lkml.org 
[lkml]   [2018]   [May]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Subject[PATCH v3 9/9] x86, nfit_test: unit test for memcpy_mcsafe()
    From
    Date
    Given the fact that the ACPI "EINJ" (error injection) facility is not
    universally available, implement software infrastructure to validate the
    memcpy_mcsafe() exception handling implementation.

    For each potential read exception point in memcpy_mcsafe(), inject a
    emulated exception point at the address identified by 'mcsafe_inject'
    variable. With this infrastructure implement a test to validate that the
    'bytes remaining' calculation is correct for a range of various source
    buffer alignments.

    This code is compiled out by default. The CONFIG_MCSAFE_DEBUG
    configuration symbol needs to be manually enabled by editing
    Kconfig.debug. I.e. this functionality can not be accidentally enabled
    by a user / distro, it's only for development.

    Cc: <x86@kernel.org>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: Tony Luck <tony.luck@intel.com>
    Cc: Al Viro <viro@zeniv.linux.org.uk>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: Andy Lutomirski <luto@amacapital.net>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Andrew Morton <akpm@linux-foundation.org>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Reported-by: Tony Luck <tony.luck@intel.com>
    Signed-off-by: Dan Williams <dan.j.williams@intel.com>
    ---
    arch/x86/Kconfig.debug | 3 +
    arch/x86/include/asm/mcsafe_test.h | 75 ++++++++++++++++++++++++++
    arch/x86/lib/memcpy_64.S | 10 +++
    tools/testing/nvdimm/test/nfit.c | 104 ++++++++++++++++++++++++++++++++++++
    4 files changed, 192 insertions(+)
    create mode 100644 arch/x86/include/asm/mcsafe_test.h

    diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
    index 192e4d2f9efc..c6dd1d980081 100644
    --- a/arch/x86/Kconfig.debug
    +++ b/arch/x86/Kconfig.debug
    @@ -72,6 +72,9 @@ config EARLY_PRINTK_USB_XDBC
    You should normally say N here, unless you want to debug early
    crashes or need a very simple printk logging facility.

    +config MCSAFE_TEST
    + def_bool n
    +
    config X86_PTDUMP_CORE
    def_bool n

    diff --git a/arch/x86/include/asm/mcsafe_test.h b/arch/x86/include/asm/mcsafe_test.h
    new file mode 100644
    index 000000000000..eb59804b6201
    --- /dev/null
    +++ b/arch/x86/include/asm/mcsafe_test.h
    @@ -0,0 +1,75 @@
    +/* SPDX-License-Identifier: GPL-2.0 */
    +#ifndef _MCSAFE_TEST_H_
    +#define _MCSAFE_TEST_H_
    +
    +#ifndef __ASSEMBLY__
    +#ifdef CONFIG_MCSAFE_TEST
    +extern unsigned long mcsafe_test_src;
    +extern unsigned long mcsafe_test_dst;
    +
    +static inline void mcsafe_inject_src(void *addr)
    +{
    + if (addr)
    + mcsafe_test_src = (unsigned long) addr;
    + else
    + mcsafe_test_src = ~0UL;
    +}
    +
    +static inline void mcsafe_inject_dst(void *addr)
    +{
    + if (addr)
    + mcsafe_test_dst = (unsigned long) addr;
    + else
    + mcsafe_test_dst = ~0UL;
    +}
    +#else /* CONFIG_MCSAFE_TEST */
    +static inline void mcsafe_inject_src(void *addr)
    +{
    +}
    +
    +static inline void mcsafe_inject_dst(void *addr)
    +{
    +}
    +#endif /* CONFIG_MCSAFE_TEST */
    +
    +#else /* __ASSEMBLY__ */
    +#include <asm/export.h>
    +
    +#ifdef CONFIG_MCSAFE_TEST
    +.macro MCSAFE_TEST_CTL
    + .pushsection .data
    + .align 8
    + .globl mcsafe_test_src
    + mcsafe_test_src:
    + .quad 0
    + EXPORT_SYMBOL_GPL(mcsafe_test_src)
    + .globl mcsafe_test_dst
    + mcsafe_test_dst:
    + .quad 0
    + EXPORT_SYMBOL_GPL(mcsafe_test_dst)
    + .popsection
    +.endm
    +
    +.macro MCSAFE_TEST_SRC reg count target
    + leaq \count(\reg), %r9
    + cmp mcsafe_test_src, %r9
    + ja \target
    +.endm
    +
    +.macro MCSAFE_TEST_DST reg count target
    + leaq \count(\reg), %r9
    + cmp mcsafe_test_dst, %r9
    + ja \target
    +.endm
    +#else
    +.macro MCSAFE_TEST_CTL
    +.endm
    +
    +.macro MCSAFE_TEST_SRC reg count target
    +.endm
    +
    +.macro MCSAFE_TEST_DST reg count target
    +.endm
    +#endif /* CONFIG_MCSAFE_TEST */
    +#endif /* __ASSEMBLY__ */
    +#endif /* _MCSAFE_TEST_H_ */
    diff --git a/arch/x86/lib/memcpy_64.S b/arch/x86/lib/memcpy_64.S
    index c3b527a9f95d..298ef1479240 100644
    --- a/arch/x86/lib/memcpy_64.S
    +++ b/arch/x86/lib/memcpy_64.S
    @@ -3,6 +3,7 @@
    #include <linux/linkage.h>
    #include <asm/errno.h>
    #include <asm/cpufeatures.h>
    +#include <asm/mcsafe_test.h>
    #include <asm/alternative-asm.h>
    #include <asm/export.h>

