Hi Bhupesh, On 2/7/2019 2:52 PM, Bhupesh Sharma wrote: > 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 virtual > addresses. > > Since at the moment we enable the support of this extensions in the > kernel via a CONFIG flags (CONFIG_ARM64_USER_VA_BITS_52), so there are > no clear mechanisms in user-space to determine this CONFIG > flag value and use it to determine the PA address range values. > > 'makedumpfile' can instead use 'MAX_USER_VA_BITS' value to > determine the maximum virtual physical address supported by user-space. > If 'MAX_USER_VA_BITS' value is greater than 'VA_BITS' than we might be > running a use-case where user-space is 52-bit and underlying kernel is > still 48-bit. The increased 'PTRS_PER_PGD' value for such cases can then > be calculated as is done by the underlying kernel (see kernel file > 'arch/arm64/include/asm/pgtable-hwdef.h' for details): Thank you for the patch. I can't test the config yet, but this looks necessary. > > I have sent a kernel patch upstream to add 'MAX_USER_VA_BITS' to > vmcoreinfo for arm64 (see [0]). > > This patch is in accordance with ARMv8 Architecture Reference Manual > version D.a > > [0]. > http://lists.infradead.org/pipermail/kexec/2019-February/022411.html > > Signed-off-by: Bhupesh Sharma <bhsharma@xxxxxxxxxx> > --- > arch/arm64.c | 105 +++++++++++++++++++++++++++++++++++++++++---------------- > makedumpfile.c | 2 ++ > makedumpfile.h | 1 + > 3 files changed, 79 insertions(+), 29 deletions(-) > > diff --git a/arch/arm64.c b/arch/arm64.c > index a1db7dc63107..b522e93f4e80 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 max_user_va_bits; > static unsigned long kimage_voffset; > > #define SZ_4K 4096 > @@ -145,7 +146,7 @@ get_page_table_level_arm64(void) > #define PGDIR_SHIFT ARM64_HW_PGTABLE_LEVEL_SHIFT(4 - (get_page_table_level_arm64())) > #define PGDIR_SIZE (_AC(1, UL) << PGDIR_SHIFT) > #define PGDIR_MASK (~(PGDIR_SIZE-1)) > -#define PTRS_PER_PGD (1 << ((va_bits) - PGDIR_SHIFT)) > +#define PTRS_PER_PGD (1 << ((max_user_va_bits) - PGDIR_SHIFT)) > > /* > * Section address mask and size definitions. > @@ -478,6 +479,46 @@ 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 */ > + 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; > + } > + > + DEBUG_MSG("va_bits : %d\n", va_bits); Please add "(_stext)" to the end of line for debugging. > + > + return TRUE; > +} > + > +static void > +get_page_offset_arm64(void) > +{ > + info->page_offset = (0xffffffffffffffffUL) << (va_bits - 1); > + > + DEBUG_MSG("page_offset : %lx\n", info->page_offset); > +} > + > int > get_machdep_info_arm64(void) > { > @@ -493,8 +534,37 @@ 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() == ERROR) > + return ERROR; These ERRORs should be FALSE. > + > + get_page_offset_arm64(); > + > + if (NUMBER(MAX_USER_VA_BITS) != NOT_FOUND_NUMBER) { > + max_user_va_bits = NUMBER(MAX_USER_VA_BITS); > + DEBUG_MSG("max_user_va_bits : %d (vmcoreinfo)\n", > + max_user_va_bits); > + } > + > + /* Check if max_user_va_bits is still not initialized. > + * If still 0, its not available in vmcoreinfo and its > + * safe to initialize it with va_bits. > + */ > + if (!max_user_va_bits) { > + max_user_va_bits = va_bits; > + DEBUG_MSG("max_user_va_bits : %d (default = va_bits)\n", > + max_user_va_bits); > + } > > if (!calculate_plat_config()) { > ERRMSG("Can't determine platform config values\n"); > @@ -533,34 +603,11 @@ 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() == ERROR) > + return ERROR; Same as above. And, it would be helpful if you would rebase this after fixing the 52-bit PA patch. Thanks, Kazu > > - 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 b7c1c01251bf..ccf7eb4408ba 100644 > --- a/makedumpfile.c > +++ b/makedumpfile.c > @@ -2291,6 +2291,7 @@ write_vmcoreinfo_data(void) > > WRITE_NUMBER("HUGETLB_PAGE_DTOR", HUGETLB_PAGE_DTOR); > #ifdef __aarch64__ > + WRITE_NUMBER("MAX_USER_VA_BITS", MAX_USER_VA_BITS); > WRITE_NUMBER("VA_BITS", VA_BITS); > WRITE_NUMBER_UNSIGNED("PHYS_OFFSET", PHYS_OFFSET); > WRITE_NUMBER_UNSIGNED("kimage_voffset", kimage_voffset); > @@ -2694,6 +2695,7 @@ read_vmcoreinfo(void) > READ_NUMBER("PAGE_BUDDY_MAPCOUNT_VALUE", PAGE_BUDDY_MAPCOUNT_VALUE); > READ_NUMBER("phys_base", phys_base); > #ifdef __aarch64__ > + READ_NUMBER("MAX_USER_VA_BITS", MAX_USER_VA_BITS); > READ_NUMBER("VA_BITS", VA_BITS); > READ_NUMBER_UNSIGNED("PHYS_OFFSET", PHYS_OFFSET); > READ_NUMBER_UNSIGNED("kimage_voffset", kimage_voffset); > diff --git a/makedumpfile.h b/makedumpfile.h > index d49f1f1fc1a9..3fa810e0bb40 100644 > --- a/makedumpfile.h > +++ b/makedumpfile.h > @@ -1933,6 +1933,7 @@ struct number_table { > long HUGETLB_PAGE_DTOR; > long phys_base; > #ifdef __aarch64__ > + long MAX_USER_VA_BITS; > long VA_BITS; > unsigned long PHYS_OFFSET; > unsigned long kimage_voffset; > -- > 2.7.4 > _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
