[Crash-utility] [PATCH v5] arm64: update the modules/vmalloc/vmemmap ranges
HAGIO KAZUHITO(萩尾 一仁)
k-hagio-ab at nec.com
Thu Mar 3 02:42:49 UTC 2022
Hi Huang Shijie,
-----Original Message-----
> v4 --> v5:
> 1.) Reset ms->struct_page_size to 0 if arm64_get_va_range() fails,
> so arm64_calc_virtual_memory_ranges() can continue its work.
>
> 2.) Tested again with the new code.
>
> v3 --> v4:
> 1.) Add struct_page_size to @ms.
> Change some functions, such as arm64_init() and arm64_get_struct_page_size().
> (Do not use the ASSIGN_SIZE, use the ms->struct_page_size instead.)
>
> 2.) Tested again with the new code.
Thank you for the update.
> + LINUX(6,0,0), /* Just a boundary, Change it later */
one thing, this is not so far and I'd like LINUX(99,0,0) or so as no limit.
But you don't need to update the patch only for this, we can change it
when merging.
Otherwise, the source code looks good to me and was cleanly built with
"make target=ARM64" on an x86_64 machine. For this patch itself:
Acked-by: Kazuhito Hagio <k-hagio-ab at nec.com>
btw, is it possible to update the arm64_calc_virtual_memory_ranges() for
dumpfiles without vmcoreinfo? e.g. ramdumps.
Thanks,
Kazu
> v2 --> v3:
> Fount two bugs in arm64_get_range_v5_17/arm64_get_range_v5_11:
> We should use the ms->CONFIG_ARM64_VA_BITS to calculate the
> vmemmep_vaddr, not use the ms->VA_BITS.
>
> v1 --> v2:
> The Crash code is based on v4.20 not v4.9.
> Changed the commit message about it.
> ---
> arm64.c | 375 ++++++++++++++++++++++++++++++++++++++++++++++++++++++--
> defs.h | 1 +
> 2 files changed, 365 insertions(+), 11 deletions(-)
>
> diff --git a/arm64.c b/arm64.c
> index 3ab8489..94203f0 100644
> --- a/arm64.c
> +++ b/arm64.c
> @@ -92,6 +92,14 @@ static void arm64_calc_VA_BITS(void);
> static int arm64_is_uvaddr(ulong, struct task_context *);
> static void arm64_calc_KERNELPACMASK(void);
>
> +struct kernel_range {
> + unsigned long modules_vaddr, modules_end;
> + unsigned long vmalloc_start_addr, vmalloc_end;
> + unsigned long vmemmap_vaddr, vmemmap_end;
> +};
> +static struct kernel_range *arm64_get_va_range(struct machine_specific *ms);
> +static void arm64_get_struct_page_size(struct machine_specific *ms);
> +
> static void arm64_calc_kernel_start(void)
> {
> struct machine_specific *ms = machdep->machspec;
> @@ -233,9 +241,10 @@ arm64_init(int when)
> machdep->pageoffset = machdep->pagesize - 1;
> machdep->pagemask = ~((ulonglong)machdep->pageoffset);
>
> + ms = machdep->machspec;
> + arm64_get_struct_page_size(ms);
> arm64_calc_VA_BITS();
> arm64_calc_KERNELPACMASK();
> - ms = machdep->machspec;
>
> /* vabits_actual introduced after mm flip, so it should be flipped layout */
> if (ms->VA_BITS_ACTUAL) {
> @@ -252,8 +261,15 @@ arm64_init(int when)
> }
> machdep->is_kvaddr = generic_is_kvaddr;
> machdep->kvtop = arm64_kvtop;
> +
> + /* The defaults */
> + ms->vmalloc_end = ARM64_VMALLOC_END;
