stuart.w.hayes@gmail.com> wrote: > > If the WSMT ACPI table is present and indicates that a fixed communication > buffer should be used, use the firmware-specified buffer instead of > allocating a buffer in memory for communications between the dcdbas driver > and firmare. Thanks for an update. I answered to previous thread. The questions / comments are still applicable here. > Signed-off-by: Stuart Hayes <stuart.w.hayes@gmail.com> > --- > v2 Bumped driver version to 5.6.0-3.3 > v3 Removed dependency on ACPI in Kconfig > Moved the added #include to be in alphabetical order > Added comments in smi_request_store() > Simplified checksum code > Changed loop searching 0xf0000 to be more readable > Reworked calculation of remap_size & smi_data_buf_size > v4 Fixed comment that starts with "Calling Interface SMI" > Fixed formatting of first "if" statement in dcdbas_check_wsmt() > > > drivers/firmware/dcdbas.c | 118 +++++++++++++++++++++++++++++++++++++++++++--- > drivers/firmware/dcdbas.h | 10 ++++ > 2 files changed, 122 insertions(+), 6 deletions(-) > > diff --git a/drivers/firmware/dcdbas.c b/drivers/firmware/dcdbas.c > index 0bdea60c65dd..4cac70d05bfc 100644 > --- a/drivers/firmware/dcdbas.c > +++ b/drivers/firmware/dcdbas.c > @@ -21,6 +21,7 @@ > */ > > #include <linux/platform_device.h> > +#include <linux/acpi.h> > #include <linux/dma-mapping.h> > #include <linux/errno.h> > #include <linux/cpu.h> > @@ -41,7 +42,7 @@ > #include "dcdbas.h" > > #define DRIVER_NAME "dcdbas" > -#define DRIVER_VERSION "5.6.0-3.2" > +#define DRIVER_VERSION "5.6.0-3.3" > #define DRIVER_DESCRIPTION "Dell Systems Management Base Driver" > > static struct platform_device *dcdbas_pdev; > @@ -49,19 +50,23 @@ 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 *eps_buffer; > > static unsigned int host_control_action; > static unsigned int host_control_smi_type; > static unsigned int host_control_on_shutdown; > > +static bool wsmt_enabled; > + > /** > * smi_data_buf_free: free SMI data buffer > */ > static void smi_data_buf_free(void) > { > - if (!smi_data_buf) > + if (!smi_data_buf || wsmt_enabled) > return; > > dev_dbg(&dcdbas_pdev->dev, "%s: phys: %x size: %lu\n", > @@ -86,7 +91,7 @@ static int smi_data_buf_realloc(unsigned long size) > if (smi_data_buf_size >= size) > return 0; > > - if (size > MAX_SMI_DATA_BUF_SIZE) > + if (size > max_smi_data_buf_size) > return -EINVAL; > > /* new buffer is needed */ > @@ -169,7 +174,7 @@ static ssize_t smi_data_write(struct file *filp, struct kobject *kobj, > { > ssize_t ret; > > - if ((pos + count) > MAX_SMI_DATA_BUF_SIZE) > + if ((pos + count) > max_smi_data_buf_size) > return -EINVAL; > > mutex_lock(&smi_data_lock); > @@ -322,8 +327,15 @@ static ssize_t smi_request_store(struct device *dev, > ret = count; > break; > case 1: > - /* Calling Interface SMI */ > - smi_cmd->ebx = (u32) virt_to_phys(smi_cmd->command_buffer); > + /* > + * Calling Interface SMI > + * > + * Provide physical address of command buffer field within > + * the struct smi_cmd... can't use virt_to_phys() on smi_cmd > + * because address may be from memremap(). > + */ > + smi_cmd->ebx = smi_data_buf_phys_addr + > + offsetof(struct smi_cmd, command_buffer); > ret = dcdbas_smi_request(smi_cmd); > if (!ret) > ret = count; > @@ -482,6 +494,93 @@ static void dcdbas_host_control(void) > } > } > > +/* WSMT */ > + > +static u8 checksum(u8 *buffer, u8 length) > +{ > + u8 sum = 0; > + u8 *end = buffer + length; > + > + while (buffer < end) > + sum += *buffer++; > + return sum; > +} > + > +static inline struct smm_eps_table *check_eps_table(u8 *addr) > +{ > + struct smm_eps_table *eps = (struct smm_eps_table *)addr; > + > + if (strncmp(eps->smm_comm_buff_anchor, SMM_EPS_SIG, 4) != 0) > + return NULL; > + > + if (checksum(addr, eps->length) != 0) > + return NULL; > + > + return eps; > +} > + > +static int dcdbas_check_wsmt(void) > +{ > + struct acpi_table_wsmt *wsmt = NULL; > + struct smm_eps_table *eps = NULL; > + u64 remap_size; > + u8 *addr; > + > + acpi_get_table(ACPI_SIG_WSMT, 0, (struct acpi_table_header **)&wsmt); > + if (!wsmt) > + return 0; > + > + /* Check if WSMT ACPI table shows that protection is enabled */ > + if (!