Hi Kazu,
On Wed, Dec 4, 2019 at 11:05 PM Kazuhito Hagio <k-hagio@xxxxxxxxxxxxx> wrote:
>
> Hi Bhupesh,
>
> Sorry for the late reply.
No problem.
> > -----Original Message-----
> > This patch adds a common feature for archs (except arm64, for which
> > similar support is added via subsequent patch) to retrieve
> > 'MAX_PHYSMEM_BITS' from vmcoreinfo (if available).
>
> We already have the calibrate_machdep_info() function, which sets
> info->max_physmem_bits from vmcoreinfo, so practically we don't need
> to add this patch for the benefit.
Since other user-space tools like crash use the 'MAX_PHYSMEM_BITS' value as well
it was agreed with the arm64 maintainers that it would be a good
approach to export the
same in vmcoreinfo and not use different methods to determine the same
in user-space.
Take an example of the PPC makedumpfile implementation for example. It
uses the following complex method of dtereming
'info->max_physmem_bits':
int
set_ppc64_max_physmem_bits(void)
{
long array_len = ARRAY_LENGTH(mem_section);
/*
* The older ppc64 kernels uses _MAX_PHYSMEM_BITS as 42 and the
* newer kernels 3.7 onwards uses 46 bits.
*/
info->max_physmem_bits = _MAX_PHYSMEM_BITS_ORIG ;
if ((array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT_EXTREME()))
|| (array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT())))
return TRUE;
info->max_physmem_bits = _MAX_PHYSMEM_BITS_3_7;
if ((array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT_EXTREME()))
|| (array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT())))
return TRUE;
info->max_physmem_bits = _MAX_PHYSMEM_BITS_4_19;
if ((array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT_EXTREME()))
|| (array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT())))
return TRUE;
info->max_physmem_bits = _MAX_PHYSMEM_BITS_4_20;
if ((array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT_EXTREME()))
|| (array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT())))
return TRUE;
return FALSE;
}
This might need modification and introduction of another
_MAX_PHYSMEM_BITS_x_y macro when this changes for a newer kernel
version.
I think this makes the code error-prone and hard to read. Its much
better to replace it with:
/* Check if we can get MAX_PHYSMEM_BITS from vmcoreinfo */
if (NUMBER(MAX_PHYSMEM_BITS) != NOT_FOUND_NUMBER) {
info->max_physmem_bits = NUMBER(MAX_PHYSMEM_BITS);
return TRUE;
} else {
..
}
I think it will reduce future reworks (as per kernel versions) and
also reduce issues while backporting makedumpfile to older kernels.
What do you think?
Regards,
Bhupesh
> > I recently posted a kernel patch (see [0]) which appends
> > 'MAX_PHYSMEM_BITS' to vmcoreinfo in the core code itself rather than
> > in arch-specific code, so that user-space code can also benefit from
> > this addition to the vmcoreinfo and use it as a standard way of
> > determining 'SECTIONS_SHIFT' value in 'makedumpfile' utility.
> >
> > This patch ensures backward compatibility for kernel versions in which
> > 'MAX_PHYSMEM_BITS' is not available in vmcoreinfo.