> + ms->vmemmap_vaddr = ARM64_VMEMMAP_VADDR;
> + ms->vmemmap_end = ARM64_VMEMMAP_END;
> +
> if (machdep->flags & NEW_VMEMMAP) {
> struct syment *sp;
> + struct kernel_range *r;
>
> /* It is finally decided in arm64_calc_kernel_start() */
> sp = kernel_symbol_search("_text");
> @@ -261,27 +277,32 @@ arm64_init(int when)
> sp = kernel_symbol_search("_end");
> ms->kimage_end = (sp ? sp->value : 0);
>
> - if (ms->VA_BITS_ACTUAL) {
> + if (ms->struct_page_size && (r = arm64_get_va_range(ms))) {
> + /* We can get all the MODULES/VMALLOC/VMEMMAP ranges now.*/
> + ms->modules_vaddr = r->modules_vaddr;
> + ms->modules_end = r->modules_end;
> + ms->vmalloc_start_addr = r->vmalloc_start_addr;
> + ms->vmalloc_end = r->vmalloc_end;
> + ms->vmemmap_vaddr = r->vmemmap_vaddr;
> + ms->vmemmap_end = r->vmemmap_end;
> + } else if (ms->VA_BITS_ACTUAL) {
> ms->modules_vaddr = (st->_stext_vmlinux & TEXT_OFFSET_MASK) -
> ARM64_MODULES_VSIZE;
> ms->modules_end = ms->modules_vaddr + ARM64_MODULES_VSIZE -1;
> + ms->vmalloc_start_addr = ms->modules_end + 1;
> } else {
> ms->modules_vaddr = ARM64_VA_START;
> if (kernel_symbol_exists("kasan_init"))
> ms->modules_vaddr += ARM64_KASAN_SHADOW_SIZE;
> ms->modules_end = ms->modules_vaddr + ARM64_MODULES_VSIZE -1;
> + ms->vmalloc_start_addr = ms->modules_end + 1;
> }
>
> - ms->vmalloc_start_addr = ms->modules_end + 1;
> -
> arm64_calc_kimage_voffset();
> } else {
> ms->modules_vaddr = ARM64_PAGE_OFFSET - MEGABYTES(64);
> ms->modules_end = ARM64_PAGE_OFFSET - 1;
> ms->vmalloc_start_addr = ARM64_VA_START;
> }
> - ms->vmalloc_end = ARM64_VMALLOC_END;
> - ms->vmemmap_vaddr = ARM64_VMEMMAP_VADDR;
> - ms->vmemmap_end = ARM64_VMEMMAP_END;
>
> switch (machdep->pagesize)
> {
> @@ -404,7 +425,12 @@ arm64_init(int when)
> case POST_GDB:
> /* Rely on kernel version to decide the kernel start address */
> arm64_calc_kernel_start();
> - arm64_calc_virtual_memory_ranges();
> +
> + /* Can we get the size of struct page before POST_GDB */
> + ms = machdep->machspec;
> + if (!ms->struct_page_size)
> + arm64_calc_virtual_memory_ranges();
> +
> arm64_get_section_size_bits();
>
> if (!machdep->max_physmem_bits) {
> @@ -419,8 +445,6 @@ arm64_init(int when)
> machdep->max_physmem_bits = _MAX_PHYSMEM_BITS;
> }
>
> - ms = machdep->machspec;
> -
> if (CRASHDEBUG(1)) {
> if (ms->VA_BITS_ACTUAL) {
> fprintf(fp, "CONFIG_ARM64_VA_BITS: %ld\n", ms->CONFIG_ARM64_VA_BITS);
> @@ -511,6 +535,336 @@ arm64_init(int when)
> }
> }
>
> +struct kernel_va_range_handler {
> + unsigned long kernel_versions_start; /* include */
> + unsigned long kernel_versions_end; /* exclude */
> + struct kernel_range *(*get_range)(struct machine_specific *);
> +};
> +
> +static struct kernel_range tmp_range;
> +#define _PAGE_END(va) (-(1UL << ((va) - 1)))
> +#define SZ_64K 0x00010000
> +#define SZ_2M 0x00200000
> +
> +/*
> + * Get the max shift of the size of struct page.
> + * Most of the time, it is 64 bytes, but not sure.
