[RFC] powerpc/pseries: delete scanlog
Tyrel Datwyler
tyreld at linux.ibm.com
Tue May 4 06:38:23 AEST 2021
On 5/3/21 10:18 AM, Nathan Lynch wrote:
> A commit from 2008 says this driver was relevant only for "older
> systems", and currently supported hardware doesn't have this
> facility. Get rid of it.
The only references I could find to scan log dump support are several Power 4+
systems, in particular the IntelliStation POWER 9114 and pSeries 615, which were
released in 2003 at the same time this code was originally introduced.
Historical Linux commit form February 2003:
https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/?id=f92e361842d5251e50562b09664082dcbd0548bb
IntelliStation and pSeries docs:
http://ps-2.retropc.se/basil.holloway/ALL%20PDF/380635.pdf
http://ps-2.kev009.com/rs6000/manuals/p/p615-6C3-6E3/6C3_and_6E3_Users_Guide_SA38-0629.pdf
Current firmware RTAS implementations have no reference to ibm,scan-log-dump,
and a long standing developer for that code has no recollection of its existence.
This appears to be a straggler from RPA and Power 4 days. Based on my
understanding that we dropped support Power 4 in mainline this looks pretty
orphaned to me and a solid candidate for removal barring and insight from
someone else that knows better.
+1
Feel free to add my RB tag to any non-RFC followup.
Reviewed-by: Tyrel Datwyler <tyreld at linux.ibm.com>
>
> Signed-off-by: Nathan Lynch <nathanl at linux.ibm.com>
> ---
> arch/powerpc/configs/ppc64_defconfig | 1 -
> arch/powerpc/configs/pseries_defconfig | 1 -
> arch/powerpc/platforms/pseries/Kconfig | 4 -
> arch/powerpc/platforms/pseries/Makefile | 1 -
> arch/powerpc/platforms/pseries/scanlog.c | 195 -----------------------
> 5 files changed, 202 deletions(-)
> delete mode 100644 arch/powerpc/platforms/pseries/scanlog.c
>
> diff --git a/arch/powerpc/configs/ppc64_defconfig b/arch/powerpc/configs/ppc64_defconfig
> index 701811c91a6f..acf13b4917c4 100644
> --- a/arch/powerpc/configs/ppc64_defconfig
> +++ b/arch/powerpc/configs/ppc64_defconfig
> @@ -26,7 +26,6 @@ CONFIG_PPC64=y
> CONFIG_NR_CPUS=2048
> CONFIG_PPC_SPLPAR=y
> CONFIG_DTL=y
> -CONFIG_SCANLOG=m
> CONFIG_PPC_SMLPAR=y
> CONFIG_IBMEBUS=y
> CONFIG_PPC_SVM=y
> diff --git a/arch/powerpc/configs/pseries_defconfig b/arch/powerpc/configs/pseries_defconfig
> index 50168dde4ea5..d120321e4eea 100644
> --- a/arch/powerpc/configs/pseries_defconfig
> +++ b/arch/powerpc/configs/pseries_defconfig
> @@ -38,7 +38,6 @@ CONFIG_MODULE_SRCVERSION_ALL=y
> CONFIG_PARTITION_ADVANCED=y
> CONFIG_PPC_SPLPAR=y
> CONFIG_DTL=y
> -CONFIG_SCANLOG=m
> CONFIG_PPC_SMLPAR=y
> CONFIG_IBMEBUS=y
> CONFIG_PAPR_SCM=m
> diff --git a/arch/powerpc/platforms/pseries/Kconfig b/arch/powerpc/platforms/pseries/Kconfig
> index 5e037df2a3a1..bf9b612a929b 100644
> --- a/arch/powerpc/platforms/pseries/Kconfig
> +++ b/arch/powerpc/platforms/pseries/Kconfig
> @@ -61,10 +61,6 @@ config PSERIES_ENERGY
> Provides: /sys/devices/system/cpu/pseries_(de)activation_hint_list
> and /sys/devices/system/cpu/cpuN/pseries_(de)activation_hint
>
> -config SCANLOG
> - tristate "Scanlog dump interface"
> - depends on RTAS_PROC && PPC_PSERIES
> -
> config IO_EVENT_IRQ
