> -----Original Message----- > With ARMv8.2-LVA architecture extension availability, arm64 hardware > which supports this extension can support upto 52-bit virtual > addresses. It is specially useful for having a 52-bit user-space virtual > address space while the kernel can still retain 48-bit/52-bit virtual > addressing. > > Since at the moment we enable the support of this extension in the > kernel via a CONFIG flag (CONFIG_ARM64_VA_BITS_52), so there are > no clear mechanisms in user-space to determine this CONFIG > flag value and use it to determine the kernel-space VA address range > values. > > 'makedumpfile' can instead use 'TCR_EL1.T1SZ' value from vmcoreinfo > which indicates the size offset of the memory region addressed by > TTBR1_EL1 (and hence can be used for determining the > vabits_actual value). > > The user-space computation for determining whether an address lies in > the linear map range is the same as we have in kernel-space: > > #define __is_lm_address(addr) (!(((u64)addr) & BIT(vabits_actual - 1))) > > I have sent a kernel patch upstream to add 'TCR_EL1.T1SZ' to > vmcoreinfo for arm64 (see [0]). > > This patch is in accordance with ARMv8 Architecture Reference Manual > version D.a > > Note that with these changes the '--mem-usage' option will not work > properly for arm64 (a subsequent patch in this series will address the > same) and there is a discussion on-going with the arm64 maintainers to > find a way-out for the same (via standard kernel symbols like _stext). > > [0].http://lists.infradead.org/pipermail/kexec/2019-November/023962.html > > Cc: Kazuhito Hagio <k-hagio@xxxxxxxxxxxxx> > Cc: John Donnelly <john.p.donnelly@xxxxxxxxxx> > Cc: kexec@xxxxxxxxxxxxxxxxxxx > Signed-off-by: Bhupesh Sharma <bhsharma@xxxxxxxxxx> > --- > arch/arm64.c | 148 +++++++++++++++++++++++++++++++++++++++++++++------------ > makedumpfile.c | 2 + > makedumpfile.h | 3 +- > 3 files changed, 122 insertions(+), 31 deletions(-) > > diff --git a/arch/arm64.c b/arch/arm64.c > index ecb19139e178..094d73b8a60f 100644 > --- a/arch/arm64.c > +++ b/arch/arm64.c > @@ -47,6 +47,7 @@ typedef struct { > static int lpa_52_bit_support_available; > static int pgtable_level; > static int va_bits; > +static int vabits_actual; > static unsigned long kimage_voffset; > > #define SZ_4K 4096 > @@ -218,12 +219,19 @@ 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) (!(((unsigned long)addr) & (1UL << (vabits_actual - 1)))) Does this check cover 5.3 or earlier kernels? There is no case that vabits_actual is zero? > + > static unsigned long long > __pa(unsigned long vaddr) > { > if (kimage_voffset == NOT_FOUND_NUMBER || > - (vaddr >= PAGE_OFFSET)) > - return (vaddr - PAGE_OFFSET + info->phys_base); > + is_linear_addr(vaddr)) > + return (vaddr + info->phys_base - PAGE_OFFSET); > else > return (vaddr - kimage_voffset); > } > @@ -253,6 +261,7 @@ 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; > @@ -287,6 +296,16 @@ get_phys_base_arm64(void) > return TRUE; > } > > + /* If both vabits_actual and va_bits are now initialized, always > + * prefer vabits_actual over va_bits to calculate PAGE_OFFSET > + * value. > + */ > + if (vabits_actual && va_bits && vabits_actual != va_bits) { > + info->page_offset = (-(1UL << vabits_actual)); > + DEBUG_MSG("page_offset : %lx (via vabits_actual)\n", > + info->page_offset); > + } > + Is this for --mem-usage? If so, let's drop from this patch and think about it later because some additional base functions will be needed for the option, I think. > if (get_num_pt_loads() && PAGE_OFFSET) { > for (i = 0; > get_pt_load(i, &phys_start, NULL, &virt_start, NULL); > @@ -406,6 +425,73 @@ get_stext_symbol(void) > return(found ? kallsym : FALSE); > } > > +static int > +get_va_bits_from_stext_arm64(void) > +{ > + ulong _stext; > + > + _stext = get_stext_symbol(); > + if (!_stext) { > + ERRMSG("Can't get the symbol of _stext.\n"); > + return FALSE; > + } > + > + /* Derive va_bits as per arch/arm64/Kconfig. Note that this is a > + * best case approximation at the moment, as there can be > + * inconsistencies in this calculation (for e.g., for > + * 52-bit kernel VA case, even the 48th bit might be set in > + * the _stext symbol). > + * > + * So, we need to rely on the actual VA_BITS symbol in the > + * vmcoreinfo for a accurate value. > + * > + * TODO: Improve this further once there is a closure with arm64 > + * kernel maintainers on the same. > + */ > + if ((_stext & PAGE_OFFSET_52) == PAGE_OFFSET_52) { > + va_bits = 52; > + } else if ((_stext & PAGE_OFFSET_48) == PAGE_OFFSET_48) { > + va_bits = 48; > + } else if ((_stext & PAGE_OFFSET_47) == PAGE_OFFSET_47) { > + va_bits = 47; > + } else if ((_stext & PAGE_OFFSET_42) == PAGE_OFFSET_42) { > + va_bits = 42; > + } else if ((_stext & PAGE_OFFSET_39) == PAGE_OFFSET_39) { > + va_bits = 39; > + } else if ((_stext & PAGE_OFFSET_36) == PAGE_OFFSET_36) { > + va_bits = 36; > + } else { > + ERRMSG("Cannot find a proper _stext for calculating VA_BITS\n"); > + return FALSE; > + } > + > + DEBUG_MSG("va_bits : %d (_stext) (approximation)\n", va_bits); > + > + return TRUE; > +} > + > +static void > +get_page_offset_arm64(void) > +{ > + /* Check if 'vabits_actual' is initialized yet. > + * If not, our best bet is to use 'va_bits' to calculate > + * the PAGE_OFFSET value, otherwise use 'vabits_actual' > + * for the same. > + * > + * See arch/arm64/include/asm/memory.h for more details. > + */ > + if (!vabits_actual) { > + info->page_offset = (-(1UL << va_bits)); > + DEBUG_MSG("page_offset : %lx (approximation)\n", > + info->page_offset); > + } else { > + info->page_offset = (-(1UL << vabits_actual)); > + DEBUG_MSG("page_offset : %lx (accurate)\n", > + info->page_offset); > + } Does this support 5.3 or earlier kernels? Thanks, Kazu > + > +} > + > int > get_machdep_info_arm64(void) > { > @@ -420,8 +506,33 @@ 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 (NUMBER(VA_BITS) != NOT_FOUND_NUMBER) { > + va_bits = NUMBER(VA_BITS); > + DEBUG_MSG("va_bits : %d (vmcoreinfo)\n", > + va_bits); > + } > + > + /* Check if va_bits is still not initialized. If still 0, call > + * get_versiondep_info() to initialize the same from _stext > + * symbol. > + */ > if (!va_bits) > - get_versiondep_info_arm64(); > + if (get_va_bits_from_stext_arm64() == FALSE) > + return