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Message-ID: <20180211175209.GA20314@roeck-us.net>
Date: Sun, 11 Feb 2018 09:52:09 -0800
From: Guenter Roeck <linux@...ck-us.net>
To: Jerry Hoemann <jerry.hoemann@....com>
Cc: wim@...ux-watchdog.org, linux-watchdog@...r.kernel.org,
linux-kernel@...r.kernel.org, rwright@....com,
maurice.a.saldivar@....com
Subject: Re: [01/10] watchdog/hpwdt: Remove legacy NMI sourcing.
On Tue, Feb 06, 2018 at 03:58:46PM -0700, Jerry Hoemann wrote:
> Gen8 and prior Proliant systems supported the "CRU" interface
> to firmware. This interfaces allows linux to "call back" into firmware
> to source the cause of an NMI. This feature isn't fully utilized
> as the actual source of the NMI isn't printed, the driver only
> indicates that the source couldn't be determined when the call
> fails.
>
> With the advent of Gen9, iCRU replaces the CRU. The call back
> feature is no longer available in firmware. To be compatible and
> not attempt to call back into firmware on system not supporting CRU,
> the SMBIOS table is consulted to determine if it is safe to
> make the call back or not.
>
> This results in about half of the driver code being devoted
> to either making CRU calls or determing if it is safe to make
> CRU calls. As noted, the driver isn't really using the results of
> the CRU calls.
>
> As the CRU sourcing of the NMI isn't required for handling the
> NMI, remove the legacy (pre Gen9) NMI sourcing and the DMI code to
> determine if the system had the CRU interface.
>
> Signed-off-by: Jerry Hoemann <jerry.hoemann@....com>
Reviewed-by: Guenter Roeck <linux@...ck-us.net>
> ---
> drivers/watchdog/hpwdt.c | 485 +----------------------------------------------
> 1 file changed, 3 insertions(+), 482 deletions(-)
>
> diff --git a/drivers/watchdog/hpwdt.c b/drivers/watchdog/hpwdt.c
> index f1f00dfc0e68..01ef52c13209 100644
> --- a/drivers/watchdog/hpwdt.c
> +++ b/drivers/watchdog/hpwdt.c
> @@ -48,6 +48,7 @@
> static unsigned int soft_margin = DEFAULT_MARGIN; /* in seconds */
> static unsigned int reload; /* the computed soft_margin */
> static bool nowayout = WATCHDOG_NOWAYOUT;
> +static unsigned int allow_kdump = 1;
> static char expect_release;
> static unsigned long hpwdt_is_open;
>
> @@ -63,373 +64,6 @@ static const struct pci_device_id hpwdt_devices[] = {
> };
> MODULE_DEVICE_TABLE(pci, hpwdt_devices);
>
> -#ifdef CONFIG_HPWDT_NMI_DECODING
> -#define PCI_BIOS32_SD_VALUE 0x5F32335F /* "_32_" */
> -#define CRU_BIOS_SIGNATURE_VALUE 0x55524324
> -#define PCI_BIOS32_PARAGRAPH_LEN 16
> -#define PCI_ROM_BASE1 0x000F0000
> -#define ROM_SIZE 0x10000
> -
> -struct bios32_service_dir {
> - u32 signature;
> - u32 entry_point;
> - u8 revision;
> - u8 length;
> - u8 checksum;
> - u8 reserved[5];
> -};
> -
> -/* type 212 */
> -struct smbios_cru64_info {
> - u8 type;
> - u8 byte_length;
> - u16 handle;
> - u32 signature;
> - u64 physical_address;
> - u32 double_length;
> - u32 double_offset;
> -};
> -#define SMBIOS_CRU64_INFORMATION 212
> -
> -/* type 219 */
> -struct smbios_proliant_info {
> - u8 type;
> - u8 byte_length;
> - u16 handle;
> - u32 power_features;
> - u32 omega_features;
> - u32 reserved;
> - u32 misc_features;
> -};
> -#define SMBIOS_ICRU_INFORMATION 219
> -
> -
> -struct cmn_registers {
> - union {
> - struct {
> - u8 ral;
> - u8 rah;
> - u16 rea2;
> - };
> - u32 reax;
> - } u1;
> - union {
> - struct {
> - u8 rbl;
> - u8 rbh;
> - u8 reb2l;
> - u8 reb2h;
> - };
> - u32 rebx;
> - } u2;
> - union {
> - struct {
> - u8 rcl;
> - u8 rch;
> - u16 rec2;
> - };
> - u32 recx;
> - } u3;
> - union {
> - struct {
> - u8 rdl;
> - u8 rdh;
> - u16 red2;
> - };
> - u32 redx;
> - } u4;
