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authorChristophe Leroy <christophe.leroy@csgroup.eu>2021-12-06 12:11:51 +0100
committerMichael Ellerman <mpe@ellerman.id.au>2022-01-24 07:29:05 +0100
commitaec982603aa8cc0a21143681feb5f60ecc69d718 (patch)
treee797e9cab54093ca7f58fc9e87a691b3d266904d /arch/powerpc
parentMerge tag 'powerpc-5.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git/p... (diff)
downloadlinux-aec982603aa8cc0a21143681feb5f60ecc69d718.tar.xz
linux-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')
-rw-r--r--arch/powerpc/include/asm/book3s/32/pgtable.h1
-rw-r--r--arch/powerpc/include/asm/book3s/64/pgtable.h2
-rw-r--r--arch/powerpc/include/asm/fixmap.h6
-rw-r--r--arch/powerpc/include/asm/nohash/32/pgtable.h1
-rw-r--r--arch/powerpc/include/asm/nohash/64/pgtable.h1
-rw-r--r--arch/powerpc/mm/pgtable.c9
6 files changed, 18 insertions, 2 deletions
diff --git a/arch/powerpc/include/asm/book3s/32/pgtable.h b/arch/powerpc/include/asm/book3s/32/pgtable.h
index 609c80f67194..f8b94f78403f 100644
--- a/arch/powerpc/include/asm/book3s/32/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/32/pgtable.h
@@ -178,6 +178,7 @@ static inline bool pte_user(pte_t pte)
#ifndef __ASSEMBLY__
int map_kernel_page(unsigned long va, phys_addr_t pa, pgprot_t prot);
+void unmap_kernel_page(unsigned long va);
#endif /* !__ASSEMBLY__ */
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 33e073d6b0c4..875730d5af40 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -1082,6 +1082,8 @@ static inline int map_kernel_page(unsigned long ea, unsigned long pa, pgprot_t p
return hash__map_kernel_page(ea, pa, prot);
}
+void unmap_kernel_page(unsigned long va);
+
static inline int __meminit vmemmap_create_mapping(unsigned long start,
unsigned long page_size,
unsigned long phys)
diff --git a/arch/powerpc/include/asm/fixmap.h b/arch/powerpc/include/asm/fixmap.h
index 947b5b9c4424..a832aeafe560 100644
--- a/arch/powerpc/include/asm/fixmap.h
+++ b/arch/powerpc/include/asm/fixmap.h
@@ -111,8 +111,10 @@ static inline void __set_fixmap(enum fixed_addresses idx,
BUILD_BUG_ON(idx >= __end_of_fixed_addresses);
else if (WARN_ON(idx >= __end_of_fixed_addresses))
return;
-
- map_kernel_page(__fix_to_virt(idx), phys, flags);
+ if (pgprot_val(flags))
+ map_kernel_page(__fix_to_virt(idx), phys, flags);
+ else
+ unmap_kernel_page(__fix_to_virt(idx));
}
#define __early_set_fixmap __set_fixmap
diff --git a/arch/powerpc/include/asm/nohash/32/pgtable.h b/arch/powerpc/include/asm/nohash/32/pgtable.h
index b67742e2a9b2..d959c2a73fbf 100644
--- a/arch/powerpc/include/asm/nohash/32/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/32/pgtable.h
@@ -64,6 +64,7 @@ extern int icache_44x_need_flush;
#ifndef __ASSEMBLY__
int map_kernel_page(unsigned long va, phys_addr_t pa, pgprot_t prot);
+void unmap_kernel_page(unsigned long va);
#endif /* !__ASSEMBLY__ */
diff --git a/arch/powerpc/include/asm/nohash/64/pgtable.h b/arch/powerpc/include/asm/nohash/64/pgtable.h
index a3313e853e5e..2816d158280a 100644
--- a/arch/powerpc/include/asm/nohash/64/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/64/pgtable.h
@@ -308,6 +308,7 @@ static inline void __ptep_set_access_flags(struct vm_area_struct *vma,
#define __swp_entry_to_pte(x) __pte((x).val)
int map_kernel_page(unsigned long ea, unsigned long pa, pgprot_t prot);
+void unmap_kernel_page(unsigned long va);
extern int __meminit vmemmap_create_mapping(unsigned long start,
unsigned long page_size,
unsigned long phys);
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