#ifndef __ASM_GENERIC_CMPXCHG_LOCAL_H #define __ASM_GENERIC_CMPXCHG_LOCAL_H #include #include extern unsigned long wrong_size_cmpxchg(volatile void *ptr) __noreturn; /* * Generic version of __cmpxchg_local (disables interrupts). Takes an unsigned * long parameter, supporting various types of architectures. */ static inline unsigned long __cmpxchg_local_generic(volatile void *ptr, unsigned long old, unsigned long new, int size) { unsigned long flags, prev; /* * Sanity checking, compile-time. */ if (size == 8 && sizeof(unsigned long) != 8) wrong_size_cmpxchg(ptr); raw_local_irq_save(flags); switch (size) { case 1: prev = *(u8 *)ptr; if (prev == old) *(u8 *)ptr = (u8)new; break; case 2: prev = *(u16 *)ptr; if (prev == old) *(u16 *)ptr = (u16)new; break; case 4: prev = *(u32 *)ptr; if (prev == old) *(u32 *)ptr = (u32)new; break; case 8: prev = *(u64 *)ptr; if (prev == old) *(u64 *)ptr = (u64)new; break; default: wrong_size_cmpxchg(ptr); } raw_local_irq_restore(flags); return prev; } /* * Generic version of __cmpxchg64_local. Takes an u64 parameter. */ static inline u64 __cmpxchg64_local_generic(volatile void *ptr, u64 old, u64 new) { u64 prev; unsigned long flags; raw_local_irq_save(flags); prev = *(u64 *)ptr; if (prev == old) *(u64 *)ptr = new; raw_local_irq_restore(flags); return prev; } #endif lass='sub right'>Tobias Klauser
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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2017-02-01 17:45:02 +0000
committerIngo Molnar <mingo@kernel.org>2017-02-01 21:17:49 +0100
commitc8f325a59cfc718d13a50fbc746ed9b415c25e92 (patch)
treed53fbdac9d0781e39a13b2ac6b2bd258cf3b4140 /net/ipv6/ip6_vti.c
parentbf29bddf0417a4783da3b24e8c9e017ac649326f (diff)
efi/fdt: Avoid FDT manipulation after ExitBootServices()
Some AArch64 UEFI implementations disable the MMU in ExitBootServices(), after which unaligned accesses to RAM are no longer supported. Commit: abfb7b686a3e ("efi/libstub/arm*: Pass latest memory map to the kernel") fixed an issue in the memory map handling of the stub FDT code, but inadvertently created an issue with such firmware, by moving some of the FDT manipulation to after the invocation of ExitBootServices(). Given that the stub's libfdt implementation uses the ordinary, accelerated string functions, which rely on hardware handling of unaligned accesses, manipulating the FDT with the MMU off may result in alignment faults. So fix the situation by moving the update_fdt_memmap() call into the callback function invoked by efi_exit_boot_services() right before it calls the ExitBootServices() UEFI service (which is arguably a better place for it anyway) Note that disabling the MMU in ExitBootServices() is not compliant with the UEFI spec, and carries great risk due to the fact that switching from cached to uncached memory accesses halfway through compiler generated code (i.e., involving a stack) can never be done in a way that is architecturally safe. Fixes: abfb7b686a3e ("efi/libstub/arm*: Pass latest memory map to the kernel") Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Tested-by: Riku Voipio <riku.voipio@linaro.org> Cc: <stable@vger.kernel.org> Cc: mark.rutland@arm.com Cc: linux-efi@vger.kernel.org Cc: matt@codeblueprint.co.uk Cc: leif.lindholm@linaro.org Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/1485971102-23330-2-git-send-email-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'net/ipv6/ip6_vti.c')