> -
> - u32 resi;
> - u32 redi;
> - u16 rds;
> - u16 res;
> - u32 reflags;
> -} __attribute__((packed));
> -
> -static unsigned int hpwdt_nmi_decoding;
> -static unsigned int allow_kdump = 1;
> -static unsigned int is_icru;
> -static unsigned int is_uefi;
> -static DEFINE_SPINLOCK(rom_lock);
> -static void *cru_rom_addr;
> -static struct cmn_registers cmn_regs;
> -
> -extern asmlinkage void asminline_call(struct cmn_registers *pi86Regs,
> - unsigned long *pRomEntry);
> -
> -#ifdef CONFIG_X86_32
> -/* --32 Bit Bios------------------------------------------------------------ */
> -
> -#define HPWDT_ARCH 32
> -
> -asm(".text \n\t"
> - ".align 4 \n\t"
> - ".globl asminline_call \n"
> - "asminline_call: \n\t"
> - "pushl %ebp \n\t"
> - "movl %esp, %ebp \n\t"
> - "pusha \n\t"
> - "pushf \n\t"
> - "push %es \n\t"
> - "push %ds \n\t"
> - "pop %es \n\t"
> - "movl 8(%ebp),%eax \n\t"
> - "movl 4(%eax),%ebx \n\t"
> - "movl 8(%eax),%ecx \n\t"
> - "movl 12(%eax),%edx \n\t"
> - "movl 16(%eax),%esi \n\t"
> - "movl 20(%eax),%edi \n\t"
> - "movl (%eax),%eax \n\t"
> - "push %cs \n\t"
> - "call *12(%ebp) \n\t"
> - "pushf \n\t"
> - "pushl %eax \n\t"
> - "movl 8(%ebp),%eax \n\t"
> - "movl %ebx,4(%eax) \n\t"
> - "movl %ecx,8(%eax) \n\t"
> - "movl %edx,12(%eax) \n\t"
> - "movl %esi,16(%eax) \n\t"
> - "movl %edi,20(%eax) \n\t"
> - "movw %ds,24(%eax) \n\t"
> - "movw %es,26(%eax) \n\t"
> - "popl %ebx \n\t"
> - "movl %ebx,(%eax) \n\t"
> - "popl %ebx \n\t"
> - "movl %ebx,28(%eax) \n\t"
> - "pop %es \n\t"
> - "popf \n\t"
> - "popa \n\t"
> - "leave \n\t"
> - "ret \n\t"
> - ".previous");
> -
> -
> -/*
> - * cru_detect
> - *
> - * Routine Description:
> - * This function uses the 32-bit BIOS Service Directory record to
> - * search for a $CRU record.
> - *
> - * Return Value:
> - * 0 : SUCCESS
> - * <0 : FAILURE
> - */
> -static int cru_detect(unsigned long map_entry,
> - unsigned long map_offset)
> -{
> - void *bios32_map;
> - unsigned long *bios32_entrypoint;
> - unsigned long cru_physical_address;
> - unsigned long cru_length;
> - unsigned long physical_bios_base = 0;
> - unsigned long physical_bios_offset = 0;
> - int retval = -ENODEV;
> -
> - bios32_map = ioremap(map_entry, (2 * PAGE_SIZE));
> -
> - if (bios32_map == NULL)
> - return -ENODEV;
> -
> - bios32_entrypoint = bios32_map + map_offset;
> -
> - cmn_regs.u1.reax = CRU_BIOS_SIGNATURE_VALUE;
> -
> - set_memory_x((unsigned long)bios32_map, 2);
> - asminline_call(&cmn_regs, bios32_entrypoint);
> -
> - if (cmn_regs.u1.ral != 0) {
> - pr_warn("Call succeeded but with an error: 0x%x\n",
> - cmn_regs.u1.ral);
> - } else {
> - physical_bios_base = cmn_regs.u2.rebx;
> - physical_bios_offset = cmn_regs.u4.redx;
> - cru_length = cmn_regs.u3.recx;
> - cru_physical_address =
> - physical_bios_base + physical_bios_offset;
> -
> - /* If the values look OK, then map it in. */
> - if ((physical_bios_base + physical_bios_offset)) {
> - cru_rom_addr =
> - ioremap(cru_physical_address, cru_length);
> - if (cru_rom_addr) {
> - set_memory_x((unsigned long)cru_rom_addr & PAGE_MASK,
> - (cru_length + PAGE_SIZE - 1) >> PAGE_SHIFT);
> - retval = 0;
> - }
> - }
> -
> - pr_debug("CRU Base Address: 0x%lx\n", physical_bios_base);
> - pr_debug("CRU Offset Address: 0x%lx\n", physical_bios_offset);
> - pr_debug("CRU Length: 0x%lx\n", cru_length);
> - pr_debug("CRU Mapped Address: %p\n", &cru_rom_addr);
> - }
> - iounmap(bios32_map);
> - return retval;
> -}
> -
> -/*
> - * bios_checksum
> - */
> -static int bios_checksum(const char __iomem *ptr, int len)
> -{
> - char sum = 0;
> - int i;
> -
> - /*
> - * calculate checksum of size bytes. This should add up
> - * to zero if we have a valid header.
