linux-kernel - [PATCH AUTOSEL 5.15 5/9] powerpc/mm: Fix boot warning with hugepages and CONFIG_DEBUG

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Message-ID: <20240823140507.1975524-5-sashal@kernel.org>
Date: Fri, 23 Aug 2024 10:04:52 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Cc: Christophe Leroy <christophe.leroy@...roup.eu>,
	Michael Ellerman <mpe@...erman.id.au>,
	Sasha Levin <sashal@...nel.org>,
	hbathini@...ux.ibm.com,
	robh@...nel.org,
	rostedt@...dmis.org,
	thorsten.blum@...lux.com,
	willy@...radead.org,
	arnd@...db.de,
	philmd@...aro.org,
	akpm@...ux-foundation.org,
	tzimmermann@...e.de,
	kent.overstreet@...ux.dev,
	rppt@...nel.org,
	linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH AUTOSEL 5.15 5/9] powerpc/mm: Fix boot warning with hugepages and CONFIG_DEBUG_VIRTUAL

From: Christophe Leroy <christophe.leroy@...roup.eu>

[ Upstream commit e7e846dc6c73fbc94ae8b4ec20d05627646416f2 ]

Booting with CONFIG_DEBUG_VIRTUAL leads to following warning when
passing hugepage reservation on command line:

  Kernel command line: hugepagesz=1g hugepages=1 hugepagesz=64m hugepages=1 hugepagesz=256m hugepages=1 noreboot
  HugeTLB: allocating 1 of page size 1.00 GiB failed.  Only allocated 0 hugepages.
  ------------[ cut here ]------------
  WARNING: CPU: 0 PID: 0 at arch/powerpc/include/asm/io.h:948 __alloc_bootmem_huge_page+0xd4/0x284
  Modules linked in:
  CPU: 0 PID: 0 Comm: swapper Not tainted 6.10.0-rc6-00396-g6b0e82791bd0-dirty #936
  Hardware name: MPC8544DS e500v2 0x80210030 MPC8544 DS
  NIP:  c1020240 LR: c10201d0 CTR: 00000000
  REGS: c13fdd30 TRAP: 0700   Not tainted  (6.10.0-rc6-00396-g6b0e82791bd0-dirty)
  MSR:  00021000 <CE,ME>  CR: 44084288  XER: 20000000

  GPR00: c10201d0 c13fde20 c130b560 e8000000 e8001000 00000000 00000000 c1420000
  GPR08: 00000000 00028001 00000000 00000004 44084282 01066ac0 c0eb7c9c efffe149
  GPR16: c0fc4228 0000005f ffffffff c0eb7d0c c0eb7cc0 c0eb7ce0 ffffffff 00000000
  GPR24: c1441cec efffe153 e8001000 c14240c0 00000000 c1441d64 00000000 e8000000
  NIP [c1020240] __alloc_bootmem_huge_page+0xd4/0x284
  LR [c10201d0] __alloc_bootmem_huge_page+0x64/0x284
  Call Trace:
  [c13fde20] [c10201d0] __alloc_bootmem_huge_page+0x64/0x284 (unreliable)
  [c13fde50] [c10207b8] hugetlb_hstate_alloc_pages+0x8c/0x3e8
  [c13fdeb0] [c1021384] hugepages_setup+0x240/0x2cc
  [c13fdef0] [c1000574] unknown_bootoption+0xfc/0x280
  [c13fdf30] [c0078904] parse_args+0x200/0x4c4
  [c13fdfa0] [c1000d9c] start_kernel+0x238/0x7d0
  [c13fdff0] [c0000434] set_ivor+0x12c/0x168
  Code: 554aa33e 7c042840 3ce0c142 80a7427c 5109a016 50caa016 7c9a2378 7fdcf378 4180000c 7c052040 41810160 7c095040 <0fe00000> 38c00000 40800108 3c60c0eb
  ---[ end trace 0000000000000000 ]---

This is due to virt_addr_valid() using high_memory before it is set.

high_memory is set in mem_init() using max_low_pfn, but max_low_pfn
is available long before, it is set in mem_topology_setup(). So just
like commit daa9ada2093e ("powerpc/mm: Fix boot crash with FLATMEM")
moved the setting of max_mapnr immediately after the call to
mem_topology_setup(), the same can be done for high_memory.

Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
Signed-off-by: Michael Ellerman <mpe@...erman.id.au>
Link: https://msgid.link/62b69c4baad067093f39e7e60df0fe27a86b8d2a.1723100702.git.christophe.leroy@csgroup.eu
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 arch/powerpc/kernel/setup-common.c | 1 +
 arch/powerpc/mm/mem.c              | 2 --
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index 42338e2921d64..6192088159a91 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -889,6 +889,7 @@ void __init setup_arch(char **cmdline_p)
 	mem_topology_setup();
 	/* Set max_mapnr before paging_init() */
 	set_max_mapnr(max_pfn);
+	high_memory = (void *)__va(max_low_pfn * PAGE_SIZE);
 
 	/*
 	 * Release secondary cpus out of their spinloops at 0x60 now that
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 01fc77564cac1..b26c0fa776de0 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -287,8 +287,6 @@ void __init mem_init(void)
 		swiotlb_init(0);
 #endif
 
-	high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);
-
 	kasan_late_init();
 
 	memblock_free_all();
-- 
2.43.0