FALSE; > + > + get_page_offset_arm64(); > + > + /* 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). > + */ > + if (NUMBER(tcr_el1_t1sz) != NOT_FOUND_NUMBER) { > + vabits_actual = 64 - NUMBER(tcr_el1_t1sz); > + DEBUG_MSG("vabits_actual : %d (vmcoreinfo)\n", > + vabits_actual); > + } > > if (!calculate_plat_config()) { > ERRMSG("Can't determine platform config values\n"); > @@ -459,34 +570,11 @@ get_xen_info_arm64(void) > int > get_versiondep_info_arm64(void) > { > - ulong _stext; > - > - _stext = get_stext_symbol(); > - if (!_stext) { > - ERRMSG("Can't get the symbol of _stext.\n"); > - return FALSE; > - } > - > - /* Derive va_bits as per arch/arm64/Kconfig */ > - if ((_stext & PAGE_OFFSET_36) == PAGE_OFFSET_36) { > - va_bits = 36; > - } else if ((_stext & PAGE_OFFSET_39) == PAGE_OFFSET_39) { > - va_bits = 39; > - } else if ((_stext & PAGE_OFFSET_42) == PAGE_OFFSET_42) { > - va_bits = 42; > - } else if ((_stext & PAGE_OFFSET_47) == PAGE_OFFSET_47) { > - va_bits = 47; > - } else if ((_stext & PAGE_OFFSET_48) == PAGE_OFFSET_48) { > - va_bits = 48; > - } else { > - ERRMSG("Cannot find a proper _stext for calculating VA_BITS\n"); > - return FALSE; > - } > - > - info->page_offset = (0xffffffffffffffffUL) << (va_bits - 1); > + if (!va_bits) > + if (get_va_bits_from_stext_arm64() == FALSE) > + return FALSE; > > - DEBUG_MSG("va_bits : %d\n", va_bits); > - DEBUG_MSG("page_offset : %lx\n", info->page_offset); > + get_page_offset_arm64(); > > return TRUE; > } > diff --git a/makedumpfile.c b/makedumpfile.c > index 4a000112ba59..baf559e4d74e 100644 > --- a/makedumpfile.c > +++ b/makedumpfile.c > @@ -2314,6 +2314,7 @@ write_vmcoreinfo_data(void) > WRITE_NUMBER("HUGETLB_PAGE_DTOR", HUGETLB_PAGE_DTOR); > #ifdef __aarch64__ > WRITE_NUMBER("VA_BITS", VA_BITS); > + WRITE_NUMBER_UNSIGNED("tcr_el1_t1sz", tcr_el1_t1sz); > WRITE_NUMBER_UNSIGNED("PHYS_OFFSET", PHYS_OFFSET); > WRITE_NUMBER_UNSIGNED("kimage_voffset", kimage_voffset); > #endif > @@ -2720,6 +2721,7 @@ read_vmcoreinfo(void) > READ_NUMBER("KERNEL_IMAGE_SIZE", KERNEL_IMAGE_SIZE); > #ifdef __aarch64__ > READ_NUMBER("VA_BITS", VA_BITS); > + READ_NUMBER_UNSIGNED("tcr_el1_t1sz", tcr_el1_t1sz); > READ_NUMBER_UNSIGNED("PHYS_OFFSET", PHYS_OFFSET); > READ_NUMBER_UNSIGNED("kimage_voffset", kimage_voffset); > #endif > diff --git a/makedumpfile.h b/makedumpfile.h > index ac11e906b5b7..7eab6507c8df 100644 > --- a/makedumpfile.h > +++ b/makedumpfile.h > @@ -974,7 +974,7 @@ int get_versiondep_info_arm64(void); > int get_xen_basic_info_arm64(void); > int get_xen_info_arm64(void); > unsigned long get_kaslr_offset_arm64(unsigned long vaddr); > -#define paddr_to_vaddr_arm64(X) (((X) - info->phys_base) | PAGE_OFFSET) > +#define paddr_to_vaddr_arm64(X) (((X) - (info->phys_base - PAGE_OFFSET))) > > #define find_vmemmap() stub_false() > #define vaddr_to_paddr(X) vaddr_to_paddr_arm64(X) > @@ -1937,6 +1937,7 @@ struct number_table { > long KERNEL_IMAGE_SIZE; > #ifdef __aarch64__ > long VA_BITS; > + unsigned long tcr_el1_t1sz; > unsigned long PHYS_OFFSET; > unsigned long kimage_voffset; > #endif > -- > 2.7.4 > _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
