@@ -101,12 +101,11 @@
.org .Lventry_start\@ + 128 // Did we overflow the ventry slot?
.endm
- .macro tramp_alias, dst, sym, tmp
- mov_q \dst, TRAMP_VALIAS
- adr_l \tmp, \sym
- add \dst, \dst, \tmp
- adr_l \tmp, .entry.tramp.text
- sub \dst, \dst, \tmp
+ .macro tramp_alias, dst, sym
+ .set .Lalias\@, TRAMP_VALIAS + \sym - .entry.tramp.text
+ movz \dst, :abs_g2_s:.Lalias\@
+ movk \dst, :abs_g1_nc:.Lalias\@
+ movk \dst, :abs_g0_nc:.Lalias\@
.endm
/*
@@ -436,8 +435,13 @@ alternative_if_not ARM64_UNMAP_KERNEL_AT_EL0
alternative_else_nop_endif
#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
msr far_el1, x29
- tramp_alias x30, tramp_exit_native, x29
- br x30
+
+ ldr_this_cpu x30, this_cpu_vector, x29
+ tramp_alias x29, tramp_exit
+ msr vbar_el1, x30 // install vector table
+ ldr lr, [sp, #S_LR] // restore x30
+ add sp, sp, #PT_REGS_SIZE // restore sp
+ br x29
#endif
.else
ldr lr, [sp, #S_LR]
@@ -728,20 +732,6 @@ alternative_else_nop_endif
.org 1b + 128 // Did we overflow the ventry slot?
.endm
- .macro tramp_exit, regsize = 64
- tramp_data_read_var x30, this_cpu_vector
- get_this_cpu_offset x29
- ldr x30, [x30, x29]
-
- msr vbar_el1, x30
- ldr lr, [sp, #S_LR]
- tramp_unmap_kernel x29
- mrs x29, far_el1
- add sp, sp, #PT_REGS_SIZE // restore sp
- eret
- sb
- .endm
-
.macro generate_tramp_vector, kpti, bhb
.Lvector_start\@:
.space 0x400
@@ -762,7 +752,7 @@ alternative_else_nop_endif
*/
.pushsection ".entry.tramp.text", "ax"
.align 11
-SYM_CODE_START_NOALIGN(tramp_vectors)
+SYM_CODE_START_LOCAL_NOALIGN(tramp_vectors)
#ifdef CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY
generate_tramp_vector kpti=1, bhb=BHB_MITIGATION_LOOP
generate_tramp_vector kpti=1, bhb=BHB_MITIGATION_FW
@@ -771,9 +761,12 @@ SYM_CODE_START_NOALIGN(tramp_vectors)
generate_tramp_vector kpti=1, bhb=BHB_MITIGATION_NONE
SYM_CODE_END(tramp_vectors)
-SYM_CODE_START(tramp_exit_native)
- tramp_exit
-SYM_CODE_END(tramp_exit_native)
+SYM_CODE_START_LOCAL(tramp_exit)
+ tramp_unmap_kernel x29
+ mrs x29, far_el1 // restore x29
+ eret
+ sb
+SYM_CODE_END(tramp_exit)
.popsection // .entry.tramp.text
#endif /* CONFIG_UNMAP_KERNEL_AT_EL0 */
@@ -1067,7 +1060,7 @@ alternative_if_not ARM64_UNMAP_KERNEL_AT_EL0
alternative_else_nop_endif
#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
- tramp_alias dst=x5, sym=__sdei_asm_exit_trampoline, tmp=x3
+ tramp_alias dst=x5, sym=__sdei_asm_exit_trampoline
br x5
#endif
SYM_CODE_END(__sdei_asm_handler)
The tramp_alias macro constructs the virtual alias of a symbol in the trampoline text mapping, based on its kernel text address, and does so in a way that is more convoluted than necessary. So let's simplify that. Also, now that the address of the vector table is kept in a per-CPU variable, there is no need to defer the load and the assignment of VBAR_EL1 to tramp_exit(). This means we can use a PC-relative reference to the per-CPU variable instead of storing its absolute address in a global variable in the trampoline rodata. And given that tramp_alias no longer needs a temp register, this means we can restore X30 earlier as well, and only leave X29 for tramp_exit() to restore. While at it, give some related symbols static linkage, considering that they are only referenced from the object file that defines them. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> --- arch/arm64/kernel/entry.S | 47 +++++++++----------- 1 file changed, 20 insertions(+), 27 deletions(-)