diff options
| author |   Christophe Leroy <christophe.leroy@c-s.fr> | 2019-03-11 08:30:31 +0000 |
|---|---|---|
| committer |   Michael Ellerman <mpe@ellerman.id.au> | 2019-04-21 23:11:46 +1000 |
| commit | e2fb9f5444312fd01627c84a3e018c1fe8ac6ebb (patch) | |
| tree | d199c5ba49c2e30fff0d9722a4522b28c5f6959f /arch/powerpc/kernel/entry_32.S | |
| parent | powerpc/32: Remove MSR_PR test when returning from syscall (diff) | |
| download | linux-dev-e2fb9f5444312fd01627c84a3e018c1fe8ac6ebb.tar.xz linux-dev-e2fb9f5444312fd01627c84a3e018c1fe8ac6ebb.zip | |
powerpc/32: Prepare for Kernel Userspace Access Protection
This patch adds ASM macros for saving, restoring and checking
the KUAP state, and modifies setup_32 to call them on exceptions
from kernel.
The macros are defined as empty by default for when CONFIG_PPC_KUAP
is not selected and/or for platforms which don't handle (yet) KUAP.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/kernel/entry_32.S')
| -rw-r--r-- | arch/powerpc/kernel/entry_32.S | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S index aaf7c5f44823..1182bf603d3c 100644 --- a/arch/powerpc/kernel/entry_32.S +++ b/arch/powerpc/kernel/entry_32.S @@ -36,6 +36,7 @@ #include <asm/asm-405.h> #include <asm/feature-fixups.h> #include <asm/barrier.h> +#include <asm/kup.h> /* * MSR_KERNEL is > 0x10000 on 4xx/Book-E since it include MSR_CE. @@ -150,8 +151,8 @@ transfer_to_handler: stw r12,_CTR(r11) stw r2,_XER(r11) mfspr r12,SPRN_SPRG_THREAD - addi r2,r12,-THREAD beq 2f /* if from user, fix up THREAD.regs */ + addi r2, r12, -THREAD addi r11,r1,STACK_FRAME_OVERHEAD stw r11,PT_REGS(r12) #if defined(CONFIG_40x) || defined(CONFIG_BOOKE) @@ -186,6 +187,8 @@ transfer_to_handler: 2: /* if from kernel, check interrupted DOZE/NAP mode and * check for stack overflow */ + kuap_save_and_lock r11, r12, r9, r2, r0 + addi r2, r12, -THREAD lwz r9,KSP_LIMIT(r12) cmplw r1,r9 /* if r1 <= ksp_limit */ ble- stack_ovf /* then the kernel stack overflowed */ @@ -272,6 +275,7 @@ reenable_mmu: /* re-enable mmu so we can */ lwz r9,_MSR(r11) /* if sleeping, clear MSR.EE */ rlwinm r9,r9,0,~MSR_EE lwz r12,_LINK(r11) /* and return to address in LR */ + kuap_restore r11, r2, r3, r4, r5 b fast_exception_return #endif @@ -423,6 +427,7 @@ BEGIN_FTR_SECTION END_FTR_SECTION_IFSET(CPU_FTR_NEED_PAIRED_STWCX) stwcx. r0,0,r1 /* to clear the reservation */ ACCOUNT_CPU_USER_EXIT(r2, r5, r7) + kuap_check r2, r4 lwz r4,_LINK(r1) lwz r5,_CCR(r1) mtlr r4 @@ -673,6 +678,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_SPE) stw r10,_CCR(r1) stw r1,KSP(r3) /* Set old stack pointer */ + kuap_check r2, r4 #ifdef CONFIG_SMP /* We need a sync somewhere here to make sure that if the * previous task gets rescheduled on another CPU, it sees all @@ -861,12 +867,12 @@ resume_kernel: /* check current_thread_info->preempt_count */ lwz r0,TI_PREEMPT(r2) cmpwi 0,r0,0 /* if non-zero, just restore regs and return */ - bne restore + bne restore_kuap andi. r8,r8,_TIF_NEED_RESCHED - beq+ restore + beq+ restore_kuap lwz r3,_MSR(r1) andi. r0,r3,MSR_EE /* interrupts off? */ - beq restore /* don't schedule if so */ + beq restore_kuap /* don't schedule if so */ #ifdef CONFIG_TRACE_IRQFLAGS /* Lockdep thinks irqs are enabled, we need to call * preempt_schedule_irq with IRQs off, so we inform lockdep @@ -885,6 +891,8 @@ resume_kernel: bl trace_hardirqs_on #endif #endif /* CONFIG_PREEMPT */ +restore_kuap: + kuap_restore r1, r2, r9, r10, r0 /* interrupts are hard-disabled at this point */ restore: |