(wsmt->protection_flags & ACPI_WSMT_FIXED_COMM_BUFFERS) || > + !(wsmt->protection_flags & ACPI_WSMT_COMM_BUFFER_NESTED_PTR_PROTECTION)) > + return 0; > + > + /* Scan for EPS (entry point structure) */ > + for (addr = (u8 *)__va(0xf0000); > + addr < (u8 *)__va(0x100000 - sizeof(struct smm_eps_table)); > + addr += 1) { > + eps = check_eps_table(addr); > + if (eps) > + break; > + } > + > + if (!eps) { > + dev_dbg(&dcdbas_pdev->dev, "found WSMT, but no EPS found\n"); > + return -ENODEV; > + } > + > + /* > + * Get physical address of buffer and map to virtual address. > + * Table gives size in 4K pages, regardless of actual system page size. > + */ > + if (upper_32_bits(eps->smm_comm_buff_addr + 8)) { > + dev_warn(&dcdbas_pdev->dev, "found WSMT, but EPS buffer address is above 4GB\n"); > + return -EINVAL; > + } > + /* > + * Limit remap size to MAX_SMI_DATA_BUF_SIZE + 8 (since the first 8 > + * bytes are used for a semaphore, not the data buffer itself). > + */ > + remap_size = eps->num_of_4k_pages * PAGE_SIZE; > + if (remap_size > MAX_SMI_DATA_BUF_SIZE + 8) > + remap_size = MAX_SMI_DATA_BUF_SIZE + 8; > + eps_buffer = memremap(eps->smm_comm_buff_addr, remap_size, MEMREMAP_WB); > + if (!eps_buffer) { > + dev_warn(&dcdbas_pdev->dev, "found WSMT, but failed to map EPS buffer\n"); > + return -ENOMEM; > + } > + > + /* First 8 bytes is for a semaphore, not part of the smi_data_buf */ > + smi_data_buf_phys_addr = eps->smm_comm_buff_addr + 8; > + smi_data_buf = eps_buffer + 8; > + smi_data_buf_size = remap_size - 8; > + max_smi_data_buf_size = smi_data_buf_size; > + wsmt_enabled = true; > + dev_info(&dcdbas_pdev->dev, > + "WSMT found, using firmware-provided SMI buffer.\n"); > + return 1; > +} > + > /** > * dcdbas_reboot_notify: handle reboot notification for host control > */ > @@ -548,6 +647,11 @@ static int dcdbas_probe(struct platform_device *dev) > > dcdbas_pdev = dev; > > + /* Check if ACPI WSMT table specifies protected SMI buffer address */ > + error = dcdbas_check_wsmt(); > + if (error < 0) > + return error; > + > /* > * BIOS SMI calls require buffer addresses be in 32-bit address space. > * This is done by setting the DMA mask below. > @@ -635,6 +739,8 @@ static void __exit dcdbas_exit(void) > */ > if (dcdbas_pdev) > smi_data_buf_free(); > + if (eps_buffer) > + memunmap(eps_buffer); > platform_device_unregister(dcdbas_pdev_reg); > platform_driver_unregister(&dcdbas_driver); > } > diff --git a/drivers/firmware/dcdbas.h b/drivers/firmware/dcdbas.h > index ca3cb0a54ab6..52729a494b00 100644 > --- a/drivers/firmware/dcdbas.h > +++ b/drivers/firmware/dcdbas.h > @@ -53,6 +53,7 @@ > #define EXPIRED_TIMER (0) > > #define SMI_CMD_MAGIC (0x534D4931) > +#define SMM_EPS_SIG "$SCB" > > #define DCDBAS_DEV_ATTR_RW(_name) \ > DEVICE_ATTR(_name,0600,_name##_show,_name##_store); > @@ -103,5 +104,14 @@ struct apm_cmd { > > int dcdbas_smi_request(struct smi_cmd *smi_cmd); > > +struct smm_eps_table { > + char smm_comm_buff_anchor[4]; > + u8 length; > + u8 checksum; > + u8 version; > + u64 smm_comm_buff_addr; > + u64 num_of_4k_pages; > +} __packed; > + > #endif /* _DCDBAS_H_ */ > > -- > 2.14.2 >
On 6/14/2018 12:26 PM, Andy Shevchenko wrote: > On Thu, Jun 14, 2018 at 6:45 PM, Stuart Hayes <stuart.w.hayes@gmail.com> wrote: >> >> If the WSMT ACPI table is present and indicates that a fixed communication >> buffer should be used, use the firmware-specified buffer instead of >> allocating a buffer in memory for communications between the dcdbas driver >> and firmare. > > Thanks for an update. > > I answered to previous thread. The questions / comments are still > applicable here. > I answered your questions in the previous thread (a while back). Please let me know if there are any more concerns with this. Thanks!
