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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
123 lines
3.6 KiB
C
123 lines
3.6 KiB
C
/*
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* fixmap.h: compile-time virtual memory allocation
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (C) 1998 Ingo Molnar
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*
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* Copyright 2008 Freescale Semiconductor Inc.
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* Port to powerpc added by Kumar Gala
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*/
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#ifndef _ASM_FIXMAP_H
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#define _ASM_FIXMAP_H
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#ifndef __ASSEMBLY__
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#include <linux/sizes.h>
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#include <linux/pgtable.h>
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#include <asm/page.h>
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#ifdef CONFIG_HIGHMEM
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#include <linux/threads.h>
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#include <asm/kmap_size.h>
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#endif
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#ifdef CONFIG_PPC64
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#define FIXADDR_TOP (IOREMAP_END + FIXADDR_SIZE)
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#else
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#define FIXADDR_SIZE 0
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#ifdef CONFIG_KASAN
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#include <asm/kasan.h>
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#define FIXADDR_TOP (KASAN_SHADOW_START - PAGE_SIZE)
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#else
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#define FIXADDR_TOP ((unsigned long)(-PAGE_SIZE))
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#endif
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#endif
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/*
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* Here we define all the compile-time 'special' virtual
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* addresses. The point is to have a constant address at
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* compile time, but to set the physical address only
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* in the boot process. We allocate these special addresses
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* from the end of virtual memory (0xfffff000) backwards.
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* Also this lets us do fail-safe vmalloc(), we
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* can guarantee that these special addresses and
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* vmalloc()-ed addresses never overlap.
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*
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* these 'compile-time allocated' memory buffers are
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* fixed-size 4k pages. (or larger if used with an increment
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* highger than 1) use fixmap_set(idx,phys) to associate
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* physical memory with fixmap indices.
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*
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* TLB entries of such buffers will not be flushed across
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* task switches.
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*/
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enum fixed_addresses {
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FIX_HOLE,
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#ifdef CONFIG_PPC32
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/* reserve the top 128K for early debugging purposes */
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FIX_EARLY_DEBUG_TOP = FIX_HOLE,
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FIX_EARLY_DEBUG_BASE = FIX_EARLY_DEBUG_TOP+(ALIGN(SZ_128K, PAGE_SIZE)/PAGE_SIZE)-1,
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#ifdef CONFIG_HIGHMEM
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FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */
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FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_MAX_IDX * NR_CPUS) - 1,
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#endif
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#ifdef CONFIG_PPC_8xx
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/* For IMMR we need an aligned 512K area */
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#define FIX_IMMR_SIZE (512 * 1024 / PAGE_SIZE)
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FIX_IMMR_START,
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FIX_IMMR_BASE = __ALIGN_MASK(FIX_IMMR_START, FIX_IMMR_SIZE - 1) - 1 +
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FIX_IMMR_SIZE,
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#endif
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#ifdef CONFIG_PPC_83xx
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/* For IMMR we need an aligned 2M area */
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#define FIX_IMMR_SIZE (SZ_2M / PAGE_SIZE)
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FIX_IMMR_START,
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FIX_IMMR_BASE = __ALIGN_MASK(FIX_IMMR_START, FIX_IMMR_SIZE - 1) - 1 +
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FIX_IMMR_SIZE,
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#endif
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/* FIX_PCIE_MCFG, */
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#endif /* CONFIG_PPC32 */
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__end_of_permanent_fixed_addresses,
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#define NR_FIX_BTMAPS (SZ_256K / PAGE_SIZE)
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#define FIX_BTMAPS_SLOTS 16
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#define TOTAL_FIX_BTMAPS (NR_FIX_BTMAPS * FIX_BTMAPS_SLOTS)
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FIX_BTMAP_END = __end_of_permanent_fixed_addresses,
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FIX_BTMAP_BEGIN = FIX_BTMAP_END + TOTAL_FIX_BTMAPS - 1,
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__end_of_fixed_addresses
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};
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#define __FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
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#define FIXADDR_START (FIXADDR_TOP - __FIXADDR_SIZE)
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#define FIXMAP_ALIGNED_SIZE (ALIGN(FIXADDR_TOP, PGDIR_SIZE) - \
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ALIGN_DOWN(FIXADDR_START, PGDIR_SIZE))
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#define FIXMAP_PTE_SIZE (FIXMAP_ALIGNED_SIZE / PGDIR_SIZE * PTE_TABLE_SIZE)
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#define FIXMAP_PAGE_NOCACHE PAGE_KERNEL_NCG
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#define FIXMAP_PAGE_IO PAGE_KERNEL_NCG
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#include <asm-generic/fixmap.h>
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static inline void __set_fixmap(enum fixed_addresses idx,
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phys_addr_t phys, pgprot_t flags)
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{
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BUILD_BUG_ON(IS_ENABLED(CONFIG_PPC64) && __FIXADDR_SIZE > FIXADDR_SIZE);
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if (__builtin_constant_p(idx))
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BUILD_BUG_ON(idx >= __end_of_fixed_addresses);
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else if (WARN_ON(idx >= __end_of_fixed_addresses))
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return;
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if (pgprot_val(flags))
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map_kernel_page(__fix_to_virt(idx), phys, flags);
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else
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unmap_kernel_page(__fix_to_virt(idx));
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}
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#define __early_set_fixmap __set_fixmap
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#endif /* !__ASSEMBLY__ */
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#endif
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