    @@ -183,6 +184,9 @@ ENTRY(memcpy_orig)
    ENDPROC(memcpy_orig)

    #ifndef CONFIG_UML
    +
    +MCSAFE_TEST_CTL
    +
    /*
    * __memcpy_mcsafe - memory copy with machine check exception handling
    * Note that we only catch machine checks when reading the source addresses.
    @@ -206,6 +210,8 @@ ENTRY(__memcpy_mcsafe)
    subl %ecx, %edx
    .L_read_leading_bytes:
    movb (%rsi), %al
    + MCSAFE_TEST_SRC %rsi 1 .E_leading_bytes
    + MCSAFE_TEST_DST %rdi 1 .E_leading_bytes
    .L_write_leading_bytes:
    movb %al, (%rdi)
    incq %rsi
    @@ -221,6 +227,8 @@ ENTRY(__memcpy_mcsafe)

    .L_read_words:
    movq (%rsi), %r8
    + MCSAFE_TEST_SRC %rsi 8 .E_read_words
    + MCSAFE_TEST_DST %rdi 8 .E_write_words
    .L_write_words:
    movq %r8, (%rdi)
    addq $8, %rsi
    @@ -237,6 +245,8 @@ ENTRY(__memcpy_mcsafe)
    movl %edx, %ecx
    .L_read_trailing_bytes:
    movb (%rsi), %al
    + MCSAFE_TEST_SRC %rsi 1 .E_trailing_bytes
    + MCSAFE_TEST_DST %rdi 1 .E_trailing_bytes
    .L_write_trailing_bytes:
    movb %al, (%rdi)
    incq %rsi
    diff --git a/tools/testing/nvdimm/test/nfit.c b/tools/testing/nvdimm/test/nfit.c
    index 4ea385be528f..a8fb63edcf89 100644
    --- a/tools/testing/nvdimm/test/nfit.c
    +++ b/tools/testing/nvdimm/test/nfit.c
    @@ -29,6 +29,8 @@
    #include "nfit_test.h"
    #include "../watermark.h"

    +#include <asm/mcsafe_test.h>
    +
    /*
    * Generate an NFIT table to describe the following topology:
    *
    @@ -2681,6 +2683,107 @@ static struct platform_driver nfit_test_driver = {
    .id_table = nfit_test_id,
    };