diff --git a/drivers/firmware/dcdbas.c b/drivers/firmware/dcdbas.c index 0bdea60c65dd..4cac70d05bfc 100644 --- a/drivers/firmware/dcdbas.c +++ b/drivers/firmware/dcdbas.c @@ -21,6 +21,7 @@ */ #include <linux/platform_device.h> +#include <linux/acpi.h> #include <linux/dma-mapping.h> #include <linux/errno.h> #include <linux/cpu.h> @@ -41,7 +42,7 @@ #include "dcdbas.h" #define DRIVER_NAME "dcdbas" -#define DRIVER_VERSION "5.6.0-3.2" +#define DRIVER_VERSION "5.6.0-3.3" #define DRIVER_DESCRIPTION "Dell Systems Management Base Driver" static struct platform_device *dcdbas_pdev; @@ -49,19 +50,23 @@ 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 *eps_buffer; static unsigned int host_control_action; static unsigned int host_control_smi_type; static unsigned int host_control_on_shutdown; +static bool wsmt_enabled; + /** * smi_data_buf_free: free SMI data buffer */ static void smi_data_buf_free(void) { - if (!smi_data_buf) + if (!smi_data_buf || wsmt_enabled) return; dev_dbg(&dcdbas_pdev->dev, "%s: phys: %x size: %lu\n", @@ -86,7 +91,7 @@ static int smi_data_buf_realloc(unsigned long size) if (smi_data_buf_size >= size) return 0; - if (size > MAX_SMI_DATA_BUF_SIZE) + if (size > max_smi_data_buf_size) return -EINVAL; /* new buffer is needed */ @@ -169,7 +174,7 @@ static ssize_t smi_data_write(struct file *filp, struct kobject *kobj, { ssize_t ret; - if ((pos + count) > MAX_SMI_DATA_BUF_SIZE) + if ((pos + count) > max_smi_data_buf_size) return -EINVAL; mutex_lock(&smi_data_lock); @@ -322,8 +327,15 @@ static ssize_t smi_request_store(struct device *dev, ret = count; break; case 1: - /* Calling Interface SMI */ - smi_cmd->ebx = (u32) virt_to_phys(smi_cmd->command_buffer); + /* + * Calling Interface SMI + * + * Provide physical address of command buffer field within + * the struct smi_cmd... can't use virt_to_phys() on smi_cmd + * because address may be from memremap(). + */ + smi_cmd->ebx = smi_data_buf_phys_addr + + offsetof(struct smi_cmd, command_buffer); ret = dcdbas_smi_request(smi_cmd); if (!ret) ret = count; @@ -482,6 +494,93 @@ static void dcdbas_host_control(void) } } +/* WSMT */ + +static u8 checksum(u8 *buffer, u8 length) +{ + u8 sum = 0; + u8 *end = buffer + length; + + while (buffer < end) + sum += *buffer++; + return sum; +} + +static inline struct smm_eps_table *check_eps_table(u8 *addr) +{ + struct smm_eps_table *eps = (struct smm_eps_table *)addr; + + if (strncmp(eps->smm_comm_buff_anchor, SMM_EPS_SIG, 4) != 0) + return NULL; + + if (checksum(addr, eps->length) != 0) + return NULL; + + return eps; +} + +static int dcdbas_check_wsmt(void) +{ + struct acpi_table_wsmt *wsmt = NULL; + struct smm_eps_table *eps = NULL; + u64 remap_size; + u8 *addr; + + acpi_get_table(ACPI_SIG_WSMT, 0, (struct acpi_table_header **)&wsmt); + if (!wsmt) + return 0; + + /* Check if WSMT ACPI table shows that protection is enabled */ + if (!(wsmt->protection_flags & ACPI_WSMT_FIXED_COMM_BUFFERS) || + !