arm64: assembler: make adr_l work in modules under KASLR
When CONFIG_RANDOMIZE_MODULE_REGION_FULL=y, the offset between loaded modules and the core kernel may exceed 4 GB, putting symbols exported by the core kernel out of the reach of the ordinary adrp/add instruction pairs used to generate relative symbol references. So make the adr_l macro emit a movz/movk sequence instead when executing in module context. While at it, remove the pointless special case for the stack pointer. Acked-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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@ -164,22 +164,25 @@ lr .req x30 // link register
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/*
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* Pseudo-ops for PC-relative adr/ldr/str <reg>, <symbol> where
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* <symbol> is within the range +/- 4 GB of the PC.
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* <symbol> is within the range +/- 4 GB of the PC when running
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* in core kernel context. In module context, a movz/movk sequence
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* is used, since modules may be loaded far away from the kernel
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* when KASLR is in effect.
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*/
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/*
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* @dst: destination register (64 bit wide)
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* @sym: name of the symbol
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* @tmp: optional scratch register to be used if <dst> == sp, which
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* is not allowed in an adrp instruction
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*/
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.macro adr_l, dst, sym, tmp=
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.ifb \tmp
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.macro adr_l, dst, sym
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#ifndef MODULE
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adrp \dst, \sym
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add \dst, \dst, :lo12:\sym
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.else
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adrp \tmp, \sym
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add \dst, \tmp, :lo12:\sym
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.endif
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#else
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movz \dst, #:abs_g3:\sym
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movk \dst, #:abs_g2_nc:\sym
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movk \dst, #:abs_g1_nc:\sym
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movk \dst, #:abs_g0_nc:\sym
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#endif
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.endm
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/*
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@ -190,6 +193,7 @@ lr .req x30 // link register
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* the address
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*/
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.macro ldr_l, dst, sym, tmp=
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#ifndef MODULE
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.ifb \tmp
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adrp \dst, \sym
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ldr \dst, [\dst, :lo12:\sym]
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@ -197,6 +201,15 @@ lr .req x30 // link register
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adrp \tmp, \sym
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ldr \dst, [\tmp, :lo12:\sym]
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.endif
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#else
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.ifb \tmp
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adr_l \dst, \sym
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ldr \dst, [\dst]
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.else
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adr_l \tmp, \sym
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ldr \dst, [\tmp]
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.endif
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#endif
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.endm
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/*
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@ -206,8 +219,13 @@ lr .req x30 // link register
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* while <src> needs to be preserved.
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*/
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.macro str_l, src, sym, tmp
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#ifndef MODULE
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adrp \tmp, \sym
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str \src, [\tmp, :lo12:\sym]
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#else
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adr_l \tmp, \sym
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str \src, [\tmp]
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#endif
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.endm
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/*
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