xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

sh: Fix up DSP context save/restore.

Browse Source 
There were a number of issues with the DSP context save/restore code,
mostly left-over relics from when it was introduced on SH3-DSP with
little follow-up testing, resulting in things like task_pt_dspregs()
referencing incorrect state on the stack.

This follows the MIPS convention of tracking the DSP state in the
thread_struct and handling the state save/restore in switch_to() and
finish_arch_switch() respectively. The regset interface is also updated,
which allows us to finally be rid of task_pt_dspregs() and the special
cased task_pt_regs().

Signed-off-by: Michael Trimarchi <michael@evidence.eu.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This commit is contained in:
Michael Trimarchi
2009-04-03 17:32:33 +00:00
committed by Paul Mundt
parent a27873cd23
commit 01ab10393c
7 changed files with 161 additions and 137 deletions
Download Patch File Download Diff File Expand all files Collapse all files

85
arch/sh/kernel/cpu/sh3/entry.S
View File

@@ -254,40 +254,6 @@ restore_all:
lds k2, pr ! restore pr
!
#ifdef CONFIG_SH_DSP
mov.l @r15+, k0 ! DSP mode marker
mov.l 5f, k1
cmp/eq k0, k1 ! Do we have a DSP stack frame?
bf skip_restore
stc sr, k0 ! Enable CPU DSP mode
or k1, k0 ! (within kernel it may be disabled)
ldc k0, sr
mov r2, k0 ! Backup r2
! Restore DSP registers from stack
mov r15, r2
movs.l @r2+, a1
movs.l @r2+, a0g
movs.l @r2+, a1g
movs.l @r2+, m0
movs.l @r2+, m1
mov r2, r15
lds.l @r15+, a0
lds.l @r15+, x0
lds.l @r15+, x1
lds.l @r15+, y0
lds.l @r15+, y1
lds.l @r15+, dsr
ldc.l @r15+, rs
ldc.l @r15+, re
ldc.l @r15+, mod
mov k0, r2 ! Restore r2
skip_restore:
#endif
!
! Calculate new SR value
mov k3, k2 ! original SR value
mov #0xf0, k1
@@ -358,7 +324,7 @@ general_exception:
add k0, k4
0:
! Setup stack and save DSP context (k0 contains original r15 on return)
bsr prepare_stack_save_dsp
bsr prepare_stack
nop
! Save registers / Switch to bank 0
@@ -374,15 +340,14 @@ general_exception:
1: .long EXPEVT
#endif
! prepare_stack_save_dsp()
! prepare_stack()
! - roll back gRB
! - switch to kernel stack
! - save DSP
! k0 returns original sp (after roll back)
! k1 trashed
! k2 trashed
prepare_stack_save_dsp:
prepare_stack:
#ifdef CONFIG_GUSA
! Check for roll back gRB (User and Kernel)
mov r15, k0
@@ -416,47 +381,9 @@ prepare_stack_save_dsp:
mov k1, r15 ! change to kernel stack
!
1:
#ifdef CONFIG_SH_DSP
! Save DSP context if needed
stc sr, k1
mov #0x10, k2
shll8 k2 ! DSP=1 (0x00001000)
tst k2, k1 ! Check if in DSP mode (passed in k2)
bt/s skip_save
mov #0, k1 ! Set marker for no stack frame
mov k2, k1 ! Save has-frame marker
! Save DSP registers on stack
stc.l mod, @-r15
stc.l re, @-r15
stc.l rs, @-r15
sts.l dsr, @-r15
sts.l y1, @-r15
sts.l y0, @-r15
sts.l x1, @-r15
sts.l x0, @-r15
sts.l a0, @-r15
! GAS is broken, does not generate correct "movs.l Ds,@-As" instr.
! FIXME: Make sure that this is still the case with newer toolchains,
! as we're not at all interested in supporting ancient toolchains at
! this point. -- PFM.
mov r15, k2
.word 0xf653 ! movs.l a1, @-r2
.word 0xf6f3 ! movs.l a0g, @-r2
.word 0xf6d3 ! movs.l a1g, @-r2
.word 0xf6c3 ! movs.l m0, @-r2
.word 0xf6e3 ! movs.l m1, @-r2
mov k2, r15
skip_save:
mov.l k1, @-r15 ! Push DSP mode marker onto stack
#endif
rts
nop
!
! 0x400: Instruction and Data TLB miss exception vector
!
@@ -468,7 +395,7 @@ handle_exception:
mova exception_data, k0
! Setup stack and save DSP context (k0 contains original r15 on return)
bsr prepare_stack_save_dsp
bsr prepare_stack
PREF(k0)
! Save registers / Switch to bank 0
@@ -572,7 +499,7 @@ ENTRY(handle_interrupt)
mova exception_data, k0
! Setup stack and save DSP context (k0 contains original r15 on return)
bsr prepare_stack_save_dsp
bsr prepare_stack
PREF(k0)
! Save registers / Switch to bank 0