diff options
| author | Christophe Leroy <christophe.leroy@csgroup.eu> | 2021-03-12 12:50:40 +0000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2021-03-29 13:22:09 +1100 |
| commit | 8f6ff5bd9b73a7912356f378adfb85e9a4e7ce65 (patch) | |
| tree | a46116ee5ec3a157e42a87c64a4578c9c765af0b /arch/powerpc/kernel/head_8xx.S | |
| parent | bce4c26a4e324cb096a3768cdc3aad4e2552c3d0 (diff) | |
powerpc/32: Only restore non volatile registers when required
Until now, non volatile registers were restored everytime they
were saved, ie using EXC_XFER_STD meant saving and restoring
them while EXC_XFER_LITE meant neither saving not restoring them.
Now that they are always saved, EXC_XFER_STD means to restore
them and EXC_XFER_LITE means to not restore them.
Most of the users of EXC_XFER_STD only need to retrieve the
non volatile registers. For them there is no need to restore
the non volatile registers as they have not been modified.
Only very few exceptions require non volatile registers restore.
Opencode the few places which require saving of non volatile
registers.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/d1cb12d8023cc6afc1f07150565571373c04945c.1615552867.git.christophe.leroy@csgroup.eu
Diffstat (limited to 'arch/powerpc/kernel/head_8xx.S')
| -rw-r--r-- | arch/powerpc/kernel/head_8xx.S | 24 |
1 files changed, 20 insertions, 4 deletions
diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S index c48de97f42fc..86f844eb0e5a 100644 --- a/arch/powerpc/kernel/head_8xx.S +++ b/arch/powerpc/kernel/head_8xx.S @@ -131,10 +131,18 @@ instruction_counter: /* Alignment exception */ START_EXCEPTION(0x600, Alignment) EXCEPTION_PROLOG 0x600 Alignment handle_dar_dsisr=1 - EXC_XFER_STD(0x600, alignment_exception) + prepare_transfer_to_handler + bl alignment_exception + REST_NVGPRS(r1) + b interrupt_return /* Program check exception */ - EXCEPTION(0x700, ProgramCheck, program_check_exception, EXC_XFER_STD) + START_EXCEPTION(0x700, ProgramCheck) + EXCEPTION_PROLOG 0x700 ProgramCheck + prepare_transfer_to_handler + bl program_check_exception + REST_NVGPRS(r1) + b interrupt_return /* Decrementer */ EXCEPTION(0x900, Decrementer, timer_interrupt, EXC_XFER_LITE) @@ -149,7 +157,12 @@ instruction_counter: /* On the MPC8xx, this is a software emulation interrupt. It occurs * for all unimplemented and illegal instructions. */ - EXCEPTION(0x1000, SoftEmu, emulation_assist_interrupt, EXC_XFER_STD) + START_EXCEPTION(0x1000, SoftEmu) + EXCEPTION_PROLOG 0x1000 SoftEmu + prepare_transfer_to_handler + bl emulation_assist_interrupt + REST_NVGPRS(r1) + b interrupt_return /* * For the MPC8xx, this is a software tablewalk to load the instruction @@ -348,7 +361,10 @@ DARFixed:/* Return from dcbx instruction bug workaround */ EXCEPTION_PROLOG_2 0x1c00 DataBreakpoint handle_dar_dsisr=1 mfspr r4,SPRN_BAR stw r4,_DAR(r11) - EXC_XFER_STD(0x1c00, do_break) + prepare_transfer_to_handler + bl do_break + REST_NVGPRS(r1) + b interrupt_return #ifdef CONFIG_PERF_EVENTS START_EXCEPTION(0x1d00, InstructionBreakpoint) |