> - */
> - for (i = 0; i < len; i++)
> - sum += ptr[i];
> -
> - return ((sum == 0) && (len > 0));
> -}
> -
> -/*
> - * bios32_present
> - *
> - * Routine Description:
> - * This function finds the 32-bit BIOS Service Directory
> - *
> - * Return Value:
> - * 0 : SUCCESS
> - * <0 : FAILURE
> - */
> -static int bios32_present(const char __iomem *p)
> -{
> - struct bios32_service_dir *bios_32_ptr;
> - int length;
> - unsigned long map_entry, map_offset;
> -
> - bios_32_ptr = (struct bios32_service_dir *) p;
> -
> - /*
> - * Search for signature by checking equal to the swizzled value
> - * instead of calling another routine to perform a strcmp.
> - */
> - if (bios_32_ptr->signature == PCI_BIOS32_SD_VALUE) {
> - length = bios_32_ptr->length * PCI_BIOS32_PARAGRAPH_LEN;
> - if (bios_checksum(p, length)) {
> - /*
> - * According to the spec, we're looking for the
> - * first 4KB-aligned address below the entrypoint
> - * listed in the header. The Service Directory code
> - * is guaranteed to occupy no more than 2 4KB pages.
> - */
> - map_entry = bios_32_ptr->entry_point & ~(PAGE_SIZE - 1);
> - map_offset = bios_32_ptr->entry_point - map_entry;
> -
> - return cru_detect(map_entry, map_offset);
> - }
> - }
> - return -ENODEV;
> -}
> -
> -static int detect_cru_service(void)
> -{
> - char __iomem *p, *q;
> - int rc = -1;
> -
> - /*
> - * Search from 0x0f0000 through 0x0fffff, inclusive.
> - */
> - p = ioremap(PCI_ROM_BASE1, ROM_SIZE);
> - if (p == NULL)
> - return -ENOMEM;
> -
> - for (q = p; q < p + ROM_SIZE; q += 16) {
> - rc = bios32_present(q);
> - if (!rc)
> - break;
> - }
> - iounmap(p);
> - return rc;
> -}
> -/* ------------------------------------------------------------------------- */
> -#endif /* CONFIG_X86_32 */
> -#ifdef CONFIG_X86_64
> -/* --64 Bit Bios------------------------------------------------------------ */
> -
> -#define HPWDT_ARCH 64
> -
> -asm(".text \n\t"
> - ".align 4 \n\t"
> - ".globl asminline_call \n\t"
> - ".type asminline_call, @function \n\t"
> - "asminline_call: \n\t"
> - FRAME_BEGIN
> - "pushq %rax \n\t"
> - "pushq %rbx \n\t"
> - "pushq %rdx \n\t"
> - "pushq %r12 \n\t"
> - "pushq %r9 \n\t"
> - "movq %rsi, %r12 \n\t"
> - "movq %rdi, %r9 \n\t"
> - "movl 4(%r9),%ebx \n\t"
> - "movl 8(%r9),%ecx \n\t"
> - "movl 12(%r9),%edx \n\t"
> - "movl 16(%r9),%esi \n\t"
> - "movl 20(%r9),%edi \n\t"
> - "movl (%r9),%eax \n\t"
> - "call *%r12 \n\t"
> - "pushfq \n\t"
> - "popq %r12 \n\t"
> - "movl %eax, (%r9) \n\t"
> - "movl %ebx, 4(%r9) \n\t"
> - "movl %ecx, 8(%r9) \n\t"
> - "movl %edx, 12(%r9) \n\t"
> - "movl %esi, 16(%r9) \n\t"
> - "movl %edi, 20(%r9) \n\t"
> - "movq %r12, %rax \n\t"