> >
> > [0]. http://lists.infradead.org/pipermail/kexec/2019-November/023960.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/arm.c | 8 +++++++-
> > arch/ia64.c | 7 ++++++-
> > arch/ppc.c | 8 +++++++-
> > arch/ppc64.c | 49 ++++++++++++++++++++++++++++---------------------
> > arch/s390x.c | 29 ++++++++++++++++++-----------
> > arch/sparc64.c | 9 +++++++--
> > arch/x86.c | 34 ++++++++++++++++++++--------------
> > arch/x86_64.c | 27 ++++++++++++++++-----------
> > 8 files changed, 109 insertions(+), 62 deletions(-)
> >
> > diff --git a/arch/arm.c b/arch/arm.c
> > index af7442ac70bf..33536fc4dfc9 100644
> > --- a/arch/arm.c
> > +++ b/arch/arm.c
> > @@ -81,7 +81,13 @@ int
> > get_machdep_info_arm(void)
> > {
> > info->page_offset = SYMBOL(_stext) & 0xffff0000UL;
> > - info->max_physmem_bits = _MAX_PHYSMEM_BITS;
> > +
> > + /* Check if we can get MAX_PHYSMEM_BITS from vmcoreinfo */
> > + if (NUMBER(MAX_PHYSMEM_BITS) != NOT_FOUND_NUMBER)
> > + info->max_physmem_bits = NUMBER(MAX_PHYSMEM_BITS);
> > + else
> > + info->max_physmem_bits = _MAX_PHYSMEM_BITS;
> > +
> > info->kernel_start = SYMBOL(_stext);
> > info->section_size_bits = _SECTION_SIZE_BITS;
> >
> > diff --git a/arch/ia64.c b/arch/ia64.c
> > index 6c33cc7c8288..fb44dda47172 100644
> > --- a/arch/ia64.c
> > +++ b/arch/ia64.c
> > @@ -85,7 +85,12 @@ get_machdep_info_ia64(void)
> > }
> >
> > info->section_size_bits = _SECTION_SIZE_BITS;
> > - info->max_physmem_bits = _MAX_PHYSMEM_BITS;
> > +
> > + /* Check if we can get MAX_PHYSMEM_BITS from vmcoreinfo */
> > + if (NUMBER(MAX_PHYSMEM_BITS) != NOT_FOUND_NUMBER)
> > + info->max_physmem_bits = NUMBER(MAX_PHYSMEM_BITS);
> > + else
> > + info->max_physmem_bits = _MAX_PHYSMEM_BITS;
> >
> > return TRUE;
> > }
> > diff --git a/arch/ppc.c b/arch/ppc.c
> > index 37c6a3b60cd3..ed9447427a30 100644
> > --- a/arch/ppc.c
> > +++ b/arch/ppc.c
> > @@ -31,7 +31,13 @@ get_machdep_info_ppc(void)
> > unsigned long vmlist, vmap_area_list, vmalloc_start;
> >
> > info->section_size_bits = _SECTION_SIZE_BITS;
> > - info->max_physmem_bits = _MAX_PHYSMEM_BITS;
> > +
> > + /* Check if we can get MAX_PHYSMEM_BITS from vmcoreinfo */
> > + if (NUMBER(MAX_PHYSMEM_BITS) != NOT_FOUND_NUMBER)
> > + info->max_physmem_bits = NUMBER(MAX_PHYSMEM_BITS);
> > + else
> > + info->max_physmem_bits = _MAX_PHYSMEM_BITS;
> > +
> > info->page_offset = __PAGE_OFFSET;
> >
> > if (SYMBOL(_stext) != NOT_FOUND_SYMBOL)
> > diff --git a/arch/ppc64.c b/arch/ppc64.c
> > index 9d8f2525f608..a3984eebdced 100644
> > --- a/arch/ppc64.c
> > +++ b/arch/ppc64.c
> > @@ -466,30 +466,37 @@ int
> > set_ppc64_max_physmem_bits(void)
> > {
> > long array_len = ARRAY_LENGTH(mem_section);
> > - /*
> > - * The older ppc64 kernels uses _MAX_PHYSMEM_BITS as 42 and the
> > - * newer kernels 3.7 onwards uses 46 bits.
> > - */
> > -
> > - info->max_physmem_bits = _MAX_PHYSMEM_BITS_ORIG ;
> > - if ((array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT_EXTREME()))
> > - || (array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT())))
> > - return TRUE;
> > -
> > - info->max_physmem_bits = _MAX_PHYSMEM_BITS_3_7;
> > - if ((array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT_EXTREME()))
> > - || (array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT())))
> > - return TRUE;
> >
> > - info->max_physmem_bits = _MAX_PHYSMEM_BITS_4_19;
> > - if ((array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT_EXTREME()))
> > - || (array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT())))
> > + /* Check if we can get MAX_PHYSMEM_BITS from vmcoreinfo */
> > + if (NUMBER(MAX_PHYSMEM_BITS) != NOT_FOUND_NUMBER) {
> > + info->max_physmem_bits = NUMBER(MAX_PHYSMEM_BITS);
> > return TRUE;
> > + } else {
> > + /*
> > + * The older ppc64 kernels uses _MAX_PHYSMEM_BITS as 42 and the
> > + * newer kernels 3.7 onwards uses 46 bits.
