system/linux
system/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux synced 2024-10-18 09:18:26 +00:00
Code Issues Packages Projects Releases Wiki Activity

powerpc/64e/interrupt: Fix nvgprs being clobbered

Browse source 
Some interrupt handlers have an "extra" that saves 1 or 2
registers (r14, r15) in the paca save area and makes them available to
use by the handler.

The change to always save nvgprs in exception handlers lead to some
interrupt handlers saving those scratch r14 / r15 registers into the
interrupt frame's GPR saves, which get restored on interrupt exit.

Fix this by always reloading those scratch registers from paca before
the EXCEPTION_COMMON that saves nvgprs.

Fixes: 4228b2c3d2 ("powerpc/64e/interrupt: always save nvgprs on interrupt")
Reported-by: Christian Zigotzky <chzigotzky@xenosoft.de>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Tested-by: Christian Zigotzky <chzigotzky@xenosoft.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210514044008.1955783-1-npiggin@gmail.com
This commit is contained in:
Nicholas Piggin 2021-05-14 14:40:08 +10:00 committed by Michael Ellerman
parent 4ec5feec1a
commit c6ac667b07
1 changed files with 24 additions and 14 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

38
arch/powerpc/kernel/exceptions-64e.S
View file

@ -340,6 +340,12 @@ ret_from_mc_except:
andi. r10,r10,IRQS_DISABLED; /* yes -> go out of line */ \
bne masked_interrupt_book3e_##n
/*
* Additional regs must be re-loaded from paca before EXCEPTION_COMMON* is
* called, because that does SAVE_NVGPRS which must see the original register
* values, otherwise the scratch values might be restored when exiting the
* interrupt.
*/
#define PROLOG_ADDITION_2REGS_GEN(n) \
std r14,PACA_EXGEN+EX_R14(r13); \
std r15,PACA_EXGEN+EX_R15(r13)
@ -535,6 +541,10 @@ __end_interrupts:
PROLOG_ADDITION_2REGS)
mfspr r14,SPRN_DEAR
mfspr r15,SPRN_ESR
std r14,_DAR(r1)
std r15,_DSISR(r1)
ld r14,PACA_EXGEN+EX_R14(r13)
ld r15,PACA_EXGEN+EX_R15(r13)
EXCEPTION_COMMON(0x300)
b storage_fault_common
@ -544,6 +554,10 @@ __end_interrupts:
PROLOG_ADDITION_2REGS)
li r15,0
mr r14,r10
std r14,_DAR(r1)
std r15,_DSISR(r1)
ld r14,PACA_EXGEN+EX_R14(r13)
ld r15,PACA_EXGEN+EX_R15(r13)
EXCEPTION_COMMON(0x400)
b storage_fault_common
@ -557,6 +571,10 @@ __end_interrupts:
PROLOG_ADDITION_2REGS)
mfspr r14,SPRN_DEAR
mfspr r15,SPRN_ESR
std r14,_DAR(r1)
std r15,_DSISR(r1)
ld r14,PACA_EXGEN+EX_R14(r13)
ld r15,PACA_EXGEN+EX_R15(r13)
EXCEPTION_COMMON(0x600)
b alignment_more /* no room, go out of line */
@ -565,10 +583,10 @@ __end_interrupts:
NORMAL_EXCEPTION_PROLOG(0x700, BOOKE_INTERRUPT_PROGRAM,
PROLOG_ADDITION_1REG)
mfspr r14,SPRN_ESR
EXCEPTION_COMMON(0x700)
std r14,_DSISR(r1)
addi r3,r1,STACK_FRAME_OVERHEAD
ld r14,PACA_EXGEN+EX_R14(r13)
EXCEPTION_COMMON(0x700)
addi r3,r1,STACK_FRAME_OVERHEAD
bl program_check_exception
REST_NVGPRS(r1)
b interrupt_return
@ -725,11 +743,11 @@ END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
* normal exception
*/
mfspr r14,SPRN_DBSR
EXCEPTION_COMMON_CRIT(0xd00)
std r14,_DSISR(r1)
addi r3,r1,STACK_FRAME_OVERHEAD
ld r14,PACA_EXCRIT+EX_R14(r13)
ld r15,PACA_EXCRIT+EX_R15(r13)
EXCEPTION_COMMON_CRIT(0xd00)
addi r3,r1,STACK_FRAME_OVERHEAD
bl DebugException
REST_NVGPRS(r1)
b interrupt_return
@ -796,11 +814,11 @@ kernel_dbg_exc:
* normal exception
*/
mfspr r14,SPRN_DBSR
EXCEPTION_COMMON_DBG(0xd08)
std r14,_DSISR(r1)
addi r3,r1,STACK_FRAME_OVERHEAD
ld r14,PACA_EXDBG+EX_R14(r13)
ld r15,PACA_EXDBG+EX_R15(r13)
EXCEPTION_COMMON_DBG(0xd08)
addi r3,r1,STACK_FRAME_OVERHEAD
bl DebugException
REST_NVGPRS(r1)
b interrupt_return
@ -931,11 +949,7 @@ masked_interrupt_book3e_0x2c0:
* original values stashed away in the PACA
*/
storage_fault_common:
std r14,_DAR(r1)
std r15,_DSISR(r1)
addi r3,r1,STACK_FRAME_OVERHEAD
ld r14,PACA_EXGEN+EX_R14(r13)
ld r15,PACA_EXGEN+EX_R15(r13)
bl do_page_fault
b interrupt_return
@ -944,11 +958,7 @@ storage_fault_common:
* continues here.
*/
alignment_more:
std r14,_DAR(r1)
std r15,_DSISR(r1)
addi r3,r1,STACK_FRAME_OVERHEAD
ld r14,PACA_EXGEN+EX_R14(r13)
ld r15,PACA_EXGEN+EX_R15(r13)
bl alignment_exception
REST_NVGPRS(r1)
b interrupt_return