[Crash-utility] Re: [PATCH] arm64: fix the determination of vmemmap and struct_page_size

Date: Sun, 28 Jul 2024 14:21:58 -0000 From: qiwu.chen(a)transsion.com Subject: [Crash-utility] [PATCH] arm64: fix the determination of vmemmap and struct_page_size To: devel(a)lists.crash-utility.osci.io Message-ID: <20240728142158.17290.96096(a)lists.crash-utility.osci.io&gt; Content-Type: text/plain; charset="utf-8" Currently, the vmemmap ptr addr is determined by the vmcoreinfo of "SYMBOL(vmemmap)", which leads to an invalid vmemmap addr showed by "help -m" for dump files without the vmcoreinfo. The value of vmemmap_end is simply set to -1 for available VA_BITS_ACTUAL case in arm64_calc_virtual_memory_ranges(), and the struct_page_size value is 0. crash> help -m |grep vmem vmemmap_vaddr: fffffffeffe00000 vmemmap_end: ffffffffffffffff vmemmap: 0000000000000000 crash> help -m |grep struct_page_size struct_page_size: 0 Introduce arm64_get_vmemmap_page_ptr() to fix the determination of vmemmap ptr addr, and fix the determination of vmemmap_end and struct_page_size in arm64_calc_virtual_memory_ranges(). crash> help -m |grep vmem vmemmap_vaddr: fffffffeffe00000 vmemmap_end: ffffffffffe00000 vmemmap: fffffffefee00000 crash> help -m |grep struct_page_size struct_page_size: 64

Signed-off-by: qiwu.chen <qiwu.chen(a)qq.com&gt; --- arm64.c | 29 +++++++++++++++++++++++------ 1 file changed, 23 insertions(+), 6 deletions(-) diff --git a/arm64.c b/arm64.c index 78e6609..ef495ec 100644 --- a/arm64.c +++ b/arm64.c @@ -159,7 +159,6 @@ arm64_vmemmap_is_page_ptr(ulong addr, physaddr_t *phys) ulong size = SIZE(page); ulong pfn, nr; - if (IS_SPARSEMEM() && (machdep->flags & VMEMMAP) && (addr >= VMEMMAP_VADDR && addr <= VMEMMAP_END) && !((addr - VMEMMAP_VADDR) % size)) { @@ -175,6 +174,25 @@ arm64_vmemmap_is_page_ptr(ulong addr, physaddr_t *phys) return FALSE; } +static void arm64_get_vmemmap_page_ptr(void) +{ + struct machine_specific *ms = machdep->machspec; + + /* If vmemmap exists, it means kernel enabled CONFIG_SPARSEMEM_VMEMMAP */ + if (arm64_get_vmcoreinfo(&ms->vmemmap, "SYMBOL(vmemmap)", NUM_HEX)) + goto out; + + /* The global symbol of vmemmap is removed since kernel commit 7bc1a0f9e1765 */ + if (!kernel_symbol_exists("vmemmap")) + ms->vmemmap = ms->vmemmap_vaddr - ((ms->phys_offset >> machdep->pageshift) * ms->struct_page_size); + else + ms->vmemmap = symbol_value("vmemmap"); + +out: + if (ms->vmemmap) + machdep->is_page_ptr = arm64_vmemmap_is_page_ptr; +} + /* * Do all necessary machine-specific setup here. This is called several times * during initialization. @@ -443,10 +461,6 @@ arm64_init(int when) machdep->stacksize = ARM64_STACK_SIZE; machdep->flags |= VMEMMAP; - /* If vmemmap exists, it means kernel enabled CONFIG_SPARSEMEM_VMEMMAP */ - if (arm64_get_vmcoreinfo(&ms->vmemmap, "SYMBOL(vmemmap)", NUM_HEX)) - machdep->is_page_ptr = arm64_vmemmap_is_page_ptr; - machdep->uvtop = arm64_uvtop; machdep->is_uvaddr = arm64_is_uvaddr; machdep->eframe_search = arm64_eframe_search; @@ -498,6 +512,7 @@ arm64_init(int when) if (!ms->struct_page_size) arm64_calc_virtual_memory_ranges(); + arm64_get_vmemmap_page_ptr(); arm64_get_section_size_bits(); if (!machdep->max_physmem_bits) { @@ -4841,6 +4856,7 @@ arm64_calc_virtual_memory_ranges(void) return; STRUCT_SIZE_INIT(page, "page"); + ms->struct_page_size = SIZE(page); switch (machdep->flags & (VM_L2_64K|VM_L3_64K|VM_L3_4K|VM_L4_4K)) { @@ -4868,7 +4884,8 @@ arm64_calc_virtual_memory_ranges(void) vmemmap_start = (-vmemmap_size - MEGABYTES(2)); ms->vmalloc_end = vmalloc_end - 1; ms->vmemmap_vaddr = vmemmap_start; - ms->vmemmap_end = -1; + ms->vmemmap_end = vmemmap_start + vmemmap_size; + return; } -- 2.25.1