Hi Pingfan, -----Original Message----- > >>> On 1/14/21 4:25 PM, kazuhito.hagio@xxxxxxxxx wrote: > >>>> From: Kazuhito Hagio <k-hagio-ab@xxxxxxx> > >>>> > >>>> Based on Bhupesh's patch and contains Pingfan's idea. > >>>> > >>>> Signed-off-by: Bhupesh Sharma <bhsharma@xxxxxxxxxx> > >>>> Signed-off-by: Kazuhito Hagio <k-hagio-ab@xxxxxxx> > >>>> --- > >>>> arch/arm64.c | 95 ++++++++++++++++++++++++++++++++++++++++++++++++---------- > >>>> makedumpfile.c | 2 ++ > >>>> makedumpfile.h | 1 + > >>>> 3 files changed, 83 insertions(+), 15 deletions(-) > >>>> > >>>> diff --git a/arch/arm64.c b/arch/arm64.c > >>>> index 61ec89a..4ece19d 100644 > >>>> --- a/arch/arm64.c > >>>> +++ b/arch/arm64.c > >>>> @@ -47,6 +47,8 @@ typedef struct { > >>>> static int lpa_52_bit_support_available; > >>>> static int pgtable_level; > >>>> static int va_bits; > >>>> +static int vabits_actual; > >>>> +static int flipped_va; > >>>> static unsigned long kimage_voffset; > >>>> > >>>> #define SZ_4K 4096 > >>>> @@ -58,7 +60,6 @@ static unsigned long kimage_voffset; > >>>> #define PAGE_OFFSET_42 ((0xffffffffffffffffUL) << 42) > >>>> #define PAGE_OFFSET_47 ((0xffffffffffffffffUL) << 47) > >>>> #define PAGE_OFFSET_48 ((0xffffffffffffffffUL) << 48) > >>>> -#define PAGE_OFFSET_52 ((0xffffffffffffffffUL) << 52) > >>>> > >>>> #define pgd_val(x) ((x).pgd) > >>>> #define pud_val(x) (pgd_val((x).pgd)) > >>>> @@ -218,12 +219,20 @@ pmd_page_paddr(pmd_t pmd) > >>>> #define pte_index(vaddr) (((vaddr) >> PAGESHIFT()) & (PTRS_PER_PTE - 1)) > >>>> #define pte_offset(dir, vaddr) (pmd_page_paddr((*dir)) + pte_index(vaddr) * > >> sizeof(pte_t)) > >>>> > >>>> +/* > >>>> + * The linear kernel range starts at the bottom of the virtual address > >>>> + * space. Testing the top bit for the start of the region is a > >>>> + * sufficient check and avoids having to worry about the tag. > >>>> + */ > >>>> +#define is_linear_addr(addr) (flipped_va ? \ > >>>> + (!((unsigned long)(addr) & (1UL << (vabits_actual - 1)))) : \ > >>>> + (!!((unsigned long)(addr) & (1UL << (vabits_actual - 1))))) > >>>> + > >>>> static unsigned long long > >>>> __pa(unsigned long vaddr) > >>>> { > >>>> - if (kimage_voffset == NOT_FOUND_NUMBER || > >>>> - (vaddr >= PAGE_OFFSET)) > >>>> - return (vaddr - PAGE_OFFSET + info->phys_base); > >>>> + if (kimage_voffset == NOT_FOUND_NUMBER || is_linear_addr(vaddr)) > >>>> + return ((vaddr & ~PAGE_OFFSET) + info->phys_base); > >>>> else > >>>> return (vaddr - kimage_voffset); > >>>> } > >>>> @@ -253,6 +262,7 @@ static int calculate_plat_config(void) > >>>> (PAGESIZE() == SZ_64K && va_bits == 42)) { > >>>> pgtable_level = 2; > >>>> } else if ((PAGESIZE() == SZ_64K && va_bits == 48) || > >>>> + (PAGESIZE() == SZ_64K && va_bits == 52) || > >>>> (PAGESIZE() == SZ_4K && va_bits == 39) || > >>>> (PAGESIZE() == SZ_16K && va_bits == 47)) { > >>>> pgtable_level = 3; > >>>> @@ -263,6 +273,7 @@ static int calculate_plat_config(void) > >>>> PAGESIZE(), va_bits); > >>>> return FALSE; > >>>> } > >>>> + DEBUG_MSG("pgtable_level: %d\n", pgtable_level); > >>>> > >>>> return TRUE; > >>>> } > >>>> @@ -383,22 +394,54 @@ get_va_bits_from_stext_arm64(void) > >>>> return TRUE; > >>>> } > >>>> > >>>> +static void > >>>> +get_page_offset_arm64(void) > >>>> +{ > >>>> + ulong page_end; > >>>> + int vabits_min; > >>>> + > >>>> + /* > >>>> + * See arch/arm64/include/asm/memory.h for more details of > >>>> + * the PAGE_OFFSET calculation. > >>>> + */ > >>>> + vabits_min = (va_bits > 48) ? 