Commit f88f06e1 authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Greg Kroah-Hartman

arm64: assembler: make adr_l work in modules under KASLR


[ Upstream commit 41c066f2 ]

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: default avatarMark Rutland <mark.rutland@arm.com>
Acked-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: default avatarSasha Levin <alexander.levin@verizon.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent aabb797b
...@@ -155,22 +155,25 @@ lr .req x30 // link register ...@@ -155,22 +155,25 @@ lr .req x30 // link register
/* /*
* Pseudo-ops for PC-relative adr/ldr/str <reg>, <symbol> where * 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) * @dst: destination register (64 bit wide)
* @sym: name of the symbol * @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= .macro adr_l, dst, sym
.ifb \tmp #ifndef MODULE
adrp \dst, \sym adrp \dst, \sym
add \dst, \dst, :lo12:\sym add \dst, \dst, :lo12:\sym
.else #else
adrp \tmp, \sym movz \dst, #:abs_g3:\sym
add \dst, \tmp, :lo12:\sym movk \dst, #:abs_g2_nc:\sym
.endif movk \dst, #:abs_g1_nc:\sym
movk \dst, #:abs_g0_nc:\sym
#endif
.endm .endm
/* /*
...@@ -181,6 +184,7 @@ lr .req x30 // link register ...@@ -181,6 +184,7 @@ lr .req x30 // link register
* the address * the address
*/ */
.macro ldr_l, dst, sym, tmp= .macro ldr_l, dst, sym, tmp=
#ifndef MODULE
.ifb \tmp .ifb \tmp
adrp \dst, \sym adrp \dst, \sym
ldr \dst, [\dst, :lo12:\sym] ldr \dst, [\dst, :lo12:\sym]
...@@ -188,6 +192,15 @@ lr .req x30 // link register ...@@ -188,6 +192,15 @@ lr .req x30 // link register
adrp \tmp, \sym adrp \tmp, \sym
ldr \dst, [\tmp, :lo12:\sym] ldr \dst, [\tmp, :lo12:\sym]
.endif .endif
#else
.ifb \tmp
adr_l \dst, \sym
ldr \dst, [\dst]
.else
adr_l \tmp, \sym
ldr \dst, [\tmp]
.endif
#endif
.endm .endm
/* /*
...@@ -197,8 +210,13 @@ lr .req x30 // link register ...@@ -197,8 +210,13 @@ lr .req x30 // link register
* while <src> needs to be preserved. * while <src> needs to be preserved.
*/ */
.macro str_l, src, sym, tmp .macro str_l, src, sym, tmp
#ifndef MODULE
adrp \tmp, \sym adrp \tmp, \sym
str \src, [\tmp, :lo12:\sym] str \src, [\tmp, :lo12:\sym]
#else
adr_l \tmp, \sym
str \src, [\tmp]
#endif
.endm .endm
/* /*
......
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