> > + */
> >
> > - info->max_physmem_bits = _MAX_PHYSMEM_BITS_4_20;
> > - if ((array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT_EXTREME()))
> > - || (array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT())))
> > - return TRUE;
> > + info->max_physmem_bits = _MAX_PHYSMEM_BITS_ORIG ;
> > + if ((array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT_EXTREME()))
> > + || (array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT())))
> > + return TRUE;
> > +
> > + info->max_physmem_bits = _MAX_PHYSMEM_BITS_3_7;
> > + if ((array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT_EXTREME()))
> > + || (array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT())))
> > + return TRUE;
> > +
> > + info->max_physmem_bits = _MAX_PHYSMEM_BITS_4_19;
> > + if ((array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT_EXTREME()))
> > + || (array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT())))
> > + return TRUE;
> > +
> > + info->max_physmem_bits = _MAX_PHYSMEM_BITS_4_20;
> > + if ((array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT_EXTREME()))
> > + || (array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT())))
> > + return TRUE;
> > + }
> >
> > return FALSE;
> > }
> > diff --git a/arch/s390x.c b/arch/s390x.c
> > index bf9d58e54fb7..4d17a783e5bd 100644
> > --- a/arch/s390x.c
> > +++ b/arch/s390x.c
> > @@ -63,20 +63,27 @@ int
> > set_s390x_max_physmem_bits(void)
> > {
> > long array_len = ARRAY_LENGTH(mem_section);
> > - /*
> > - * The older s390x kernels uses _MAX_PHYSMEM_BITS as 42 and the
> > - * newer kernels uses 46 bits.
> > - */
> >
> > - info->max_physmem_bits = _MAX_PHYSMEM_BITS_ORIG ;
> > - if ((array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT_EXTREME()))
> > - || (array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT())))
> > + /* Check if we can get MAX_PHYSMEM_BITS from vmcoreinfo */
> > + if (NUMBER(MAX_PHYSMEM_BITS) != NOT_FOUND_NUMBER) {
> > + info->max_physmem_bits = NUMBER(MAX_PHYSMEM_BITS);
> > return TRUE;
> > + } else {
> > + /*
> > + * The older s390x kernels uses _MAX_PHYSMEM_BITS as 42 and the
> > + * newer kernels uses 46 bits.
> > + */
> >
> > - info->max_physmem_bits = _MAX_PHYSMEM_BITS_3_3;
> > - if ((array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT_EXTREME()))
> > - || (array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT())))
> > - return TRUE;
> > + info->max_physmem_bits = _MAX_PHYSMEM_BITS_ORIG ;
> > + if ((array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT_EXTREME()))
> > + || (array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT())))
> > + return TRUE;
> > +
> > + info->max_physmem_bits = _MAX_PHYSMEM_BITS_3_3;
> > + if ((array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT_EXTREME()))
> > + || (array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT())))
> > + return TRUE;
> > + }
> >
> > return FALSE;
> > }
> > diff --git a/arch/sparc64.c b/arch/sparc64.c
> > index 1cfaa854ce6d..b93a05bdfe59 100644
> > --- a/arch/sparc64.c
> > +++ b/arch/sparc64.c
> > @@ -25,10 +25,15 @@ int get_versiondep_info_sparc64(void)
> > {
> > info->section_size_bits = _SECTION_SIZE_BITS;
> >
> > - if (info->kernel_version >= KERNEL_VERSION(3, 8, 13))
> > + /* Check if we can get MAX_PHYSMEM_BITS from vmcoreinfo */
> > + if (NUMBER(MAX_PHYSMEM_BITS) != NOT_FOUND_NUMBER)
> > + info->max_physmem_bits = NUMBER(MAX_PHYSMEM_BITS);
> > + else if (info->kernel_version >= KERNEL_VERSION(3, 8, 13))