> bool "IO Event Interrupt support"
> depends on PPC_PSERIES
> diff --git a/arch/powerpc/platforms/pseries/Makefile b/arch/powerpc/platforms/pseries/Makefile
> index c8a2b0b05ac0..754d1102de08 100644
> --- a/arch/powerpc/platforms/pseries/Makefile
> +++ b/arch/powerpc/platforms/pseries/Makefile
> @@ -8,7 +8,6 @@ obj-y := lpar.o hvCall.o nvram.o reconfig.o \
> firmware.o power.o dlpar.o mobility.o rng.o \
> pci.o pci_dlpar.o eeh_pseries.o msi.o
> obj-$(CONFIG_SMP) += smp.o
> -obj-$(CONFIG_SCANLOG) += scanlog.o
> obj-$(CONFIG_KEXEC_CORE) += kexec.o
> obj-$(CONFIG_PSERIES_ENERGY) += pseries_energy.o
>
> diff --git a/arch/powerpc/platforms/pseries/scanlog.c b/arch/powerpc/platforms/pseries/scanlog.c
> deleted file mode 100644
> index 2879c4f0ceb7..000000000000
> --- a/arch/powerpc/platforms/pseries/scanlog.c
> +++ /dev/null
> @@ -1,195 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0-or-later
> -/*
> - * c 2001 PPC 64 Team, IBM Corp
> - *
> - * scan-log-data driver for PPC64 Todd Inglett <tinglett at vnet.ibm.com>
> - *
> - * When ppc64 hardware fails the service processor dumps internal state
> - * of the system. After a reboot the operating system can access a dump
> - * of this data using this driver. A dump exists if the device-tree
> - * /chosen/ibm,scan-log-data property exists.
> - *
> - * This driver exports /proc/powerpc/scan-log-dump which can be read.
> - * The driver supports only sequential reads.
> - *
> - * The driver looks at a write to the driver for the single word "reset".
> - * If given, the driver will reset the scanlog so the platform can free it.
> - */
> -
> -#include <linux/module.h>
> -#include <linux/types.h>
> -#include <linux/errno.h>
> -#include <linux/proc_fs.h>
> -#include <linux/init.h>
> -#include <linux/delay.h>
> -#include <linux/slab.h>
> -#include <linux/uaccess.h>
> -#include <asm/rtas.h>
> -#include <asm/prom.h>
> -
> -#define MODULE_VERS "1.0"
> -#define MODULE_NAME "scanlog"
> -
> -/* Status returns from ibm,scan-log-dump */
> -#define SCANLOG_COMPLETE 0
> -#define SCANLOG_HWERROR -1
> -#define SCANLOG_CONTINUE 1
> -
> -
> -static unsigned int ibm_scan_log_dump; /* RTAS token */
> -static unsigned int *scanlog_buffer; /* The data buffer */
> -
> -static ssize_t scanlog_read(struct file *file, char __user *buf,
> - size_t count, loff_t *ppos)
> -{
> - unsigned int *data = scanlog_buffer;
> - int status;
> - unsigned long len, off;
> - unsigned int wait_time;
> -
> - if (count > RTAS_DATA_BUF_SIZE)
> - count = RTAS_DATA_BUF_SIZE;
> -
> - if (count < 1024) {
> - /* This is the min supported by this RTAS call. Rather
> - * than do all the buffering we insist the user code handle
> - * larger reads. As long as cp works... :)
> - */
> - printk(KERN_ERR "scanlog: cannot perform a small read (%ld)\n", count);
> - return -EINVAL;
> - }
> -
> - if (!access_ok(buf, count))
> - return -EFAULT;
> -
> - for (;;) {
> - wait_time = 500; /* default wait if no data */
> - spin_lock(&rtas_data_buf_lock);
> - memcpy(rtas_data_buf, data, RTAS_DATA_BUF_SIZE);
> - status = rtas_call(ibm_scan_log_dump, 2, 1, NULL,
> - (u32) __pa(rtas_data_buf), (u32) count);
> - memcpy(data, rtas_data_buf, RTAS_DATA_BUF_SIZE);
