On 9/17/20 5:53 PM, Michal Suchánek wrote:
Hello, On Wed, Sep 16, 2020 at 10:52:27PM +0530, Ganesh Goudar wrote:To test machine check handling, add debugfs interface to inject slb multihit errors. To inject slb multihit: #echo 1 > /sys/kernel/debug/powerpc/mce_error_inject/inject_slb_multihit Signed-off-by: Ganesh Goudar <ganes...@linux.ibm.com> Signed-off-by: Mahesh Salgaonkar <mah...@linux.vnet.ibm.com> --- arch/powerpc/Kconfig.debug | 9 ++ arch/powerpc/sysdev/Makefile | 2 + arch/powerpc/sysdev/mce_error_inject.c | 148 +++++++++++++++++++++++++ 3 files changed, 159 insertions(+) create mode 100644 arch/powerpc/sysdev/mce_error_inject.c diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug index b88900f4832f..61db133f2f0d 100644 --- a/arch/powerpc/Kconfig.debug +++ b/arch/powerpc/Kconfig.debug @@ -398,3 +398,12 @@ config KASAN_SHADOW_OFFSET hex depends on KASAN default 0xe0000000 + +config MCE_ERROR_INJECT + bool "Enable MCE error injection through debugfs" + depends on DEBUG_FS + default y + help + This option creates an mce_error_inject directory in the + powerpc debugfs directory that allows limited injection of + Machine Check Errors (MCEs). diff --git a/arch/powerpc/sysdev/Makefile b/arch/powerpc/sysdev/Makefile index 026b3f01a991..7fc102222b77 100644 --- a/arch/powerpc/sysdev/Makefile +++ b/arch/powerpc/sysdev/Makefile @@ -52,3 +52,5 @@ obj-$(CONFIG_PPC_XICS) += xics/ obj-$(CONFIG_PPC_XIVE) += xive/obj-$(CONFIG_GE_FPGA) += ge/+ +obj-$(CONFIG_MCE_ERROR_INJECT) += mce_error_inject.o diff --git a/arch/powerpc/sysdev/mce_error_inject.c b/arch/powerpc/sysdev/mce_error_inject.c new file mode 100644 index 000000000000..ca4726bfa2d9 --- /dev/null +++ b/arch/powerpc/sysdev/mce_error_inject.c @@ -0,0 +1,148 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Machine Check Exception injection code + */ + +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/vmalloc.h> +#include <linux/fs.h> +#include <linux/debugfs.h> +#include <asm/debugfs.h> + +static inline unsigned long get_slb_index(void) +{ + unsigned long index; + + index = get_paca()->stab_rr; + + /* + * simple round-robin replacement of slb starting at SLB_NUM_BOLTED. + */ + if (index < (mmu_slb_size - 1)) + index++; + else + index = SLB_NUM_BOLTED; + get_paca()->stab_rr = index; + return index; +} + +#define slb_esid_mask(ssize) \ + (((ssize) == MMU_SEGSIZE_256M) ? ESID_MASK : ESID_MASK_1T) + +static inline unsigned long mk_esid_data(unsigned long ea, int ssize, + unsigned long slot) +{ + return (ea & slb_esid_mask(ssize)) | SLB_ESID_V | slot; +} + +#define slb_vsid_shift(ssize) \ + ((ssize) == MMU_SEGSIZE_256M ? SLB_VSID_SHIFT : SLB_VSID_SHIFT_1T) + +static inline unsigned long mk_vsid_data(unsigned long ea, int ssize, + unsigned long flags) +{ + return (get_kernel_vsid(ea, ssize) << slb_vsid_shift(ssize)) | flags | + ((unsigned long)ssize << SLB_VSID_SSIZE_SHIFT); +} + +static void insert_slb_entry(char *p, int ssize) +{ + unsigned long flags, entry; + struct paca_struct *paca; + + flags = SLB_VSID_KERNEL | mmu_psize_defs[MMU_PAGE_64K].sllp; + + preempt_disable(); + + paca = get_paca();This seems unused?
Thanks, ill remove it.
+ + entry = get_slb_index(); + asm volatile("slbmte %0,%1" : + : "r" (mk_vsid_data((unsigned long)p, ssize, flags)), + "r" (mk_esid_data((unsigned long)p, ssize, entry)) + : "memory"); + + entry = get_slb_index(); + asm volatile("slbmte %0,%1" : + : "r" (mk_vsid_data((unsigned long)p, ssize, flags)), + "r" (mk_esid_data((unsigned long)p, ssize, entry)) + : "memory"); + preempt_enable(); + p[0] = '!'; +} + +static void inject_vmalloc_slb_multihit(void) +{ + char *p; + + p = vmalloc(2048); + if (!p) + return; + + insert_slb_entry(p, MMU_SEGSIZE_1T); + vfree(p); +} + +static void inject_kmalloc_slb_multihit(void) +{ + char *p; + + p = kmalloc(2048, GFP_KERNEL); + if (!p) + return; + + insert_slb_entry(p, MMU_SEGSIZE_1T); + kfree(p); +} + +static ssize_t inject_slb_multihit(const char __user *u_buf, size_t count) +{ + char buf[32]; + size_t buf_size; + + buf_size = min(count, (sizeof(buf) - 1)); + if (copy_from_user(buf, u_buf, buf_size)) + return -EFAULT; + buf[buf_size] = '\0'; + + if (buf[0] != '1') + return -EINVAL; + + inject_vmalloc_slb_multihit(); + inject_kmalloc_slb_multihit();This is missing the test of multihit in paca which is for some reason special.
I will add it, Thanks
Thanks Michal+ return count; +} + +static ssize_t inject_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + static ssize_t (*func)(const char __user *, size_t); + + func = file->f_inode->i_private; + return func(buf, count); +} + +static const struct file_operations inject_fops = { + .write = inject_write, + .llseek = default_llseek, +}; + +static int mce_error_inject_setup(void) +{ + struct dentry *mce_error_inject_dir; + + mce_error_inject_dir = debugfs_create_dir("mce_error_inject", + powerpc_debugfs_root); + + if (mmu_has_feature(MMU_FTR_HPTE_TABLE)) { + (void)debugfs_create_file("inject_slb_multihit", 0200, + mce_error_inject_dir, + &inject_slb_multihit, + &inject_fops); + } + + return 0; +} + +device_initcall(mce_error_inject_setup); -- 2.26.2