48 : va_bits; > >>>> + page_end = -(1UL << (vabits_min - 1)); > >>>> + > >>>> + if (SYMBOL(_stext) > page_end) { > >>>> + flipped_va = TRUE; > >>>> + info->page_offset = -(1UL << vabits_actual); > >>>> + } else { > >>>> + flipped_va = FALSE; > >>>> + info->page_offset = -(1UL << (vabits_actual - 1)); > >>>> + } > >>>> + > >>>> + DEBUG_MSG("page_offset : %lx (from page_end check)\n", > >>>> + info->page_offset); > >>>> +} > >>>> + > >>>> int > >>>> get_machdep_info_arm64(void) > >>>> { > >>>> + /* Check if va_bits is still not initialized. If still 0, call > >>>> + * get_versiondep_info() to initialize the same. > >>>> + */ > >>>> + if (!va_bits) > >>>> + get_versiondep_info_arm64(); > >>>> + > >>>> /* Determine if the PA address range is 52-bits: ARMv8.2-LPA */ > >>>> if (NUMBER(MAX_PHYSMEM_BITS) != NOT_FOUND_NUMBER) { > >>>> info->max_physmem_bits = NUMBER(MAX_PHYSMEM_BITS); > >>>> + DEBUG_MSG("max_physmem_bits : %ld (vmcoreinfo)\n", info->max_physmem_bits); > >>>> if (info->max_physmem_bits == 52) > >>>> lpa_52_bit_support_available = 1; > >>>> - } else > >>>> - info->max_physmem_bits = 48; > >>>> + } else { > >>>> + if (va_bits == 52) > >>>> + info->max_physmem_bits = 52; /* just guess */ > >>>> + else > >>>> + info->max_physmem_bits = 48; > >>>> > >>>> - /* Check if va_bits is still not initialized. If still 0, call > >>>> - * get_versiondep_info() to initialize the same. > >>>> - */ > >>>> - if (!va_bits) > >>>> - get_versiondep_info_arm64(); > >>>> + DEBUG_MSG("max_physmem_bits : %ld (guess)\n", info->max_physmem_bits); > >>>> + } > >>>> > >>>> if (!calculate_plat_config()) { > >>>> ERRMSG("Can't determine platform config values\n"); > >>>> @@ -409,7 +452,6 @@ get_machdep_info_arm64(void) > >>>> info->section_size_bits = SECTIONS_SIZE_BITS; > >>>> > >>>> DEBUG_MSG("kimage_voffset : %lx\n", kimage_voffset); > >>>> - DEBUG_MSG("max_physmem_bits : %ld\n", info->max_physmem_bits); > >>>> DEBUG_MSG("section_size_bits: %ld\n", info->section_size_bits); > >>>> > >>>> return TRUE; > >>>> @@ -444,10 +486,33 @@ get_versiondep_info_arm64(void) > >>>> return FALSE; > >>>> } > >>>> > >>>> - info->page_offset = (0xffffffffffffffffUL) << (va_bits - 1); > >>>> + /* > >>>> + * See TCR_EL1, Translation Control Register (EL1) register > >>>> + * description in the ARMv8 Architecture Reference Manual. > >>>> + * Basically, we can use the TCR_EL1.T1SZ > >>>> + * value to determine the virtual addressing range supported > >>>> + * in the kernel-space (i.e. vabits_actual) since Linux 5.9. > >>>> + */ > >>>> + if (NUMBER(TCR_EL1_T1SZ) != NOT_FOUND_NUMBER) { > >>>> + vabits_actual = 64 - NUMBER(TCR_EL1_T1SZ); > >>>> + DEBUG_MSG("vabits_actual : %d (vmcoreinfo)\n", vabits_actual); > >>>> + } else if ((va_bits == 52) && (SYMBOL(mem_section) != NOT_FOUND_SYMBOL)) { > >>>> + /* > >>>> + * Linux 5.4 through 5.10 have the following linear space: > >>>> + * 48-bit: 0xffff000000000000 - 0xffff7fffffffffff > >>>> + * 58-bit: 0xfff0000000000000 - 