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powerpc/mm/book3s64: Fix build error with SPARSEMEM disabled

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With CONFIG_SPARSEMEM disabled the below kernel build error is observed.

 arch/powerpc/mm/init_64.c:477:38: error: use of undeclared identifier 'SECTION_SIZE_BITS'

CONFIG_MEMORY_HOTPLUG depends on CONFIG_SPARSEMEM and it is more clear
to describe the code dependency in terms of MEMORY_HOTPLUG. Outside
memory hotplug the kernel uses memory_block_size for kernel directmap.
Instead of depending on SECTION_SIZE_BITS to compute the direct map
page size, add a new #define which defaults to 16M(same as existing
SECTION_SIZE)

Fixes: 4d15721177 ("powerpc/mm: Cleanup memory block size probing")
Signed-off-by: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202308251532.k9PpWEAD-lkp@intel.com/
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230828074658.59553-1-aneesh.kumar@linux.ibm.com
This commit is contained in:
Aneesh Kumar K.V 2023-08-28 13:16:57 +05:30 committed by Michael Ellerman
parent c37b6908f7
commit f1424755db
1 changed files with 15 additions and 4 deletions
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19
arch/powerpc/mm/init_64.c
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@ -472,12 +472,23 @@ static int __init dt_scan_mmu_pid_width(unsigned long node,
return 1;
}
/*
* Outside hotplug the kernel uses this value to map the kernel direct map
* with radix. To be compatible with older kernels, let's keep this value
* as 16M which is also SECTION_SIZE with SPARSEMEM. We can ideally map
* things with 1GB size in the case where we don't support hotplug.
*/
#ifndef CONFIG_MEMORY_HOTPLUG
#define DEFAULT_MEMORY_BLOCK_SIZE SZ_16M
#else
#define DEFAULT_MEMORY_BLOCK_SIZE MIN_MEMORY_BLOCK_SIZE
#endif
static void update_memory_block_size(unsigned long *block_size, unsigned long mem_size)
{
unsigned long section_size = 1UL << SECTION_SIZE_BITS;
for (; *block_size > section_size; *block_size >>= 2) {
unsigned long min_memory_block_size = DEFAULT_MEMORY_BLOCK_SIZE;
for (; *block_size > min_memory_block_size; *block_size >>= 2) {
if ((mem_size & *block_size) == 0)
break;
}
@ -507,7 +518,7 @@ static int __init probe_memory_block_size(unsigned long node, const char *uname,
/*
* Nothing in the device tree
*/
*block_size = MIN_MEMORY_BLOCK_SIZE;
*block_size = DEFAULT_MEMORY_BLOCK_SIZE;
else
*block_size = of_read_number(prop, dt_root_size_cells);
/*