> - "movl %eax, 28(%r9) \n\t"
> - "popq %r9 \n\t"
> - "popq %r12 \n\t"
> - "popq %rdx \n\t"
> - "popq %rbx \n\t"
> - "popq %rax \n\t"
> - FRAME_END
> - "ret \n\t"
> - ".previous");
> -
> -/*
> - * dmi_find_cru
> - *
> - * Routine Description:
> - * This function checks whether or not a SMBIOS/DMI record is
> - * the 64bit CRU info or not
> - */
> -static void dmi_find_cru(const struct dmi_header *dm, void *dummy)
> -{
> - struct smbios_cru64_info *smbios_cru64_ptr;
> - unsigned long cru_physical_address;
> -
> - if (dm->type == SMBIOS_CRU64_INFORMATION) {
> - smbios_cru64_ptr = (struct smbios_cru64_info *) dm;
> - if (smbios_cru64_ptr->signature == CRU_BIOS_SIGNATURE_VALUE) {
> - cru_physical_address =
> - smbios_cru64_ptr->physical_address +
> - smbios_cru64_ptr->double_offset;
> - cru_rom_addr = ioremap(cru_physical_address,
> - smbios_cru64_ptr->double_length);
> - set_memory_x((unsigned long)cru_rom_addr & PAGE_MASK,
> - smbios_cru64_ptr->double_length >> PAGE_SHIFT);
> - }
> - }
> -}
> -
> -static int detect_cru_service(void)
> -{
> - cru_rom_addr = NULL;
> -
> - dmi_walk(dmi_find_cru, NULL);
> -
> - /* if cru_rom_addr has been set then we found a CRU service */
> - return ((cru_rom_addr != NULL) ? 0 : -ENODEV);
> -}
> -/* ------------------------------------------------------------------------- */
> -#endif /* CONFIG_X86_64 */
> -#endif /* CONFIG_HPWDT_NMI_DECODING */
>
> /*
> * Watchdog operations
> @@ -486,30 +120,12 @@ static int hpwdt_my_nmi(void)
> */
> static int hpwdt_pretimeout(unsigned int ulReason, struct pt_regs *regs)
> {
> - unsigned long rom_pl;
> - static int die_nmi_called;
> -
> - if (!hpwdt_nmi_decoding)
> - return NMI_DONE;
> -
> if ((ulReason == NMI_UNKNOWN) && !hpwdt_my_nmi())
> return NMI_DONE;
>
> - spin_lock_irqsave(&rom_lock, rom_pl);
> - if (!die_nmi_called && !is_icru && !is_uefi)
> - asminline_call(&cmn_regs, cru_rom_addr);
> - die_nmi_called = 1;
> - spin_unlock_irqrestore(&rom_lock, rom_pl);
> -
> if (allow_kdump)
> hpwdt_stop();
>
> - if (!is_icru && !is_uefi) {
> - if (cmn_regs.u1.ral == 0) {
> - nmi_panic(regs, "An NMI occurred, but unable to determine source.\n");
> - return NMI_HANDLED;
> - }
> - }
> nmi_panic(regs, "An NMI occurred. Depending on your system the reason "
> "for the NMI is logged in any one of the following "
> "resources:\n"
> @@ -675,84 +291,10 @@ static struct miscdevice hpwdt_miscdev = {
> * Init & Exit
> */
>
> -#ifdef CONFIG_HPWDT_NMI_DECODING
> -#ifdef CONFIG_X86_LOCAL_APIC
> -static void hpwdt_check_nmi_decoding(struct pci_dev *dev)
> -{
> - /*
> - * If nmi_watchdog is turned off then we can turn on
> - * our nmi decoding capability.