> + */
> +static int arm64_get_struct_page_max_shift(struct machine_specific *ms)
> +{
> + unsigned long v = ms->struct_page_size;
> +
> + if (16 < v && v <= 32)
> + return 5;
> + if (32 < v && v <= 64)
> + return 6;
> + if (64 < v && v <= 128)
> + return 7;
> +
> + error(FATAL, "We should not have such struct page size:%d!\n", v);
> + return 0;
> +}
> +
> +/*
> + * The change is caused by the kernel patch since v5.17-rc1:
> + * "b89ddf4cca43 arm64/bpf: Remove 128MB limit for BPF JIT programs"
> + */
> +static struct kernel_range *arm64_get_range_v5_17(struct machine_specific *ms)
> +{
> + struct kernel_range *r = &tmp_range;
> + unsigned long v = ms->CONFIG_ARM64_VA_BITS;
> + unsigned long vmem_shift, vmemmap_size;
> +
> + /* Not initialized yet */
> + if (v == 0)
> + return NULL;
> +
> + if (v > 48)
> + v = 48;
> +
> + /* Get the MODULES_VADDR ~ MODULES_END */
> + r->modules_vaddr = _PAGE_END(v);
> + r->modules_end = r->modules_vaddr + MEGABYTES(128);
> +
> + /* Get the VMEMMAP_START ~ VMEMMAP_END */
> + vmem_shift = machdep->pageshift - arm64_get_struct_page_max_shift(ms);
> + vmemmap_size = (_PAGE_END(v) - PAGE_OFFSET) >> vmem_shift;
> +
> + r->vmemmap_vaddr = (-(1UL << (ms->CONFIG_ARM64_VA_BITS - vmem_shift)));
> + r->vmemmap_end = r->vmemmap_vaddr + vmemmap_size;
> +
> + /* Get the VMALLOC_START ~ VMALLOC_END */
> + r->vmalloc_start_addr = r->modules_end;
> + r->vmalloc_end = r->vmemmap_vaddr - MEGABYTES(256);
> + return r;
> +}
> +
> +/*
> + * The change is caused by the kernel patch since v5.11:
> + * "9ad7c6d5e75b arm64: mm: tidy up top of kernel VA space"
> + */
> +static struct kernel_range *arm64_get_range_v5_11(struct machine_specific *ms)
> +{
> + struct kernel_range *r = &tmp_range;
> + unsigned long v = ms->CONFIG_ARM64_VA_BITS;
> + unsigned long vmem_shift, vmemmap_size, bpf_jit_size = MEGABYTES(128);
> +
> + /* Not initialized yet */
> + if (v == 0)
> + return NULL;
> +
> + if (v > 48)
> + v = 48;
> +
> + /* Get the MODULES_VADDR ~ MODULES_END */
> + r->modules_vaddr = _PAGE_END(v) + bpf_jit_size;
> + r->modules_end = r->modules_vaddr + MEGABYTES(128);
> +
> + /* Get the VMEMMAP_START ~ VMEMMAP_END */
> + vmem_shift = machdep->pageshift - arm64_get_struct_page_max_shift(ms);
> + vmemmap_size = (_PAGE_END(v) - PAGE_OFFSET) >> vmem_shift;
> +
> + r->vmemmap_vaddr = (-(1UL << (ms->CONFIG_ARM64_VA_BITS - vmem_shift)));
> + r->vmemmap_end = r->vmemmap_vaddr + vmemmap_size;
> +
> + /* Get the VMALLOC_START ~ VMALLOC_END */
> + r->vmalloc_start_addr = r->modules_end;
> + r->vmalloc_end = r->vmemmap_vaddr - MEGABYTES(256);
> + return r;
> +}
> +
> +static unsigned long arm64_get_pud_size(void)
> +{
> + unsigned long PUD_SIZE = 0;
> +
> + switch (machdep->pagesize) {
> + case 4096:
> + if (machdep->machspec->VA_BITS > PGDIR_SHIFT_L4_4K) {
> + PUD_SIZE = PUD_SIZE_L4_4K;
> + } else {
> + PUD_SIZE = PGDIR_SIZE_L3_4K;
> + }
> + break;
> +
> + case 65536:
> + PUD_SIZE = PGDIR_SIZE_L2_64K;
> + default:
> + break;
> + }
> + return PUD_SIZE;
> +}
> +
> +/*
> + * The change is caused by the kernel patches since v5.4, such as:
> + * "ce3aaed87344 arm64: mm: Modify calculation of VMEMMAP_SIZE"
> + * "14c127c957c1 arm64: mm: Flip kernel VA space"
> + */
> +static struct kernel_range *arm64_get_range_v5_4(struct machine_specific *ms)
> +{
