Hi Kazu, On Thu, Jan 14, 2021 at 3:33 PM piliu <piliu@xxxxxxxxxx> wrote: > > > > 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. > > 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 > > So even more aggressive, we can exclude the need of vabits_actual > totally in this patch. As Pingfan noted, this approach still has issues and it failed on my arm64 board in the limited testing I did today. I will do some more testing tomorrow and come back with an approach which addresses the same and also takes into account Pingfan's concerns. Thanks, Bhupesh _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec