renegade-project/linux-next
2
0
Fork 0
mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-22 20:23:57 +08:00
Code

powerpc/64s/exception: Remove lite interrupt return

Browse Source 
Regular interrupt return restores NVGPRS whereas lite returns do not.
This is clumsy: most interrupts can return without restoring NVGPRS in
most of the time, but there are special cases that require it (when
registers have been modified by the kernel). So change interrupt
return to not restore NVGPRS, and have interrupt handlers restore them
explicitly in the cases that requires it.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200225173541.1549955-30-npiggin@gmail.com
This commit is contained in:
Nicholas Piggin 2020-02-26 03:35:38 +10:00 committed by Michael Ellerman
parent 6cc0c16d82
commit 702f098052
2 changed files with 14 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
arch/powerpc/kernel/entry_64.S
View File

@ -479,12 +479,6 @@ _ASM_NOKPROBE_SYMBOL(fast_interrupt_return)
.globl interrupt_return
interrupt_return:
_ASM_NOKPROBE_SYMBOL(interrupt_return)
REST_NVGPRS(r1)
.balign IFETCH_ALIGN_BYTES
.globl interrupt_return_lite
interrupt_return_lite:
_ASM_NOKPROBE_SYMBOL(interrupt_return_lite)
ld r4,_MSR(r1)
andi. r0,r4,MSR_PR
beq .Lkernel_interrupt_return

24
arch/powerpc/kernel/exceptions-64s.S
View File

@ -1529,7 +1529,7 @@ EXC_COMMON_BEGIN(hardware_interrupt_common)
RUNLATCH_ON
addi r3,r1,STACK_FRAME_OVERHEAD
bl do_IRQ
b interrupt_return_lite
b interrupt_return
GEN_KVM hardware_interrupt
@ -1557,6 +1557,7 @@ EXC_COMMON_BEGIN(alignment_common)
GEN_COMMON alignment
addi r3,r1,STACK_FRAME_OVERHEAD
bl alignment_exception
REST_NVGPRS(r1) /* instruction emulation may change GPRs */
b interrupt_return
GEN_KVM alignment
@ -1620,6 +1621,7 @@ EXC_COMMON_BEGIN(program_check_common)
3:
addi r3,r1,STACK_FRAME_OVERHEAD
bl program_check_exception
REST_NVGPRS(r1) /* instruction emulation may change GPRs */
b interrupt_return
GEN_KVM program_check
@ -1716,7 +1718,7 @@ EXC_COMMON_BEGIN(decrementer_common)
RUNLATCH_ON
addi r3,r1,STACK_FRAME_OVERHEAD
bl timer_interrupt
b interrupt_return_lite
b interrupt_return
GEN_KVM decrementer
@ -1807,7 +1809,7 @@ EXC_COMMON_BEGIN(doorbell_super_common)
#else
bl unknown_exception
#endif
b interrupt_return_lite
b interrupt_return
GEN_KVM doorbell_super
@ -2076,6 +2078,7 @@ EXC_COMMON_BEGIN(emulation_assist_common)
GEN_COMMON emulation_assist
addi r3,r1,STACK_FRAME_OVERHEAD
bl emulation_assist_interrupt
REST_NVGPRS(r1) /* instruction emulation may change GPRs */
b interrupt_return
GEN_KVM emulation_assist
@ -2194,7 +2197,7 @@ EXC_COMMON_BEGIN(h_doorbell_common)
#else
bl unknown_exception
#endif
b interrupt_return_lite
b interrupt_return
GEN_KVM h_doorbell
@ -2224,7 +2227,7 @@ EXC_COMMON_BEGIN(h_virt_irq_common)
RUNLATCH_ON
addi r3,r1,STACK_FRAME_OVERHEAD
bl do_IRQ
b interrupt_return_lite
b interrupt_return
GEN_KVM h_virt_irq
@ -2271,7 +2274,7 @@ EXC_COMMON_BEGIN(performance_monitor_common)
RUNLATCH_ON
addi r3,r1,STACK_FRAME_OVERHEAD
bl performance_monitor_exception
b interrupt_return_lite
b interrupt_return
GEN_KVM performance_monitor
@ -2668,6 +2671,7 @@ EXC_COMMON_BEGIN(altivec_assist_common)
addi r3,r1,STACK_FRAME_OVERHEAD
#ifdef CONFIG_ALTIVEC
bl altivec_assist_exception
REST_NVGPRS(r1) /* instruction emulation may change GPRs */
#else
bl unknown_exception
#endif
@ -3057,7 +3061,7 @@ do_hash_page:
cmpdi r3,0 /* see if __hash_page succeeded */
/* Success */
beq interrupt_return_lite /* Return from exception on success */
beq interrupt_return /* Return from exception on success */
/* Error */
blt- 13f
@ -3074,7 +3078,7 @@ handle_page_fault:
addi r3,r1,STACK_FRAME_OVERHEAD
bl do_page_fault
cmpdi r3,0
beq+ interrupt_return_lite
beq+ interrupt_return
mr r5,r3
addi r3,r1,STACK_FRAME_OVERHEAD
ld r4,_DAR(r1)
@ -3089,9 +3093,9 @@ handle_dabr_fault:
bl do_break
/*
* do_break() may have changed the NV GPRS while handling a breakpoint.
* If so, we need to restore them with their updated values. Don't use
* interrupt_return_lite here.
* If so, we need to restore them with their updated values.
*/
REST_NVGPRS(r1)
b interrupt_return