> + struct kernel_range *r = &tmp_range;
> + unsigned long v = ms->CONFIG_ARM64_VA_BITS;
> + unsigned long kasan_shadow_shift, kasan_shadow_offset, PUD_SIZE;
> + unsigned long vmem_shift, vmemmap_size, bpf_jit_size = MEGABYTES(128);
> + char *string;
> + int ret;
> +
> + /* Not initialized yet */
> + if (v == 0)
> + return NULL;
> +
> + if (v > 48)
> + v = 48;
> +
> + /* Get the MODULES_VADDR ~ MODULES_END */
> + if (kernel_symbol_exists("kasan_init")) {
> + /* See the arch/arm64/Makefile */
> + ret = get_kernel_config("CONFIG_KASAN_SW_TAGS", NULL);
> + if (ret == IKCONFIG_N)
> + return NULL;
> + kasan_shadow_shift = (ret == IKCONFIG_Y) ? 4: 3;
> +
> + /* See the arch/arm64/Kconfig*/
> + ret = get_kernel_config("CONFIG_KASAN_SHADOW_OFFSET", &string);
> + if (ret != IKCONFIG_STR)
> + return NULL;
> + kasan_shadow_offset = atol(string);
> +
> + r->modules_vaddr = (1UL << (64 - kasan_shadow_shift)) + kasan_shadow_offset
> + + bpf_jit_size;
> + } else {
> + r->modules_vaddr = _PAGE_END(v) + bpf_jit_size;
> + }
> +
> + r->modules_end = r->modules_vaddr + MEGABYTES(128);
> +
> + /* Get the VMEMMAP_START ~ VMEMMAP_END */
> + vmem_shift = machdep->pageshift - arm64_get_struct_page_max_shift(ms);
> + vmemmap_size = (_PAGE_END(v) - PAGE_OFFSET) >> vmem_shift;
> +
> + r->vmemmap_vaddr = (-vmemmap_size - SZ_2M);
> + if (THIS_KERNEL_VERSION >= LINUX(5, 7, 0)) {
> + /*
> + * In the v5.7, the patch: "bbd6ec605c arm64/mm: Enable memory hot remove"
> + * adds the VMEMMAP_END.
> + */
> + r->vmemmap_end = r->vmemmap_vaddr + vmemmap_size;
> + } else {
> + r->vmemmap_end = 0xffffffffffffffffUL;
> + }
> +
> + /* Get the VMALLOC_START ~ VMALLOC_END */
> + PUD_SIZE = arm64_get_pud_size();
> + r->vmalloc_start_addr = r->modules_end;
> + r->vmalloc_end = (-PUD_SIZE - vmemmap_size - SZ_64K);
> + return r;
> +}
> +
> +/*
> + * The change is caused by the kernel patches since v5.0, such as:
> + * "91fc957c9b1d arm64/bpf: don't allocate BPF JIT programs in module memory"
> + */
> +static struct kernel_range *arm64_get_range_v5_0(struct machine_specific *ms)
> +{
> + struct kernel_range *r = &tmp_range;
> + unsigned long v = ms->CONFIG_ARM64_VA_BITS;
> + unsigned long kasan_shadow_shift, PUD_SIZE;
> + unsigned long vmemmap_size, bpf_jit_size = MEGABYTES(128);
> + unsigned long va_start, page_offset;
> + int ret;
> +
> + /* Not initialized yet */
> + if (v == 0)
> + return NULL;
> +
> + va_start = (0xffffffffffffffffUL - (1UL << v) + 1);
> + page_offset = (0xffffffffffffffffUL - (1UL << (v - 1)) + 1);
> +
> + /* Get the MODULES_VADDR ~ MODULES_END */
> + if (kernel_symbol_exists("kasan_init")) {
> + /* See the arch/arm64/Makefile */
> + ret = get_kernel_config("CONFIG_KASAN_SW_TAGS", NULL);
> + if (ret == IKCONFIG_N)
> + return NULL;
> + kasan_shadow_shift = (ret == IKCONFIG_Y) ? 4: 3;
> +
> + r->modules_vaddr = va_start + (1UL << (v - kasan_shadow_shift)) + bpf_jit_size;
> + } else {
> + r->modules_vaddr = va_start + bpf_jit_size;
> + }
> +
> + r->modules_end = r->modules_vaddr + MEGABYTES(128);
> +
> + /* Get the VMEMMAP_START ~ VMEMMAP_END */
> + vmemmap_size = (1UL << (v - machdep->pageshift - 1 + arm64_get_struct_page_max_shift(ms)));
> +
> + r->vmemmap_vaddr = page_offset - vmemmap_size;
> + r->vmemmap_end = 0xffffffffffffffffUL; /* this kernel does not have VMEMMAP_END */
> +
