evie/android_kernel_oneplus_msm8998
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

FROMLIST: arm64: entry: Hook up entry trampoline to exception vectors

Browse source 
Hook up the entry trampoline to our exception vectors so that all
exceptions from and returns to EL0 go via the trampoline, which swizzles
the vector base register accordingly. Transitioning to and from the
kernel clobbers x30, so we use tpidrro_el0 and far_el1 as scratch
registers for native tasks.

Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Tested-by: Shanker Donthineni <shankerd@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
(cherry picked from git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git
 commit 4bf3286d29f3a88425d8d8cd53428cbb8f865f04)

Change-Id: Id1e175bdaa0ec2bf8e59f941502183907902a710
[ghackmann@google.com: adjust context, replacing
 alternative_if_not ARM64_WORKAROUND_845719 block with upstream version]
Signed-off-by: Greg Hackmann <ghackmann@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
This commit is contained in:
Will Deacon 2017-11-14 14:24:29 +00:00 • committed by Greg Kroah-Hartman
parent 3dcb846744
commit 75f5a2df1d
1 changed files with 38 additions and 11 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

49
arch/arm64/kernel/entry.S
View file

@ -73,10 +73,26 @@
.macro kernel_ventry, el, label, regsize = 64
.align 7
#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
.if \el == 0
.if \regsize == 64
mrs x30, tpidrro_el0
msr tpidrro_el0, xzr
.else
mov x30, xzr
.endif
.endif
#endif
sub sp, sp, #S_FRAME_SIZE
b el\()\el\()_\label
.endm
.macro tramp_alias, dst, sym
mov_q \dst, TRAMP_VALIAS
add \dst, \dst, #(\sym - .entry.tramp.text)
.endm
.macro kernel_entry, el, regsize = 64
.if \regsize == 32
mov w0, w0 // zero upper 32 bits of x0
@ -235,24 +251,20 @@ alternative_else_nop_endif
.if \el == 0
ldr x23, [sp, #S_SP] // load return stack pointer
msr sp_el0, x23
tst x22, #PSR_MODE32_BIT // native task?
b.eq 3f
#ifdef CONFIG_ARM64_ERRATUM_845719
alternative_if_not ARM64_WORKAROUND_845719
nop
nop
#ifdef CONFIG_PID_IN_CONTEXTIDR
nop
#endif
alternative_else
tbz x22, #4, 1f
alternative_if ARM64_WORKAROUND_845719
#ifdef CONFIG_PID_IN_CONTEXTIDR
mrs x29, contextidr_el1
msr contextidr_el1, x29
#else
msr contextidr_el1, xzr
#endif
1:
alternative_endif
alternative_else_nop_endif
#endif
3:
.endif
msr elr_el1, x21 // set up the return data
@ -274,7 +286,22 @@ alternative_endif
ldp x28, x29, [sp, #16 * 14]
ldr lr, [sp, #S_LR]
add sp, sp, #S_FRAME_SIZE // restore sp
eret // return to kernel
#ifndef CONFIG_UNMAP_KERNEL_AT_EL0
eret
#else
.if \el == 0
bne 4f
msr far_el1, x30
tramp_alias x30, tramp_exit_native
br x30
4:
tramp_alias x30, tramp_exit_compat
br x30
.else
eret
.endif
#endif
.endm
.macro irq_stack_entry