> - */
> - hpwdt_nmi_decoding = 1;
> -}
> -#else
> -static void hpwdt_check_nmi_decoding(struct pci_dev *dev)
> -{
> - dev_warn(&dev->dev, "NMI decoding is disabled. "
> - "Your kernel does not support a NMI Watchdog.\n");
> -}
> -#endif /* CONFIG_X86_LOCAL_APIC */
> -
> -/*
> - * dmi_find_icru
> - *
> - * Routine Description:
> - * This function checks whether or not we are on an iCRU-based server.
> - * This check is independent of architecture and needs to be made for
> - * any ProLiant system.
> - */
> -static void dmi_find_icru(const struct dmi_header *dm, void *dummy)
> -{
> - struct smbios_proliant_info *smbios_proliant_ptr;
> -
> - if (dm->type == SMBIOS_ICRU_INFORMATION) {
> - smbios_proliant_ptr = (struct smbios_proliant_info *) dm;
> - if (smbios_proliant_ptr->misc_features & 0x01)
> - is_icru = 1;
> - if (smbios_proliant_ptr->misc_features & 0x1400)
> - is_uefi = 1;
> - }
> -}
>
> static int hpwdt_init_nmi_decoding(struct pci_dev *dev)
> {
> int retval;
> -
> - /*
> - * On typical CRU-based systems we need to map that service in
> - * the BIOS. For 32 bit Operating Systems we need to go through
> - * the 32 Bit BIOS Service Directory. For 64 bit Operating
> - * Systems we get that service through SMBIOS.
> - *
> - * On systems that support the new iCRU service all we need to
> - * do is call dmi_walk to get the supported flag value and skip
> - * the old cru detect code.
> - */
> - dmi_walk(dmi_find_icru, NULL);
> - if (!is_icru && !is_uefi) {
> -
> - /*
> - * We need to map the ROM to get the CRU service.
> - * For 32 bit Operating Systems we need to go through the 32 Bit
> - * BIOS Service Directory
> - * For 64 bit Operating Systems we get that service through SMBIOS.
> - */
> - retval = detect_cru_service();
> - if (retval < 0) {
> - dev_warn(&dev->dev,
> - "Unable to detect the %d Bit CRU Service.\n",
> - HPWDT_ARCH);
> - return retval;
> - }
> -
> - /*
> - * We know this is the only CRU call we need to make so lets keep as
> - * few instructions as possible once the NMI comes in.
> - */
> - cmn_regs.u1.rah = 0x0D;
> - cmn_regs.u1.ral = 0x02;
> - }
> -
> /*
> * Only one function can register for NMI_UNKNOWN
> */
> @@ -780,33 +322,17 @@ static int hpwdt_init_nmi_decoding(struct pci_dev *dev)
> dev_warn(&dev->dev,
> "Unable to register a die notifier (err=%d).\n",
> retval);
> - if (cru_rom_addr)
> - iounmap(cru_rom_addr);
> return retval;
> }
>
> static void hpwdt_exit_nmi_decoding(void)
> {
> +#ifdef CONFIG_HPWDT_NMI_DECODING
> unregister_nmi_handler(NMI_UNKNOWN, "hpwdt");
> unregister_nmi_handler(NMI_SERR, "hpwdt");
> unregister_nmi_handler(NMI_IO_CHECK, "hpwdt");
> - if (cru_rom_addr)
> - iounmap(cru_rom_addr);
> +#endif
> }
> -#else /* !CONFIG_HPWDT_NMI_DECODING */
> -static void hpwdt_check_nmi_decoding(struct pci_dev *dev)
> -{
> -}
> -
> -static int hpwdt_init_nmi_decoding(struct pci_dev *dev)
> -{
> - return 0;
> -}
> -
> -static void hpwdt_exit_nmi_decoding(void)
> -{
> -}
> -#endif /* CONFIG_HPWDT_NMI_DECODING */
>
> static int hpwdt_init_one(struct pci_dev *dev,
> const struct pci_device_id *ent)
> @@ -814,11 +340,6 @@ static int hpwdt_init_one(struct pci_dev *dev,
> int retval;
>
> /*
> - * Check if we can do NMI decoding or not
> - */
> - hpwdt_check_nmi_decoding(dev);
> -
> - /*
> * First let's find out if we are on an iLO2+ server. We will
> * not run on a legacy ASM box.
> * So we only support the G5 ProLiant servers and higher.
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