(wsmt->protection_flags & ACPI_WSMT_COMM_BUFFER_NESTED_PTR_PROTECTION)) + return 0; + + /* Scan for EPS (entry point structure) */ + for (addr = (u8 *)__va(0xf0000); + addr < (u8 *)__va(0x100000 - sizeof(struct smm_eps_table)); + addr += 1) { + eps = check_eps_table(addr); + if (eps) + break; + } + + if (!eps) { + dev_dbg(&dcdbas_pdev->dev, "found WSMT, but no EPS found\n"); + return -ENODEV; + } + + /* + * Get physical address of buffer and map to virtual address. + * Table gives size in 4K pages, regardless of actual system page size. + */ + if (upper_32_bits(eps->smm_comm_buff_addr + 8)) { + dev_warn(&dcdbas_pdev->dev, "found WSMT, but EPS buffer address is above 4GB\n"); + return -EINVAL; + } + /* + * Limit remap size to MAX_SMI_DATA_BUF_SIZE + 8 (since the first 8 + * bytes are used for a semaphore, not the data buffer itself). + */ + remap_size = eps->num_of_4k_pages * PAGE_SIZE; + if (remap_size > MAX_SMI_DATA_BUF_SIZE + 8) + remap_size = MAX_SMI_DATA_BUF_SIZE + 8; + eps_buffer = memremap(eps->smm_comm_buff_addr, remap_size, MEMREMAP_WB); + if (!eps_buffer) { + dev_warn(&dcdbas_pdev->dev, "found WSMT, but failed to map EPS buffer\n"); + return -ENOMEM; + } + + /* First 8 bytes is for a semaphore, not part of the smi_data_buf */ + smi_data_buf_phys_addr = eps->smm_comm_buff_addr + 8; + smi_data_buf = eps_buffer + 8; + smi_data_buf_size = remap_size - 8; + max_smi_data_buf_size = smi_data_buf_size; + wsmt_enabled = true; + dev_info(&dcdbas_pdev->dev, + "WSMT found, using firmware-provided SMI buffer.\n"); + return 1; +} + /** * dcdbas_reboot_notify: handle reboot notification for host control */ @@ -548,6 +647,11 @@ static int dcdbas_probe(struct platform_device *dev) dcdbas_pdev = dev; + /* Check if ACPI WSMT table specifies protected SMI buffer address */ + error = dcdbas_check_wsmt(); + if (error < 0) + return error; + /* * BIOS SMI calls require buffer addresses be in 32-bit address space. * This is done by setting the DMA mask below. @@ -635,6 +739,8 @@ static void __exit dcdbas_exit(void) */ if (dcdbas_pdev) smi_data_buf_free(); + if (eps_buffer) + memunmap(eps_buffer); platform_device_unregister(dcdbas_pdev_reg); platform_driver_unregister(&dcdbas_driver); } diff --git a/drivers/firmware/dcdbas.h b/drivers/firmware/dcdbas.h index ca3cb0a54ab6..52729a494b00 100644 --- a/drivers/firmware/dcdbas.h +++ b/drivers/firmware/dcdbas.h @@ -53,6 +53,7 @@ #define EXPIRED_TIMER (0) #define SMI_CMD_MAGIC (0x534D4931) +#define SMM_EPS_SIG "$SCB" #define DCDBAS_DEV_ATTR_RW(_name) \ DEVICE_ATTR(_name,0600,_name##_show,_name##_store); @@ -103,5 +104,14 @@ struct apm_cmd { int dcdbas_smi_request(struct smi_cmd *smi_cmd); +struct smm_eps_table { + char smm_comm_buff_anchor[4]; + u8 length; + u8 checksum; + u8 version; + u64 smm_comm_buff_addr; + u64 num_of_4k_pages; +} __packed; + #endif /* _DCDBAS_H_ */
If the WSMT ACPI table is present and indicates that a fixed communication buffer should be used, use the firmware-specified buffer instead of allocating a buffer in memory for communications between the dcdbas driver and firmare. Signed-off-by: Stuart Hayes <stuart.w.hayes@gmail.com> --- v2 Bumped driver version to 5.6.0-3.3 v3 Removed dependency on ACPI in Kconfig Moved the added #include to be in alphabetical order Added comments in smi_request_store() Simplified checksum code Changed loop searching 0xf0000 to be more readable Reworked calculation of remap_size & smi_data_buf_size v4 Fixed comment that starts with "Calling Interface SMI" Fixed formatting of first "if" statement in dcdbas_check_wsmt() drivers/firmware/dcdbas.c | 118 +++++++++++++++++++++++++++++++++++++++++++--- drivers/firmware/dcdbas.h | 10 ++++ 2 files changed, 122 insertions(+), 6 deletions(-)