diff options
| author | Christophe Leroy <christophe.leroy@csgroup.eu> | 2021-03-12 12:50:15 +0000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2021-03-29 13:22:03 +1100 |
| commit | 0fc1e93481f67a49f67c9168b71842eeb0998b25 (patch) | |
| tree | 7d2e62db7ac9b60cf9e481f1f826f6a11ec3c6ea /arch/powerpc/kernel/head_40x.S | |
| parent | 26c468860c32022ffe9caf16691764b77fb8eead (diff) | |
powerpc/40x: Prepare for enabling MMU in critical exception prolog
In order the enable MMU early in exception prolog, implement
CONFIG_VMAP_STACK principles in critical exception prolog.
There is no intention to use CONFIG_VMAP_STACK on 40x,
but related code will be used to enable MMU early in exception
in a later patch.
Also address (critirq_ctx - PAGE_OFFSET) directly instead of
using tophys() in order to win one instruction.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/3fd75ee54c48307119acdbf66cfea966c1463bbd.1615552866.git.christophe.leroy@csgroup.eu
Diffstat (limited to 'arch/powerpc/kernel/head_40x.S')
| -rw-r--r-- | arch/powerpc/kernel/head_40x.S | 40 |
1 files changed, 37 insertions, 3 deletions
diff --git a/arch/powerpc/kernel/head_40x.S b/arch/powerpc/kernel/head_40x.S index 5b337bf49bcb..1468f38c3860 100644 --- a/arch/powerpc/kernel/head_40x.S +++ b/arch/powerpc/kernel/head_40x.S @@ -89,6 +89,12 @@ _ENTRY(crit_srr0) .space 4 _ENTRY(crit_srr1) .space 4 +_ENTRY(crit_r1) + .space 4 +_ENTRY(crit_dear) + .space 4 +_ENTRY(crit_esr) + .space 4 _ENTRY(saved_ksp_limit) .space 4 @@ -107,32 +113,60 @@ _ENTRY(saved_ksp_limit) mfspr r11,SPRN_SRR1 stw r10,crit_srr0@l(0) stw r11,crit_srr1@l(0) +#ifdef CONFIG_VMAP_STACK + mfspr r10,SPRN_DEAR + mfspr r11,SPRN_ESR + stw r10,crit_dear@l(0) + stw r11,crit_esr@l(0) +#endif mfcr r10 /* save CR in r10 for now */ mfspr r11,SPRN_SRR3 /* check whether user or kernel */ andi. r11,r11,MSR_PR - lis r11,critirq_ctx@ha - tophys(r11,r11) - lwz r11,critirq_ctx@l(r11) + lis r11,(critirq_ctx-PAGE_OFFSET)@ha + lwz r11,(critirq_ctx-PAGE_OFFSET)@l(r11) beq 1f /* COMING FROM USER MODE */ mfspr r11,SPRN_SPRG_THREAD /* if from user, start at top of */ lwz r11,TASK_STACK-THREAD(r11) /* this thread's kernel stack */ +#ifdef CONFIG_VMAP_STACK +1: stw r1,crit_r1@l(0) + addi r1,r11,THREAD_SIZE-INT_FRAME_SIZE /* Alloc an excpt frm */ + LOAD_REG_IMMEDIATE(r11,MSR_KERNEL & ~(MSR_IR | MSR_RI)) + mtmsr r11 + isync + lwz r11,crit_r1@l(0) + stw r11,GPR1(r1) + stw r11,0(r1) + mr r11,r1 +#else 1: addi r11,r11,THREAD_SIZE-INT_FRAME_SIZE /* Alloc an excpt frm */ tophys(r11,r11) stw r1,GPR1(r11) stw r1,0(r11) tovirt(r1,r11) +#endif stw r10,_CCR(r11) /* save various registers */ stw r12,GPR12(r11) stw r9,GPR9(r11) mflr r10 stw r10,_LINK(r11) +#ifdef CONFIG_VMAP_STACK + lis r9,PAGE_OFFSET@ha + lwz r10,crit_r10@l(r9) + lwz r12,crit_r11@l(r9) +#else lwz r10,crit_r10@l(0) lwz r12,crit_r11@l(0) +#endif stw r10,GPR10(r11) stw r12,GPR11(r11) +#ifdef CONFIG_VMAP_STACK + lwz r12,crit_dear@l(r9) + lwz r9,crit_esr@l(r9) +#else mfspr r12,SPRN_DEAR /* save DEAR and ESR in the frame */ mfspr r9,SPRN_ESR /* in them at the point where the */ +#endif stw r12,_DEAR(r11) /* since they may have had stuff */ stw r9,_ESR(r11) /* exception was taken */ mfspr r12,SPRN_SRR2 |