0xfff7ffffffffffff > >>>> + */ > >>>> + if (SYMBOL(mem_section) & (1UL << (52 - 1))) > >>> > >>> Sorry but I do not think any SYMBOL(x) is inside the range of linear > >>> mapping address. All of them should be beyond kimage_vaddr. > > > > As for this, SYMBOL(mem_section) is a bit special and shows the value in the > > mem_section variable, not the address of it, by kernel commit a0b1280368d1. > > > > Actually on my tiny arm64 board.. > > > > # strings /proc/kcore | less > > ... > > OSRELEASE=5.4.0-1025-raspi > > PAGESIZE=4096 > > SYMBOL(init_uts_ns)=ffffd6db0fa10568 > > SYMBOL(node_online_map)=ffffd6db0fa0a808 > > SYMBOL(swapper_pg_dir)=ffffd6db0f42b000 > > SYMBOL(_stext)=ffffd6db0e481000 > > SYMBOL(vmap_area_list)=ffffd6db0fa51680 > > SYMBOL(mem_map)=ffffd6db0fbc0240 > > SYMBOL(contig_page_data)=ffffd6db0faed6c0 > > SYMBOL(mem_section)=ffff0000eb809300 <<-- > > LENGTH(mem_section)=1024 > > SIZE(mem_section)=16 > > OFFSET(mem_section.section_mem_map)=0 > > ... > > NUMBER(VA_BITS)=48 > > > > So at least if the kernel is configured with CONFIG_SPARSEMEM_EXTREME, > You are right. Exactly, your method works in this case. > > > I thought this would work. This is just a user tool effort to broaden > > supported kernels, instead of necessary information from the kernel, > > no need to support all kernels. > > I hold a private opinion against the solution based on kernel version, > since it raises extra effort to cope with different releases which back > port some upstream patches without advancing kernel version. I agree with you, we should avoid depending on kernel version if we can. I left the 3/4 patch intact for possible use of kernel version method, but for now, the patchset doesn't use kernel version with your idea! :) > > > > And the current makedumpfile's implementation, SYMBOL(mem_section) is set > > to the address of the mem_section variable with -x option, so I wrote on > > the cover letter that this patchset doesn't support "with -x option if > > vabits_actual=52" case yet. > > > >>> > >>> Having vabits_actual is introduced and precise to resolve > >>> is_lm_address(), but if it is not available, could we survive? > >>> > >>> _PAGE_OFFSET(52) < _PAGE_END(52) < _PAGE_OFFSET(48) < _PAGE_END(48) > >>> Translating into numbers: > >>> 0xfff0000000000000 < 0xfff8000000000000 < 0xffff000000000000 < > >>> 0xffff800000000000 > >>> > >>> Refer to linux/Documentation/arm64/memory.rst, the line > >>> ffffa00010000000 fffff81ffffeffff ~88TB vmalloc > >>> > >>> It comes to the conclusion that any symbol > SYMBOL(_text) > _PAGE_END(48). > >>> > >>> So is_lm_address() can looks like > >>> if (addr > _PAGE_END(48)), it is kimage > >>> else, it is linear mapping > > > > This sounds good and will work. > > > >>> > >>> So even more aggressive, we can exclude the need of vabits_actual > >>> totally in this patch. > > > > Interesting, but if vabits_actual is not available, I wonder how we can > > get info->page_offset. Seems it's used mainly for p2v conversion and > > Ashamed. I will make the best of the fact that va_bits=52 kernel only > has _PAGE_OFFSET(52). It looks not elegant, but should work. ok, thanks for your help! Kazu _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec