diff options
| author |   Christophe Leroy <christophe.leroy@csgroup.eu> | 2021-12-06 11:11:51 +0000 |
|---|---|---|
| committer |   Michael Ellerman <mpe@ellerman.id.au> | 2022-01-24 17:29:05 +1100 |
| commit | aec982603aa8cc0a21143681feb5f60ecc69d718 (patch) | |
| tree | e797e9cab54093ca7f58fc9e87a691b3d266904d /arch/powerpc/mm/pgtable.c | |
| parent | Merge tag 'powerpc-5.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux (diff) | |
| download | linux-dev-aec982603aa8cc0a21143681feb5f60ecc69d718.tar.xz linux-dev-aec982603aa8cc0a21143681feb5f60ecc69d718.zip | |
powerpc/fixmap: Fix VM debug warning on unmap
Unmapping a fixmap entry is done by calling __set_fixmap()
with FIXMAP_PAGE_CLEAR as flags.
Today, powerpc __set_fixmap() calls map_kernel_page().
map_kernel_page() is not happy when called a second time
for the same page.
WARNING: CPU: 0 PID: 1 at arch/powerpc/mm/pgtable.c:194 set_pte_at+0xc/0x1e8
CPU: 0 PID: 1 Comm: swapper Not tainted 5.16.0-rc3-s3k-dev-01993-g350ff07feb7d-dirty #682
NIP: c0017cd4 LR: c00187f0 CTR: 00000010
REGS: e1011d50 TRAP: 0700 Not tainted (5.16.0-rc3-s3k-dev-01993-g350ff07feb7d-dirty)
MSR: 00029032 <EE,ME,IR,DR,RI> CR: 42000208 XER: 00000000
GPR00: c0165fec e1011e10 c14c0000 c0ee2550 ff800000 c0f3d000 00000000 c001686c
GPR08: 00001000 b00045a9 00000001 c0f58460 c0f50000 00000000 c0007e10 00000000
GPR16: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
GPR24: 00000000 00000000 c0ee2550 00000000 c0f57000 00000ff8 00000000 ff800000
NIP [c0017cd4] set_pte_at+0xc/0x1e8
LR [c00187f0] map_kernel_page+0x9c/0x100
Call Trace:
[e1011e10] [c0736c68] vsnprintf+0x358/0x6c8 (unreliable)
[e1011e30] [c0165fec] __set_fixmap+0x30/0x44
[e1011e40] [c0c13bdc] early_iounmap+0x11c/0x170
[e1011e70] [c0c06cb0] ioremap_legacy_serial_console+0x88/0xc0
[e1011e90] [c0c03634] do_one_initcall+0x80/0x178
[e1011ef0] [c0c0385c] kernel_init_freeable+0xb4/0x250
[e1011f20] [c0007e34] kernel_init+0x24/0x140
[e1011f30] [c0016268] ret_from_kernel_thread+0x5c/0x64
Instruction dump:
7fe3fb78 48019689 80010014 7c630034 83e1000c 5463d97e 7c0803a6 38210010
4e800020 81250000 712a0001 41820008 <0fe00000> 9421ffe0 93e1001c 48000030
Implement unmap_kernel_page() which clears an existing pte.
Reported-by: Maxime Bizon <mbizon@freebox.fr>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Tested-by: Maxime Bizon <mbizon@freebox.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/b0b752f6f6ecc60653e873f385c6f0dce4e9ab6a.1638789098.git.christophe.leroy@csgroup.eu
Diffstat (limited to 'arch/powerpc/mm/pgtable.c')
| -rw-r--r-- | arch/powerpc/mm/pgtable.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/powerpc/mm/pgtable.c b/arch/powerpc/mm/pgtable.c index abb3198bd277..6ec5a7dd7913 100644 --- a/arch/powerpc/mm/pgtable.c +++ b/arch/powerpc/mm/pgtable.c @@ -206,6 +206,15 @@ void set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, __set_pte_at(mm, addr, ptep, pte, 0); } +void unmap_kernel_page(unsigned long va) +{ + pmd_t *pmdp = pmd_off_k(va); + pte_t *ptep = pte_offset_kernel(pmdp, va); + + pte_clear(&init_mm, va, ptep); + flush_tlb_kernel_range(va, va + PAGE_SIZE); +} + /* * This is called when relaxing access to a PTE. It's also called in the page * fault path when we don't hit any of the major fault cases, ie, a minor |