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arm: vectors: use local symbol names for vector entry points
maillist inclusion commit 11f8bbc5b0d4d76b3d7114bf9af1805607a20372 category: feature feature: ARM kaslr support bugzilla: 47952 CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/ardb/linux.git/commit/?h=arm-kaslr-latest&id=11f8bbc5b0d4d76b3d7114bf9af1805607a20372 ------------------------------------------------- The location of the ARM vector table in virtual memory is not a compile time constant, and so the virtual addresses of the various entry points are rather meaningless (although they are most likely to reside at the offsets below) ffff1004 t vector_rst ffff1020 t vector_irq ffff10a0 t vector_dabt ffff1120 t vector_pabt ffff11a0 t vector_und ffff1220 t vector_addrexcptn ffff1240 T vector_fiq However, when running with KASLR enabled, the virtual addresses are subject to runtime relocation, which means we should avoid to take absolute references to these symbols, not only directly (by taking the address in C code), but also via /proc/kallsyms or other kernel facilities that deal with ELF symbols. For instance, /proc/kallsyms will list their addresses as 0abf1004 t vector_rst 0abf1020 t vector_irq 0abf10a0 t vector_dabt 0abf1120 t vector_pabt 0abf11a0 t vector_und 0abf1220 t vector_addrexcptn 0abf1240 T vector_fiq when running randomized, which may confuse tools like perf that may use /proc/kallsyms to annotate stack traces. So use .L prefixes for these symbols. This will prevent them from being visible at all outside the assembler source. Signed-off-by:Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: