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51c3c62b58
This stops us from doing code patching in init sections after they've
been freed.
In this chain:
kvm_guest_init() ->
kvm_use_magic_page() ->
fault_in_pages_readable() ->
__get_user() ->
__get_user_nocheck() ->
barrier_nospec();
We have a code patching location at barrier_nospec() and
kvm_guest_init() is an init function. This whole chain gets inlined,
so when we free the init section (hence kvm_guest_init()), this code
goes away and hence should no longer be patched.
We seen this as userspace memory corruption when using a memory
checker while doing partition migration testing on powervm (this
starts the code patching post migration via
/sys/kernel/mobility/migration). In theory, it could also happen when
using /sys/kernel/debug/powerpc/barrier_nospec.
Cc: stable@vger.kernel.org # 4.13+
Signed-off-by: Michael Neuling <mikey@neuling.org>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
74 lines
2.1 KiB
C
74 lines
2.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_POWERPC_SETUP_H
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#define _ASM_POWERPC_SETUP_H
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#include <uapi/asm/setup.h>
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#ifndef __ASSEMBLY__
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extern void ppc_printk_progress(char *s, unsigned short hex);
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extern unsigned int rtas_data;
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extern unsigned long long memory_limit;
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extern bool init_mem_is_free;
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extern unsigned long klimit;
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extern void *zalloc_maybe_bootmem(size_t size, gfp_t mask);
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struct device_node;
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extern void note_scsi_host(struct device_node *, void *);
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/* Used in very early kernel initialization. */
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extern unsigned long reloc_offset(void);
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extern unsigned long add_reloc_offset(unsigned long);
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extern void reloc_got2(unsigned long);
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#define PTRRELOC(x) ((typeof(x)) add_reloc_offset((unsigned long)(x)))
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void check_for_initrd(void);
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void mem_topology_setup(void);
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void initmem_init(void);
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void setup_panic(void);
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#define ARCH_PANIC_TIMEOUT 180
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#ifdef CONFIG_PPC_PSERIES
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extern void pseries_enable_reloc_on_exc(void);
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extern void pseries_disable_reloc_on_exc(void);
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extern void pseries_big_endian_exceptions(void);
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extern void pseries_little_endian_exceptions(void);
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#else
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static inline void pseries_enable_reloc_on_exc(void) {}
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static inline void pseries_disable_reloc_on_exc(void) {}
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static inline void pseries_big_endian_exceptions(void) {}
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static inline void pseries_little_endian_exceptions(void) {}
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#endif /* CONFIG_PPC_PSERIES */
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void rfi_flush_enable(bool enable);
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/* These are bit flags */
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enum l1d_flush_type {
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L1D_FLUSH_NONE = 0x1,
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L1D_FLUSH_FALLBACK = 0x2,
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L1D_FLUSH_ORI = 0x4,
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L1D_FLUSH_MTTRIG = 0x8,
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};
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void setup_rfi_flush(enum l1d_flush_type, bool enable);
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void do_rfi_flush_fixups(enum l1d_flush_type types);
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#ifdef CONFIG_PPC_BARRIER_NOSPEC
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void setup_barrier_nospec(void);
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#else
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static inline void setup_barrier_nospec(void) { };
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#endif
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void do_barrier_nospec_fixups(bool enable);
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extern bool barrier_nospec_enabled;
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#ifdef CONFIG_PPC_BARRIER_NOSPEC
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void do_barrier_nospec_fixups_range(bool enable, void *start, void *end);
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#else
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static inline void do_barrier_nospec_fixups_range(bool enable, void *start, void *end) { };
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#endif
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#endif /* !__ASSEMBLY__ */
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#endif /* _ASM_POWERPC_SETUP_H */
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