    +static char mcsafe_buf[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
    +
    +enum INJECT {
    + INJECT_NONE,
    + INJECT_SRC,
    + INJECT_DST,
    +};
    +
    +static void mcsafe_test_init(char *dst, char *src, size_t size)
    +{
    + size_t i;
    +
    + memset(dst, 0xff, size);
    + for (i = 0; i < size; i++)
    + src[i] = (char) i;
    +}
    +
    +static bool mcsafe_test_validate(unsigned char *dst, unsigned char *src,
    + size_t size, unsigned long rem)
    +{
    + size_t i;
    +
    + for (i = 0; i < size - rem; i++)
    + if (dst[i] != (unsigned char) i) {
    + pr_info_once("%s:%d: offset: %zd got: %#x expect: %#x\n",
    + __func__, __LINE__, i, dst[i],
    + (unsigned char) i);
    + return false;
    + }
    + for (i = size - rem; i < size; i++)
    + if (dst[i] != 0xffU) {
    + pr_info_once("%s:%d: offset: %zd got: %#x expect: 0xff\n",
    + __func__, __LINE__, i, dst[i]);
    + return false;
    + }
    + return true;
    +}
    +
    +void mcsafe_test(void)
    +{
    + char *inject_desc[] = { "none", "source", "destination" };
    + enum INJECT inj;
    +
    + if (IS_ENABLED(CONFIG_MCSAFE_TEST)) {
    + pr_info("%s: run...\n", __func__);
    + } else {
    + pr_info("%s: disabled, skip.\n", __func__);
    + return;
    + }
    +
    + for (inj = INJECT_NONE; inj <= INJECT_DST; inj++) {
    + int i;
    +
    + pr_info("%s: inject: %s\n", __func__, inject_desc[inj]);
    + for (i = 0; i < 512; i++) {
    + unsigned long expect, rem;
    + void *src, *dst;
    + bool valid;
    +
    + switch (inj) {
    + case INJECT_NONE:
    + mcsafe_inject_src(NULL);
    + mcsafe_inject_dst(NULL);
    + dst = &mcsafe_buf[2048];
    + src = &mcsafe_buf[1024 - i];
    + expect = 0;
    + break;
    + case INJECT_SRC:
    + mcsafe_inject_src(&mcsafe_buf[1024]);
    + mcsafe_inject_dst(NULL);
    + dst = &mcsafe_buf[2048];
    + src = &mcsafe_buf[1024 - i];
    + expect = 512 - i;
    + break;
    + case INJECT_DST:
    + mcsafe_inject_src(NULL);
    + mcsafe_inject_dst(&mcsafe_buf[2048]);
    + dst = &mcsafe_buf[2048 - i];
    + src = &mcsafe_buf[1024];
    + expect = 512 - i;
    + break;
    + }
    +
    + mcsafe_test_init(dst, src, 512);
    + rem = __memcpy_mcsafe(dst, src, 512);
    + valid = mcsafe_test_validate(dst, src, 512, expect);
    + if (rem == expect && valid)
    + continue;
    + pr_info("%s: copy(%#lx, %#lx, %d) off: %d rem: %ld %s expect: %ld\n",
    + __func__,
    + ((unsigned long) dst) & ~PAGE_MASK,
    + ((unsigned long ) src) & ~PAGE_MASK,
    + 512, i, rem, valid ? "valid" : "bad",
    + expect);
    + }
    + }
    +
    + mcsafe_inject_src(NULL);
    + mcsafe_inject_dst(NULL);
    +}
    +
    static __init int nfit_test_init(void)
    {
    int rc, i;
    @@ -2689,6 +2792,7 @@ static __init int nfit_test_init(void)
    libnvdimm_test();
    acpi_nfit_test();
    device_dax_test();
    + mcsafe_test();

    nfit_test_setup(nfit_test_lookup, nfit_test_evaluate_dsm);

    \
     
     \ /
      Last update: 2018-05-04 02:17    [W:3.289 / U:0.408 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site