> - spin_unlock(&rtas_data_buf_lock);
> -
> - pr_debug("scanlog: status=%d, data[0]=%x, data[1]=%x, " \
> - "data[2]=%x\n", status, data[0], data[1], data[2]);
> - switch (status) {
> - case SCANLOG_COMPLETE:
> - pr_debug("scanlog: hit eof\n");
> - return 0;
> - case SCANLOG_HWERROR:
> - pr_debug("scanlog: hardware error reading data\n");
> - return -EIO;
> - case SCANLOG_CONTINUE:
> - /* We may or may not have data yet */
> - len = data[1];
> - off = data[2];
> - if (len > 0) {
> - if (copy_to_user(buf, ((char *)data)+off, len))
> - return -EFAULT;
> - return len;
> - }
> - /* Break to sleep default time */
> - break;
> - default:
> - /* Assume extended busy */
> - wait_time = rtas_busy_delay_time(status);
> - if (!wait_time) {
> - printk(KERN_ERR "scanlog: unknown error " \
> - "from rtas: %d\n", status);
> - return -EIO;
> - }
> - }
> - /* Apparently no data yet. Wait and try again. */
> - msleep_interruptible(wait_time);
> - }
> - /*NOTREACHED*/
> -}
> -
> -static ssize_t scanlog_write(struct file * file, const char __user * buf,
> - size_t count, loff_t *ppos)
> -{
> - char stkbuf[20];
> - int status;
> -
> - if (count > 19) count = 19;
> - if (copy_from_user (stkbuf, buf, count)) {
> - return -EFAULT;
> - }
> - stkbuf[count] = 0;
> -
> - if (buf) {
> - if (strncmp(stkbuf, "reset", 5) == 0) {
> - pr_debug("scanlog: reset scanlog\n");
> - status = rtas_call(ibm_scan_log_dump, 2, 1, NULL, 0, 0);
> - pr_debug("scanlog: rtas returns %d\n", status);
> - }
> - }
> - return count;
> -}
> -
> -static int scanlog_open(struct inode * inode, struct file * file)
> -{
> - unsigned int *data = scanlog_buffer;
> -
> - if (data[0] != 0) {
> - /* This imperfect test stops a second copy of the
> - * data (or a reset while data is being copied)
> - */
> - return -EBUSY;
> - }
> -
> - data[0] = 0; /* re-init so we restart the scan */
> -
> - return 0;
> -}
> -
> -static int scanlog_release(struct inode * inode, struct file * file)
> -{
> - unsigned int *data = scanlog_buffer;
> -
> - data[0] = 0;
> - return 0;
> -}
> -
> -static const struct proc_ops scanlog_proc_ops = {
> - .proc_read = scanlog_read,
> - .proc_write = scanlog_write,
> - .proc_open = scanlog_open,
> - .proc_release = scanlog_release,
> - .proc_lseek = noop_llseek,
> -};
> -
> -static int __init scanlog_init(void)
> -{
> - struct proc_dir_entry *ent;
> - int err = -ENOMEM;
> -
> - ibm_scan_log_dump = rtas_token("ibm,scan-log-dump");
> - if (ibm_scan_log_dump == RTAS_UNKNOWN_SERVICE)
> - return -ENODEV;
> -
> - /* Ideally we could allocate a buffer < 4G */
> - scanlog_buffer = kzalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL);
> - if (!scanlog_buffer)
> - goto err;
> -
> - ent = proc_create("powerpc/rtas/scan-log-dump", 0400, NULL,
> - &scanlog_proc_ops);
> - if (!ent)
> - goto err;
> - return 0;
> -err:
> - kfree(scanlog_buffer);
> - return err;
> -}
> -
> -static void __exit scanlog_cleanup(void)
> -{
> - remove_proc_entry("powerpc/rtas/scan-log-dump", NULL);
> - kfree(scanlog_buffer);
> -}
> -
> -module_init(scanlog_init);
> -module_exit(scanlog_cleanup);
> -MODULE_LICENSE("GPL");
>
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