> + /* Get the VMALLOC_START ~ VMALLOC_END */
> + PUD_SIZE = arm64_get_pud_size();
> +
> + r->vmalloc_start_addr = r->modules_end;
> + r->vmalloc_end = page_offset - PUD_SIZE - vmemmap_size - SZ_64K;
> + return r;
> +}
> +
> +static struct kernel_va_range_handler kernel_va_range_handlers[] = {
> + {
> + LINUX(5,17,0),
> + LINUX(6,0,0), /* Just a boundary, Change it later */
> + get_range: arm64_get_range_v5_17,
> + }, {
> + LINUX(5,11,0), LINUX(5,17,0),
> + get_range: arm64_get_range_v5_11,
> + }, {
> + LINUX(5,4,0), LINUX(5,11,0),
> + get_range: arm64_get_range_v5_4,
> + }, {
> + LINUX(5,0,0), LINUX(5,4,0),
> + get_range: arm64_get_range_v5_0,
> + },
> +};
> +
> +#define ARRAY_SIZE(a) (sizeof (a) / sizeof ((a)[0]))
> +
> +static unsigned long arm64_get_kernel_version(void)
> +{
> + char *string;
> + char buf[BUFSIZE];
> + char *p1, *p2;
> +
> + if (THIS_KERNEL_VERSION)
> + return THIS_KERNEL_VERSION;
> +
> + string = pc->read_vmcoreinfo("OSRELEASE");
> + if (string) {
> + strcpy(buf, string);
> +
> + p1 = p2 = buf;
> + while (*p2 != '.')
> + p2++;
> + *p2 = NULLCHAR;
> + kt->kernel_version[0] = atoi(p1);
> +
> + p1 = ++p2;
> + while (*p2 != '.')
> + p2++;
> + *p2 = NULLCHAR;
> + kt->kernel_version[1] = atoi(p1);
> +
> + p1 = ++p2;
> + while ((*p2 >= '0') && (*p2 <= '9'))
> + p2++;
> + *p2 = NULLCHAR;
> + kt->kernel_version[2] = atoi(p1);
> + }
> + free(string);
> + return THIS_KERNEL_VERSION;
> +}
> +
> +/* Return NULL if we fail. */
> +static struct kernel_range *arm64_get_va_range(struct machine_specific *ms)
> +{
> + struct kernel_va_range_handler *h;
> + unsigned long kernel_version = arm64_get_kernel_version();
> + struct kernel_range *r = NULL;
> + int i;
> +
> + if (!kernel_version)
> + goto range_failed;
> +
> + for (i = 0; i < ARRAY_SIZE(kernel_va_range_handlers); i++) {
> + h = kernel_va_range_handlers + i;
> +
> + /* Get the right hook for this kernel version */
> + if (h->kernel_versions_start <= kernel_version &&
> + kernel_version < h->kernel_versions_end) {
> +
> + /* Get the correct virtual address ranges */
> + r = h->get_range(ms);
> + if (!r)
> + goto range_failed;
> + return r;
> + }
> + }
> +
> +range_failed:
> + /* Reset ms->struct_page_size to 0 for arm64_calc_virtual_memory_ranges() */
> + ms->struct_page_size = 0;
> + return NULL;
> +}
> +
> +/* Get the size of struct page {} */
> +static void arm64_get_struct_page_size(struct machine_specific *ms)
> +{
> + char *string;
> +
> + string = pc->read_vmcoreinfo("SIZE(page)");
> + if (string)
> + ms->struct_page_size = atol(string);
> + free(string);
> +}
> +
> /*
> * Accept or reject a symbol from the kernel namelist.
> */
> @@ -4272,7 +4626,6 @@ arm64_calc_VA_BITS(void)
> #define ALIGN(x, a) __ALIGN_KERNEL((x), (a))
> #define __ALIGN_KERNEL(x, a) __ALIGN_KERNEL_MASK(x, (typeof(x))(a) - 1)
> #define __ALIGN_KERNEL_MASK(x, mask) (((x) + (mask)) & ~(mask))
> -#define SZ_64K 0x00010000
>
> static void
> arm64_calc_virtual_memory_ranges(void)
> diff --git a/defs.h b/defs.h
> index bf2c59b..81ac049 100644
> --- a/defs.h
> +++ b/defs.h
> @@ -3386,6 +3386,7 @@ struct machine_specific {
> ulong VA_START;
> ulong CONFIG_ARM64_KERNELPACMASK;
> ulong physvirt_offset;
> + ulong struct_page_size;
> };
>
> struct arm64_stackframe {
> --
> 2.30.2
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