> > info->max_physmem_bits = _MAX_PHYSMEM_BITS_L4;
> > - else {
> > + else
> > info->max_physmem_bits = _MAX_PHYSMEM_BITS_L3;
> > +
> > + if (info->kernel_version < KERNEL_VERSION(3, 8, 13)) {
> > info->flag_vmemmap = TRUE;
> > info->vmemmap_start = VMEMMAP_BASE_SPARC64;
> > info->vmemmap_end = VMEMMAP_BASE_SPARC64 +
> > diff --git a/arch/x86.c b/arch/x86.c
> > index 3fdae93084b8..f1b43d4c8179 100644
> > --- a/arch/x86.c
> > +++ b/arch/x86.c
> > @@ -72,21 +72,27 @@ get_machdep_info_x86(void)
> > {
> > unsigned long vmlist, vmap_area_list, vmalloc_start;
> >
> > - /* PAE */
> > - if ((vt.mem_flags & MEMORY_X86_PAE)
> > - || ((SYMBOL(pkmap_count) != NOT_FOUND_SYMBOL)
> > - && (SYMBOL(pkmap_count_next) != NOT_FOUND_SYMBOL)
> > - && ((SYMBOL(pkmap_count_next)-SYMBOL(pkmap_count))/sizeof(int))
> > - == 512)) {
> > - DEBUG_MSG("\n");
> > - DEBUG_MSG("PAE : ON\n");
> > - vt.mem_flags |= MEMORY_X86_PAE;
> > - info->max_physmem_bits = _MAX_PHYSMEM_BITS_PAE;
> > - } else {
> > - DEBUG_MSG("\n");
> > - DEBUG_MSG("PAE : OFF\n");
> > - info->max_physmem_bits = _MAX_PHYSMEM_BITS;
> > + /* Check if we can get MAX_PHYSMEM_BITS from vmcoreinfo */
> > + if (NUMBER(MAX_PHYSMEM_BITS) != NOT_FOUND_NUMBER)
> > + info->max_physmem_bits = NUMBER(MAX_PHYSMEM_BITS);
> > + else {
> > + /* PAE */
> > + if ((vt.mem_flags & MEMORY_X86_PAE)
> > + || ((SYMBOL(pkmap_count) != NOT_FOUND_SYMBOL)
> > + && (SYMBOL(pkmap_count_next) != NOT_FOUND_SYMBOL)
> > + && ((SYMBOL(pkmap_count_next)-SYMBOL(pkmap_count))/sizeof(int))
> > + == 512)) {
> > + DEBUG_MSG("\n");
> > + DEBUG_MSG("PAE : ON\n");
> > + vt.mem_flags |= MEMORY_X86_PAE;
> > + info->max_physmem_bits = _MAX_PHYSMEM_BITS_PAE;
> > + } else {
> > + DEBUG_MSG("\n");
> > + DEBUG_MSG("PAE : OFF\n");
> > + info->max_physmem_bits = _MAX_PHYSMEM_BITS;
> > + }
> > }
> > +
> > info->page_offset = __PAGE_OFFSET;
> >
> > if (SYMBOL(_stext) == NOT_FOUND_SYMBOL) {
> > diff --git a/arch/x86_64.c b/arch/x86_64.c
> > index 876644f932be..eff90307552c 100644
> > --- a/arch/x86_64.c
> > +++ b/arch/x86_64.c
> > @@ -268,17 +268,22 @@ get_machdep_info_x86_64(void)
> > int
> > get_versiondep_info_x86_64(void)
> > {
> > - /*
> > - * On linux-2.6.26, MAX_PHYSMEM_BITS is changed to 44 from 40.
> > - */
> > - if (info->kernel_version < KERNEL_VERSION(2, 6, 26))
> > - info->max_physmem_bits = _MAX_PHYSMEM_BITS_ORIG;
> > - else if (info->kernel_version < KERNEL_VERSION(2, 6, 31))
> > - info->max_physmem_bits = _MAX_PHYSMEM_BITS_2_6_26;
> > - else if(check_5level_paging())
> > - info->max_physmem_bits = _MAX_PHYSMEM_BITS_5LEVEL;
> > - else
> > - info->max_physmem_bits = _MAX_PHYSMEM_BITS_2_6_31;
> > + /* Check if we can get MAX_PHYSMEM_BITS from vmcoreinfo */
> > + if (NUMBER(MAX_PHYSMEM_BITS) != NOT_FOUND_NUMBER) {
> > + info->max_physmem_bits = NUMBER(MAX_PHYSMEM_BITS);
> > + } else {
> > + /*
> > + * On linux-2.6.26, MAX_PHYSMEM_BITS is changed to 44 from 40.
> > + */
> > + if (info->kernel_version < KERNEL_VERSION(2, 6, 26))
> > + info->max_physmem_bits = _MAX_PHYSMEM_BITS_ORIG;
> > + else if (info->kernel_version < KERNEL_VERSION(2, 6, 31))
> > + info->max_physmem_bits = _MAX_PHYSMEM_BITS_2_6_26;
> > + else if(check_5level_paging())
> > + info->max_physmem_bits = _MAX_PHYSMEM_BITS_5LEVEL;
> > + else
> > + info->max_physmem_bits = _MAX_PHYSMEM_BITS_2_6_31;
> > + }
> >
> > if (!get_page_offset_x86_64())
> > return FALSE;
> > --
> > 2.7.4
> >
>
>
>
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