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| author | Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2017-01-11 17:54:53 +0300 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2017-01-12 21:10:52 +0300 |
| commit | 41c066f2c4d436c535616fe182331766c57838f0 (patch) | |
| tree | a805b9567c20c7d8b3853d57b6915b80ca7c5b49 /arch/arm64 | |
| parent | 69d012345a1a32d3f03957f14d972efccc106a98 (diff) | |
| download | linux-41c066f2c4d436c535616fe182331766c57838f0.tar.xz | |
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>
Diffstat (limited to 'arch/arm64')
| -rw-r--r-- | arch/arm64/include/asm/assembler.h | 36 |
1 files changed, 27 insertions, 9 deletions
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h index 446f6c46d4b1..3a4301163e04 100644 --- a/arch/arm64/include/asm/assembler.h +++ b/arch/arm64/include/asm/assembler.h @@ -164,22 +164,25 @@ lr .req x30 // link register /* * Pseudo-ops for PC-relative adr/ldr/str <reg>, <symbol> where - * <symbol> is within the range +/- 4 GB of the PC. + * <symbol> is within the range +/- 4 GB of the PC when running + * in core kernel context. In module context, a movz/movk sequence + * is used, since modules may be loaded far away from the kernel + * when KASLR is in effect. */ /* * @dst: destination register (64 bit wide) * @sym: name of the symbol - * @tmp: optional scratch register to be used if <dst> == sp, which - * is not allowed in an adrp instruction */ - .macro adr_l, dst, sym, tmp= - .ifb \tmp + .macro adr_l, dst, sym +#ifndef MODULE adrp \dst, \sym add \dst, \dst, :lo12:\sym - .else - adrp \tmp, \sym - add \dst, \tmp, :lo12:\sym - .endif +#else + movz \dst, #:abs_g3:\sym + movk \dst, #:abs_g2_nc:\sym + movk \dst, #:abs_g1_nc:\sym + movk \dst, #:abs_g0_nc:\sym +#endif .endm /* @@ -190,6 +193,7 @@ lr .req x30 // link register * the address */ .macro ldr_l, dst, sym, tmp= +#ifndef MODULE .ifb \tmp adrp \dst, \sym ldr \dst, [\dst, :lo12:\sym] @@ -197,6 +201,15 @@ lr .req x30 // link register adrp \tmp, \sym ldr \dst, [\tmp, :lo12:\sym] .endif +#else + .ifb \tmp + adr_l \dst, \sym + ldr \dst, [\dst] + .else + adr_l \tmp, \sym + ldr \dst, [\tmp] + .endif +#endif .endm /* @@ -206,8 +219,13 @@ lr .req x30 // link register * while <src> needs to be preserved. */ .macro str_l, src, sym, tmp +#ifndef MODULE adrp \tmp, \sym str \src, [\tmp, :lo12:\sym] +#else + adr_l \tmp, \sym + str \src, [\tmp] +#endif .endm /* |