[PATCH] powerpc/mm: fix early initialization failure for MMUs with no hash table

From: Vladimir Oltean
Date: Fri Nov 26 2021 - 21:07:20 EST


The blamed patch attempted to do a trivial conversion of
map_mem_in_cams() by adding an extra "bool init" argument, but by
mistake, changed the way in which two call sites pass the other boolean
argument, "bool dry_run".

As a result, early_init_this_mmu() now calls map_mem_in_cams() with
dry_run=true, and setup_initial_memory_limit() calls with dry_run=false,
both of which are unintended changes.

This makes the kernel boot process hang here:

[ 0.045211] e500 family performance monitor hardware support registered
[ 0.051891] rcu: Hierarchical SRCU implementation.
[ 0.057791] smp: Bringing up secondary CPUs ...

Issue noticed on a Freescale T1040.

Fixes: 52bda69ae8b5 ("powerpc/fsl_booke: Tell map_mem_in_cams() if init is done")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Vladimir Oltean <vladimir.oltean@xxxxxxx>
---
arch/powerpc/mm/nohash/tlb.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/mm/nohash/tlb.c b/arch/powerpc/mm/nohash/tlb.c
index 89353d4f5604..647bf454a0fa 100644
--- a/arch/powerpc/mm/nohash/tlb.c
+++ b/arch/powerpc/mm/nohash/tlb.c
@@ -645,7 +645,7 @@ static void early_init_this_mmu(void)

if (map)
linear_map_top = map_mem_in_cams(linear_map_top,
- num_cams, true, true);
+ num_cams, false, true);
}
#endif

@@ -766,7 +766,7 @@ void setup_initial_memory_limit(phys_addr_t first_memblock_base,
num_cams = (mfspr(SPRN_TLB1CFG) & TLBnCFG_N_ENTRY) / 4;

linear_sz = map_mem_in_cams(first_memblock_size, num_cams,
- false, true);
+ true, true);

ppc64_rma_size = min_t(u64, linear_sz, 0x40000000);
} else
--
2.25.1